-->Physiology and Ecology

Phenotypic and genetic diversity of sugarcane ( Saccharum L. )protospecies and landraces

2015/12/14 15:20:34

In order to explore genetic diversity and relationship among different sugarcane species,select excellent sugarcane germplasm and parental combination for hybridization,the present study was conducted for genetic diversity analysis using 18 genotypes of protospecies and landraces of sugarcane(Saccharum spp.)with 14 quantitative traits. The results showed that the phenotypic and genetic diversity of sugarcane was highly significant in sucrose% cane,stalk weight,leaf width,stalk diameter and fiber% cane by coefficient of variation and correlation analysis of 14 quantitative traits. Four principal components of quantitative traits named quality factor,growth factor,maturity factor and photosynthetic factor,respectively,were extracted from principal component analysis, and the cumulative contribution rate of four principal components was 83.48%. Ten desirable genotypes of sugarcane had higher values of quantitative traits than the averages in factor analysis in turn as follows:Sampana→Tiangeda→Heqingcao Ganzhe→Guilin Zhuzhe→Tanzania→Mango→Guzhizhe→Dadaozailai→Tuojianghong→Chunnee. The 18 accessions could be divided into five clusters based on the genetic distance,and potential hybrid may be developed by crossing Sampana with Tiangeda and/or Sampana with Heqingcao Ganzhe. It suggested that we should not only consider the complementary of main traits,but also genetic distance when we select parents for crossing in sugarcane breeding. The present study proved that factor analysis was good to help the parental selection and determine crossing combinations in sugarcane breeding program.

Triterpene biosynthesis in Euphorbia pekinensis induced by methyl jasmonate

2015/12/14 15:20:35

Euphorbia pekinensis is a perennial herb. The part of medicine is the dried root and is our traditional Chinese medicine. E. pekinensis have distributed in many provinces in China except for Tibet and Xinjiang. In recent years, medicine studies have showed that it can also be used on carbuncle swollen,sore-toxin,etc. So there are an increasing number of people who pay attention to it nowadays and later greatly exploit and unearth to it. But E. pekinensis with dried roots need many years cultivation and the deterioration of environmental pollution problem leads to the resources become more and more deficient. Therefore, many research workers faced the problem that how to relieve the resource tension of E. pekinensis. This is an important topic in development and utilization of the medicinal plant resources and it is also a huge challenge to science research personnel. Modern research shows that E. pekinensis mainly contains the active ingredient of three terpenoids, two terpenoids, flavonoids, alkaloids, organic acid, ect. The effective components of some commom medicinal plants are the three terpenoids and they have good activity in antiviral,antitumor,immune regulation and so on. So the terpenoids of Euphorbia pekinensis plays an important role in disease treatment. With the rapid development of molecular biology and the increasingly research in technology, the plant terpenoid metabolism pathway has been well studied. Now the key enzymes such as hmgr,sqs and fps play an important role in the metabolic flow. Now the researcher has made greatly progress in gene clone and activity research. But there are few reports in controlling the expression of the key enzyme of terpenoid metabolic pathway to induce the synthesis of terpenoids. Therefore,it is significantly important to study the metabolic pathway of the terpenoid synthesis in E. pekinensis and use the means of gene engineering and technology to greatly increase the output of target product in order to solve the problem of the shortage in medicinal resource of E. pekinensis. In this study, the callus of E. pekinensis was induced by methyl jasmonate with different concentrations in different treatment times. These treated calluses were respectively divided into two parts: one was used to extract total RNA,then reverse-transcribed to cDNA,transcript levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase(hmgr),farnesyl pyrophosphate synthase(fps)and squalene synthase(sqs)were determined by quantitative real-time PCR using actin gene as internal reference. The other part was used to extract triterpenoids whose content was detected by spectrophotometry. The results of quantitative real-time PCR showed that methyl jasmonate could induce the expression of these three genes,but the expression patterns were different. The result of total triterpenoids detection showed that methyl jasmonate induced the accumulation of total triterpenoids up to 27% compared with untreated sample. These results would afford the reference for the research on the molecular mechanism that methyl jasmonate promotes the accumulation of total triterpenoids.

Effects of fertilization on nutrient concentrations of different root orders' fine roots in Cinnamomum camphora seedings

2015/12/14 15:20:30

Setting one-yearold potted Cinnmomum camphora seedlings as the research object, using exponential fertilization method, we detected the first to the fifth order fine roots C, N and P contents, in order to explore the effects of fertilization on C. camphora seedlings, and to provide a theoretical basis for C. camphor fast growing and efficient use of resources in nurturing process. The results were as follows:(1)C concentrations of the differences orders' fine root were not significant, with the rise of the root order, while C content overall upward trend. Fertilization had no significant effect on the C concentration of fine root(P>0.05);(2)N and P concentrations of first order roots were the maximum, while fifth order roots were the minimum, with the rise of root orders. N and P concentrations significantly decreased(P<0.05);(3)N significantly increased the N content level of the first to the second fine roots, P fertilizer significantly increased the P content of a root, mix of nitrogen and phosphorus fertilizer could improve the root uptake of P;(4)C:N:P had a significant difference in different root orders roots;(5)The first order roots' mean C:N:P was 366:16:1, the fifth order root 807:12:1, with increased root order, C ratio of three kinds of elements increased significantly, while the N:P changed little;(6)Fertilization did not change the proportion of C; however, N fertilizer or mix of nitrogen and phosphorus fertilizer significantly increased the N proportion of the first to second order roots. In conclusion: The treatment 9 pairs of C. camphor on seedling stage indicators impact most significantly. A fertilizer with the nitrogen 4 g·plant^-1, the phosphorus 4 g·plant^-1 and the potassium 2 g·plant^-1, would have significant promote growing for growing and development of fine roots in C. camphor seedlings.

Influence of soil covered cultivation on shoot quality of Phyllostachys prominens

2015/12/14 15:20:30

To enhance the shoot quality and economic profit, appearance quality, content of nutrient, flavour substance and amino acid in Phyllostachys prominens shoot from soil covered bamboo cultivation stand(one-year soil covered stand, two-year soil covered stand and non-covered stand)were investigated, and effects of soil covered cultivation on shoot quality and palatability were also analyzed. The results showed that compared to non-covered stand, individual weight increased by 107.58% for one-year soil covered stand and 165.73% for two-year soil covered stand, while edible parts ratios increased by 8.77% for one-year soil covered stand and 13.63% for two-year soil covered stand. Furthermore, there was significant difference among different soil-covered stand on individual weight and edible parts ratios of P. prominens shoot. Shoot length of soil covered stand was higher than that of non-covered stand, and there was no difference on shoot length between one-year soil covered stand and two-year soil covered stand. No difference on shoot diameter existed between one-year soil covered stand and non-covered stand, but those all was lower than shoot diameter of two-year soil covered stand. Compared to non-covered stand, content of protein, tannin, oxalic acid, total acid, cellulose, lignin and amino acid of P. prominens shoot in soil covered stand decreased apparently overall, while soluble sugar, fat and ratio of sugar to acid of P. prominens shoot form soil covered stand increased obviously. Proportion of delicious, sweet and aromatic amino acid increased, and bitter amino acid proportion of P. prominens shoot in soil covered stand decreased. All results indicated that shoot appearance quality of soil covered stand enhanced obviously, and fragrance and sweetness increased obviously, while acid and astringent taste of P. prominens shoot form soil covered stand decreased evidently, shoot quality and palatability enhanced greatly, and the effects on shoot quality and palatability of two-year soil coverage were more evident and beneficial.

Growth and physiological responses of Leucobryum juniperoideum to different nitrogen stresses

2015/12/14 15:20:33

Leucobryum juniperoideum is a common bryophyte in the southeast china,which is considered to be an ideal ornamental plant used in garden. Nitrogen(N)is a kind of necessary element to plant growth, but excess N can be capable of causing serious injury to the most plants. According to recent studies, the diversity of bryophytes was severely decreased by the more and more increasing N deposition. In order to reveal the growth and physiological responses of L. juniperoideum to the intensification of N deposition, three forms of nitrogen, i.e. lime nitrate(Ca(NO₃)₂)representing the nitrate N, ammonium bicarbonate(NH₄HCO₃)representing the ammonium N and ammonium nitrate(NH₄NO₃ )representing the mixed N, were used in the treatments of simulating N deposition. The gametophyte material used in this experiment was propagated by shattered fragments and cultured in the greenhouse six months ahead of the first fertilization. The gradient of N concentration was 0, 2, 4, 8, 16 gN·m^-2 prepared using a solution of lime nitrate, ammonium nitrate and ammonium nitrate respectively. The results showed that the tissue N contents of L. juniperoideum were raised as the increasing of the three kinds of nitrogen concentration and the increasing tissue N contents of Ca(NO₃)₂, NH₄HCO₃ and NH₄NO₃ were 69.1%, 25.7% and 43.1% respectively. The dead plant rate of L. juniperoideum gametophyte also increased as the three kinds of nitrogen fertilization concentration rising,but there are remarkable differences among the three kinds of nitrogen treatments, and the dead plant rate of Ca(NO₃)₂, NH₄HCO₃ and NH₄NO₃ were 16.5%, 12.5% and 13.9% respectively. As well as the net weight of the L. juniperoideum, the plant height came out different as the three kinds of nitrogen concentration rising. The net weight and the plant height all added by the treatments of low concentration NH₄HCO₃(4 gN·m^-2),but not by nitrate N and mixed N treatments, and three kinds of nitrogen treatments all cause the reduction of the net weight and the plant height as the N concentration rising. The changes of the Chlorophyll(a, b)contents by three N treatments all occurred from increase to decrease, but the Chlorophyll(a,b)contents of NH₄HCO₃treatments were higher than other N forms at the same concentration, and the NH₄HCO₃ concentration of decreasing Chlorophyll(a, b)content was higher than Ca(NO₃)₂and NH₄NO₃. There existed an obviously similar variation tendency of the superoxide dismutase(SOD)among the three kinds of nitrogen treatments,which increased as the N concentration rising, while the soluble protein content and the praline content increased at lower N concentration and reduced at higher N concentration. These physiological indexes were not synchronous among the three N treatments. It was demonstrated in the experiments that L. juniperoideum was more sensitive to nitrate N than ammonium N,and small ammonium N additions(4 gN·m^-2)tended to increased its growth,while nitrate N additions decreased its growth. Therefore, ammonium N could be used as the N source of L. juniperoideum and the low concentration of nitrogen additions was critical to the fertilization of L. juniperoideum.

Variation for morphology and biomass of Gentiana rigescens in agroforestry system

2015/12/14 15:20:32
Environment and species composition affect crops yield of agroforestry system. The aim of the present study was to investigate the influence of different cultivation systems on morphological traits and biomass of the traditional medicinal plant Gentiana rigescens, and to provide a theoretical basis for management of multiple cropping of medicinal plants. All the samples were collected from six cultivation systems, G. rigescens-Camellia sinensis var. sinensis (young tea trees), Gentiana rigescens-Camellia sinensis var. sinensis(ten years old tea trees), Gentiana rigescens-Chaenomeles sinensis, Gentiana rigescens-Alnus nepalensis, Gentiana rigescens-Eucalyptus robusta systems and monoculture(Gentiana rigescens grown on the slope of the valley). Stem height, stem diameter, leaf length, root diameter and biomass etc. were measured and recorded at the individual level. The statistically significant differences of the traits of G. rigescens collected from six cultivation systems were analyzed by one-way ANOVA and student-newman-keuls test. Correlation analysis and multiple linear stepwise regression analysis were used to study relationships between morphological traits and biomass. The results showed that the stem height were the highest in monoculture and G. rigescens-Camellia sinensis var. sinensis (young tea trees)systems,(37.32±8.36)cm and(37.31±9.62)cm, respectively. The lowest stem height was(19.08±12.40)cm which was found in Gentiana rigescens-Eucalyptus robusta system. The stem diameter ranged from(0.36±0.13)cm in monoculture to(0.23±0.04)cm in Gentiana rigescens-Eucalyptus robusta system. The highest values of root length were found in the samples intercropped with young tea trees and ten years old tea trees, respectively, whereas the lowest value was found in the samples intercropped with Alnus nepalensis. There was no significant difference of root diameter values among six cultivation systems(P<0.05). However, the highest biomass was found in monoculture system while the lowest in Gentiana rigescens-Eucalyptus robusta system. Correlation analysis displayed that stem height, stem diameter and fibrous root number had very significant positive correlations with the biomass, respectively(R=0.514, P<0.01; R=0.510, P<0.01; R=0.339, P<0.01). But root length/stem length had very significant negative correlation with biomass(R=-0.295,P<0.01). Multiple linear stepwise regression analysis showed that different morphological traits had different contribution for biomass accumulation. Stem high, stem diameter, fibrous root number and root diameter were key traits for the accumulation of biomass under six cultivation systems. Monoculture system could improve better light condition for the growth and biomass accumulation of Gentiana rigescens than other cultivation systems. However, plant intercropped with Eucalyptus robusta had the lowest values of biomass and stem height. It may be affected by biotic and abiotic stresses. Monoculture, Gentiana rigescens-Camellia sinensis var. sinensis and Gentiana rigescens-Chaenomeles sinensis systems were the high yield cultivation systems for Gentiana rigescens. All the results of the study provided useful information for species mix in agroforestry system and development of cultivation techniques.

Above-and below-ground biomass distribution of main alpine meadow plants and impact of degradation on root/shoot ratio and root area

2015/12/14 15:20:32
Understanding on distribution of above-and below-ground biomass and the effects of degradation on root/shoot ratio and root area is crucial to predict the degraded processes in the alpine meadow. First, In Naqu Ecological and Environmental Observation and Research Station of Kobresia pygmaea Fence(2009 enclosed)select native vegetation place randomly selected Kobresia pygmaea, K. humilis, Stipa purpurea, Potentilla bifurca and Carex moorcroftii five species, degradation choice(compared with native vegetation)of Potentilla bifurca and Carex moorcroftii, then drying to constant weight and using a scanner to scan the surface area of roots. Finally, the use of different species and different levels of sampling two-way ANOVA to test the effects of above-and below-ground biomass, according to species and degraded state, the use of two-way ANOVA to test effects on aboveground biomass, and the use of the species, sampling levels and degraded state three-way ANOVA to examine the influence of biomass, root and shoot ratio and root surface area on Potentilla bifurca and Carex moorcroftii. Our results showed that belowground biomass of Kobresia pygmaea, K. humilis and Stipa purpurea mainly concentrated in the 0-10 cm soil layer which was about 70% of total belowground biomass of 0-30 cm, and belowground of 0-30 cm was about 96% of the total above-and below-ground biomass. Belowground biomass of 0-10 cm for Potentilla bifurca and Carex moorcroftii was about 50% of the total belowground biomass of 0-30 cm. Belowground biomass of 0-30 cm for Potentilla bifurca and Carex moorcroftii was about 57% and 85% of total above-and below-ground biomass respectively. As main plant species for the degraded alpine meadow, we found that degradation decreased aboveground biomass, belowground biomass, its root/shoot ratio and root surface area for Potentilla bifurca; and it increased aboveground biomass but reduced root/shoot ratio for C. moorcroftii, whereas there was no significant effect on its belowground biomass and root surface area.

Comparative study concerning the effects of rare species treatments on RDA ordination

2015/12/14 15:20:31
On the basis of redundancy analysis(RDA), eliminating the rare species whose frequency and coverage are less than 5% in Dongling Mountain of Beijing and our objective was to explore the effects of rare species on RDA ordination and summarizing the using-actuality of two methods. In this paper, Monte Carlo permutation test was used to analyse their relationship between species and environmental variables, and the correlation of corresponding ordination axes of two methods was measured by Spearman's rho correlation. The results were as follows:(1)The Monte Carlo permutation test results showed that their species and environmental variables had a significant correlation;(2)From the perspective of the cumulative percentage variance of species-environment relation, the RDA results of eliminating rare species had a higher amount of the interpretation of species-environment relationship both in the first two axes and the first four axes, therefore, it could better explain the relationship between species and the environment;(3)Two-dimensional RDA ordination diagram revealed the distribution of environmental variables, samples and species were basically the same; the results from the Spearman rank correlation of corresponding axes showed that the third axis of untreated rare species corresponded to the forth axis of eliminating rare species and the forth axis of untreated rare species corresponded to the third axis of eliminating rare species, whereas there were very prominent relationships between their first four axes(P<0.001), which revealed the same environmental gradient. In conclusion, the findings in this study suggested that the results of two methods were basically the same when the number of environmental factors was less, but some differences were existed on the explanation tendency for their environmental factor.

Effects of different altitudes on plant growth and quality of chrysanthemum at high altitude

2015/12/14 15:20:29
In this paper,the main vegetative growth indexes of chrysanthemum such as height of plant,number of ground stem diameter,number of branches and the main reproductive growth indexes of chrysanthemum such as number of flower, weight of flower,diameter of flower, thickness of flower which were introduced and cultivated at different altitude in Baoxing of Sichuan Province were measured by field trials and the main quality indexes of the chrysanthemum samples such as content of Chlorogenic acid,contents of Luteolin and Isochlorogenic acid A were measured by laboratory analysis. The measured data were prossed by variance and correlation analysis to find the difference of plant growth and quality for medication of chrysanthemum which were introduced and cultivated at different altitude at high altitude area. The results showed that the vegetable growth index such as height of plant,the reproductive growth indexes such as number of flower,weight of flower,diameter of flower,thickness of flower and the quality indexes such as content of Luteolm and Isochlorogenic acid A of chrysanthemum were affected significantly by the elevation gradient at high attitude area(P>0.05). The vegetable growth indexes such as diameter of groung stem, number of braches and the quality index such as content of Chlorogenic acid of chrysanthemum were affected insignificantly by the elevation gradient at high attitude area(P<0.05). The vegetable growth index such as height of plant and the quality indexes such as number of flower, diameter of flower of chrysanthemum had a significant correlation with the elevation gradient at high attitude area(P<0.05). The elevation gradient at high attitude area had a significant effects on the plant growth of chrysanthemum exclude a few vegetable growth indexes such as the number of braches and diameter of ground stem. Within a certain range of altitudes(2 051-2 405 m)at high attitude area,the elevation gradient had insignificant effects on the quality formation of chrysanthemum. The quality of chrysanthemum all met the medicinal condition within the altitude of 2 051-2 598 m according to the minimum limits standard of active ingredients of chrysanthemum in the “Pepole's Republic of China Pharmacopoeia(2010 edition)” and the chrysanthemum had a best quality for medication which were introduced and cultivated around the altitude of 2 329 m. This study provided a theoretical basis for the introduction and cultivation of chrysanthemum for medication in the high altitude area.

Sunipia nigricans, a new recorded species of Orchidaceae from Yunnan, China

2015/12/14 15:20:35
Sunipia including about 23 species was restricted to Southeast Asia. In China, genus of Sunipia is represented by twelve species. During our fieldwork in Pu'er Prefecture southern Yunnan from 2011 to 2013, one new recorded species from China was discovered and here reported. Its Chinese name was entitled by meaning of specific names. This species is characterized by purple perianth, unbranched pollinarium stipe terminated with 4 spherical solid pollinias differed from others of this genus.

A newly naturalized plant in Qinghai-Tibetan Plateau

2015/12/14 15:20:33
Tagetes minuta L. is reported as the newly naturalized plant in Qinghai-Tibetan Plateau.

Carbon, nitrogen and phosphorus stoichiometry of typical plants in karst area of Maocun, Guilin

2015/12/14 15:20:36
The balance between various elements of the ecosystem has been the focus of research related to the ecology of global change and biogeochemical cycles. Ecological stoichiometry is the study of the balance of energy and elements in biological systems and based on the general laws of physics, chemistry and biology. Ecological stoichiometry provides an integrated approach to investigating the stoichiometric relationships and rules in biogeochemical cycling and ecological processes. The primary nutrient elements, carbon(C), nitrogen(N)and phosphorus(P), play an important role in plant growth and regulating various botanic physiological functions. The cycling of N and P are tightly coupled to C cycling in ecosystems, primarily through aspects related to ecosystem carbon primary production. Leaf C, N and P stoichiometry varies throughout many aspects of plant biology. The ratios of C:N, C:P and N:P may reflect the balance between the plant demand in relation to N and P availability and may constrain various processes. Carbon, nitrogen, and phosphorus stoichiometry of plants reflect the utilization efficiency of plants with regard to soil nutrient elements. After a long period of evolution, plants had form and their own unique ecophysiology and ecological stoichiometry in karst landscapes. Carbon, nitrogen, phosphorus stoichiometry of plant leaves can reveal the regularity of nutrient cycling within karst ecosystems. Three quadrats, sized 20 m×20 m, in a secondary forest in the karst area of Maocun, Guilin were selected. A total of 186 samples of 12 plant types were collected. The ecological stoichiometry of carbon, nitrogen, and phosphorus were analyzed using multivariate statistical analysis to study the relationship between them and explored ecological indicating functions of carbon, nitrogen, and phosphorus stoichiometry in karst ecosystems. The results were as follows: Firstly,C, N, and P values in the samples' plant leaves were(456.19±2.16)mg·g^-1,(7.71±0.26)mg·g^-1, and(0.89±0.02)mg·g^-1, respectively. Carbon, nitrogen, and phosphorus values were all lower than China's and global averages. Although the higher contents of N and P in the karst limestone soil because of their low availability and their slow uptake and utilization efficiencies, nitrogen and phosphorus still presented as common limitations to plant growth within the karst area. Secondly, in this study, C:N, C:P, and N:P in the plant leaves of the samples were 80.86±6.74, 639.65±53.79, and 10.42±0.89, respectively. Because the contents of N and P in plant leaves in the karst area were significantly lower, it resulted in higher C:N and C:P values. Thirdly, the rules of N:P was less than 14, indicating nitrogen limits; N:P was more than 16,indicating nitrogen limits; and N:P between 14 and 16 showed that nitrogen and phosphorus limits were not entirely suitable for determining the limiting nutrient elements within the karst area. Lastly, correlation analysis between elements showed that there was a significant negative correlation between leaf C and N(P<0.01), and a significantly negative correlation between C and P(P<0.05), while there was a significant positive correlation between N and P(P<0.01). This correlation reflected the change of the relative consistency of nutrient elements of plants. The results contributed to the understanding of plant adaptive mechanisms and ecological geochemical process, providing the theory basis for ecological control of the karst area.

Habitat adaptation of two dominant tree species in a subtropical monsoon forest: leaf functional traits and hydraulic properties

2015/12/14 17:15:01
During the long-term processes of evolution and development,plant species yield a set of morphological,structural and physiological characteristics through their interactions with the environment,and these characteristics indicate their ecological adaptive strategies to the environment. Within forest communities,topographic and edaphic variations often lead to habitat heterogeneity,and hence tend to directly or undirectly influence the distribution patterns of plant species. Thus,it is an important question that how plant species distribution is related to its ecological adaptive strategies in forest commnuties with high habitat heterogeneity. Ardisia quinquegona and Aidia canthioides are two dominant evergreen tree species in the subtropical monsoon evergreen broad-leaved forest within the 20 ha forest biodiversity monitoring plot at Dinghushan National Nature Reserve in Zhaoqing City,Guangdong Province,China. The two tree species are distributed in different habitats including mountain ridge,slope,and valley. To understand the relation of their ecological strategies of habitat adaptation to their distribution patterns in the forest,a comparative study was conducted on their leaf functional traits and hydraulic properties among the three different habitats. Functional traits measured include leaf area(LA),leaf thickness,leaf length/leaf width ratio,specific leaf area(SLA),and leaf dry matter content(LDMC),while hydraulic properties include sapwood specific hydraulic conductivity,leaf specific conductivity,huber value,wood density(WD),leaf water potential at turgor loss point(π⁰)and saturated leaf water potential( π¹⁰⁰). The results showed that A. quinquegona tended to adapt to different habitats mainly through the adjustment of leaf area LA,WD and osmotic regulation. In contrast to A. quinquegona,A. canthioides had a stronger ability to adapt to the environment,especially mountain ridge and slope habitats,via the strategy of “slow growth rate and high survival rate”. It mainly made fine adjustment on SLA,WD and osmotic regulation,and used the strategy of efficient conservation of nutrients(low SLA,high LDMC). Moreover,the soil factors that limit leaf functional traits and plant hydraulics differed between the two studied tree species. Our results revealed that both species were suitable to survive in mount ridge and slope rather than in valley,while they differed in habitat adaptation strategies regarding leaf functional traits and hydraulic properties,although they both were dominant species in the subtropical monsoon evergreen broad-leaved forest.

Determination of the stable carbon isotope composition in atmospheric carbon dioxide based on plants cultured in bidirectional tracers

2015/12/14 17:15:02
Based on the characteristics that plants can take advantage of carbonic anhydrase enzyme to catalyze the bicarbonate ions into carbon dioxide and water,which can serve as substrates for photosynthesis,two sodium bicarbonate whose δ¹³C_PDB value differences were greater than 10‰ were used as the carbon isotope labeling and to bidirectional water culture Orychophragmus violaceus and Brassica juncea lasted for 24 h in this study,respectively. The daily mean stable carbon isotope compositions in two different times and environments were investigated and analyzed according to isotope ratio mass spectrometry(IRMS)technique. In particular,Environment 1 represented adding some sodium bicarbonate to solutions to get different concentrations of bicarbonate solution and Environment 2 represented adding some polyethylene glycol to solutions to get different concentrations of PEG solutions. These results showed that δ_Ca values in the Environment 1 were related to the concentrations of added exogenous sodium bicarbonate to solution,but these in the Environment 2 had no significant correlation with PEG concentration in the treatment solution,these results in this study suggested that the daily mean stable carbon isotope composition of atmospheric carbon dioxide had no relationship with the cultured plant species,but was related to the concentration of exogenous bicarbonate ion added to the culture solution and growth rate of the two plants. The data obtained with good reproducibility and reliability,accurately determined the stable carbon isotope composition of atmospheric carbon dioxide in test environments. This study confirmed that the method was a very powerful tool for monitoring the carbon isotope composition and sources of atmospheric carbon dioxide in different times and places for further.

Species diversity and floristic composition of the fern flora of Yunnan, China

2015/12/14 17:15:02
Based on the field investigation and plant classification, the floristic analysis of fern in Yunnan Province was studied. We made Flora of Yunnan(Vol. 20 and Vol. 21)complete,which was the principal research material,by using the list of local ferns in Mt. Ailaoshan Nature Reserve,Xishuangbanna,Yuengling Nature Reserve,Dulong River and so on supplementing the list of pteridophyte in Yunnan,through routine method of statistical analysis method and the analysis of the floristic geography study of ferns in Yunnan,in order to find out the number of species in Yunnan ferns,the floristic composition characteristics and contact area of the surrounding area. The results were as follows:The fern flora of Yunnan consisted of 60 families,193 genera and 1 530 species(including varieties and forms),and the family,genera and species accounting for the total number of ferns in Chinese were 58.8%,83.9% and 95.2% respectively; The number of families containing more than 30 species was 13 and the number of families containing more than 5 genera was 11 in this 60 families, these genera and species accounting for the total number of ferns in Yunnan Province was 56.5% and 79.2%, especially the Dryopteridaceae, Athyriaceae, Polypodiaceae, thelypteridaceae, there were 761 species of ferns belonging to 70 genera in 4 families, accounted for 36.3% and 49.7% respectively,the number of genera containing more than 30 species was 11,accounted for 5.7% and 41.7% respectively,and the dominant genera were Dryopteris,Polystichum,Athyrium,Asplenium,Selaginella,the five genera had 403 species which accounted for 26.3% of the total species in this area; the peteridophyte florae did not contain the families endemic in Yunnan Province,but had four endemic families in Asia: Peranemaceae,Monachosoraceae,Davalliaceae,Gymnogrammitidaceae; The floristic analyses showed that the main elements were tropical and subtropical in nature, the families in tropical and subtropical distributions accounted for 66.6% in the family areal type and the tropical distribution type had 112 genera,which accounted for 68.7% of the total genera(excluding the Cosmopolitan); The fern flora of Yunnan was an important part of East Asia,there were 31 genera distributed in East Asia and 6 genera in China alone,respectively accounted for 19.0% and 3.7% of the total genera in addition to the cosmopolitan; The fern floras of Yunnan,Tibet and Taiwan,China shared common floristic elements,and origin,as well as the background of species differentiation,the similarity coefficient of genera was about 70% and the similarity coefficient of species was about 30%,their common originated in tropical and subtropical areas; At the genus level,tropical floristic composition accounted for 68.7%,temperate floristic elements 27.6%,there was a certain degree of floristic transition; The intensity of floristic differentiation at family level was 3.2 and at genus level was 7.9. The flora differentiations both at family and genus levels are strong.

Cloning and functional analysis of a flavonoid-3-O- glucosyltransferas gene from Indosasa hispida

2015/12/14 17:15:03
Flavonoid -3-O- glucosyltransferase(3GT)is the key enzyme in anthocyanins biosynthesis,which transforms unstable anthocyanidins into stable anthocyanins. The function of Flavonoid -3-O- glucosyltransferase in bamboo is unclear,although many flavonoid -3-O- glucosyltransferases from other plant had been reported,so far. Indosasa hispida McClure cv. Rain bow is of few bamboo species which can produce anthocyanins in clum. Therefore,I. hispida McClure cv. Rain bow is very important material to reveal the function of Flavonoid -3-O- glucosyltransferase in bamboo and the mechanism of anthocyanins biosynthesis in bamboo. Therefore,it is first step to clone 3GT gene from I. hispida McClure cv. Rain bow. First,gene special primers of 3GT were obtained based on the homology analysis of reported flavonoid -3-O- glucosyltransferase,and the RNA was extracted from yound red clum which produce anthocyanins part in I. hispida McClure cv. Rain bow by Trizol method. And then gene fragment of I. hispida McClure cv. Rainbow was cloned with special primers of 3GT. According to the obtained fragment sequence,the primers were designed,which were used in rapid amplification of cDNA ends(RACE). Next,the 3' end and 5' end sequence of 3GT were obtained by RACE,the full length gene of Ih3GT was assembled by ATG software. Finally,the full length gene of Ih3GT was cloned from I. hispida McClure cv. Rainbow by reverse transcription-polymerase chain reaction(RT-PCR). ORF analysis program was used to confirm open reading frame,MEGA software was used to construct phylogenetic tree. the DNAman software was used in Homology analysis,and semi RT-PCR was applied in gene expression profile. The results showed that the cDNA sequence of Ih3GT consisted of 1 425 bp open reading frame(ORF)which encodes 474 amino acid, Ih3GT and 3GT from Poaceae were grouped in same clade,the deduced protein of 3GT from I. hispida McClure cv. Rain bow shared 69% identities with 3GT of Oryza sativa and shared 67% identities with 3GT of Brachypodium distachyon. Homology analysis showed that deduced Ih3GT protein had a glycosyltransferase signature domain PSPG-box. Expression profiling with semi RT-PCR analysis revealed that Ih3GT was expressed in young red culm and was not expressed in old culm,old leaf,young leaf and shoot. This implied that the expression of Ih3GT from I. hispida McClure cv. Rain bow showed obvious tissue specificity. This study will provide useful information to reveal mechanism of anthocyanins biosynthesis in I. hispida McClure cv. Rainbow in future. Ih3GT gene can be transformed into Eschera coli,and heterologous expression obtain Ih3GT protein and detect the enzyme activity of Ih3GT,and it can also be transformed into Arabidopsis thaliana or Oryza sativa,the function of Ih3GT will be confirmed by heterologous expression. The obtained Ih3GT also can been implied in bamboo breeding or other horticultural plants by genetic engineering.

Didymoplexiella Garay, a newly recorded genus of Orchidaceae from Guangxi, China

2015/12/14 17:15:04
Didymoplexiella Garay, a newly recorded genus of Orchidaceae from Guangxi, China is reported. This genus is closely related to Didymoplexis Griff., but is distinguished from it by the presence of elongate, filiform stelidia that extend from the column wings and by the absence of a column foot. Didymoplexiella siamensis only distributed in Taiwan and Hainan island, China, but now it is also discovered in Shiwandashan National Nature Reserve of Guangxi. Detailed morphological description and field photos were provided,and the biogeographic significance of the discovery was discussed.

Leaf structure traits and their correlation of five tree seedlings of Fagaceae family

2016/5/31 17:34:53
After sand reservoir in the condition of low temperature and cultivation in the greenhouse of the collected seeds, 5 tree species(Castanopsis fargesii, C. sclerophylla, Castanea henryi, C. mollissima and Quercus acutissima)seedlings of Fagaceae family in the mid-subtropical zone of China were transplanted into the common garden. The leaf size, leaf thickness, specific leaf area, leaf dry matter content, leaf nitrogen concentration, leaf phosphorus concentration, ratio of leaf nitrogen and phosphorus concentration and their correlation of two-year old seedlings in the growing season were investigated in this paper. The results were as follows:(1)The leaf size and specific leaf area of Castanea henryi were the maximum, its leaf nitrogen concentration was the highest and its leaf dry matter content was the lowest. The leaf size of Castanopsis fargesii was the minimum, its leaf nitrogen concentration and leaf phosphorus concentration were the lowest. The leaf thickness and specific leaf area of C. sclerophylla was the minimum and its leaf dry matter content was the highest. For C. mollissima seedlings, the leaf thickness was the minimum. In the meanwhile, there was no significant difference of the ratio of leaf nitrogen and phosphorus concentration among the 5 tree seedlings.(2)Pearson and linear regression analysis indicated that leaf sizes of the 5 tree seedlings were in a highly significant positive correlation with leaf nitrogen concentration(P<0.01)and significant positive correlation with specific leaf area(P<0.05). The leaf thickness was in a highly significant negative correlation with leaf size(P<0.01)and significant positive correlation with leaf dry matter content(P<0.05). The correlation among specific leaf area and leaf dry matter content, leaf nitrogen concentration was highly significant negative and positive respectively(P<0.01). At the same time, it was significantly and negatively correlated with leaf phosphorus concentration(P<0.05). The correlation among leaf nitrogen concentration and leaf dry matter content, leaf phosphorus concentration was significant negative and positive respectively(P<0.01). The results indicated that the seven leaf structure trait indicators of the 5 tree seedlings of Fagaceae family exhibited a certain interspecific difference, but the order of the same indicator and its difference significance were different; while the correlation of the seven leaf structure trait indicators among all of the five tree seedlings was not the same.

Diurnal variation of photosynthetic characteristics of five kinds of arbor dominant species in Napahai

2016/5/31 17:34:53
In order to understand the photosynthetic physiological ecology characteristics and its response to environmental factors of arbor dominant species in alpine environment of Napahai,use LI-6400 portable photosynthesis measuring system to determine the characters of diurnal change of net photosynthetic rate(Pn)and the physiological, transpiration rate(Tr)and water using efficiency(WUE)and analyzed ecological factors of the 5 dominant species in Napahai. And compare the correlation analysis of photosynthesis parameters and environmental factors. The results were as follows:(1)According to the determination of the 5 dominant tree species, daily variation of Pn of the species showed bimodal type except for Quercus aquifolioides. The level of peak value of Pn was: Picea asperata> Pinus densata> Crataegus pinnatifida> Populus rotundifolia>Quercus aquifolioides. The numbers of Pn were 21.583 3,21.566 7,15.208 3,14.1833 and 11.866 7 μmol·m^-2·s^-1.(2)Tr and Gs of the species were higher in the noon and lower in the morning and evening, which are consistent with PAR. Ci was instead point to the trend of Pn.(3)The average of WUE and LUE were consistent with the Pn. Picea asperata and Pinus densata were relatively higher. The numbers of WUE were 3.27 and 5.82 mmol·m^-2·s^-1; the numbers of LUE were 4.42% and 2.99%. Quercus aquifolioides was the lowest, only 0.92 mmol·m^-2·s^-1and 0.74%.(4)Pn of the species had significant response to the change of PAR and Gs. WUE of conifer was significantly greater than broad leaved tree species; it was more efficient to the alpine environment strategy. Planting large area of Picea asperata in the mountains around the lake has efficient practical significance for the regional vegetation restoration.

Air negative ion concentrations and their affecting factors in Guangdong Chebaling National Nature Reserve

2016/5/31 17:34:54
The negative air ion(NAI)is one of the most important indicators of air quality, and is of great significance to human being's living environment. The authors selected 10 typical observation sites in Guangdong Chebaling National Nature Reserve and measured the NAI concentrations in summer and autumn. The results showed that NAI concentrations in the reserve was relatively high, with the NAI concentrations at all the observation sites above 700 ions·cm^-3. The NAI near waters was the highest, followed by those in forest, lawn and building in a decreasing sequence. NAI concentrations in autumn at the ten sites exhibited a decreasing order of river near the museum(Site 10), starting point of drift(Site 7), waterfall(Site 8), waterfall pillar(Site 9), conifer-broad leaved forest(Site 5), coniferous forest(Site 6), lawn near the museum(Site 3), Danzhu Pit(Site 1), suspension bridge(Site 2)and office(Site 4). There was a significant difference in NAI concentration between sites 7, 8, 9, 10 and sites 1, 2, 3, 4, 5, 6. In summer, the NAI concentrations at the ten sites showed a decreasing order of sites 8, 10, 9, 7, 5, 6, 1, 3, 2 and 4. NAI at sites 7, 8, 9, 10 was significantly higher than other sites. NAI at sites 5, 6 was significantly higher than sites 1, 2, 3, 4. Site 4 was significantly lower than other sites. Season, water and vegetation type were found to influence the NAI concentrations in the reserve.

Steady-state and dynamic photosynthetic performance in the shade-demanding plant Amorphophallus xiei under different levels of growth irradiance

2016/5/31 17:34:54
Amorphophallus xiei is a typically shade-demanding plant that originates from the tropical rainforest located in southwest of Yunnan Province. In the agricultural production, A. xiei is commonly cultivated under the shade condition. The photosynthetic performance, photosynthetic induction characteristics, photosynthetic pigment, and leaf nitrogen(N)partitioning were examined in A. xiei grown along a light gradient, and the purposes of the present study were to reveal the adaptive mechanism to growth irradiance levels. Area- and mass-based maximum net photosynthetic assimilation rate(A_max), photosynthetic pigment content, maximum carboxylation rate, and maximum electron transport rate as well as specific leaf area significantly increased with decreasing growth irradiance levels; however, dark respiration rate and light compensation point decreased significantly. In the process of photosynthetic induction, the induction time to reach 50% of A_max was the shortest(81.4 s)and the induction state of 10 min was the highest(87.3%)in the individuals grown under the 17% of full sunlight. Moreover, there was a negative correlation between the induction time to reach 50% and 90% of A_max and the initial stomatal conductance across all the treatments. The fraction of leaf N allocated to carboxylation and bioenergetics firstly increased and then decreased with the decreasing growth irradiance levels, and the maximum values were recorded in individuals grown under 17% of full sunlight; at the same time, the fraction of leaf N allocated to light-harvesting components increased significantly with decreasing growth irradiance levels. These results suggested that the typical shade-demanding plants A. xiei acclimate to low growth irradiance by enhancing the capacity of leaf to utilize low light and dynamic light, and by adopting the strategy of N resource allocation that might efficiently overcome light shortage.

Effects of AMF inoculation on the growth and chlorophyll fluorescence of Sorghum bicolor × S. sudanense in coal wastes

2016/5/31 0:00:00
To improve the growth and survival rate of plants in three types of coal wastes, we chose two kinds of arbuscular mycorrhizal fungis, Glomus mosseae (G. m)and G. versiforme (G. v), to study the effects of pure fungi, mixed bacteria on growth and photosynthetic fluorescence of Sorghum bicolor &#215; S. sudanense in three types of coal wastes which were that fly ash(S1), coal gangue(S2)and the mixture of fly ash and coal gangue(S3)and the mixture of sand and earth(S4)which was the control group. The results were as follows:(1)In the four substrates, the symbiotic associations were successfully established between AMF and Sorghum bicolor × S. sudanense. The inoculation of G. m could obviously improved the infection rate to 49.04%, 57.40% and 43.34% in the substrates of S1, S3 and S4 and the mixed inoculation treatment had the best infection rate to 49.33% in the substrate of S2.(2)The plant height, root length, content of chlorophyll, F_v/F_o, qP and Yield of Sorghum bicolor × S. sudanense in three types of coal wastes significantly decreased. Inoculation of AM fungi significantly promoted the growth and photosynthetic efficiency of Sorghum bicolor &#215; S. sudanense. Comparing with other treatments, inoculation of G.m significantly improved the root length, dry weight, the content of chlorophyll, F_v/F_o, qP and Yield in the substrates of S1, S3 and S4. In the substrate of S2, inoculation of G.v significantly increased the root length, dry weight and had little difference with mixed inoculation treatment on chlorophyll fluorescence parameters. The result indicated that the growth and photosynthesis of Sorghum bicolor &#215; S. sudanense was inhibited in the composite adversity of different types of coal wastes. AM fungi was capable of alleviating the damage cased by the adverse factors of different types of coal mining wastes on Sorghum bicolor &#215; S. sudanense by means of improve leaf chlorophyll content, photosynthesis, chlorophyll fluorescence and growth, and enhance Sorghum bicolor × S. sudanense's stress-resistance. G.m was more suitable for the revegetation of fly ash and the mixture of fly ash and coal gangue, while G.v was more suitable for the revegetation of coal gangue.

Population structure and dynamics of the endemic plant Acer guizhouense in Guizhou Province

2016/5/31 17:34:54
Acer guizhouense is a kind of evergreen broad-leaved tree with scientific and economic value, which only distributed at 770-1 000 m in evergreen and deciduous broad-leaved mixed forest with mountain barrier in Xinzhou Town of Huangping County in Guizhou Province. So, it has significant value to explore conservation biology of endemic plants by studying its population structure and dynamic change. We took general survey in suspected distribution area, set up plots in dense area for full investigation, and analyzed the population structure and quantity dynamics pattern. The results were as follows:(1)The natural distribution region of A. guizhouense was very narrow, covered about 0.3 km² in Leiping with a total of 2 600 trees. The dense area was 0.03 km², average population density 78 800 trees/km². The sporadic distribution was 0.27 km², average population density ≤1 500 trees/km². The species occasionally distributed in about 0.05 km² Feiyunya of Dongpo Village. But there was no natural distribution between Leiping and Dongpo. According to the SAFE index and evaluation standard of IUCN, A. guizhouense was EN species.(2)The structure of A. guizhouense population was increasing and the proportion of young tree in population was 63.23%. The size of population density was young trees>middle-aged trees>adult trees. There were 2 peaks in the Ⅰ and Ⅸ age-classes on the mortality rate curve and disappearance rate curve respectively, then there were 2 troughs in Ⅲ-Ⅷ andⅩ-Ⅺ age-classes. So the survival curve of population was more in line with the characteristics of Deevey-Ⅲ model.(3)The main reason of few population individuals of A. guizhouense was the plant death or loss caused by human deforestation and habitat destruction. It is a practical and effective reasonable protection measure to carry out artificial breeding and ex situ cultivation when we strengthen the in situ conservation.

Genetic diversity and genetic structure of the northern margin populations of Hippophae neurocarpa

2016/5/31 17:34:54
We analyzed five natural populations of Hippophae neurocarpa in the Qilian area of Qinghai Province with SSR molecular markers, in order to understand the genetic diversity of the northern margin populations of H. neurocarpa on the small geographic scales and the genetic structure of the populations which distribute fragmentally, and to provide reference for resource protection of H. neurocarpa populations. We used six microsatellite primers to amplify the DNA of 107 samples and detected 27 alleles, with the range of 2-9 and a mean value of 4.67 per locus. The average observed heterozygosity(Ho)and expected heterozygosity(He)of H. neurocarpa populations was 0.142 and 0.230 respectively, and the range Shannon information index(I)was between 0.280-0.567 with a average value of 0.374. The results showed that the genetic diversity of the northern margin populations of H. neurocarpa was abundant. The coefficient of genetic differentiation(Fst)was 0.483. Molecular variance analysis(AMOVA)indicated that 48.33% of the variation existed among the populations, and 51.67% existed within the populations. No significant correlation between genetic distance and geographic distance was detected by Mental test and the detection of gene flow found that Nm was only 0.328 among populations. These results suggested that genetic drift was one of the key factors for the differentiation of populations. The 5 populations were divided into 2 groups based on the structure analysis. UPGMA clustering showed that the 5 populations were clustered into 2 branches, one of which was ARX, which was consistent with the results of the principal coordinate analysis. According to the analysis of the genetic structure, it is suggested to protect populations in situ as many as possible.

Effects of different calcium levels on photosynthesis and protective enzyme activities of colorful Hosta

2016/5/31 17:34:54
The effects of different calcium levels on photosynthesis and protective enzyme activities of Hosta leaves were studied by using colorful Hosta as test materials. The results showed that the net photosynthetic rate(Pn), stomatal conductance(Gs), Intercellular CO₂ concentration(Ci), transpiration rate(Tr)and the maximum photochemical efficiency(F_v/F_m)of the colorful Hosta leaves all showed a single peak curve with the increasing of calcium levels, and the highest peak level was 90 mg·L^-1 Ca²⁺. While the apparent electron transport rate(ETR)also changed as a single peak curve and the peak was 50 mg·L^-1 Ca²⁺. The initial fluorescence(F0)and maximum fluorescence(F_m) first increased and then decreased, finally increased in calcium levels of 0-360 mg·L^-1, and 90 mg·L^-1Ca²⁺ was the highest. The change of Pn and Gs were positively correlated with Ci. Meanwhile, the activities of peroxidase(POD)and catalase(CAT)and the contents of MAD and soluble protein(SP)of leaves all showed a single valley curve and the minimum was 90 mg·L^-1 Ca²⁺, while the activity of superoxide dismutase(SOD)had declined steadily. The results obtained from above showed that the decrease of Pn of colorful Hosta mainly resulted from the stomatal factors. The best spraying concentration of calcium was 90 mg·L^-1 which could enhance photosynthesis and reduce protective enzyme activities.

Comparative study on the photosynthetic light response characteristics of Dysosma guangxiensis and D. versipellis

2016/5/31 17:34:54
In order to understand the ecophysiological adaptation mechanisms of the endangered plants Dysosma guangxiensis to light environment, we studied the photosynthetic light response characteristics of D. guangxiensis and the same genera vulnerable species D. versipellis with Li-6400 Portable Photosynthesis(Li-Cor Inc., USA), and then discussed the endangered mechanism of D. guangxiensis. The results showed that the light compensation point of D. guangxiensis and D. versipellis was 440 and 530 μmol·m^-2·s^-1, the light compensation point was 13.25 and 13.10 μmol·m^-2·s^-1, the maximum net photosynthetic rate was 3.62 and 6.81 μmol·m^-2·s^-1, and the apparent quantum yield was 0.065 and 0.042 μmol·μmol^-1, respectively. That is to say, the two species are shade herb, but the light compensation point and the saturation point are higher than the general shade herb, and 10%-30% shading forest habitat are conducive to the growth of the two species; compared with D. versipellis, the photosynthetic capacity of D. guangxiensis was weak, the light saturation point was lower, but its quantum efficiency under low light was higher. In comparison, the net photosynthetic rate, transpiration rate and stomatal conductance of D. versipellis were higher than those of D. guangxiensis under most light intensities, but the water use efficiency of D. guangxiensis was higher than that of the former, which indicated that the photosynthetic strategy of D. guangxiensis was more conservative, with lower photosynthetic accumulation as the cost to maintain higher water use efficiency, in order to maintain the water balance in body.

Damage characteristics of Phyllostachys violascens forests and relationship with bamboo status and mulching management exposed to freezing stresses

2018/12/27 10:51:23
To analyze the damage characteristics of Phyllostachys violascens forests and relationship with mulching management after the freezing rain and snow events, the damage characteristics of bamboo with different ages and diameters at breast height(DBH)from the bamboo stand under different periods and types of mulching management were investigated. The bamboo leaves were hurt severely, turning yellow with icing cover, dehydration or complete leaf abscission. The stems of serious damaged bamboos shrinked and became black, and chlorisis occured to the leaf sheaths. The damage degrees of bamboo with 3 cm≤DBH<5 cm were Type Ⅰ and Type Ⅲ damages, while Type Ⅳ damage for bamboo with DBH<3 or DBH≥5 increased obviously. The damage degree of 2- and 3-year old bamboo was Type Ⅰ and Type Ⅱ damages, while that of 1- and >3-year old bamboo was Type Ⅲ and Type Ⅳ damages. The damage degree of bamboo from the bamboo stand with short-term mulching management(≤3 a)showed Type Ⅰ and Type Ⅲ damages, while that for long-term mulching management(≥5 a)was Type Ⅲ and Type Ⅳ damages. Furthermore, the bamboo of Type Ⅳ damage from stand of respite-mulching(3-year mulching + 2-year respite)was lower than 20%, which was damaged more slightly. It can be concluded that bamboo ages, DBH and mulching management influence damage degree of bamboo greatly under freezing stress. The bamboo with medium DBH(3 cm≤DBH<5 cm)and 2-and 3-year old was damaged slightly which is suitable bamboo with high tolerance under low temperature stress. Bamboo from the stands in long-term mulching management(≥5 a)was damaged greatly, while that for bamboo stand of respite-mulching(3-year mulching + 2-year respite)management was damaged slightly. The suitable duration for mulching management is three years to increase resistance of bamboo against freezing stress.

Outstanding universal value of plant diversity and conservation in Emeishan World Heritage Site

2018/12/27 10:51:23
We took the original plants and vegetation communities of Emeishan World Heritage Site as the study object and assessed the outstanding universal value from the aspects of species diversity, species composition, floristic composition, vegetation type and vertical distribution pattern, and briefly summarized the current situation of the endangered plants and the problems in protection and development in Emeishan World Heritage Site, based on the world heritage documents and vast literature. The results were as follows:(1)Emeishan World Heritage Site had more than 3 200 plant species belonging to 242 families as well as a large number of endemic species and tertiary-relic species.(2)Compared with the vertical band spectrum of other humid subtropical mountain forests in China, the subtropical forest vegetation types of Emeishan World Heritage Site was complete. Moreover, the eastern type of evergreen broad-leaved forest occupied a significant position in the vertical forest zones of Emeishan. It was particularly important that its upper limit of altitude was the highest and the span was the largest. The characteristics of the forest community in the eastern subtropical evergreen broad-leaved forest were typical.(3)The flora was complex and diverse, including tropical, subtropical and temperate plant elements, and the geographical distribution of China-Japan and China-Himalaya.(4)However, due to the effects of human being activities, such as tourism development, infrastructure construction, and natural disturbances including climate warming, geological disasters on the vegetations and communities of the world heritage site, the plant diversities decreased obviously, the rare and endangered plants were increasingly threatened, the typical community area degenerated and the stability was reduced in the Emeishan World Heritage Site. Therefore, for the purpose of protecting its outstanding universal value and realizing the sustainable development of the world heritage site, we suggest that plant diversities, environmental factors and anthropogenic activities should be monitored dynamically in Emeishan area, on the basis of delineating rare plant protected areas and specialized protection of the plant habitats.

Transformation of Siraitia grosvenorii with 2A11-iaaM gene

2018/12/27 10:51:23
To solve the seedless fruit and artificial pollination problems of Siraitia grosvenorii, we used pBI121-Gus to construct chimeric expression vector(pBI121-2A11-iaaM-Gus)with fruit specific promoter 2A11 and auxin synthesis key enzyme tryptophan monooxygenase enzyme gene iaaM. We took leaf disc of female plants as explants to study the antibiotics sensitivity, the impact of bacteriostatic in different concentrations of agrobacterium EHA105, and the different microbial infection time, to establish an efficient agrobacterium-mediated genetic transformation system of S. grosvenorii, and to create the parthenocarpy germplasm of S. grosvenorii. We also designed gene specific primers, and detected the positive plants by PCR technique and transplanted into the field, while recorded the hereditary characters of the transgenic plants. The results showed that the chimeric expression vector(pBI121-2A11-iaaM-Gus)related to parthenocarpy character of S. grosvenorii was successfully constructed, and the agrobacterium-mediated genetic transformation system of S. grosvenorii leaf disc was established. The optimal concentration of infection of agrobacterium tumefaciens was the OD₆₀₀ value 0.3-0.5, while the optimal infection time was 10 min. And the optimal selective medium was with 5 mg·L^-1 kanamycin and 300 mg·L^-1 cefotaxime sodium. PCR results showed that four female plants of S. grosvenorii were tested positive. We propagated the four positive female plants in the plant tissue culture room and transplanting the propagated 24 positive female plants to the field. Then the field investigation showed that there were five female plants flowering normally with a proportion of 20.8%, and the S. grosvenorii young fruits which had not been artificially pollinated were observed, which suggested the parthenocarpy character was expressed. The study, integrating the exogenetic parthenocarpy gene into the S. grosvenorii genome and preliminarily expressed, based on expression vector construction and the agrobacterium-mediated genetic transformation system of S. grosvenorii, provides the information for the subsequent study of the genetic physiology, the creation of the transgenosis parthenocarpy germplasm of S. grosvenorii, and solving the seedless fruit and artificial pollination problems of S. grosvenorii.

Light-response of PS Ⅱ fluorescence parameters on Vallisneria natans and Potamogeton malaianus to various water depths in Poyang Lake

2018/12/27 10:51:23
In order to study the effects of water depth on the chlorophyll fluorescence characteristics of typical submerged macrophyte, Vallisneria natans and Potamogeton malaianus were selected as test materials in Poyang Lake wetland. Water levels(0.5,1.0,1.5,2.0,2.5 m)were controlled by buckets, minimum fluorescence( F_o), maximum fluorescence(F_m), the maximum actinic light efficiency of PS Ⅱ(F_v/F_m), effective quantum yield [Y(Ⅱ)], photochemical quenching coefficient(qP ), non-photochemical quenching coefficient(qN ), unregulated energy dissipation quantum yield [Y(NO)] were measured by a submerged, modulated fluorescence spectrometer(Diving-pam). The variation of each parameter with depths was explored. The results showed that the maximum biomass of Vallisneria natans appeared in 1.5-2.0 m water depth, and that of Potamogeton malaianus appeared in 1.0-1.5 m water depth. F_o of each macrophyte decreased first and then increased, while the fluorescence parameters [F_m, F_v/F_m, F_v/F_o, Y(Ⅱ), qP] all increased first and then decreased. F_v/F_m and F_v/F_o of Vallisneria natans reached the maximum under the condition of 2.0 m, but the maximum of Potamogeton malaianus appeared at 1.5 m. At the same depth, qN of Vallisneria natans was lower than that of Potamogeton malaianus. The change trend of qP was reversed. The maximum Y(Ⅱ)of Vallisneria natans appeared in the range of 1.5-2.0 m water depth, but for Potamogeton malaianus, it appeared at 1.0-1.5 m. Y(NO) showed significant differences with changes of water depths, too high or too low water depth all inhibited plant growth. The relative photosynthetic electron transport rate(ETR)was significantly different between different water depth treatments. The maximum ETR of Vallisneria natans was smaller than that of Potamogeton malaianus which indicates that it has strong resistance to weak light. In summary, under the condition of 1.5-2.0 m water depth, Vallisneria natans has the strongest photosynthetic capacity and can grow the best, and Potamogeton malaianus is the most suitable for growth in 1.0-1.5 m.

Effects of arbuscular mycorrhizal fungi on growth, lateral root number and root endogenous hormones of Camellia sinensis ‘Fuding Dabaicha'

2018/12/27 10:51:23
The study was conducted to analyze the effects of Claroideoglomus etunicatum, Diversispora spurca, D. versiformis and a mixture of three arbuscular mycorrhizal fungi(AMF)species on plant growth, lateral root number and root endogenous hormones in the potted Camellia sinensis ‘Fuding Dabaicha' seedlings. After twelve weeks of AMF inoculation, roots of C. sinensis ‘Fuding Dabaicha' could be colonized by these AMF treatments, varied from 18.85% to 40.23%. AMF inoculation heavily increased plant height, total leaf area, taproot length, the number of the first- and third-order lateral roots, but the number of second-order lateral root was markedly reduced(except for mixed-AMF). Root abscisic acid, zeatin riboside, gibberellin and brassinolide levels were significantly increased by sole AMF inoculation, but the levels of methyl jasmonate in roots were significantly decreased(except for Clariodeoglomus etunicatum). Correlationship analysis revealed that mycorrhiza-regulated hormone changes in roots of Camellia sinensis ‘Fuding Dabaicha' were closely related with mycorrhiza-improved lateral root number. In addition, C. etunicatum exhibited the best effects on stimulating plant growth, and mixed AMF treatment represented the best effects on improving root morphology and lateral root number. Therefore, the management of mycorrhizas should be strengthened in tea cultivation in the future.

Allelopathic effects of Eupatorium adenophorum leaf aqueous extracts to Vicia faba

2018/12/27 10:51:23
Exotic invasive plants can alter ecosystem and displace the native plants by releasing allelochemicals to the surrounding environment by means of leaching, natural volatilization, root exudation and plant litter decomposition. In this study, Vicia faba seeds were treated with different concentrations of Eupatorium adenophorum leaf aqueous extracts. The effects of E. adenophorum leaf aqueous extracts on the micronucleus, chromosome aberration, apoptosis, chlorophyll and nitrogen content and photosynthetic physiological characteristics of Vicia faba were studied in this paper. The results were as follows:(1)The treatment of Eupatorium adenophorum leaf aqueous extracts significantly inhibited the root tip elongation and cell mitosis of Vicia faba, and induced chromosome aberration and cell micronucleus in the root tip cells of V. faba. With the increasing concentration of leaf water extracts, mitosis index significantly decreased and micronucleus rate of root tip cells significantly increased. In addition, the treatment of high concentration leaf aqueous extracts significantly affected apoptosis and necrosis of V. faba root tip cells.(2)The content of chlorophyll and nitrogen in leaves of V. faba decreased significantly, and the maximum net photosynthetic rate and biomass of V. faba seedlings were significantly decreased. In conclusion, Eupatorium adenophorum leaf aqueous extracts may cause the oxidative damage of the root tip of Vicia faba and the elongation of the root tip, and the inhibitory effect of leaf water extract showed a certain dose effect. At the same time, the damage and inhibition effects of Eupatorium adenophorum leaf aqueous extracts on the root tip of Vicia faba might affect the uptake of nitrogen, and thus had a significantly negative effect on the photosynthetic physiological performance and biomass accumulation of broad bean seedlings.

Effects of clonal integration on patterns of nitrogen allocated to photosystem in Phyllostachys bissetii under heterogeneity light environment

2018/12/27 10:51:23
In this study, a pot experiment was conducted and clonal fragment of Phyllostachys bissetii with two successive ramets was used as experimental materials to examine the effects of clonal integration on the patterns of nitrogen, allocated to photosystem in P. bissetii under heterogeneity light environment. The main results were as follows:(1)When grown in shade, ramets connected with an unshaded mother plant displayed higher potential maximum net photosynthetic rate(P_max), leaf nitrogen content(N_M and N_A), chlorophyll content and total partition coefficients of leaf nitrogen in photosynthetic apparatus(P_T)than severed ramets.(2)The connected apical ramets had higher partition coefficients of leaf nitrogen in carboxylation components and bioenergetics components than that of in light-harvesting components.(3)There were no significant differences in unit-area leaf mass and nitrogen content between the two treatments of connected and severed proximal ramets in natural lighting conditions, while connected ramets displayed higher P_max, P_T and chlorophyll concentration. The results suggested that clonal integration affects the patterns of nitrogen allocated to photosystem in shaded apical ramets, and ensure young ramets maintain higher photosynthetic capacity, which impel the whole clone fragment had higher survival advantages.

Effects of Fe fertilizer siphon transfusion on photosynthetic parameters and organelle structure of iron chlorosis in apple trees

2018/12/27 10:51:23
Taking Fuji Apple(Malus pumila)as the testing variety and effects of Fe fertilizer into apple through siphon, three treatments were set, including: infusion of Fe fertilizer(600 times FeSO₄·7H₂O)into apple tree through siphon, infusion of deionized water and CK(no treatment). Retrieved green leaves were observed and chlorophyll content and photosynthetic parameters were measured. Ultra microstructure of chloroplast and mitochondria were observed by electron microscopic scanning. In Fe fertilizer treatment, greening levels changed from 2.01 to 0.53 and the chlorophyll contents were increased even by 200%. Meanwhile, net photosynthesis rate was increased by 68%, transpiration rate was increased by 21%, and stomatal conductance was increased by 49%, while the intercellular CO₂ concentration was decreased by 100%. Compared to infusion of deionized water treatment and CK, in Fe fertilizer treatment, the chloroplast number was increased with larger size; and the number of starch granules and osmiophilic granules were decreased; grana lamellae structure was more clear, as well as the mitochondrial crista with more quantity. After Fe fertilizer applied, the yellow leaves retrieved green again obviously. And the synthesize of chlorophyll was improved, and the membrane structure of chloroplast and mitochondrion were recovered. In conclusion, Fe fertilizer infused into Fuji apple through siphon can correct chlorosis.

Micropropagation in vitro of Actinidia chinensis ‘Yangshi Jinhong 50'

2018/12/27 10:51:23
In order to establish the rapid and efficient propagation system in vitro, we used stem with axillary bud of Actinidia chinensis ‘Yangshi Jinhong 50' as the explant, and used tissue culture to study suitable explants sterilization method, best plant growth regulator combination in Actinidia chinensis ‘Yangshi Jinhong 50'. We established two kinds of in vitro regeneration modes. Mode I: the axillary buds of stem with axillary bud were induced directly; Mode Ⅱ: the callus was induced first, and then the adventitious buds were induced. The results showed that the best sterilization method for stems with axillary buds was 75% alcohol 30 s + 15% Ca(ClO)₂ 5 min+ 0.1% mercuric chloride 8 min; In Mode I, the plant growth substances combination of MS + 4.0 mg·L^-1 6-BA+ 0.1 mg·L^-1 NAA for axillary bud germination had the best the induction rate; In Mode Ⅱ, callus rate of inducing stem bottom was more than 80%, the optimal medium that induced stems bottom callus to generate adventitious buds was MS+ 3.0 mg·L^-1 6-BA+ 0.3 mg·L^-1 NAA; the best plant growth substances combination in tufted bud culture was MS+ 4.0 mg·L^-1 6-BA+ 0.4 mg·L^-1 NAA; the best plant growth substances combination in rooting culture was 1/2 MS+ 0.9 mg·L^-1 IBA, getting the differentiation of adventitious root about 20 d and complete plant 40 d. After the seedlings rooted, transplanted the seedlings to the substrate, the seedlings reached the 96% survival rate in the substrate with the garden soil:sand = 1:1. Through this study, the micropropagation system in vitro of Actinidia chinensis ‘Yangshi Jinhong 50' was established, which provides the basis for the research of genetic transformation in Actinidia chinensis Planch.

Effects of UV-B radiation on biosynthesis of terpenoids and expression of related genes in Chrysanthemum indicum var. aromaticum

2019/7/29 11:19:07
In this study, Chrysanthemum indicum var. aromaticum was used as material. We examined the changes of biosynthesis of terpenoid and expression of related genes in C. indicum var. aromaticum following the treatment of different durations(0, 0.5, 1, 2, 4 h)of 400 μw·cm^-2 UV-B radiation. The results were as follows:(1)The short time of UV-B radiation could significantly promote the expression of related genes in C. indicum var. aromaticum. Compared with the control, 0.5, 1, 2, 4 h treatment of UV-B radiation increased the expression of related genes. Meanwhile, relative expressions of HMGR, DXR, TPS, GPS reached the peak after two hours' treatment of UV-B radiation. As well as the relative expressions of FPS and DXS reached the maximum at four hours' treatment. A significant increase in FPS gene expression was found when plant exposed to four hours of UV-B duration(69 times compared with control).(2)In mevalonate pathway(MVA), the contents of calamenene, cadinene increased following the change of FPS gene expression during four hours of UV-B radiation. The change of the content of 1-caryophyllene was consistent with the change of HMGR gene expression, which increased first and then decreased.(3)In the pathway of 2-methyl-D-erythritol-4-phosphate(MEP), the contents of α-thujone, thujone and β-thujone showed the same trend as the expressions of DXR, TPS and GPS. The content of cajuputole generally increased during four hours' treatment responding to the change of DXS gene expression. In summary, the data indicate that UV-B radiation can change the regulation of terpenoid biosynthesis in C. indicum var. aromaticum by affecting some key genes' expressions.

cDNA-AFLP analysis of differentially expressed genes during flowering in Osmanthus fragrans

2019/7/29 11:19:07
Osmanthus fragrans is an important traditional fragrant flower in China. Floral color and scent as the important ornamental characters are influenced by flowering process. Reports on the components of floral color and scent and related synthetic genes have been reported. However, studies on the synthesis and molecular basis of floral color and scent during flowering process are rarely reported. The study established a cDNA-AFLP system suitable for multiple samples and analyzed genes differential expression at different flowering stages. Finally, 283 TDFs with specific expression in petals and differential expression during flowering were successfully cloned and sequenced. Public databases blast showed that 120 TDFs had no homologous sequences, 12 TDFs had homologous sequences but their functions were unknown, and 150 TDFs had known biological functions, including the secondary metabolism, primary metabolism and development process, ect. qRT-PCR results of 6 TDFs with known functions comparing with cDNA-AFLP displayed that 4 TDFs with higher transcriptional level had consistent expression level. These results would be helpful to understand the gene expression of petals during flowering processes, and provide useful information for exploiting the mechanism of the floral color and scent formation of O. fragrans from molecular level.

Effects of copper stress on growth and antioxidant enzymes in sugarcane

2019/7/29 11:19:07
Sugarcane is the most important sugar and energy crop. It is also the potential plant for remediation of high metal-polluted soil. To evaluate the physiological response of sugarcane to copper(Cu)stress, the weight of sugarcane, content of chlorophyll, relative electrical conductivity in leaves and activities of antioxidant enzymes in roots were examined by hydroponics. The results revealed that the growth of sugarcane inhibited by Cu stress. The weight of shoot and content of chlorophyll decreased with the increase of Cu content in nutrient solution, while the copper content in shoot and relative electrical conductivity in leaves increased in response to copper stress. The malonaldehyde(MDA)content was increased significantly by 25.5% under 400 μmol·L^-1 treatment at 24 h when compared with the control, and then the rate increase raised with the prolonging of treatment time. The MDA content increased notably after 72 h under 100 μmol·L^-1 Cu treatment. The activities of SOD, POD and CAT changed significantly after 24 h treatment, but notable differences were found among different enzymes. The activities of SOD firstly dropped under 100 μmol·L^-1 treatment, and then increased with the increase of Cu content in solution under 200 μmol·L^-1 treatment, following with decrease of enzyme activities under 400 μmol·L^-1 treatment at 24 h, 48 h and 7 d. However, the activities of SOD increased with the increase of Cu content in solution at 72 h. The activities of POD increased with the increase of Cu content in solution, following with decline of enzyme activities under high content of Cu treatment at 24, 48 and 7 h except at 72 d. The activities of CAT decreased significantly with the increase of Cu content in solution and with the prolonging of stress time. The activities of CAT declined by 89.98%, 96.88% and 98.50% under three Cu treatments, respectively on the seventh day. Thus, the growth of sugarcane was greatly inhibited by copper stress and the change of SOD, POD and CAT activities might play an important role in alleviating oxidative stress caused by Cu stress.

Effects of light quality and seed size on fourteen species of plants in Puer region

2019/7/29 11:19:07
In order to provide a scientific reference for the protection of local plants, the germination characteristics of fourteen common plant seeds in Puer were studied under the conditions of white light, dark, red light and blue light, and the relationships between seed size and germination percentage and germination rate were analyzed. The results showed that light qualities had significant effects on seed germination percentage and germination rate on Elsholtzia blanda, Osyris quadripartita, Oxyspora paniculata, Ageratum conyzoides(P<0.05). The quality of light had no effect on the germination percentage and germination rate of ten species,Vernonia volkameriifolia, Gordonia chrysandra, Laggera pterodonta, Dodonaea viscosa, Crotalaria zanzibarica, Tadehagi triquetrum, Urena lobata, Shuteria vestita, Eurya groffii and Shuteria involucrata(P>0.05). Among the ten species, only the seeds of S. involucrata had germination rate > 20%, all others < 20%. Elsholtzia blanda seeds had the highest percentage in white(89.9%)and red light(84.7%), germinated the fastest in red light(4.93)and at the latest in blue light(11.3 d). The germination percentage of Osyris quadripartita seeds was the highest(80.4%)and their germination rate was the fastest in white light(2.71), the case was opposite under dark and blue light(43.9% and 38%). The seeds of O. quadripartita germinated firstly under white and red light(11 d)and lastly under dark light(21.7 d). The O. paniculata seeds had germination rate > 86% under white and blue light and dark condition, had germination rate of 32% and germinated slowest in red light(1.29), and germinated lastly in blue light(13 d). The Ageratum conyzoides seeds had highest germination percentage(71.3%)and germination rate(6.46)in red light, lowest in dark condtion(42.5% and 2.62). The germination initiation time of Vernonia volkameriifolia was the first in dark condition(6 d), then was white light(7 d), and the last was in blue(8 d)and red light(7.7 d). There was a significant negative correlation between seed germination rate and seed size in fourteen species. There was also a negative correlation between seed germination rate, germination initiation time and seed size, but it was not significant. The relationship between seed size and germination percentage, germination rate and initiation time did not change with the change of light quality.

Rooting and transplanting techniques of tissue culture plantlets of Vaccinium dunalianum

2019/7/29 11:19:07
Vaccinium dunalianum is one of the main plant sources for arbutin which is widely used in cosmetic formulations as the natural active agents to whiten the skin. During the tissue culture process of V. dunalianum, the base of the rooting plantlets obtained by the current culture medium often formed the callus, which significantly affected the survival rate after transplantation. In order to improve the rooting quality of the proliferation plantlets and survival rate of the transplanted plantlets of V. dunalianum. The optimum medium components for the root induction of the proliferation plantlets of V. dunalianum, including hormone types and concentrations, medium types and sucrose concentrations, were analyzed by the single factor experiment, and further probed the effects of different substrate ratios on the survival rate of the transplanted V. dunalianum plantlets in this study. The results showed that the medium types and the hormone types and their concentrations had more significant effects on the rooting rate than sucrose concentration. For the root induction, the optimal hormone and its concentration were IBA 2.0 mg·L^-1, the optimal media was 1/4MS and the optimal sucrose concentration was 15 g·L^-1. The most suitable medium for the root induction of the proliferation plantlets of V. dunalianum was 1/4MS+ IBA 2.0 mg·L^-1+ activated carbon 0.1 mg·L^-1+ sucrose 15 g·L^-1, by which the rooting rate could reach 100%, and the average number of roots was 7.67 per plant. The root system of proliferation plantlets of V. dunalianum was radially extended and none callus was formed at the base of the rooting plantlets. In addition, the tissue culture plantlets of V. dunalianum grew strong and had dark-green leaves. For the transplantation of V. dunalianum plantlets, the optimal media for transplantation was the 100% humus, in which the survival rate reached 83.7%, and the tissue culture plantlets obtained by the experiments grew well and had healthy leaves. The optimization system established by this study, which had effectively improved the roots quality and rooting rate of the proliferation plantlets and the survival rate of the transplanted plantlets of V. dunalianum, and provided scientific and technological support for the large-scale production of high quality V. dunalianum plants.

Effect of soil water content and inoculation with Funneliformis mosseae on growth of Bretschneidera sinensis seedlings

2019/7/29 11:19:07
In this paper, the mycorrhizal infection rates of Bretschneidera sinensis under different water treatments(40%, 60%, 80%, 100%)and time points were determined. Quantified morphological characteristics of the seedlings such as height, ground diameter, and number of leaves, together with malonaldehyde content and survival rate in the inoculation group and the control group before and after different water treatments were also determined. The results were as follows:(1)Under the condition of relative soil moisture content of 60%, the infection rates of mycelium, arbuscula and the total were the highest, low moisture content(40%)and high moisture content(≥80%)were not conducive to mycorrhizal fungi on the seedlings infestation.(2)The content of malondialdehyde in the inoculated seedlings was significantly lower than that of the control at 40% and 60% treatments, which suggested that inoculation with Funneliformis mosseae could increase seedling resistance to drought stress, but with no obvious effect on treatments of 80% and 100% high moisture content.(3)The relative water content of soil suitable for seedling growth under natural and inoculated conditions was 80% and 60%, respectively.(4)Under the same water conditions, the survival rate of inoculated seedlings was higher than that of the control, with the highest(90%)under 60% treatment, while the survival rate of seedlings was relatively low at 40% low moisture content and 100% saturated moisture content.

Schima argentea communities in the middle Luoxiao Mountains

2019/7/29 11:19:07
Schima argentea is a tall evergreen tree of Theaceae. It is often used as a fire-resistant species for afforestation. It has important ecological value. Luoxiao Mountains is an important habitat in eastern Asia. Four typical S. argentea communities in the middle Luoxiao Mountains, including Jinggang Mountain, Qiyun Mountain, Nanfengmian Mountain and Wuzhifeng Mountain, are studied with the method of community studies. This can help to enrich vegetation types study in Luoxiao Mountains. It can also help to explore relationship among S. argentea, altitude and latitude. The results were as follows:(1)The four communities separately contain vascular plants 84 species in 50 genera in 30 families, 106 species in 70 genera in 45 families, 78 species in 47 genera in 33 families, and 99 species in 66 genera in 38 families.(2)S. argentea is the dominant species in Jinggang Mountain and Qiyun Mountain, and it has the highest important value in the community, while it is the secondary dominant species in Nanfengmian Mountain and Wuzhifeng Mountain.(3)In Jinggang Mountain, Qiyun Mountain and Wuzhifeng Mountain, species richness is high and species distribute evenly, while in Nanfengmian Mountain, species richness is low and species distribute unevenly.(4)The succession stages of S. argentea population are different in the four communities. Jinggang Mountain and Qiyun Mountain populations are from stable stage to decaying stage. Nanfengmian Mountain population is in the decaying stage. Wuzhifeng Mountain population is in decaying stage, but it will re-invade into the community in the future.(5)Phanerophytes in all communities are above 75% of the total species, followed by geophytes and hemicryptophytes. In conclusion, four communities are divided into two types: one is the Nanfengmian Mountain community, mainly characterized by Rhododendron simiarum forest; the other is the communities of Jinggang Mountain, Qiyun Mountain and Wuzhifeng Mountain, which has abundant species, high biodiversity and tropical genera. The species number decreases with the increase of altitude, and decreases with the increase of latitude. Schima argentea communities are typical representatives of evergreen broad-leaved forest in the middle subtropical zone. The coexistence of S. argentea communities at different succession stages is another proof that the middle Luoxiao Mountains is a plant habitat.

Effects of water Cu pollution on growth and chlorophyll fluorescence characteristics of Vallisneria natans

2019/2/20 18:17:02
Vallisneria natans was selected as test materials and cultured in different concentrations of Cu polluted water. The lengths of leaves and roots, biomass, photosynthetic pigment, heavy metal content and chlorophyll fluorescence parameters of V. natans were observed. The results showed that the lengths of leaves and roots, biomass of V. natans were significantly decreased with the increase of Cu concentration. The leaves gradually lost chlorosis, the chlorophyll a decreased more than the chlorophyll b, and carotenoids had the smallest decline. Cu content in the leaves of V. natans increased significantly(P<0.05)with the increase of Cu concentration, and there was no significant difference in Cu content of roots between treatment groups. V. natans has normal photosynthetic activity when Cu was less than 0.5 mg·L^-1 in water. Except for the 0.5 mg·L^-1 treatment group, F_m, F_v/F_m, F_v/F_o, qP and Y(Ⅱ)were significantly lower than the control group(P<0.05), while qN, Y(NPQ)and Y(NO)showed an upward trend, in which F_v/F_o was the most sensitive to Cu pollution. In summary, the growth of V. natans was inhibited with the increase of Cu concentration, the efficiency of utilizing light energy of leaves was decreased, and the electron transfer of PS Ⅱ reaction center was obviously inhibited. V. natans consumed excess light energy in the form of heat through self-regulation, to reduce the extent of damage to PS Ⅱ reaction center. V. natans was a Cu hyperaccumulator which can be used an alternative species for ecological restoration of low-Cu-polluted water.

Effects of Cd stress on physiological characteristics of alfalfa and its Cd enrichment

2019/2/20 18:17:02
Taking seedlings of alfalfa variety ‘Medicago sativa cv. Gannong No. 3', we studied the effects of Cd stress on the length of stem and root, biomass, the contents of chlorophyll and malonyldialdehyde(MDA), the activities of superoxide dismutase(SOD)and peroxide enzyme(POD), Cd enrichment and Cd subcellular distribution in leaf of alfalfa seedlings under Cd stress with concentration between 0 to 20 mol·L^-1 for 10 d. The results showed that length of stem and root, chlorophyll content increased under lower Cd concentration(0.125 mmol·L^-1)stress. However, lower length of stem and root, biomass and chlorophyll content were observed under the higher Cd concentration(0.5～2.0 mmol·L^-1)stress. Accumulation of reactive oxygen species(ROS)in alfalfa seedlings under Cd stress caused membrane lipid system peroxidation, MDA content increased significantly, while the activity of SOD and POD was significantly enhanced. When the concentration of Cd stress was 0.5 mmol·L^-1, the activity of SOD and POD reached the maximum, which may be a protective reaction of plants to environmental stress, antioxidant enzyme system was started up to remove ROS accumulated during Cd stress and to mitigate membrane lipid peroxidation damage caused by Cd stress. Subcellular distribution of Cd in leaf was in the order of cell wall, cytoplasm, mitochondria, chloroplast, and the content of Cd in each subcellular fraction increased with the concentration increase of Cd stress. When the concentration of Cd was 0.125 mmol·L^-1, purification rate of Cd in the shoots of individual plants grown in nutrient solution for 10 d up to 0.214%, and the purification rate of Cd for whole pot plant per unit volume up to 15.5%. When the concentration of Cd was 2.0 mmol·L^-1, the content of Cd in the aboveground part of alfalfa seedlings was 89.36 μg·g^-1. Those results suggest that alfalfa has a very strong enrichment ability for Cd, although it does not meet the critical criteria for Cd-rich plants. However, alfalfa has a good application value in the phytoremediation of Cd-contaminated soil, considering the plant biomass, Cd tolerance, Cd enrichment, and purification rate of Cd.

Effects of saline-alkali stress on growth of Chrysanthemum morifolium ‘Hanluhong'

2019/2/20 18:17:02
We studied effects of saline-alkali stress on growth of Chrysanthemum morifolium ‘Hanluhong' and growth adaptability by simulating the saline-alkali stress intensity of Qingtongxia area. Three pH gradients(7.0, 8.0, 9.0)were set up in the experiment. Under each pH gradient, two neutral salts(NaCl and Na₂SO₄)and two alkaline salts(Na₂CO₃ and NaHCO₃)were used to configure mixed solutions with different saline concentrations(0, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%). Plant height, root length, photosynthetic characteristics and chlorophyll fluorescence were measured after each treatment. The results were as follows:(1)High concentration salt solution and pH value resulted in the decrease of these growth indexes.(2)The elongation rates of plant height and root length decreased at first and then increased in the imitating group with pH 8.0 and 0.4% salt concentration. When the stress time extended, the photosynthesis parameters, the maximum photochemical efficiency and the potential photochemical activity of photosystem Ⅱ decreased, but there was no significant differences among these fluorescence parameters. Considering the data of plant height, root length, photosynthesis and chlorophyll fluorescence, we deem that high saline-alkali environment is not beneficial to the growth and development of C. morifolium ‘Hanluhong', but C. morifolium ‘Hanluhong' can normally grow under the saline-alkali stress in Qingtongxia area. Therefore, it could be used in vegetation and ecological environment restoration for its salt and alkaline resistance.

Effects of slow-released sand selenium on selenium enrichment and growth of green cabbage

2019/2/20 18:17:02
Natural sand selenium(Se)is a readily available product which is air permeable and watertight. It is a kind of good matrix for producing Se enrichment plant. In order to test the efficiency of sand Se in cultivating green cabbage and provide Se as a nutrition source, we set five groups of experiments: CK(control group without fertilization), CT(natural sand Se), CT1(chicken manure:Sand Se=1:1), CT2(chicken manure:sand Se=1:2), CT3(chicken manure). The results showed that sand Se addition significantly increased Se content of green cabbage by 45%, 61% and 64%. Compared with the CK and CT3 groups, the yield, leaf thickness and water use efficiency of the green cabbage in CT2 increased significantly by 45%, 22.78% and 56.66%, respectively. Soil manganese and zinc content accounted for 72% variation of the green cabbage biomass and soil zinc accounted for 66% variation of the water use efficiency. These indicate that sand Se, particularly when mixed with chicken manure, not only can provide Se as a nutrition but also is beneficial to green cabbage yield.

Community characteristics of Castanopsis platyacantha, Schima scinensis forest in Wumeng Mountain

2019/2/20 18:17:02
Wumeng Mountain is located in the joint zonation between western semi-humid evergreen broad-leaved forest and eastern humid evergreen broad-leaved forest in China. Formation Castanopsis platyacantha, Schima sinensis is a typical forest in this area with complex and diverse types that are only occurrence of Yunnan. In order to understand the community characteristics of this formation in more details, and to find out its relationship with the eastern moist evergreen broad-leaved forest, in this paper, we made clustering analysis on the basis of canopy and shrub layer species. And then, we analyzed the dominant species in tree and shrub layers by DBH class structure, height class structure, and importance value, and carried out ordination analysis by DCA, CCA, and DCCA to reveal the relationship between community features and environmental gradients. Finally, we compared the communities with the similar ones in Emei Mountain. The results were as follows:(1)Castanopsis platyacantha, Schima sinensis community in Wumeng Mountain could be divided into six types: Castanopsis platyacantha community, Castanopsis platyacantha, Schima sinensis community, Castanopsis platyacantha, Dipentodon sinicus community, Fagus longipetiolata, Schima sinensis, Castanopsis platyacantha community, Schima sinensis, Lithocarpus hancei community, and Dipentodon sinicus, Schima sinensis community.(2)There was a large proportion of Castanopsis platyacantha trees in old age, and a great number of seedlings of Schima sinensis in the community. Meanwhile, bamboo species were tyipical dominant in the shrub layer.(3)Community patterns were mainly influenced by elevation, slope, and annual solar radiation.(4)Dominate tree species' population structures of similar communities in Emei Mountain were stationary or expansive type, but those were characteristics of constrictive type in Wumeng Mountain.

Characteristics of CO₂ flux and concentration in coniferous and broad-leaved mixed forest in Dinghu Mountain

2019/2/20 18:17:02
We analyzed the variation characteristics of the CO₂ flux, net ecosystem CO₂ exchange(NEE), CO₂ concentration and the relationship with meteorological variables on the basis of the CO₂ flux data and meteorological data of the southern subtropical evergreen broad-leaved forest flux observation station of Dinghu Mountain, a typical forest vegetation ecosystem in the Pearl River Delta. The research results were as follows:(1)The diurnal variation of CO₂ concentration appeared to be in the form of “peak-valley”. Specifically, the CO₂ concentration variation was nearly at its peak at night or around sunrise. And the CO₂ concentration variation was nearly at its valley in the afternoon; Diurnal variation of CO₂ flux generally appeared to be a “valley” curve, approaching minimum value(negative)around noon and reaching maximum(positive)in the morning and at night.(2)The seasonal average of CO₂ flux could be shown as the following order: spring> summer> winter> autumn. The order of the seasonal average of CO₂ concentration could be shown as the following order: winter> spring> autumn> summer, from which we could find that the non-growth season was higher than the growth season in that it was related to the seasonal variation of CO₂ source/sink intensity caused by the seasonal variation of plant phenology.(3)In 2012, the average annual concentration of CO₂ in Dinghushan forest ecosystem was 664.7 mg·m^-3. The annual mean value of CO₂ flux was -0.079 mg·m^-2·s^-1, and net ecosystem CO₂ exchange capacity(NEE)was -611 g C·m^-2·a^-1, which indicates that mixed confer-broadleaf forest at the Dinghu Mountain has strong carbon sink function in rapid growth during recent years.(4)CO₂ flux and CO₂ concentration had a significantly negative correlation with the temperature and the pressure difference of saturated water, of which the correlation between CO₂ concentration and the temperature was the highest, and the second was the saturated vapor pressure difference, which indicates that the temperature and saturated vapor pressure difference are the key meteorological factors that affect CO₂ flux and CO₂ concentration. We found that carbon sink function of Dinghu Mountain forest ecosystem had been enhanced in recent years, which could be influenced by human activities and climate change.

New discovery of floristic region of Central China

2019/2/20 18:17:02
As provincial new distributions, one genus and eight species(including two varieties)of dicotyledon from West Hubei and Northwest Hunan are reported in this paper. Among these species, new distributions of Hubei are Tubocapsicum anomalum, Thalictrum alpinum var. elatum, Sanguisorba filiformis, S. officinalis var. glandulosa, Embelia undulate, Physaliastrum chamaesarachoides, Mentha sachalinensis and Salvia tricuspis. Among these species, Tubocapsicum anomalum belongs to Tubocapsicum, which is a newly recorded genus in Hubei. New distribution of Hunan is Gleadovia mupinense. According to IUCN Red List Criteria, G. mupinense is regarded as endangered(EN). These new distributions enrich floristic region of central China and have some significance for plant protection.

An introduction to the main forest vegetation types of mainland SE Asia(Indochina Peninsula)

ZHU Hua — 2019/1/21 11:02:48
The vegetation of mainland Southeast Asia is less known to science. This article introduces the studies up to now on the vegetation of mainland Southeast Asia(Indochina peninsula), and describes the main fo-rest vegetation types based on fragmentary information and field visits. Seven main terraneous and wet land forest vegetation types, including coniferous forest, coniferous-broad-leaved mixed forest, tropical montane evergreen broad-leaved forest, tropical rain fo-rest, tropical seasonal moist forest, tropical monsoon forest, and dry thorny thickets/woodland(savanna), are recognized. Of them, the coniferous forest includes two subtypes: temperate coniferous forest and tropical coniferous forest; the coniferous-broad-leaved mixed forest includes also two subtypes: warm temperate and temperate coniferous-broad-leaved mixed forests; and the tropical rain forest includes four main vegetation subtypes: tropical lowland evergreen rain forest, tropical seasonal rain forest(tropical lowland semi-evergreen rain forest), tropical montane rain forest, and peat swamp forest. The study history of the vegetation in the region, its classification, physiognomic characteristics, and do-minant species composition, are also concisely introduced.

Overview of forage plant resources in rocky desertification area and its development and utilization analysis

2019/1/21 11:02:48
China's forage plants are rich in resources and variety, and they are the main components of grassland resources. A wide variety of forage plant resources is not only one of the main feed sources for the development of herbivorous and herbivorous animals, but also plays an important role in maintaining terrestrial ecological balance. The development and utilization of forage plant resources will be helpful not only to alleviate the shortage of forage grass and fodder in the development of animal husbandry, but also to solve the problem of “the contradiction between human and animal food”. The development and utilization of forage plant resources can also meet the needs of herbivorous animal husbandry project construction in the comprehensive management of rocky desertification, and promote the ecological restoration of rocky desertification areas, so as to achieve the purpose of combining rock desertification treatment and poverty reduction. We studied the ecological, economic and social values of forage plant resources, based on general situation of forage plant resources in rocky desertification area through literature review. For the comprehensive development and utilization value of forage plants, we analyzed their roles in the ecological restoration, regional economic development and ecological civilization construction in rock desertification areas. From forage plant their own features and characteristics of rocky desertification area geology and the consciousness of the local residents, we discussed the existing problems of development and utilization at forage plant resources in the rocky desertification area, and put forward the corresponding solution countermeasures. It is pointed out that the comprehensive development and utilization of forage plant resources in rocky desertification area is conducive to the herbivorous animal husbandry and ecological civilization construction and regional economic development in rocky desertification area. It is an effective way to alleviate the contradiction between people and land and promote the comprehensive management of rocky desertification, which also has great prospects for development and utilization.

Allelopathic effects of aqueous extract of Ageratina adenophora on seven native plant seedlings in growth and chlorophyll

2019/1/21 11:02:48
Ageratina adenophora was used as the donor, and seven kinds of native plants were used as the receptor, they were Pinus massoniana, Cunninghamia lanceolate, Broussonetia papyifera, Castanea mollissima, Zanthoxylum bungeanu, Camellia oleifera, Pyracantha fortuneana, respectively. We studied the allelopathic effects of Ageratina adenophora aqueous extract solution on chlorophyll content and growth of seedlings of tested plants. The results are as follows:(1)A. adenophora aqueous aqueous extract solution at low concentration can improve the chlorophyll a, chlorophyll b and total chlorophyll contents of Zanthoxylum bungeanu and Pyracantha fortuneana, but the effects on chlorophyll of the other five species was not significant. Ageratina adenophora aqueous extract solution at high concentration reduced the chlorophyll a, chlorophyll b and total chlorophyll contents of Cunninghamia lanceolate, Castanea mollissima, Broussonetia papyifera significantly. The chlorophyll b of Pyracantha fortuneana decreased significantly, while the chlorophyll b of Pinus massoniana increased on the contrary, there was no significant influence on Castanea mollissima and Zanthoxylum bungeanu.(2)We measured the receptor plant growth parameters and found that, Ageratina adenophora aqueous extract solution at high concentration had significant inhibitory effects on all growth parameters of the six receiver plants except for Castanea mollissima. Ageratina adenophora aqueous extract solution at low concentration could improve the ground diameters and crown widths of Pyracantha fortuneana, Zanthoxylum bungeanu and Cunninghamia lanceolata, but had no significant effects on growth parameters of the other four species.

Characteristics and spatial distribution of forest gap in a northern tropical karst seasonal rainforest in Nonggang, Guangxi, South China

2019/1/21 11:02:48
Forest gap is the dominant form of disturbance in many forest ecosystems. Gaps play an important role in forest helping to maintain forest regeneration and dynamics. Little is known about the gap pattern and characteristics of karst seasonal rain forests. In this study, high-spatial-resolution Worldview-3 satellite imagery was coupled with field data to assess gap disturbance regime and its pattern in a 15 hm² northern tropical karst seasonal rain forest dynamic plot in Nonggang National Nature Reserve, Guangxi. Total 305 gaps were identified, ranging in size from 10 to 371 m² and with mean size 52.3 m². The canopy gap fraction was 10.6%, and gap density was about 20 per hectare. The spatial pattern of gaps was clustered at scale 0-50 m. Significant association was found between gaps and big trees(DBH≥10 cm), and null associations between gaps and small trees(DBH<10 cm)and between gaps and standing dead trees. The prevailing ecological factors had different influence on gap distribution and gap characteristics. Convexity, altitude above channel(AAH)and tree species richness had significant effect on the gaps distribution. Gap size was significantly influenced by slope, mean elevation and tree species richness. Gap perimeter was mainly affected by mean elevation, rock-bareness rate(RBR), topographic wetness index(TWI), AAH and tree species abundance. These results indicated that gap disturbance was very frequent in karst seasonal rain forests, and there were topographic differentiation in spatial distribution and characteristics of gaps resulted by the combination effects of unique special karst geological conditions, habitats and the biological characteristics of karst forest.

Variation of total organic carbon flux in forest hydrological processes in karst experimental site, Guilin

2019/1/21 11:02:48
In order to reveal the annual variation characteristics of TOC concentration and flux in different vegetation canopies, total organic carbon(TOC)concentration and its flux in precipitation, throughfall, stemflow, borehole water and epikarst spring water were monitored in two typical vegetations(Toona sinensis and Caesalpinia decapetala )in karst rocky mountain area, Guilin, Guangxi. The results indicated that in the process of rainfall through the atmosphere-vegetation-soil/rock profile, the variation trend of TOC concentration was stemflow>throughfall>borehole water>epikarst spring water>rainfall. The TOC concentration in throughfall and stemflow was bigger in rainy season and smaller in drought season. The monthly TOC concentration in borehole water and epikarst spring water was relatively stable. The increase of TOC concentration was different, and average increment and amplitude of TOC concentration in throughfall and stemflow were larger than that in borehole water and spring water. The TOC concentration of stemflow was negatively correlated with stemflow water quantity in Toona sinensis forest. TOC average monthly flux was throughfall in Caesalpinia decapetala > throughfall in Toona sinensis > precipitation> spring >stemflow in Toona sinensis > stemflow in Caesalpinia decapetala. The TOC flux under shrub rain(204.86 kg·hm^-2)was 1.3 times that in Toona sinensis(153.48 kg·hm^-2). The TOC flux from rainfall input was 63.06 kg·hm^-2, with 48.29 kg·hm^-2 TOC flux from epikarst spring output. The TOC difference between input and output was 14.77 kg·hm^-2, which indicate that TOC in system was a positive balance. When precipitation entered vegetation, vegetation canopy, as “TOC live reservoir”, increased TOC flux and was a carbon “source”, however, soil-rock system in epikarst zone, as “TOC dead reservoir”, was carbon “sink” with absorption, filtration and fixing of TOC.

Features of soil mineral elements in man-made forest of Guizhou karst mountain area

2019/1/21 11:02:49
In order to illustrate the soil mineral element feature of community level, we discussed the content features of mineral elements and the correlations and classified metallic element and non-metallic element with the typical man-made forest in Guizhou karst mountain area as object. The results indicated that there were large differences in the soil mineral element contents of the typical man-made forest in the area, meanwhile the elements had different ranges in the different tree species. The change rules of Zn, Cr, Fe, Ti, Al, Mg, Ni, Co were relatively consistent, Ca and Sr's were relatively similar. The content of As, Se, Si were high in Eucalyptus robusta forest, Cupressus funebris forest and Eriobotrya japonica forest, while the contents of S, Na, Cl were just the opposite. The change rule of different mineral elements was not in conformity with different forest types, which indicated that the extraction and accumulation ability of plant root system were different. There was a degree of relativity among mineral elements, the correlativity of different mineral elements differed and represented enhancement inhibitory effect, and especially Fe and Ca had close relationship with other elements. The interaction effect and measure equilibrium relationship of mineral elements were the key to analyze the features of element compositions and a scientific problem deserved to be further studied. The research results are in favor of mastering nutrient element accumulation features and regulation, and have an important theoretic and practical significance to soil nutrient management of typical plantation in the area.

Plant diversity and composition of ecological floating bed affect domestic sewage purification

2019/1/21 11:02:49
Ecological floating bed system has been the hotspot of research and application in the comprehensive management of polluted water environment. In order to analyze the effects of its plant diversity and composition on purification of domestic sewage, we established five species diversity levels and two composition arrangements by using Arundo donax as dominant and constructive species, and measured the plant growth, system productivity and N, P, COD removal rates. The results showed that the individual biomass and relative growth rate(RGR)of wetland plants(such as A. donax)decreased with increasing species diversity, while the survival and growth of mesophytes were promoted. Higher species diversity decreased the productivity of the system, but increased significantly the removal rates of N, P and COD. At the same level of species diversity, the combination with more mesophytes had lower system productivity than that with more wetland plant species, but the former had higher N, P and COD removal rates. Under the same species diversity and combination, P removal rate was the highest, N removal rate was followed, and COD removal rate was the lowest. Moreover, their removal rates showed a trend of slow decline after rapid increase with time. These results indicate that the species richness and combination of ecological floating bed system can affect domestic sewage purification. In the process, pollutants can be removed by direct absorption and adsorption of plants, but the role of microorganisms may be more important.

Effects of different regeneration modes on understory plant functional group in Eucalyptus plantations

2019/1/21 11:02:49
We evaluated the relationships between composition, distribution and regeneration modes of understory plant functional groups and environmental factors, through the combination methods of field investigation and analyzed experimental to elucidate the changing rules of understory plant functional group in two different regenerated Eucalyptus plantations and the related influencing factors. Our results indicated that the species richness of understory plant functional groups in forest generated after five years increased but not significantly(P>0.05)compared to control plots(cut-over land)except for forbs. The 5-year forest regeneration caused increasing of relative abundance of vines and ferns, but that of grass was significantly decreased(P<0.05). The relative coverage had a great resemblance to relative abundance, which exhibited increasing in woody plants, vines and ferns in 5-year regeneration forest, but decreasing in grass(P<0.05). Principal component analysis(PCA)showed that the composition and distribution of understory plant functional groups significantly changed in sprouting regeneration forest and planting regeneration forest compared to control plots. Redundancy analysis(RDA)revealed that canopy light transmittance, slope aspect, soil porosity and N/P ratios were key factors in regulating plant functional groups in Eucalyptus plantations, and the accumulative effects explained more than 75.0% of total variations in understory plant functional groups. The sequencing mode analysis suggested that canopy light transmittance was the most significant factor in affecting understory plant functional groups in Eucalyptus plantations. We found in short-term studies that sprouting and planting regeneration had limited effects on the understory plant functional groups in Eucalyptus plantations, and which may be caused by similar canopy structure and soil physicochemical properties.

Plant growth-promoting traits of yeasts on Jatrophacurcas under lead and cadmium stresses

2019/12/27 10:09:50
In order to screen yeasts with resistance and adsorption to lead and cadmium, to construct a Jatropha curcas root-yeast phytoremediation system, and to promot the growth of J. curcas under high concentrations of lead and cadmium stresses, in this study, three endophytic yeasts with lead and cadmium resistance were isolated by surface-sterilized methods from the healthy J. curcas root, Davidia involucrata stem, D. involucrata root, named as Jc, Di1, Di2, respectively. The isolate were identified as Rhodotorula sp., Candida sp., Debaryomyces sp. based on morphologic, physiological and biochemical characteristics. They could grow on the PDA medium with a concentration of 500 mg·L^-1 Pb(NO₂)₂ or 50 mg·L^-1 CdCl₂·2.5 H₂O. Rhodotorula sp.(Jc)and Candida sp.(Di1)yeasts with adsorb ability of lead and cadmium were used to inoculate J. curcas seedling to study effects on the growth of J. curcas under cadmium and lead stresses; from morphological, biochemical and physiological characteristics, antioxidase of J. curcas plants inoculated yeasts under lead and cadmium stresses were also measured. The dry weights of J. curcas roots, shoots, leaves and whole plants showed a significant increase when the Rhodotorula sp.(Jc)and Candida sp.(Di1)yeasts were inoculated compared with non-inoculated CK plants. The plant growth-promoting effects of Rhodotorula sp. Jc and Candida sp. Di1 yeasts could be attributed to decreasing concentration of lead and cadmium in root, shoot and leaf; increasing activities of POD, SOD and CAT and concentration of chlorophyll, as well as concentration of nitrogen, phosphate in whole plant; and decreasing the concentration of malondialdehyde(MDA). Therefore, Rhodotorula sp.(Jc )and Candida sp.(Di1)yeasts may act as passivator of lead and cadmium to promote the growth of J. curcas under lead and cadmium stresses. This study is very important to improve phytoremediation efficiency of lead and cadmium contaminated soil by Jatropha curcas.

Photoinhibition and recovery of photosystem Ⅱ of three broad-leaved evergreens under low temperature stress

2019/12/27 10:09:50
The limits on photosynthesis of subtropical evergreen trees imposed by winter low temperature are mainly from photoinhibition of photosynthetic apparatus. To understand the extent of photoinhibition of photosystem Ⅱ(PS Ⅱ)and the mechanism of photoprotection of evergreen trees under winter low temperature stress, PS Ⅱ photoinhibition and recovery were studied in three broad-leaved evergreen tree species Photinia &#215; fraseri, Eriobotrya japonica and Cinnamomum bodinieri. The results were as follows: PS Ⅱ of Cinnamomum bodinieri was severely depressed and suffered photoinhibition under freezing and chilling temperature, and function of PS Ⅱ was unable to fully recover at spring normal temperature. Photinia &#215; fraseri showed the most unaffected PS Ⅱ function and the least photoinhibition, whereas the situation in Eriobotrya japonica was in the intermediate. Accordingly, Photinia &#215; fraseri maintained the level of non-photochemical quenching(NPQ)almost as high as at normal temperature, and NPQ of Eriobotrya japonica showed a little decrease but recovered at normal temperature condition. Cinnamomum bodinieri displayed the lowest NPQ under low temperature and was unable to totally recover. Furthermore, all the three tree species showed a strong negative relationship between NPQ and PS Ⅱ photoinhibition, which was indicated by the maximum potential photochemical efficiency of PS Ⅱ(F_v/F_m)and the quantum yield of non-regulated energy dissipation of PS Ⅱ [Y(NO)]. Overall, the results demonstrate that Photinia &#215; fraseri is more resistant to low temperature stress than Eriobotrya japonica and Cinnamomum bodinieri in terms of PS Ⅱ. At the same time, NPQ plays an important role for protecting PS Ⅱ of these trees from photoinhibition under low temperature.

Absorption of poorly soluble phosphorus by sugarcane seedlings and its response to low phosphorus stress

2019/12/27 10:09:50
In order to make clear the physiological and biochemical mechanism of sugarcane adapting to low phosphorus stress, to tap the potential of sugarcane self-phosphorus, and to reveal the possible mechanisms of sugarcane adaptation to low phosphorus stress, the absorption of insoluble phosphorus in sugarcane seedlings, the physiological responses to root and root architecture under low phosphorus stress by hydroponic and pot-culture were studied, by using two sugarcane varieties ROC22 and ROC10 as materials. The results were as follows:(1)The number of leaves, the dry weight of the shoots and the biomass of sugarcane in the culture medium with insoluble phosphorus(Ca-P and Al-P)as phospho-rus source, were significantly increased compared with those treated with phosphorus deficiency(-P). Moreover, compared with the control(+P), the total phosphorus accumulation of sugarcane also increased significantly, reaching 30%-77% of the phosphorus accumulation in the control(+P)treatment.(2)Under the condition of low phosphorus, the roots of sugarcane seedlings tended to distribute in deep soil, the total volume of roots increased, the longest root length became longer, and the distribution of shallow roots increased.(3)Under the low phosphorus environment, the sugarcane seedlings were obviously acidified in the rhizosphere environment, and the root exudates could dissolve the inso-luble aluminum phosphorus, and the activity of acid phosphatase in the plants was also significantly enhanced. The above results indicate that sugarcane seedlings have strong ability to absorb and use insoluble phosphorus, while roots increase under low phosphorus conditions, the roots of the main roots and the distribution of shallow roots increase, the acidification of the rhizosphere and the enhancement of acid phosphatase activity in the plants, which may be an important me-chanism for sugarcane seedlings to adapt to the phosphorus deficiency environment.

Effects of gallic acid on cell structure of Xanthomonas oryzae pv. oryzicola

2019/12/27 10:09:50
Gallic acid(GA)is a phenolic compound, and presents various biological activities in plants. Our previous experiments demonstrated a relatively strong inhibitory effect of GA on Xanthomonas oryzae pv. oryzicola(Xoc). In order to elucidate the effects of GA on the cell structure and membrane permeability of the pathogen, morphological structures of bacteria treated with GA were observed by electron microscopy, the integrity and the permeabilities of membrane of Xoc were investigated by determining the release from cells of materials that absorb at 260 nm, and changes in the fluorescence of cells treated with the fluorescein diacetate(FDA)and lactate dehydrogenase(LDH)activity. After treating with 200 μg·mL^-1of GA, many pits and irregular vesicles were found on the cell surface under electron microscopy, indicating that GA could damage the cell walls of Xoc. The electrical conductivity from Xoc suspensions 24 h after GA treatment was 135.48 μS·cm^-1(that of control was 127.85 μS·cm^-1), and the fluorescence intensity of Xoc suspensions 2 h after GA decreased by 58.10%, indicating that cells leaked electrolytes and cytosolic contents. Meanwhile, the acti-vities of LDH in bacterial suspensions treated with GA also increased, suggesting that GA could damage the structure of the bacterial cell membrane. In addition, the absorbance at 260 nm from Xoc suspensions was 1.004(that of control was 0.018), indicating that GA could negatively affect Xoc cell wall integrity. These results indicate that GA can not only alter the permeability of the cell membrane of Xoc, but also can impact the integrity of cell membrane.

Recalcitrance of Quercus wutaishanica seeds— Sensitivity to desiccation and low temperature

2019/12/27 10:09:50
Experiments of desiccation treated by silica gel(rapid desiccation)and electric constant temperature at 35 ℃ drying oven(slow desiccation)and cold(4 ℃)and frozen storage(-4 ℃)were conducted to investigate the sensitivity of Quercus wutaishanica seeds to desiccation and low temperature and their effects on the seed germination. The results showed that high water content(96.0%)and germination percentage(78.9%)of Q. wutaishanica seeds at shedding period. The germination percentage(GP), germination rate(GR), germination index(GI)and vigor index(VI)of seeds desiccated rapidly and slowly all exhibited trends of decline, with the prolonging of desiccation time and the decreasing of seed water content. Desiccation treatment of 96 h(the water content of seeds desiccated rapidly and slowly was 66.0% and 69.8%, respectively)led to entire loss of seed viability. A significantly positive relationship was detected between the seed viability and water content of Q. wutaishanica seeds, while slight desiccation facilitated the seed germination. Seeds desiccated rapidly had higher tolerance to drying compared with seeds desiccated slowly. Seeds of Q. wutaishanica could not tolerate low temperature storage and the GP, GR, GI and VI all markedly declined after being coldly storage at 4 ℃ for 30 d or frozenly storage at -4 ℃ for 6 h. Cold storage at 4 ℃ for 90 d or frozen stored at -4 ℃ for 48 h resulted in that all seeds lost their viabilities.

Effects of heavy metal nickel stress on physiological and biochemical characteristics of Helianthus annuus seedlings

2019/12/27 10:09:50
In order to reveal the response mechanism of Helianthus annuus nickel stress, nutrient solution culture experiments were carried out to probe the affection of heavy metal nickel on physiological and biochemical characteristics by using Helianthus annuus seedlings as materials. The results showed that low nickel concentration(≤10 mg·L^-1)was beneficial to the seedlings growth, and high nickel concentration(≥50 mg·L^-1)had obvious inhibitory effects on seedlings. With the increasing of nickel concentration, the physiological and biochemical indexes changed greatly, in which chlorophyll, soluble sugar(SS), soluble protein(SP), peroxidase(POD)activity, free proline(Pro), all their contents increased when the nickel concentration was 1-10 mg·L^-1, and decreased when the nickel concentration was 50-100 mg·L^-1; but the content of malondialdehyde(MDA)continued to rise. This indicates that the seedlings can used autoregulation to improve resistibility by increasing POD, Pro and MDA in low nickel concentration(1-10 mg·L^-1), and that seedlings have certain resistance to heavy metal nickel, while high concentration(50-100 mg·L^-1)nickel stress will destroy its own defense system so as to affect the growth and development of seedlings.

Species abundance distribution feature and protection priority area of the national protected wild plants in Guizhou Province

2019/12/27 10:09:50
We used the national protected wild plants as indicator species and combined with the statistical survey information of the national protected wild plants in the county(city, district)to analyze the geographical distribution feature of species richness based on the GIS technology in Guizhou Province. We applied Dobson algorithm to identify the protection priority area of national protected plant. Then we used the information of existing nature reserves to assess the protection status of the national protected wild plants priority conservation areas in Guizhou. The results were as follows:(1)In terms of the species richness distribution of the national key protected wild plants in Guizhou, the southern region was generally higher than the northern region, and the species richness of the area extending inland from the provincial boundary was obviously decreasing.(2)In terms of the 75% and 100% national protected wild plants conservation levels, four and seventeen counties(cities, districts)like Libo County, were identified priority conservation areas. Among them, one and nine national priority zones of key protection of wild plants covered less than 5% of the nature reserves, and 68.26% of the areas involved were at city/county level.(3)The areas with abundant wild plant species under state key protection and the biodiversity hotspots in the whole province had good spatial correspondence with the selected priority areas in Guizhou.(4)Local protection of wild plants under state key protection should be carried out in priority areas with rich geographical distribution of wild plants under state key protection combined with priority areas selected in this study in Guizhou.

Hypochaeris albiflora and Solanum diphyllum, two newly naturalized plants in mainland China

2019/12/27 10:09:50
Two newly naturalized plants, namely Hypochaeris albiflora (Kuntze)Azevêdo-Gonç. & Matzenb.(Asteraceae)and Solanum diphyllum Linn.(Solanaceae), were first recorded in mainland China. Hypochaeris albiflora is native to South America, and has become locally naturalized in Panlong District, Yunnan Province, Southwest China. In genus Hypochaeris, H. albiflora is characterized by its basal leaves entire or dentate, sometimes pinnately lobed to deeply lobed, cauline leaves linear, capitula cylindrical or narrowly campanulate, florets white and achene with four ribs. Solanum diphyllum is native to the Mexico and Central America, it is now found naturalized in Mengla County, Yunnan Province, Southwest China. S. diphyllum is a perennial evergreen shrub and characterized by its upper leaves usually arranged in pairs on each node and unequal in size, mature fruits yellow. In additon, the potential harm and invasive risks of these two naturalized plants are briefly assessed as well.

Effects of exogenous ascorbic acid on alleviating aluminum stress in rice seedlings

2020/5/18 11:13:48
The aim of the experment was to study the effects of exogenous ascorbic acid(AsA)on oxidative damage of rice under aluminum(A1³⁺)stress. A hydroponic experiment was conducted with the Peak 1A(sterile line, Indica)and Dian Superior 35(Hybrid, Japonica)to study the effects of exogenous AsA on the contents of H₂O₂ and endogenous AsA and the activities of antioxidant enzyme in roots of the two rice varieties under 50 μmol·L^-1A1³⁺ stress. The results showed that the content of endogenous AsA was 0.90-fold of the control, and the content of H₂O₂was 0.55-fold to 1.3-fold, the activities of SOD, POD, CAT and APX were 0.83-fold to 1.6-fold, 1.0-fold to 1.3-fold, 0.85-fold to 1.2-fold, 1.0-fold to 1.8-fold higher than that of the control in roots of the two rice varieties under A1³⁺ stress for 24 h, respectively. Under exogenous AsA treatment for 24 h, the content of endogenous AsA was 1.2-fold of the control, and the activities of SOD, POD, CAT and APX were 1.2-fold to 2.2-fold, 1.5-fold to 1.6-fold, 1.3-fold to 1.7-fold,1.2-fold to 2.6-fold higher than that of the control, respectively, while the content of H₂O₂was only 0.1-fold to 0.6-fold higher than that of the control in rice roots. There results indicate that Al³⁺ stress can increase the degree of membrane peroxidation, and induced antioxidant enzyme activities to enhance the ability of scavenging ROS. While application of exogenous AsA not only could alleviate the oxidative damage induced by Al³⁺ stress, but also had a significant effect on reducing the damage of cell membrane system by enhancing antioxidant enzyme activities and AsA content, thereby promoting the rice growth, which provided theoretical information for exogenous AsA to improve the ability of rice to adapt to Al³⁺ stress.

Global transcriptome analysis of Botrychium ternatum and screening of its plant hormone signal transduction related genes

2020/5/18 11:13:48
Botrychium ternatum is a commonly used folk medicinal plant, its growth and development have some typical representative characteristics of some fern plants. But researches on it mainly focus on chemical constituents, clinical and pharmacological effects, classification and distribution investigation, few about its molecular biology.Plant hormone is a sort of small signal molecular and has very important function to plant growth and development, and plant hormone signal transduction plays a key role in hormonal equilibrium. To obtain related information, Illumina HiSeq 2500 platform was used to perform transcriptome sequencing and bioinformatics analysis were carried out afterwards. Results showed 6.67 Gb clean reads was obtained and 58 646 Unigenes were assembled with an average length of 1 023 bp. Unigenes were annotated in nonredundant protein database(NR), nucleotide sequence database(NT), gene ontology(GO), clusters of eukaryotic orthologous groups(COG), Kyoto encyclopedia of genes and genomes(KEGG),Swissprot and Interpro databases with an overall annotation rate of 69.25%.Through GO annotation, 20 762 genes were annotated to three terms and 52 functional groups. A total of 20 633 genes were divided into 25 functional cluster by COG annotation. Through KEGG analysis, 29 377 genes were mapped to five groups and nineteen sub-groups pathways. In addition, 41 gene families related to eight plant hormone signal transduction pathways were screened. Through BLAST and ESTScan, 43 102 coding sequences(CDS)were found, with average length 749 bp, N50 1 137. 60 transcript factor gene families with total 1 520 genes were screened out, including C3H, MYB,MYB-related, bHLH,AP2-EREBP,WRKY and GRAS. 17 195 single-nucleotide polymorphisms(SNP)were found, including 11 122 transitions and 6 073 transversion. And 8 245 simple sequence repeats were found, among them di-nucleotide repeats and tri-nucleotide repeats rank the top two abundance. These data sets provide functional and structural information of global transcriptome and putative genes involving plant hormone signal transduction, and basic data for further research on the growth, development and variety identification of B. ternatum.

A comparative study on diversity and composition of greening tree species in parks of different ages in Chongqing

2020/5/18 11:13:48
Greening tree communities in fifteen comprehensive parks in Chongqing were investigated to analyze the impact of park age on the diversity and composition, and homogeneity among parks. Park age was divided into three stages including before liberation(before 1949), before the municipality period(1950-1998)and after the municipality period(after 1999). The results were as follows:(1)There were 59 tree species, belonging to 28 families and 48 genera, among which native tree species accounted for 81.36%, exotic tree species accounted for 18.64%.(2)There was no significant differences in the richness of park trees among the three stages, but the tree abundances in the park after liberation and after the municipality period were significantly higher than that before liberation; The proportion of alien tree species in community was no significant differences among the three stages; The application of Ficus virens, F. concinna, and Koelreuteria bipinnata in the park was decreasing, while the application of Cerasus serrulata, Magnolia grandiflora, Osmanthus fragrans, and Michelia champaca was increasing.(3)The degree of homogeneity between parks of different ages was low, but the Jaccard similarity index between plant communities in the parks before liberation was significantly higher than that in the other two stages. There was no significant relationships between the Jaccard similarity index and the age of park. The historical factors, garden culture and modern urban greening regulations may be the limiting factors for the use of alien species and may lead to a low degree of homogeneity of small-scale plant communities.

Effects of culture conditions on induction of Panax quinquefolium adventitious roots

2020/5/18 11:13:49
This study reported the improved induction rate and growth speed of Panax quinquefolium adventitious roots cultured on the basal media supplemented with varying IBA, sucrose, NO₃^-:NH₄⁺ ratio and PO₄^3-, etc. The results were as follows: In the whole process of adventitious root induction, three main phases could be distinguished including dedifferentiation(callus formation), redifferentiation(initiation of adventitious root), and elongation of roots. And it achieved the best induction of adventitious roots from explants cultured on the MS containing high concentration of mineral elements, which probably fulfilling the requirement for nutrients at stage of callus formation. Amid experiments of IBA, at a concentration of 2 mg·L^-1 was the most effective in inducing adventitious roots with(96±3.5)% of induction rate, at which dense distribution of adventitious roots on the surface of callus could be observed. Additionally, 30 g·L^-1 sucrose was proved to be the optimal concentration, however, it would grow into stubbly roots upon the increase of sucrose concentration. Furthermore, the effect of NO₃^-:NH₄⁺ ratio and PO₄^3-concentration on adventitious root induction was also evaluated. The maximum induction rate was obtained in 20:10 ratio of NO₃^- to NH₄⁺(total N source of 30 mmol·L^-1)and 25.0 mmol·L^-1 PO₄^3-, respectively. The present data suggest that modification of media ingredients can significantly enhance the induction and growth of P. quinquefolium adventitious roots, which would provide theoretical support for following large-scale culture of P. quinquefolium adventitious roots.

Geographic variation of seed and seedling traits of Dalbergia odorifera from different places

2020/5/18 11:13:49
To reveal variation rule of phenotypic traits of seed and seedling of Dalbergia odorifera from different places, nine phenotypic traits of seed and seedling growth were compared and analyzed through variance analysis, correlation analysis and principal component analysis, by taking seeds from ten locations of Hainan, Fujian, Guangxi and Guangdong and the seedlings cultivated in Guilin as experimental materials. The results were as follows: There was considerable variability in the phenotypic traits of D. odorifera seeds and seedlings, and the differences among the nine phenotypic traits were extremely significant. The average coefficient of variation(CV)of each trait was 12.50%, ranging from 7.94% to 18.89%. The variation of seedling growth traits was above that of seed traits, showing that the seed traits had higher stability. Relevant analysis showed that there were separate correlations among all phenotypic traits, between phenotypic traits and geographic-climatic factors. There was no significant correlation between phenotypic traits and longitude, latitude and annual precipitation. Altitude, annual average temperature and annual rainfall were the major factors affecting the traits of D.odorifera seeds and seedlings. Three families with better seed morphology, seedling growth and germination were screened out by principal component comprehensive score method on which the families were confirmed in growing areas of Xianyou, Danzhou and Jianfengling. The study provides a scientific information for the screening of D. odorifera germplasm resources.

Effects of different calcium ion concentrations on photosynthetic and physiological indexes of calcicole-type and calcifuge-type golden Camellia

2021/3/8 10:07:44
In order to explore the physiological adaptation mechanism of calcicole-type golden Camellia to high calciumion environment and analyze the main reasons that the calcifuge-type golden Camellia can not grow on calcareous soil,a pot experiment was conducted with two species of calcicole-type golden Camellia(Camellia multipetala and C. limonia)and two species of calcifuge-type golden Camellia(C. nitidissima and C. tunghinensis)seedlings. To exclude the influences from other confounding factors, each pot was filled with sand instead of soil. The seedlings were treated with four Ca levels, 5, 25, 50, 100 mmol·L^-1. The photosynthetic and physiological indexes of two different types of golden Camellia were measured. The results were as follows: The net photosynthetic rate(P_n), stomatal conductance(G_s), actual photochemical efficiency(ΦPS Ⅱ), electron transfer efficiency(ETR), Chl a, Chl b and total Chl of the calcifuge-type golden Camellia decreased with the increase of Ca²⁺ concentration, which indicates that the photosynthetic capacity of these two species decreased under the high calciumion environment; While these indexes in the calcicole-type golden Camellia did not change significantly under different Ca²⁺ concentrations, indicating high calciumion environment did not affect its normal photosynthesis. The content of malondialdehyde and the PS Ⅱ maximum photochemical efficiency(F_v/F_m)of the calcifuge-type golden Camellia did not change significantly under high calciumion environment, indicating that its photosynthetic membrane system has not been damaged. With the increase of Ca²⁺ concentration, the proline content of the calcifuge-type golden Camellia increased significantly, while the soluble sugar content did not change much; The proline and soluble sugar content in calcicole-type golden Camellia were not obviously changed under different Ca²⁺ concentration, but the soluble sugar content in calcicole-type golden Camellia was significantly higher than that of the calcifuge-type golden Camellia. Calcicole-type golden Camellia were not sensitive to the external calciumion concentration, its physiological mechanism of adaptation to high calciumion may be related to the higher content of soluble sugar in leaves; However, the adaptability of calcifuge-type Camellia to high calciumion environment was poor, which may be the main reason for its inability to grow on calcareous soil.

Effects of drought-rewatering on leaf water potential of two Dendrobium plants

2021/3/8 10:07:44
Dendrobium plants are attached to other plants or rocks, and water is difficult to obtain. Its special water use strategy is an important guarantee for its survival and development. In order to clarify the adaptability and mechanism of Dendrobium plants to drought stress, three-year-old D. nobile and D. officinale were selected, and the drought stress and rewatering treatment were carried out by potted water control, and leaf water potential changes of the two Dendrobium species were studied under different drought durations and rewatering conditons. The results were as follows: With the prolongation of drought time, the leaf water potential of the two Dendrobium species were increased; The leaf water potential of D. nobile increased from(-1.04±0.02)MPa at the time of full water supply to(-0.86±0.03)MPa at 60 d of drought, and the leaf water potential of D. officinale increased from(-1.04±0.02)MPa to(-0.87±0.03)MPa; The two Dendrobium species showed the drought-tolerant adaptation mechanism of high-water potential delayed dehydration; Rewatering after the end of drought, the leaf water potential of the two Dendrobium species showed a downward trend with the increase of rewatering time; After rewatering for 20 d, the leaf water potentials of D. nobile and D. officinale were(-0.96±0.05)MPa and(-0.96±0.02)MPa, respectively, and did not return to the level of sufficient water supply before drought; Correlation analysis showed significant correlation between soil moisture content and leaf water potential(P<0.05). In summary, both Dendrobium plants showed strong drought stress tolerance ability and relatively poor post-stress recovery ability.

Effects of selenate at different concentrations on growth and physiological indexes of tea tree

2021/3/8 10:07:44
Using hydroponic experiments with one-year-old cutting seedlings, we investigated the effects of sodium selenate(Se concentration of 0, 0.15, 0.3, 1.5, 3, 5 and 8 mg·L^-1)on selenium accumulation, plant growth, physiological index, and microscopic structure of tea tree. The results were as follows: The selenium contents in the roots and shoot of tea seedlings were positively correlated with the selenium level in the nutrient solution; With the increase of selenium level, the plant growth indexes including the fresh weight of tea seedling, the number of lateral roots, the root biomass, the contents of photosynthetic pigments, and root activity tended to increase initially and then decrease, and the tea quality indexes such as tea polyphenols, soluble protein and soluble sugar contents also presented the similar trend; However, the contents of malondialdehyde, hydrogen peroxide, and proline decreased in treatments of low selenium levels, and then increased in treatments of high selenium levels. Anatomical analysis of the root tips revealed different effects on the microscopic structure of roots under low and high selenium concentration. The cortex parenchyma cells of root treated with the low Se concentration(0.15, 0.3 and 1.5 mg·L^-1)were intact and well-shaped, and the root epidermal cells were smaller; Treatments at high selenium level(Se≥3 mg·L^-1)demonstrated larger root epidermal cells and damaged parenchyma cells with irregular shape, which showed stress responses. All together, the findings revealed that Se(IV)induced dual effects on tea seedlings. Se-supplementation with appropriate level(0.3 mg·L^-1)showed beneficial effects on plant growth and tea quality by improving root activity and photosynthetic efficiency, minimizing the accumulation of peroxide and proline, and increasing both of the biomass and tea polyphenols contents. While excessive-Se(especially at 8 mg·L^-1 Se)showed opposite effects on the parameters mentioned above and led to the reduction of plant growth and tea quality. These data might be helpful to explore the mechanism of dual effects of selenate on the growth of tea tree and provide reference for cultivation of Se-enriched tea.

Morphological and photosynthetic physiological characteristics of Melia azedarach seedlings under

2021/3/8 10:07:44
To explore the response mechanism of Melia azedarach to salt stress and to provide reference for the application of M. azedarach in saline and alkaline areas. One-year-old M. azedarach seedlings grown in pots were used as materials, and subjected to sodium sulphate or sodium carbonate of three concentrations(200, 400, 600 mmol·L^-1)for 40 d to study the growth, physiological and photosynthetic parameters. The results were as follows: The growth of seedling height, ground diameter and biomass showed downward trends with the increase of salt concentration under neutral or alkaline salt stress, and the decline was greater under alkaline salt stress. Salt stress increased the root to shoot ratio. On the 10th day, all photosynthetic parameters showed similar decline characteristics under neutral or alkaline salt stress, and the decrease extent under alkaline salt stress was significantly greater than those under neutral salt stress. With the increase of treatment time, the net photosynthetic rate and transpiration rate decreased significantly under neutral salt or alkaline salt. With the increase of salt concentration, the chlorophyll content showed a downward trend. Salt stress of 200 mmol·L^-1 had little effect on the chlorophyll content, but 400 and 600 mmol·L^-1 salt stress had significant effect on the chlorophyll content. Under 600 mmol·L^-1 alkaline salt stress, the relative conductivity and saturated water deficit of M. azedarach leaves were the highest, significantly higher than those of other treatments. At the same concentration, the relative conductivity and saturated water deficit under alkaline salt stress were significantly higher than those under neutral salt stress. It can be seen that M. azedarach has a certain salt-alkali tolerance, the effect of alkaline salt on the M. azedarach seedlings is greater than neutral salt.

Effects of Sophora moorcroftiana endophytic bacteria on germination of black highland barley seeds and seedling growth

2021/3/8 10:07:44
In order to study the effects of inoculating different sophora moorcroftiana nodule endophytes on the germination and physiological traits of black highland barley seeds, the endophytic bacteria of sophora moorcroftiana nodules which promoted the growth of black highland barley seedlings were screened. Black highland barley seeds inoculated with endophytic bacteria of different sophora moorcroftiana nodules and black highland barley seeds not inoculated with strains were used as research materials, and culture dishes were used as substrates to observe the seed germination and seedling growth of black highland barleys. The germination rate, germination potential, germination index, plant height, root length, root number, root-shoot ratio, physiological characteristics of plant dry/fresh weight of black highland barley after inoculation with different endophytic bacteria were determined, and the different treatments were subordinated. Comprehensive evaluation of functions. The results showed that the germination rates of strains R7 and R17 reached 100%, the germination potential of R17, R18 and R19 reached 90%, and the germination indexes of R17 and R18 were 45.38% and 32.05%, respectively. Under different treatments, the average root length of R21, R14 and R7 was inhibited by CK1, and the changes were -50%, -34.28% and -28.99%, respectively. The plant height of black highland barley seedlings was compared with CK1, and only four strains promoted plant height, which were R5, R18, R22 and R28. The number of roots of black highland barley seedlings was compared with CK1, Except that R15 and R21 inhibited, the other strains promoted the number of seedlings of seedlings, but there was no significant difference in the number of roots under R17, R18 and R19 treatments(P>0.05). Compared with CK1, there were only four strains that promoted the fresh weight of plants, which were R2, R18, R22 and R28. The dry weight of strains R5, R6 and R14 were lower than that of control CK1, and the others had significant differences compared with CK1(P<0.05). The results indicate that the different endophytic strains of different sophora moorcroftiana nodules have significant effects on the seed germination and seedling physiological traits of black highland barley(P<0.05). The comprehensive evaluation results of inoculating different nodule endophytic effects showed that R17, R18, R28 and R20 were inoculated. The sub-function value of the black highland barley seed of R19 strain is 6.71, 6.45, 6.31, 5.81, 5.76, which can be initially selected as an excellent growth-promoting strain.

Variation analysis of flavonoid contents in seeds and yield traits on recombinant inbred line population of tartary buckwheat

2021/3/8 10:07:44
In order to reveal the main factors affecting the flavonoids content of tartary buckwheat in seeds and select high flavonoids content lines, we determined the flavonoids content in seeds of a tartary buckwheat recombinant inbred lines(RILs)population derived from a cross of “Xiaomiqiao × Jinqiao 2”. The genetic variation of seed yield, 100-seed weight, seed length to width ratio, plant height, branch number and flavonoids content in seeds were analyzed on RILs population. The relationship between flavonoids content in grains and yield traits was explored by correlation analysis. Variance analysis of flavonoids content in RILs population with different seed colors or shell types was carried out, cluster analysis for the RILs population was carried out based on the phenotypic data of investigated traits, and the excellent lines were selected by variance analysis among groups. The results were as follows:(1)The flavonoids content in seeds, 100-seed weight, seed yield, and seed length to width ratio of ‘Jinqiao 2' were significantly higher than those of ‘Xiaomiqiao'; The flavonoids content in seeds of the RILs population ranged from 1.34% to 3.05% with the coefficient variation of 12.23%; The coefficient of variation of yield traits ranged from 9.38% to 25.17%, in which grain yield was the largest, followed by 100-seed weight, and seed length to width ratio was the smallest; The tremendous transgressive segregation for flavonoids content in seeds was observed in the population.(2)There was no significant correlation between flavonoids content in seeds and the investigated agronomic traits; Seed yield was significantly positively correlated to 100-seed weight and plant height.(3)There were no significant differences in flavonoids content among lines with different seed colors or shell types.(4)The RILs population could be divided into six groups at the euclidean distance of 17.6-20.6. Group C3 and Group C6 had the highest flavonoids content in seeds, with the average values of 2.39% and 2.35% respectively. Group C2 had fine performance in plant height, branch number, seed yield, 100-seed weight, and seed length to width ratio.

Physiological response of Thuarea involuta under salt stress

2021/3/8 10:07:44
In order to test the ability of Thuarea involuta to adapt to adversity and to reveal its mechanism of salt tolerance, we collected samples from the tropical coral Xisha Dongdao Island, and selected vigorous plants as the subsequent experiment materials through vegetative propagation, which were then treated with different salt stress degrees. We studied the effects of treatments with different NaCl concentrations on the contents of Malondialdehyde(MDA), antioxidase and osmotic regulator in leaves of T. involuta. The results were as follows:(1)The increase of NaCl concentration did not accelerate the membrane lipid peroxidation of T. involuta leaf cells under a short term of salt treatment(28 d), but the peroxidation effect worsened with the extension of salt treatment time and increase of NaCl concentration, which also, resluted in a gradually rising of the content of MDA, reaching the peak at 400 mmol·L^-1of NaCl concentration.(2)Under the short term of salt stress treatment(28 d), the activities of SOD and CAT were significantly increased under the low(200 mmol·L^-1)and high(400 mmol·L^-1)NaCl concentrations, respectively, the activity of POD gradually ascended with the increase of salt stress time and NaCl concentration.(3)We discovered that under salt treatment, T. involuta accumulated SP and PRO to improve the osmotic regulation ability, which balanced the osmotic potential inside and outside the cell membranes and lowered the demage of salt stress. In conclusion, T. involuta can apply both of the antioxidant enzyme defense system and osmotic regulation mechanism under salt stress, to reduce the damage caused by lipid peroxidation of cell membrane and to ease physiological drought. In this case, we regarded the species has high salt tolerance. The results can provide scientific foundation for artificial community construction of T. involuta, vegetation restoration and landscaping design on South China Sea Islands, and it has great significance for sustainable development to tropical coral islands in China.

Variation analysis of leaf morphology and growth characteristics of Cinnamomum camphora with different provenances

2021/3/8 10:07:44
In order to understand the leaf morphological characteristics and growth differences of Cinnamomum camphora from different provenances, we measured and analyzed the leaf morphological characteristics and growth indexes of C. camphora from 30 provenances, including leaf length, width, petiole lenghth, perimeter, leaf area, length to width ratio, morphous factor, plant height and ground diameter. The results were as follows:(1)The coefficient of variance of leaf morphological characteristics were 3.88%-16.14% among the 30 provenances, which indicated that the most significant difference among provenances. There existed high heritability in leaf length, leaf width, leaf petiole lenghth, leaf thickness, leaf area, leaf perimeter,reached more than 75%,and the leaf length to width ratio and morphous factor reached more than 60%.There were significant differences in leaf morphological characteristics and growth of C. camphora from different provenances, and the difference of C. camphora leaf traits was controlled by genetic control to a certain degree. The leaf morphological characteristics were different in all of the individuals within provenances. The variation coefficients of leaf length, width, area, petiole lenghth and length to width ratio were larger, while the variation coefficients of perimeter, leaf thickness and morphological factors were smaller.(2)Principal component analysis was performed to select three principal components and their cumulative contributions of variance accouted for 86.18%. Leaf length, area, perimeter, width and thickness were dominating elements, and these parameters played an important role in the division of leaf morphology.(3)There were significant differences in plant height and ground diameter among provenances. The provenances from Hunan of China had the best growth performance, followed by Fujian, Jiangsu, China and Osaka, Japan. The native provenances from Jiangxi, China was no advantage, and the growth performance was poor. The plant height and ground diameter were differences in all of the individuals within provenances. The variation coefficient of plant height and ground diameter from Huanggang of Hubei, China provenances was smaller and the uniformity among individuals was better. The variation coefficient from Yichang of Hubei and Anfu of Jiangxi, China provenances was larger and the difference among individuals was larger, which creates conditions for the selection of superior plants. It is suggested that there are rich genetic variations in C. camphora provenances and within provenances, which provide basic materials for the breeding and improvement of C. camphora with high quality provenances and improved varieties.

Contents and potential ecological risk assessment of heavy metals in soil and Siraitia grosvenorii at the hilly region in Longsheng County Taking Baozeng Village as an example

2021/3/8 10:07:44
Longsheng County is one of the three main producing areas of Siraitia grosvenorii in Guilin City, the contents of heavy metals in soil and S. grosvenorii might affect the healthy development of S. grosvenorii in this area. To explore the safety of S. grosvenorii orchard, heavy metals(As, Cu, Zn, Pb, Cd, Cr, Hg)in the soil(0-10 cm,10-20 cm)and fruit of S. grosvenorii in the hilly region in Longsheng were measured, and their potential ecological risks were evaluated through Hankanson method. The results were as follows:(1)The average content of the heavy metals in the soil(0-10 cm,10-20 cm)of S. grosvenorii orchard reached the Eco-SSLs standard request of the national agricultural land evaluation criterion(GB-15618-2018), with the average values in soil(0-10 cm)of As, Cu, Zn, Pb, Cd, Cr, Hg were 3.67, 18.00, 58.39, 17.01, 0.10, 28.57, 0.08 mg·kg^-1, and in soil(10-20 cm)were 1.93, 12.56, 21.47, 10.51, 0.04, 17.09, 0.02 mg·kg^-1, respectively.(2)The ecological risk status of heavy metals in soil(0-10 cm)of S. grosvenorii orchard in the hilly region of North Guangxi was a low ecological risk generally. The average ecological risk index values at different points were 105.29, which represented a low ecological risk. The potential ecological risk decreased with the sequence of Hg, Cd, Pb, Cu, As, Cr and Zn, and all the metals except for Hg and Cd had a low ecological risk. The potential ecological risk index caused by Hg and Cd reached 50.16 and 42.05, representing a moderate ecological risk, which contributed around 47.6% and 39.9% of the total potential ecological risk. The ecological risk status of heavy metals in soil(10-20 cm)of S. grosvenorii orchard was a low ecological risk. The average ecological risk index values at different points were 38.96, which had a low ecological risk. The potential ecological risk decreased following the sequence of Cd, Hg, Cu, Pb, As, Cr and Zn.(3)The average content of the heavy metals in the fruit of S. grosvenorii orchard with the values of As, Cu, Zn, Pb, Cd, Cr, Hg were 0.000 24, 0.273, 1.10, 0.001 6, 0.000 13,0.000 13 and 0.000 12 mg·kg^-1, respectively, which represented a low ecological risk. The potential ecological risk decreased with the sequence of Hg, Cu, Cd, Zn, Pb, As and Cr. It was showed that the average ecological risk index values of different samples were 0.211 93, with little ecological risk. Therefore, the S. grosvenorii planted at Baozeng Village reached the safety and quality standard.

Variation of biological traits and quality characteristics in Lithocarpus litseifolius seeds from different provenances

2021/12/30 0:00:00
In order to investigate variation of biological traits and quality characteristics in Lithocarpus litseifolius seeds, four biological traits, four nutrient contents and three quality characteristics were measured from ten provenances in eight provinces. The correlation and cluster analysis of eleven seed characteristic parameters were carried out. The results were as follows:(1)The mean values of single seed weight, seed length, seed numbers per panicle and panicle length were 1.82 g, 14.57 mm, 16.43 grain and 11.78 cm respectively, and variation of four biological traits of seeds from different provenances reached extremely significant level.(2)The average values of protein, fat, reducing sugar and starch of seed were 4.75 g/100 g, 0.97 g/100 g, 1.13%, 74.23 g/100 g respectively. Starch had the smallest difference among four nutrient indexes.(3)The average values of hundred-grain weight, rate of water content and viability of seeds were 172.92 g, 42.05% and 53.00% respectively. Three quality characteristics of seeds from different provenances varied greatly.(4)Variation of four biological traits of seeds had positively or negatively correlation with starch and protein, and seed length had a positive correlation with fat and reducing total sugar.(5)The correlation between biological traits and habitat factors was very complex. Panicle length had a positive significant correlation with frost-free-period, the correlation coefficient reached 0.832. In the mean time, panicle length had a negative correlation with altitude, the correlation coefficient reached -0.698. The quality of seed became slightly worse with latitude increasing.(6)Seeds were classified into three groups based on clustering analysis. Group I was characterized by short panicle and high nutrient content. Group Ⅱ was seized of long panicle and high viability. Group Ⅲ had seeds numerous and high starch content. Seed clustering did not show geographical effects. In a word, variation of biological traits and quality characteristics of seeds from different provenances were very rich, which indicate that there is a genetic basis from different provenances for progeny differentiation, and provenance screening needs to be combined with field experiments.

Phytoremediation of Cd, As, Pb contaminated farmland by flower plants and extracted essential oil application

2021/12/30 0:00:00
To improve the economic value of phytoremediation, three flower plants i.e. Tagetes patula, Cosmos bipinnata and Centaurea cyanus were chosen in this study to investigate their remediation and reutilization potentials. The pilot-scale experiments were carried out in Cd, As and Pb contaminated farmland near the mining area in Guangxi. The metal amounts, bioconcentration factor(BCF)and biotranslocation factor(BTF)of three flower plants towards Cd, As and Pb were analyzed and calculated. In order to develop a novel reutilization method of the harvested plants, the essential oil was extracted from the aboveground biomasses. The inhibitory effects of plant essential oil on the growth of pathogenic bacteria were studied, and the antibacterial effects of the oil as well as in the sanitizer were also investigated. The results were as follows:(1)The studied area was heavily polluted. Cd and As contents in the soil were above risk intervention values, whereas Pb content was above risk screening value. It indicated that the area was at high-level of soil contamination risk by Cd, As and Pb.(2)The studied three flower plants had good resistance to high-level contamination of Cd, As and Pb in the soil. Tagetes patula and Cosmos bipinnata extracted higher contents of Cd and Pb from the soil, whilst Cosmos bipinnata showed the lowest metal enrichment amounts. These flower plants possessed high level of BCFs and BTFs towards Cd, moderate level for Pb, but the lowest level for As. In general, the metal extraction ability of three flower plants in descending order was Tagetes patula > Cosmos bipinnata > Centaurea cyanus, and the metal enrichment preference was Cd>Pb>As.(3)The Tagetes patula oil was found to have a good inhibition effect(<10 CFU·mL^-1)towards Escherichia coli, Staphyloccocus aureus and Salmonella typhimurium. Given the high metal accumulation in Tagetes patula, no significant amounts of metals were detected in the extracted oil. It also prolongated the antibacterial effect of the sanitizer as long as 480 min. Therefore, Tagetes patula is not only preferred in the phytoremediation of metal-contaminated farmland, but also the essential oil extracted from the harvested biomasses can be developed as an antibacterial agent. This study provides the theoretical basis for the novel reutilization of metal-concentrated plants harvested from the phytoremediation.

Effects of different treatments on survival rates and physiological characteristics of bare-root transplanted seedlings of Phoebe zhennan and P. chekiangensis

2021/12/30 0:00:00
This study aimed to explore the effects of combination of three different concentrations of super-absorbent polymer and ABT on the survival rate and physiological characteristics of bare-root seedlings transplanted with Phoebe zhennan(ZN)and P. chekiangensis(ZJN). P. zhennan and P. chekiangensis bare-root seedlings were treated with three different concentrations of super-absorbent polymer combined with ABT rooting powder, and the survival rate and physiological indexes of seedlings after transplanting were measured. Then, all indexes were comprehensively evaluated to decide the recovery of seedlings under different conditions by the membership function analysis. The results were as follows: Compared to the control group, the survival rates of ZN and ZJN were significantly increased under the treatment; The number of new leaves in ZN was increased, while there was no differences in the number of new leaves in ZJN; The contents of chlorophyll and carotenoid were significantly increased, especially in ZN1 group or ZJN1 group; The values of(GA₃+ZR+IAA)/ABA and IAA/ABA in ZN and ZJN were significantly elevated, and there were no significant differences between different treatments in ZN, whereas the value was higher in ZJN1 than that in the ZJN2 treatment group; The contents of soluble protein and soluble sugar were significantly decreased; The membership function analysis showed that the ranking of survival rate of the bare-root transplanted seedlings were ZN1>ZN2>CK and ZJN1>ZJN2>CK, respectively. In conclusion, the combination treatments of super-absorbent polymer and ABT promoted the survival of ZN and ZJN bare-root transplantation seedlings, and the level of ZN1 or ZJN1 was better.

Comparison of growth and physiological characteristics of Ormosia henryi seedlings from different provenances

2021/12/30 0:00:00
In order to understand the growth characteristics and differences of different Ormosia henryi provenances in Guiyang, we collected seeds from ten different provenances of O. henryi and conducted seedling experiments. We compared differences in seedling height, root collar diameter, biomass, leaf photosynthetic parameters, photosynthetic pigment, activity of nitrate reductase, content of nitrate nitrogen and the root activity of the biannual seedlings, and then analyzed the differences in ten provenances of O. henryi. The results were as follows:(1)There were significant differences in the net photosynthetic rate(P_n), stomatal conductance(G_s), intercellular carbon dioxide concentration(C_i), transpiration rate(T_r)and water use efficiency(WUE)among ten O. henryi provenances(P<0.05), indicating that different O. henryi provenances showed significant differences in photosynthetic characteristics and light use efficiency. Plants from Hangzhou and Yongkang of Zhejiang had the higher photosynthetic growth potential.(2)There were significant differences in chlorophyll content, nitrate reductase, nitrate nitrogen and root activity among provenances. The contents of chlorophyll a and chlorophyll b and total content of chlorophyll were the highest in Jian'ou of Fujian provenance. These plants could efficiently transfer the accumulated light energy during the initial reaction of photosynthesis and promote carbon assimilation. Huaxi of Guizhou provenance had the highest nitrate reductase activity, the highest nitrate nitrogen content, and strong utilization ability of nitrogen elements, which could promote the synthesis of plant protein, amino acid and chlorophyll. The root system from plants in the Wangmo of Guizhou provenance had the greatest activity and the ability to absorb nutrients.(3)There were significant differences in the distribution of seedling height, ground diameter and biomass among all provenances. The plants from Hangzhou of Zhejiang provenance had luxuriant branches and leaves, developed roots and good growth performance, while the plants from Huangshan of Anhui provenance were short and had poor growth performance. Hangzhou of Zhejiang provenance distributed more biomass in roots and leaves to increase the ability of roots to absorb nutrients and leaves to acquire light energy. Huangshan of Anhui provenance accumulated the least biomass and had the worst growth.(4)The adaptability of ten provenances of O. henryi was comprehensively evaluated by principal component analysis. The results showed that Hangzhou of Zhejiang provenance > Liping of Guizhou provenance > Yongkang of Zhejiang provenance > Wangmo of Guizhou provenance > Jian'ou of Fujian provenance > Kaili of Guizhou provenance > Shiqian of Guizhou provenance > Hauxi of Guizhou provenance > Pingtang of Guizhou provenance > Huangshan of Anhui provenance. In conclusion, Plants from Hangzhou of Zhejiang, Liping of Guizhou and Yongkang of Zhejiang O. henryi provenances had high potential for adaptation and growth potential in Guiyang.

Physiological basis of Liquidambar formosana leaves during leaf color transformation in autumn

2021/12/30 0:00:00
To investigate the key physiological mechanisms of leaf colorization of Liquidambar formosana in autumn, the plants with three leaf colors(green, yellow and red)were used as the experimental material. The contents of leaf-color parameters(L^*, a^*,b^*), pigment, soluble sugar and soluble protein were determined, and their correlations were analyzed. The results were as follows:(1)During leaf discoloration period, the contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids were greatly decreased, and anthocyanin content was accumulated in large quantities.(2)The contents of chlorophyll and carotenoids remained high in the green-colored leaves, and the anthocyanin content increased by 4.2 times, and the proportion of pigment remained stable. The contents of chlorophyll and carotenoid were the lowest in yellow-colored leaves, and the anthocyanin content increased by 4.4 times. The leaf-color parameters b^* content was significantly negatively correlated with the contents of chlorophyll and carotenoid, but significantly positively correlated with the ratio of anthocyanin to carotenoid. The contents of chlorophyll and carotenoid in the red-colored leaves was slightly higher than the yellow-colored leaves, and the anthocyanin content increased by 27.2 times. The leaf-color parameters a^* content was significantly negatively correlated with contents of chlorophyll and carotenoid, and significantly positively correlated with anthocyanin content, but not significantly correlated with the ratio of pigment.(3)The contents of soluble sugar and soluble protein were higher in the red-colored leaves. The contents of chlorophyll and carotenoid were kept high to keep the green leaves during the discoloration period, and the pigment ratio remained stable. Extensive degradation of chlorophyll and carotenoids, and the increasing ratio of anthocyanin to carotenoid results in yellow leaves. Chlorophyll degradation and anthocyanin synthesis results in red leaves.

Spatial distribution and habitat characteristic of Pinus kwangtungensis in the Guangdong Nanling 20 hm² forest dynamics plot

2022/8/7 11:36:30
Understanding the ecological processes that affect species distribution patterns is fundamental to the conservation and restoration of rare and endangered species. Pinus kwangtungensis is an endemic and Class-II protected plant in China. However, environmental change and human disturbance result in habitat damage and population decline. In order to understand current situation of its population, spatial distribution pattern and habitat characteristics, and to guide the conservation and restoration of this species, we established a 20 hm² forest dynamics plot in the Nanling National Nature Reserve, Guangdong Province. All woody plants with diameter at breast height ≥1 cm were monitored, and multiple environmental factors, including soil and topography, were measured. We used a size-class analysis to predict population trends, the spatial point pattern analysis(L function)to reveal spatial distribution of individuals, and established a Zero-Inflated Poisson(ZIP)regression model to explore the important environmental factors that affect individual distribution. The results were as follows:(1)size-class distribution was “bell-shaped”, the number of small size-class individuals was low, indicating that population regeneration was limited. P. kwangtungensis preferred the slopes and ridges with high altitude and steep terrain, showing a strong habitat specialization.(2)Spatial point pattern analysis(L function)presented that spatial distribution was significantly aggregated compared with null models, which might cause by dispersal limitation and habitat heterogeneity.(3)The ZIP regression model showed that high soil ammonium nitrogen, available potassium and low organic matter content associated with the occurrence of P. kwangtungensis (from 0 to 1), and the abundance(from 1 to N)was positively correlated with altitude, species diversity, and mean DBH, but negatively correlated with tree height, ammonium nitrogen, total phosphorus, and total potassium. The results indicate that the unstable size-class structure and intraspecific competition caused by spatial aggregation will accelerate the decline of the population, we suggest that the habitats with low soil nutrients at high elevations should be conserved preferentially, and reduce anthropogenic disturbance to maintain the original habitats.

Changes of tissue structures, photosynthetic characteristics and pigment contents of Liquidambar formosana leaves in the process of turning red

2022/8/7 11:36:30
Liquidambar formosana is an excellent landscape ecological tree species because its leaves turn red gradually after autumn, which is of great ornamental value. In this paper, the changes of tissue structures, photosynthetic characteristics and pigment contents of L. formosana leaves were continuously monitored, and the relationships between leaf structures and photosynthetic characteristics and pigment were analyzed in order to understand the relationships between leaf structure changes and leaf color. The results were as follows:(1)During the discoloration process of L. formosana leaves, the epidermal cells were oval and closely arranged, no obvious cell variation was observed, no villi and wax were attached to the surface, and the upper epidermal cells were closely arranged with palisade tissue cells, there was no large air chamber.(2)With the leaf turning red gradually, the leaf structure changed significantly. The thickness of leaf, upper epidermis, palisade tissue, spongy tissue and stomatal aperture decreased gradually, whereas the length and width of stomatal apparatus and the area of single stomatal apparatus gradually increased.(3)With the change of leaf structure, the chlorophyll content decreased gradually, resulting in the decrease of net photosynthetic rate. When light damage occurred, leaves protected themselves by synthesizing anthocyanins in the vacuoles of palisade tissue cells, then a large amount of anthocyanins caused the leaf surface to show red. Therefore, the decrease of chlorophyll content and the accumulation of anthocyanins were the direct reasons for the redness of L. formosana leaves. To sum up, the red color of L. formosana leaves is the combination result of a series of physiological structure characteristics.

Effects of nitrogen fertilization depth and water stress on quinoa seedling physiological characteristics and yield

2022/8/7 11:36:30
To explore the response mechanism of quinoa(Chenopodium quinoa)to fertilization depth and water stress. Quinoa in pots were used as materials to set three nitrogen fertilization treatments [D1, placement of controlled-release urea(CRU)at 0-8 cm depth; D2, placement of CRU at 8-16 cm depth; D3, placement of CRU at 16-24 cm depth] and three kinds of water treatments(W1, normal moisture; W2, moderate drought; W3, severe drought)to discuss the effects of quinoa seedling physiological characteristics and yield. The results were as follows:(1)Under the same water condition, with the increase of fertilization depth, the growth indexes(plant height, stem diameter, leaf area, aboveground biomass, length of main root, surface area of root, root volume), physiological indexes [superoxide(SOD)activity, peroxidase(POD)activity, catalase(CAT)activity, soluble sugar content, soluble protein content, and the total chlorophyll content] and yield index tended to increase initially and then decrease. D2 treatment(appropriate deep nitrogen fertilization)was higher than D1(shallow deep nitrogen fertilization)and D3 treatment(bottom deep nitrogen fertilization).(2)Under the same nitrogen fertilization depth, with the increase of drought stress, the growth indexes and yield index of quinoa decreased gradually, and the physiological indexes were rising firstly and then decreasing. It was suggested that the water demand of quinoa seedlings was obvious, which could adapt to drought to some extent by increasing antioxidant enzyme activities and osmotic regulating substances. In practice, attention should be paid to the supply of water in seedling stage to promote the formation of yield in the later stage of growth. In conclusion, suitable water and nitrogen management(D2W1)can promote the growth and physiological characteristics of quinoa, and enhance the drought resistance of quinoa and improve the yield of quinoa. The results of this study provide a reference for further study on water and fertilization management and high yield cultivation of quinoa.

Effects of exogenous SA on root exudates of Helianthus tuberosus under aluminum stress

2022/8/7 11:36:30
To investigate the effects of aluminum stress on root exudates of Helianthus tuberosus and the alleviating effect of exogenous salicylic acid(SA), we used aluminum-tolerant Nanjing H. tuberosus and aluminum-sensitive Ziyang H. tuberosus as experimental materials and set aluminum concentration of 500 μmol·L^-1 by soil culture method, and analyzed the effects of different concentrations(10, 100, 1 000 μmol·L^-1)of SA on the organic acids and amino acids in root exudates of H. tuberosus and related metabolic enzymes in root tips under aluminum stress. The results were as follows:(1)Concentrations of citric acid, oxalic acid and malic acid in the root exudates of H. tuberosus increased under single Al stress, and the increase was greater in Nanjing H. tuberosus than in Ziyang H. tuberosus; The activities of citrate synthase and malate dehydrogenase increased under single Al stress; The proline content increased significantly, and the concentration of total amino acids decreased significantly.(2)The concentrations of citric acid, oxalic acid and malic acid secreted by the root system ofNanjing H. tuberosus were increased to different degrees after the addition of exogenous SA, but the oxalic acid secreted by the root system of Ziyang H. tuberosus was significantly reduced after treatment with high concentration(1 000 μmol·L^-1)of SA, and there was no significant change in malic acid concentration under all concentrations of SA treatment; The citrate synthase activity appeared to be enhanced to different degrees, but it had little effect on malate dehydrogenase activity in the root tips of Nanjing H. tuberosus, and malate dehydrogenase activity in the root tips of Ziyang H. tuberosus was significantly reduced after treatment with high concentration(1 000 μmol·L^-1)of SA; The proline content decreased significantly, from terms of changes in total amino acid concentration, the maximum alleviating effect was obtained at high concentration(1 000 μmol·L^-1)SA for Nanjing H. tuberosus and at low concentration(10 μmol·L^-1)SA for Ziyang H. tuberosus. Therefore, H. tuberosus responds to aluminum toxicity by secreting organic acids, and exogenous SA can promote the rate of organic acid metabolism in the root system of H. tuberosus to secrete more organic acids to alleviate aluminum stress, and this alleviation effect is better in Nanjing H. tuberosus, which is relatively strong in aluminum tolerance.

Influence of gravel content of soil on growth and root characteristics of Handeliodendron bodinieri seedlings

2022/8/7 11:36:30
In order to explore the influence of gravel content of soil on the growth and root of the rare and endangered plant Handeliodendron bodinieri seedlings, one month age of H. bodinieri seedlings were used as materials and five pot experiments with different soil gravel contents [0(CK), 20%, 40%, 60% and 80%] were carried out and the most suitable soil gravel content for the growth of H. bodinieri seedlings were selected. The results were as follows:(1)The gravel content of soil had a highly significant influence on the growth of H. bodinieri seedlings. Seedling height and ground diameter of relative growth rate, leaf area, seedling quality index, biomass(root, leaf and whole plant)and root-shoot ratio were all maximum when gravel content was 40%.(2)The gravel content of soil had a very significant influence on root morphology of H. bodinieri seedlings. The total root length and root surface area all reached the maximum when gravel content was 40%. However, the root average diameter decreased with the increase of the gravel content, and reached the minimum when the gravel content of soil was 80%.(3)The gravel content of soil had no obvious influence on root topological architecture and fractal characteristic of H. bodinieri seedlings, but had very significant influence on root average link length and root forks numbers. Root topological index(TI), modified topological index(q_a, q_b)all tended to be one in every treatment, so the branching pattern of the roots of H. bodinieri seedlings was close to fishtail branching in different gravel contents of soil. The root average link length increased first and then decreased with the increase of gravel content, and reached the maximum at 40% gravel content. The root forks number of H. bodinieri seedlings showed a gradually decreasing growth trend with the increase of gravel content.(4)According to the results of comprehensive evaluation of the seedlings growth, root morphology and architecture, H. bodinieri seedlings had the best growth status when the gravel content of soil was 40%. Therefore, adding a suitable amount of gravel in the soil can promote the growth of H. bodinieri seedlings. The seedling growth status and seedings quality index were the best under the treatment of gravel content of 40%.

Differences in growth, photosynthesis and resistance physiology of Morus alba and Broussonetia papyrifera under bicarbonate treatments

2022/8/7 11:36:30
To investigate the effects ofHCO^-₃ on the growth and physiological characteristics of plants under the stress of bicarbonate in karst environment. The growth, photosynthetic capacity, antioxidant enzyme activity, osmotic regulation substance content and cell membrane damage of Broussonetia papyrifera and Morus alba seedlings under three different concentrations of NaHCO₃(0, 15, 30 mmol·L^-1, respectively)were examined in the present study. The results were as follows:(1)Under HCO^-₃ treatment, the growth and photosynthetic capacity of Broussonetia papyrifera and Morus alba seedlings were significantly inhibited, accompanying the physiological responses of leaf cells to antioxidant and osmotic stress were significant.(2)The inhibitory effects of HCO^-₃ on the growth of Broussonetia papyrifera and Morus alba were concentration-dependent, and showed significant differences among examined concentrations(P<0.05).(3)The inhibitory effects of the growth, photosynthesis, antioxidant enzyme system and osmotic regulation system and the damage of plant cells under 30 mmol·L^-1HCO^-₃treatment were significantly stronger than those of 15 mmol·L^-1HCO^-₃ treatment.(4)Under the same concentration of HCO^-₃, the growth, photosynthetic capacity, antioxidant enzyme activity, osmotic regulating substance content of Broussonetia papyrifera were significantly higher than those of Morus alba, and its leaf cell damage was significantly lower than that of M. alba. The results mentioned above indicate that HCO^-₃ inhibits the growth, photosynthesis and resistance physiology of M. alba and Broussonetia papyrifera under bicarbonate stress, and the tolerance of B. papyrifera to bicarbonate stress is better than that of Morus alba, which means that Broussonetia papyrifera is more adaptable to the environment of bicarbonate stress. This study provides scientific support for the adaptation mechanism of Moraceae to karst environment.

Bioinformatics analysis of CBL-CIPK signaling system participating in the formation of cold resistance in Jatropha curcas

2022/7/20 10:21:33
Calcineurin B-like calcium sensor(CBL)is a Ca²⁺-binding protein that mediates the Ca²⁺ signal transduction process by interacting with Calcineurin B-like calcium sensor interacting protein kinase(CIPK). CBL-CIPK signaling system is involved in the response of plants to a variety of stress conditions. For insight into the chilling mechanism of CBL and CIPK in Jatropha curcas, the CBL and CIPK gene families were identified from J. curcas based on the BLAST method, and then the phylogenetic relationship, gene structure, expression profile, and functional interaction were analyzed. The results were as follows:(1)A total of 8 CBL and 18 CIPK genes were identified from J.curcas genome. The protein length of CBLs and CIPKs ranged from 211 to 257 aa and 422 to 484 aa, respectively, and the putative isoelectric point ranged from 4.65 to 5.08 and 6.20 to 9.26, respectively.(2)Furthermore, all the CBL genes family contained 8-10 exons, while the CIPK genes family were divided into significant 1-2 exons(11 genes)and 12-15 exons(7 genes).(3)Sequence alignment revealed that CBL proteins identified 1 atypical EF-hand motif consisting of 14 amino acid residues and three typical EF-hand motifs with different substitutions, while CIPK proteins contained kinase domains in N-terminal and self-inhibiting FISL/NAF domains in C-terminal.(4)Chromosome mapping analysis indicated that 26 J. curcas CBL and CIPK genes were distributed with different densities on nine chromosomes.(5)Transcriptome data analysis showed that most of the CBL and CIPK genes were highly expressed in J. curcas leaves, roots and seeds. Among them, the up-regulated expression of JcCIPK14 and JcCIPK18 reached significant levels under cold stress, which was involved in the cold resistance of J. curcas. All the results of this study might lay a significant foundation for further studies on the gene function and chilling signaling transduction mechanism of CBL and CIPK gene families in J. curcas.

Effects of different soil selenium levels on growth and partial physiological characteristics of Atractylodes macrocephala seedlings

2022/7/20 10:21:33
Although selenium(Se)has not been considered an essential element for higher plants, but moderate Se plays an important role in promoting plant growth. Therefore, it is of great significance to learn the roles and underlying mechanism of Se in regulating the growth of Atractylodes macrocephala. In this study, a pot experiment was conducted to explore the comprehensive effects of different Se treatments(0, 5, 10, 25, 50, 100 milligram Se per kilogram air-dry soil)on growth of A. macrocephala seedlings. The results were as follows:(1)5 mg·kg^-1 Se treatment increased the fresh weight, leaf SPAD value(soil and plant analyzer development value)and leaf soluble sugar(SS)content of A. macrocephala seedlings by 8.8%, 8.4% and 60.3%, respectively; While decreased the leaf soluble protein(SP)and malondialdehyde(MDA)contents by 32.1% and 18.9% respectively, as well as depressed the activities of peroxidase(POD)and catalase(CAT), compared with the control.(2)Treatments of Se >25 mg·kg^-1 were not beneficial to the growth of A. macrocephala seedlings, resulting in a significant increase in MDA and superoxide anion radical(·O₂^-)content, which destroyed the antioxidant system.(3)Principal component analysis showed that fresh weight, plant height, leaf SP content and activities of CAT and POD could be defined as critical indexes to learn the growth condition of A. macrocephala seedlings. In conclusion, the appropriate soil Se levels could significantly promote the growth of A. macrocephala seedlings, and 5 mg·kg^-1 soil Se level was the optimum. Application of appropriate Se to the soil could be beneficial for efficient breeding and industrial production of A. macrocephala.

Annual growth rhythm of Melia azedarach seedlings from different seed sources

CAI Jinfeng, YU Wanwen, WANG Guibin, CAO Fuliang — 2022/7/20 10:21:33
Melia azedarach is widely distributed in China and has a wide range of genetic variation. In order to study the growth characters of one-year-old seedlings of M. azedarach from different seed sources, the growth characters of seedling height, ground diameter, compound leaf growth and biomass accumulation of M. azedarach seedlings from 15 seed sources were observed, and the growth rhythm was fitted by logistic equation. The results were as follows:(1)There were significant differences between seedling height and ground diameter(P<0.05), and significant differences between root biomass, stem biomass and compound leaf(P<0.01).(2)The growth of seedling height and ground diameter showed a slow-fast-slow growth pattern with type S. Compared with the emergence time of seedling height growth peak, the emergence time of ground diameter growth peak was later.(3)The R² of logistic fitting equation was 0.976-0.994, which reached the extremely significant correlation level, indicating that the growth rhythm of M. azedarach can be fitted by logistic equation.(4)According to theoretical calculation and practical observation, the duration of fast-growing stage of ground diameter was generally 20-30 d longer than that of high-speed growth stage of seedling. The time of seedling height and ground diameter entering fast-growing stage and ending fast-growing stage in northern locality was earlier than that in southern locality.(5)All though traits were negatively correlated with latitude, seedling height, biomass and leaf area were positively correlated with longitude, while other traits were negatively correlated with longitude. In general M. azadarach begongs to full-time growth type with significant differences in growth traits among seed sources. The growth was regulated by both latitude and longitude, mainly by latitude.

Effects of salt stress on seed germination of Chenopodium quinoa

2022/7/20 10:21:33
Reclaimed water can irrigate farmland, but anions in water can cause salt stress to the plants. In order to study the effects of salt stress on seed germination characteristics, radicle and germ growth of Chenopodium quinoa, this experiment was designed to measure germination rate, germination vigor, radical and germ elongation inhibition rate in six types of quinoa cultivars(Red quinoa, China-red quinoa, Tai-red quinoa, Tai purple-red quinoa, Yellow quinoa, and Tai yellow-red quinoa)under three types of salt treatments(NaCl, Na₂SO₄, NaHCO₃ and control). The salt tolerance of different quinoa varieties was comprehensively evaluated by using the mean square error decision method, and the varieties with strong salt tolerance under different salt stresses were preliminarily selected. The results were as follows:(1)Na₂SO₄ had the most obvious inhibition effect on germination index of seeds, and the germination rates of six quinoa varieties were relatively low, which kept below 5%, and growth rates in which values were all 0 in four of the cultivars except for Yellow and Tai yellow-red quinoa. The inhibition rates of Na₂SO₄ on radicle and germ of the other five quinoa varieties were 100% except for Yellow quinoa, the growth rates of China-red quinoa and Tai yellow-red quinoa under NaCl treatment were higher than that of the control, at 9 h and 21 h, the radicle inhibition rates were -28.32% and -37.57%.(2)The results of the mean aquare error decision method showed that China-red quinoa had higher resistance to NaCl and NaHCO₃, and Yellow quinoa had higher resistance to Na₂SO₄. All the above results indicate that salt stress is not conducive to the seed germination and growth of quinoa, but planting suitable varieties in different salt areas can improve the survival rate and growth quality of quinoa, so as to reach the requirements of landscaping using reclaimed water as irrigation.

A preliminary study on construction mechanism of vertical structure in Castanopsis orthacantha community

2022/7/20 10:21:33
Exploring the mechanism of species coexistence based on functional traits has become a hot topic of community ecology in recent years. This study was aimed to understand the reasons for the establishment of the vertical structure, and to investigate the functional traits of plant leaves at different layers of the semi-humid evergreen broad-leaf forest in Qiongzhu Temple, Kunming. The results were as follows:(1)All plant functional traits showed varying degrees of trends at different layers.(2)The Castanopsis orthacantha community was divided into three layers according to plant life forms, i.e. tree, shrub, and herb, which were consistent with the clustering results of functional traits.(3)The S.E.S PW values at the tree, shrub and herb layers were all < 0, indicating that the functional structure in the community exhibited a significant divergence. In summary, the adaptation of leaf functional traits of different species in plant communities to different combinations of light and water conditions in the vertical direction of the community, was the main influence on the establishment of the vertical structure, which supporting habitat filtering is the main ecological process in the establishment of the vertical structure. Species at different layers had different functional traits, and the species diversity at the same layer increased through the varying degrees of competitive exclusion. The formation of community vertical structure was the result of changes in environmental factors in the vertical direction within the community; species with different needs for resources were distributed at different heights, and vertical structure was an effective use of resources, and increased species diversity within the community.

Effects of Chimonobambusa utilis management on species diversity and dominant population structures of Castanopsis platyacantha community in Jinfo Mountain

2022/7/20 10:21:33
To explore the effects of Chimonobambusa utilis management on species diversity and dominant population structures of Castanopsis platyacantha community in Jinfo Mountain, the natural community of Castanopsis platyacantha and the managed community of Chimonobambusa utilis in Jinfo Mountain were used as the research object to analyze species composition characteristics, species diversity and dominant population structures in the two communities. The results were as follows:(1)A total of 84 species of vascular plants in the plots were found, belonging to 40 families and 63 genera, dominated by Lauraceae, Rosaceae, Fagaceae and Theaceae; Castanopsis platyacantha was the dominant species in the community, Schima sinensis and Lithocarpus henryi were the subordinates and Chimonobambusa utilis was the dominant species in the shrub layer, which the species composition of Castanopsis platyacantha community in Jinfo Mountain was similar to other subtropical regions.(2)The species richness of the shrub layer of the managed community was significantly lower than that of the natural community, and the Shannon-Wiener index and Pielou index of the herb layer were significantly lower than that of the natural community.(3)Dominant tree species of Castanopsis platyacantha and Lithocarpus henryi in the natural community were stable populations, but those were declining populations in the managed community, and Schima sinensis in the two communities appeared to be in decline.(4)The ratio of total sprouts to total individuals, number of multi-stemmed individuals/number of all individuals and seedling relative dominance value of Castanopsis platyacantha, Schima sinensis and Lithocarpus henryi in the natural community were higher than those in the management community of Chimonobambusa utilis. In conclusion, the Chimonobambusa utilis management has a negative impact on the species diversity with the strongest on the shrub and herb layers of Castanopsis platyacantha community in Jinfo Mountain, and the managed activities significantly affect the renewal and maintenance of the dominant species in Castanopsis platyacantha community.

Analyses on distribution characteristics and protection effect of wild Paphiopedilum in Guizhou Province

2022/7/20 10:21:33
Paphiopedilum of Orchidaceae is a “flagship” group in biodiversity conservation, with high research value and ornamental value, and it grows in special environment. In order to understand the resource status and conservation effect of Paphiopedilum in Guizhou Province, this study conducted a special investigation of wild Paphiopedilum, and the resource status, distribution pattern, threatened factors and local protection of them were analyzed. The results are as follows:(1)A total of 103 distribution sites of eight species of Paphiopedilum are found in this special survey, distributed in 27 counties, with the southern and southwestern regions as the main distribution areas, their habitats are complex and diverse, and the natural distribution are uneven.(2)Their distribution areas are sorted from the largest to the smallest as P. micranthum > P. barbigerum > P. malipoense > P. bellatulum > P. hirsutissimum > P. dianthum > P. emersonii > P. concolor, the order of resource richness from high to low is P. micranthum > P. barbigerum > P. hirsutissimum > P. bellatulum > P. malipoense > P. emersonii > P. dianthum > P. concolor.(3)The plants of this genus suffer from complex disturbance factors and serious threats, among which overexploitation, drought, habitat degradation and fragmentation are the main reasons for its endangered status.(4)Two species of the genus “effective protection(EP)”, one species of “well protection(WP)”, two species of “general protection(GP)”, three species of “less protection(LP)”, two species of “unknown protection status(UPS)” because no target species are found. The species conservation rate is 100%, but the conservation rate of distribution sites is 29.13%. There are significant differences in population conservation rates among different species. It is suggested that relevant departments should enhance the protection intensity of Paphiopedilum plants in Guizhou, and further optimize the protection mode and scope, so as to ensure the sustainable survival and development of these rare and endangered plant resources.

Community composition and structure dynamics of secondary coniferous and broad-leaved mixed forest in Dongbaishan, Zhejiang Province

2022/7/20 10:21:33
Secondary coniferous and broad-leaved mixed forest is very common in subtropical regions. Studying the community succession characteristics and regeneration rules of the secondary coniferous and broad-leaved mixed forest will provide a scientific basis for vegetation restoration and forest management in this area. Using two datasets(2013 and 2018)from a permanent 1 hm² secondary coniferous and broad-leaved mixed forest plot in Dongbaishan(DBS), we analyzed the community composition and structure dynamics of tree species composition, community species diversity, species importance values, and size class structure and so on. The results were as follows:(1)Species richness and individual numbers were significantly reduced in the community during 2013-2018(P<0.05);(2)In the plot, 1 505 individuals DBH≥1 cm died, with an annual average mortality of 6.40%, and 71 new individuals recruited, with an annual average recruitment rate of 0.35%;(3)The community species diversity indexes declined significantly(P<0.05), of which Margalef richness index changed greatly, decreased by 25.03%, and Shannon-Wiener index decreased by 11.88%;(4)The dominant position of evergreen broad-leaved tree species were strengthening, while coniferous tree species were gradually reduced;(5)During the five years, the proportion of large and medium size class plants gradually increased, while the proportion of small size class plants gradually decreased. In general, the community composition and structure dynamics of the secondary coniferous and broad-leaved mixed forest community in DBS changed significantly during 2013-2018. The community is in a rapid succession stage from secondary coniferous and broad-leaved mixed forest to evergreen broad-leaved forest.

Construction of model framework for invasion prediction of alien plants based on functional traits

2022/12/23 12:18:09
Predicting the potential invasiveness of alien plants is important for biodiversity conservation study. The phylogenetic relationship between alien plants and native species is usually used to predict invasion, however, Darwin's naturalization conundrum predicts two completely different results(i.e. Darwin's naturalization hypothesis and Darwin's preadaptation hypothesis). In this study, we analyzed the connotation of Darwin's naturalization conundrum and suggested that the base of invasion prediction should be changed from a pairwise phylogenetic relationship between alien plants and native plants to the functional similarity between alien plants and native communities. The interspecific differentiation and intraspecific variation of functional traits may be different but not contradictory strategies of alien plants to achieve successful invasion. On this basis, this study constructed the functional similarity between alien plants and native communities through the multidimensional hypervolume of traits and putted forward the research framework and basic flow for invasion prediction based on the similarity. This construction of mechanism model framework helps understand the invasion mechanism and provides practical guidance for potential invasion prediction of alien plants. However, to accurate prediction of alien plants not only depends on the selection of functional traits, but also on the invasive habitat independence, the importance of spatial scales, and even the invasiveness of native communities. Future research is necessary to verify and improve the model through control experiments.

Dormancy type and germination of Epimedium sagittatum seeds

2022/12/23 12:18:09
Epimedium sagittatum plants have an important medicinal value and a huge market demand, but the characteristics on dormancy and germination of their seeds are still unclear, which seriously affects its industrial seedling production and cultivation. In order to verify the type of seed dormancy and the optimal way to release and promote dormacy, using the mature seeds of E. sagittatum as experimental materials, we investigated the water uptake and the desiccation tolerance of seeds, as well as the effects of temperature, stratification and phytohormone on seed dormancy and germination. The results were as follows:(1)E. sagittatum seeds had no physical dormancy but had desiccation tolerance.(2)The germination percentage of seeds was zero at 4-25 ℃ and darkness, and these seeds had dormancy characteristics.(3)The embryo/seed ratio was very small, as well as embryo growth and development and seed germination rate and germination percentage were increased by stratification at 4 ℃, 10 ℃ percentage rate and fluctuating temperature stratification.(4)Gibberellin and fluridone significantly increased the germination rate and germination percentage of seeds. In sum, all the above results indicate that the dormancy type of E. sagittatum seeds is morphophysiological dormancy, and the optimal method to release dormancy and promote germination is to stratify the seeds at 10 ℃ for 30 d and then transfer to the environment of 4 ℃. This study provides the reference for industrial culturing seedlings of E. sagittatum.

Allelopathy of aqueous extract from Metasequoia glyptostroboides litter on its seed germination and growth

2022/12/23 12:18:09
To explore whether the allelopathy of Metasequoia glyptostroboides litter is an obstacle to its natural regeneration, eight concentrations(200, 100, 50, 20, 10, 5, 2, 1 g·L^-1 and CK)of aqueous extracts from fresh and natural litter of M. glyptostroboides were set to analyze the allelopathic effects of aqueous extracts of different types and concentrations on seed germination and growth of M. glyptostroboides. The results were as follows:(1)The aqueous extract of the fresh M. glyptostroboides litter had no significant effects on seed germination rate and germination energy(P>0.05), but had significant effects on germination index(P<0.05), and seed germination was significantly inhibited by 1, 100, 200 g·L^-1 treatments. The effects of aqueous extracts of the natural M. glyptostroboides litter on three indexes of seed germination were not significant(P>0.05), but the inhibitory effect was reflected in 5, 10, 50, 200 g·L^-1.(2)The shoot length, hypocotyl length and main root length of M. glyptostroboides seeds were significantly different between different concentrations of fresh and natural litter aqueous extracts(P<0.05), and decreased gradually with the increase of aqueous extract concentrations(≥10 g·L^-1), especially in the range from 50 to 200 g·L^-1.(3)Compared with seed germination, the aqueous extracts of fresh and natural M. glyptostroboides litters had stronger inhibitory effect on the growth of seeds after germination, and the allelopathic effect of fresh litter was stronger than that of natural litter.(4)The main root length was the most sensitive to allelochemicals among seeds germination and growth indexes.(5)The dynamic change of shoot length growth of M. glyptostroboides seeds accords with the “S” type growth curve(R2≥0.988). In summary, the litter of M. glyptostroboides has a certain allelopathic inhibitory effect on its own seed germination and growth, which affects the natural regeneration of its population. It is suggested that the litter under the forest should be properly cleaned to promote the natural renewal of the M. glyptostroboides population in the management of M. glyptostroboides populations.

Effects of Cr⁶⁺ on photosynthetic characteristics and trace element absorption of Coix lacryma-jobi in constructed wetland

2022/12/23 12:18:09
In order to understand the effects of Cr⁶⁺ stress on the photosynthetic characteristics and trace element absorption of Coix lacryma-jobi, we investigated the effects of Cr stress on the growth, photosynthetic characteristics, antioxidant enzyme activity and microelement absorption of C. lacryma-jobi by constructing a miniature vertical flow C. lacryma-jobi artificial wetland with 1/2 Hoagland's nutrient solution containing 0, 5, 20, 40 mg·L^-1 Cr⁶⁺ wastewater as irrigation water. The results were as follows:(1)Low concentration(5 mg·L^-1)of Cr⁶⁺ had no significant effects on plant height, stem thickness and tillering of C. lacryma-jobi, while high concentrations(20, 40 mg·L^-1)of Cr⁶⁺ significantly inhibited the growth of C. lacryma-jobi.(2)Net photosynthetic rate (P_n), stomatal conductance(G_s)and transpiration rate(T_r)of C. lacryma-jobi leaves were increased to different degrees under low Cr⁶⁺ treatment, with the increases ranging from 6.8% to 54.8%, from 13.0% to 40.3% and from 9.1% to 36.4%, respectively. Under the high concentration of Cr⁶⁺ treatment, the P_n, G_s and T_rof leaves decreased significantly, but the intercellular CO₂ concentration(C_i)increased significantly.(3)Both superoxide dismutase(SOD)and peroxidase(POD)activities of C. lacryma-jobi leaves increased with increasing treatment time; SOD activity of C. lacryma-jobi leaves did not significantly differ from the control under low Cr⁶⁺ treatment, and was significantly inhibited under high Cr⁶⁺ treatment. The POD activity and malondialdehyde(MDA)content of C. lacryma-jobi leaves increased with the increase of Cr⁶⁺treatment concentration.(4)The absorption of Cu, Fe, Mn and Zn by roots, stems and leaves was significantly inhibited by high concentration of Cr⁶⁺ treatment.(5)The removal rate of Cr⁶⁺ by the artificial wetland was up to 99% under 5 and 20 mg·L^-1 Cr⁶⁺ treatments, and 86% under 40 mg·L^-1 Cr⁶⁺ treatment. All the results indicate that Cr⁶⁺ stress leads to a significant decrease in the absorption of Fe, Mn, Zn and Cu, hinders photosynthesis, impairs antioxidant systems and inhibits plant growth, which ultimately leads to a decrease in the ability of the artificial wetland to treat Cr⁶⁺ containing wastewater.

Effects of nitrogen, phosphorus and potassium on growth and nutrient status of potted Hydrangea macrophylla ‘Hanatemari'

2022/12/23 12:18:09
In order to guide the rational fertilization of potted Hydrangea macrophylla, the effects of nitrogen(N), phosphorus(P)and potassium(K)at four levels(N, K₂O: 0, 4, 8, 12 g·plant^-1; P₂O₅: 0, 1.5, 3.0, 4.5 g·plan^-1)on growth and nutrient status of two-year-old potted H. macrophylla ‘Hanatemari' were investigated by the balanced fertilization design of “3414” method. The optimal fertilization dosage was determined by critical concentration method to provide evidence for rational fertilization of potted ‘Hanatemari'. The results were as follows:(1)N fertilization treatments, all of the seedling height, canopy diameter, plant growth index(PGI), aboveground and whole plant biomasses of ‘Hanatemari' increased with the increasing of N fertilization dosage, while these parameters did not change significantly or slightly decreased as the N fertilization dosage exceeded Level 2.(2)Low-level fertilization treatments of P(P1)and K(K1)were beneficial to the biomass accumulation of ‘Hanatemari'.(3)The nutrient contents in leaves and stems of H. macrophylla ‘Hanatemari' increased with the increasing of N, P and K fertilization dosages. However, the contents of K in roots did not change significantly with the increasing of K fertilization levels, and there were no significant differences from the control.(4)According to the critical concentration method, the suitable contents of N in H. macrophylla ‘Hanatemari' leaves ranged from 35.31 to 46.64 g·kg^-1, and P ranged from 1.88 to 2.28 g·kg^-1. Considering nutrient content, PGI and production cost, the optimal fertilization dosages of N, P and K for H. macrophylla ‘Hanatemari' are N2(8 g N·plant^-1), P1(1.5 g P₂O₅·plant^-1)and K1(4 g K₂O·plant^-1), respectively.

Comparative analysis of differential metabolites between Calophaca sinica and Glycine max based on LC-MS metabolomics technology

2023/12/30 21:36:09
Calophaca sinica is a rare wild plant endemic to North China. To explore the nutritive value of C. sinica, the comparative metabolomics of C. sinica and Glycine max(as control group)seeds were studied by liquid chromatography-mass spectrometry(LC-MS). The results were as follows:(1)A total of 1 857 metabolites were detected in these two species, and 1 698 metabolites were similar in composition and content(>90%), and only 159 differential metabolites(<10%).(2)Among the metabolites, nine were different in components, of which five were unique to C. sinica, and the others 150 were different in content, of which 48 chemical components(about 30%)were higher in C. sinica than in Glycine max.(3)Eight pathways were significantly enriched with differential metabolites(P<0.1)by KEGG annotation, and it mainly including the biosynthesis pathways of primary metabolite(various amino acid)and secondary metabolites(such as matairesinol, arachidonic acid and diterpenoids).(4)Among these statistically significant differential chemical components, of which lower content in Calophoca sinica are mainly primary metabolites, and higher content are mainly secondary metabolites. These secondary metabolites play an active role in regulating blood glucose, repairing bone damage, enhancing immunity, anti-inflammatory and anti-cancer. In summary, the result supports that the nutritional value of C. sinica is similar to that of Glycine max, and it also has a positive effect on improving human sub-health status. Meanwhile, this study provides us a relatively comprehensive understanding of the nutritive value and metabolic components of Calophaca sinica and necessary data for the deep development and efficient utilization of C. sinica resources in future.

Absorption and distribution of different forms of nitrogen in two legumes and organs

2023/12/30 21:36:09
Legumes are abundant in the nitrogen deficient desert ecosystems, which is the center of supplying available nitrogen and the important pioneer species in this region. However, the studies on nitrogen uptake and utilization by legumes in desert ecosystems have rarely been reported so far. In this study Astragalus flexus and A. arpilobus, which are widely distributed in the Gurbantunggut Desert, were selected as the research objects. Three different nitrogen forms(¹⁵N-NH₄⁺, ¹⁵N-NO₃^-, ¹⁵N-glycine)were added to 0-5 cm and 5-15 cm soil layers, respectively, to study the absorption and distribution strategies of different forms of nitrogen in two plants and their organs. The results were as follows:(1)In different soil layers, both plants preferred to absorb nitrate nitrogen, and the maximum absorption rates of A. flexus and A. arpilobus were 3.26, 2.59 μg·g^-1· h^-1, respectively.(2)In different soil layers, there were significant differences in the uptake and allocation of different nitrogen sources among plant organs(P < 0.05). The uptake of ¹⁵N in root of A. flexus was higher than that of A. arpilobus, and the three different nitrogen forms were mainly allocated to leaves.(3)In different soil layers, the contribution rates of different nitrogen sources to both plants were ¹⁵N-NO₃^-> ¹⁵N-glycine > ¹⁵N-NH₄⁺, and the contribution rates of nitrate nitrogen to nitrogen absorption of A. flexus ranged from 37% to 41%, while the maximum contribution rate to the nitrogen absorption of A. arpilobus was 45%.(4)There were significant differences in recovery rates of different nitrogen forms between different organs of plants(P<0.05). In the 0-5 cm soil layer, the recovery rate of nitrate nitrogen was leaf > stem > root, while in the 5-15 cm soil layer, the rate was leaf > root > stem. In general, in the Gurbantunggut Desert ecosystem, different life forms legumes had both consistency and difference in nitrogen uptake and allocation capacity, and were affected by different soil depths and nitrogen forms. The results provide theoretical basis for nitrogen uptake, utilization and allocation of legumes in arid and semi-arid regions of Xinjiang.

Effects of exogenous NO treatment on aluminum stress resistance of four Eucalyptus seedlings

2023/12/30 21:36:09
To investigate the effect of exogenous nitric oxide(NO)on aluminum tolerance of Eucalyptus seedlings under aluminum stress. In this study, sodium nitroproside(SNP)was used as exogenous NO donor in four kinds of Eucalyptus seedlings(Eucalyptus grandis, E. urophylla, E. tereticornis, E. urophylla&#215;E. grandis). The effects of different concentrations of NO(0, 50, 100, 200, 400, 800 μmol·L^-1)on the physiological indices of ROS, antioxidant enzyme activities and the contents of organic osmotic regulatory substances of Eucalyptus seedlings under 120 mg·L^-1 aluminum stress were studied, and the differences of aluminum tolerance of four Eucalyptus species under NO treatment were compared. The results were as follows:(1)The addition of exogenous NO(50 μmol·L^-1≤NO≤200 μmol·L^-1)under aluminum stress promoted the contents of soluble sugar and soluble protein, the activities of antioxidant enzymes(SOD, POD, CAT, APX), the removal of ROS in the body, the reduction of MDA accumulation, and the improvement of aluminum stress resistance. However, under high concentration of NO(≥800 μmol·L^-1), the activities of antioxidant enzymes and the contents of osmotic regulatory substances decreased in Eucalyptus seedlings, showing stress response.(2)NO significantly improved the aluminum tolerance of sensitive Eucalyptus, but not significantly improved the aluminum tolerance of tolerant Eucalyptus. Finally, the aluminum resistance of four Eucalyptus species tended to be consistent under the action of NO.(3)SOD, MDA, CAT, O₂^-, soluble protein and soluble sugar could be used as key indicators to evaluate the aluminum tolerance of Eucalyptus. This study provides a scientific reference for the selection of aluminum tolerance germplasm resources of Eucalyptus, and laid a foundation for further understanding of the mechanism of NO regulating the difference of aluminum tolerance between Eucalyptus species.

Plastic responses of native and exotic herbaceous species to temporal heterogeneity in water conditions

2023/12/30 21:36:09
In recent years, many studies have shown that extreme climate events occur more frequently. The extreme climate led to frequent drought and inundation events, which affected the growth of both exotic and native plants. In order to discuss the strategies of exotic and native plants in adapting to temporal heterogeneity in water conditions by investigating their responses to the sequence of drought and inundation events, four native and four exotic perennial herbaceous species in western Montana, USA were used as study objects. All plants were treated with moderate water(CK), initial inundation before drought(I-D)and initial drought before inundation(D-I)conditions, and variations in a series of morphological and biomass traits were measured. The results were as follows:(1)Compared with CK, both D-I and I-D treatments significantly reduced the total biomass of exotic species(P<0.05).(2)D-I treatment significantly reduced the total biomass at the early stage, and late belowground biomass and root/shoot of native species, but significantly improved their later relative growth(P<0.05).(3)D-I treatment significantly reduced the scaling exponent of the allometric relationship between belowground biomass and aboveground biomass for all plants, with a higher allometric exponent for exotic species than native species(P<0.05). In conclusion, the sequence of extreme events(inundation and drought)can alter the allocation of biomass between exotic and native plants. Early drought is more likely to reduce the accumulation of plant biomass than late drought, but it can promote the growth of native species in late period. The total biomass of native species is not reduced under environmental stress, indicating that native species have a strong ability to maintain phenotypic stability. Distribution patterns of aboveground and belowground biomass relationships are different between native and exotic species under D-I treatment.

Effects of water content on sugar metabolism of Malus &#215; robusta seed cryopreservation

2023/12/30 21:36:09
Water content is a key factor influencing the seed cryopreservation, but its effecting mechanism is not fully understood. In order to explore the effect and way of water content on the viability of seed cryopreservation on viability, Malus &#215; robusta seeds with different water contents were obtained by silica gel. The seed viability, sugar content and related enzyme indexes before and after cryopreservation were measured and correlation analysis were done. The results were as follows:(1)After 15 days of cryopreservation, the viability of seeds with different water contents was different, and the viability of seeds showed a trend of increasing and then decreasing as the water content of seeds decreased, and the seeds with 9.02% water content had the highest germination rate, at 53.33%. But after 120 days of cryopreservation, the viability of seeds increased as the water content decreased, and the seeds with 6.40% water content got the highest germination rate, at 27.78%. This indicates that the water content of Malus &#215; robusta seeds has a significant effect on the viability after cryopreservation. It is affected by the storage time in liquid nitrogen, and the optimum water content decreases as the storage time extended in liquid nitrogen.(2)Correlation analysis showed that there was a significant negative correlation between water content and viability(r=-0.82). There was significant negative correlation with fructose and sucrose content, acid invertase, fructokinase, while seed germination rate was significantly positive correlation with these indexes, suggesting that water content affects the contents of sucrose and fructose through effecting the activity of acid converting enzymes, which in turn affects sucrose metabolism to respond to low temperature and dehydration stress, ultimately leading to differences in viability. The seed viability was also affected by fructose metabolism through fructose kinase. Besides, alginate was one of the important regulatory substances of Malus &#215; robusta seed in response to water and low temperature stresses. In summary, water content has a significant effect on the viability of Malus &#215; robusta seeds cryopreservation through the combined effects of sucrose and fructose metabolism. This study provides a theoretical reference to further explore the cryopreservation mechanism of seed.

Effects of cerium oxide nanoparticles seed priming on seed germination and seedling growth of pepper under salt stress

2023/12/30 21:36:09
Cerium oxide nanoparticles(CeO₂NP_S)have been shown to improve the salt tolerance of plant due to the potential to eliminate free radicals and the antioxidation properties. However, the effects and mechanisms of seed priming with CeO₂NP_S on pepper plant are unclear. To reveal impacts of CeO₂NP_S seed priming on the germination and seedling growth of peeper plants under salt stress, using the Maoshu 360 variety of pepper(Capsicum annuum)as material, a total of seven concentrations of treatments(0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 mmol·L^-1)and a control of un-treatment were carried out to investigate effects of CeO₂NP_S seed priming on seed germination rate, seedling biomass, and physiological and biochemical indexes under salt stress. The results were as follows:(1)In the seed priming with 0.5 mmol·L^-1 CeO₂NP_S, soluble protein, content of proline, activity of catalase(CAT), content of ascorbic acid(AsA)and ratio of AsA/DHA significantly increased and levels of the superoxide anion(O₂^-)significantly decreased. There was no loss of viability for the seeds primed with cerium oxide nanoparticles. Indeed their germination rate and germination potential were enhanced under salt stress, and their germination index, and vigor index were improved under salt stress.(2)Under salt stress, seedlings from seeds primed with 0.4 mmol·L^-1 CeO₂NP_S showed the highest fresh weight, dry weight, and root length; additionally, soluble protein content, AsA content and AsA/DHA ratio were also improved. In conclusion, seed priming with CeO₂NP_S can not only enhance seed germination under salt stress by decreasing seed water potential, accelerating storage substances metabolism and improving antioxidant capacity but also promote seedling growth through boosting protein synthesis and ascorbic acid-glutathione cycle(AsA-GSH).

Effects of exogenous salicylic acid on morphology and physiology of pitaya seedlings under low temperature stress

2023/12/30 21:36:09
Pitaya(Hylocereus undatus)is a typical tropical cash crop that is not chilling-tolerant. Low temperature stress seriously affects the quality and yield of pitaya. It is an efficient and safe method to apply exogenous natural substances to improve the chilling tolerance of plants. Salicylic acid(SA)not only regulates many physiological and biochemical processes such as seed germination, growth, fruiting and senescence, but also helps plants to cope with biotic and abiotic stresses. However, the role of exogenous SA in chilling tolerance of pitaya has not been reported. To explore the effect of exogenous SA on the morphology structure and physiology of pitaya seedlings under low temperature, the leaves of ‘Zihonglong' seedlings were sprayed with SA at four concentrations(0.1, 0.3, 0.5, 0.7 mmol·L^-1). after spraying for 48 h, seedlings were incubated at 4 ℃. The change in the morphology and leaf tissue structure of pitaya seedlings were observed on 0, 3, 6, 9 d. Physiological indexes such as relative electrical conductivity, contents of malondialdehyde, contents of osmotic regulators(soluble sugar, soluble protein, proline)and antioxidant enzyme(superoxide dismutase, peroxidase, catalase, glutathione S-transferase)activities in leaves were measured. The results were as follows:(1)Under low temperature stress, pitaya seedlings showed chilling injury of Grade 0, Grade Ⅰ and Grade Ⅱ. The leaf shape, color and cell structure of pitaya with different chilling injury symptoms were quite different. The percentages of Grade Ⅰ and Grade Ⅱ chilling injury of pitaya seedlings treated with SA were significantly reduced.(2)Compared with the low temperature control, SA treatment could reduce the relative conductivity and malondialdehyde contents of pitaya leaves, and increase the contents of osmotic regulators and antioxidant enzyme activities.(3)After comparing with different SA treatments, SA at 0.3 mmol·L^-1 had the best effects on relieving chilling injury symptoms, reducing the relative conductivity and malondialdehyde content, increasing the soluble sugar and proline content, and increasing the activities of superoxide dismutase and glutathione S-transferase. The optimal SA concentrations for increasing soluble protein content, peroxidase activity and catalase activity were 0.7, 0.1 and 0.5 mmol·L^-1, respectively. In summary, exogenous SA could alleviate chilling injury of pitaya seedlings under 4 ℃, and has a positive physiological effect on improving chilling tolerance of seedlings, and exogenous SA at 0.3 mmol·L^-1 is more suitable.

Expression analysis of HsAP2-3 gene and interaction detection of HsAP2-3 with other proteins in Huperzia serrata

2025/9/30 10:22:28
Huperzia serrata, which belongs to the genus Huperzia involved in the family Lycopodiaceae, is a perennial, rare and endangered medicinal plant spread in northwest and southwest of China and also other countries. H. serrata is used extensively for treatment of contusions, strains, swellings, schizophrenia, myasthenia gravis, and organophosphate poisoning. However, it grows extremely slowly, which hampered its clinical investigation and application. It is well known that APETALA2(AP2)transcription factor plays crucial roles in the regulation of plant growth and development. In order to explore the biological function of AP2 in H. serrata, this study screened and cloned one AP2-like gene, HsAP2-3(GenBank accession number: OR103132), based on the transcriptome and full-length transcriptome data. Bioinformatics analysis, transcript expression analysis, and protein interaction assays of HsAP2-3 were further carried out. The results were as follows:(1)The HsAP2-3 CDS was 1 734 bp in length and encoded 577 amino acids, and the relative molecular weight and isoelectric point of the HsAP2-3 protein were 64.21 kDa and 8.85, respectively. HsAP2-3 protein contained two typical AP2 domains and a conserved nuclear localization signal site.(2)Phylogenetic tree analysis showed that HsAP2-3 were clustered within the euAP2 clade of the AP2 subfamily, and had the closest relationship with the Picea abies' AP2-like protein, the latter of which were demonstrated to be involved in the regulation of plant growth and development.(3)Quantitative real-time PCR results showed that HsAP2-3 was expressed in roots, stems, young leaves, and mature leaves of Huperzia serrata at different developmental stages, indicating ubiquitous regulation patterns.(4)Yeast two-hybrid assays demonstrated that HsAP2-3 had not transactivation activity, and could form homodimers in Y2HGold yeast cells.(5)The results of protein-interaction network analysis showed that HsAP2-3 has extensive interactions with transcription factors that regulate plant growth and development, including auxin response factors, abscisic acid-insensitive proteins, late elongated hypocotyl proteins, circadian clock associated proteins and B3 domain-containing transcription factors. Overall, these results suggest that HsAP2-3 may be involved in the growth and development of H. serrata in the form of homodimers or protein complexes with other factors, laying the foundation for further illustrating the biological function of HsAP2-3.

Identification and analysis of glucose transporter proteins (HbGLUTs)gene family in rubber tree

2025/9/30 10:22:28
Glucose is not only the basic energy source for organisms but also serves as a precursor in various synthetic metabolic processes. Glucose transport proteins(GLUTs)can regulate glucose levels within organisms and play a crucial role in maintaining glucose homeostasis. Currently, the functions of the GLUT family in rubber trees(Hevea brasiliensis)and their roles in key biological processes such as sugar homeostasis and latex regeneration remain unclear. Therefore, this study employed bioinformatics methods to identify GLUTs in rubber trees and systematically analyzed the physicochemical properties, protein structures, conserved motifs, phylogenetic development, cis-acting element structural features, and gene expression patterns of the gene family members. The results were as follows:(1)A total of 31 members of the HbGLUTs family members(HbGLUT1-HbGLUT31)were identified, all located in the cell membrane, with the number of transmembrane domains ranging from 9 to 24(both HbGLUT1 and HbGLUT2 contained 24 transmembrane domains), and the secondary structure was primarily composed of α-helix.(2)Evolutionary analysis revealed that HbGLUTs were functionally similar to human GLUTs in terms of classification. Type I subfamily members(such as HbGLUT8 and HbGLUT15)had conserved hexose transport functions and maintained latex production homeostasis by rapidly supplementing glucose during latex regeneration; it is speculated that Type Ⅱ and Type Ⅲ subfamily members evolved diverse transport capabilities for substrates such as fructose and myo-inositol. Among them, Type Ⅲ subfamily members(such as HbGLUT3, HbGLUT17, HbGLUT18)were highly expressed in various tissues, and their promoters contained stress-related elements, indicating their involvement in plant stress responses.(3)Tissue-specific expression analysis showed that HbGLUTs were generally expressed at low levels in latex, but some genes of Type I subfamily were crucial for latex regeneration. Additionally, several members(such as HbGLUT21 and HbGLUT28, etc.)were highly expressed specifically in flowers, supporting the high energy requirements of the reproductive process. This study provides important clues for elucidating the functions of HbGLUTs in latex regeneration and stress responses, laying a foundation for further research on sugar transport proteins in rubber trees.

ERF-Ⅶ transcription factor RAP2.12 regulates submergence-induced anthocyanin biosynthesis in Arabidopsis thaliana seedlings

2025/9/30 10:22:28
Submergence stress, a major environmental constraint in agriculture, causes oxygen deficiency in plant tissues, thereby impairing plant growth, development, and survival. One notable adaptive response of plants to submergence is the accumulation of anthocyanins — flavonoid pigments with strong antioxidant properties that help mitigate reactive oxygen species(ROS)-induced damage. These compounds also play important roles in stress signaling and metabolic reprogramming. Although enhanced anthocyanin accumulation under submergence has been observed in multiple plant species, the underlying regulatory mechanisms, particularly at the transcriptional level, remain poorly understood. To clarify the molecular mechanism of submergence-induced anthocyanin biosynthesis, this study investigated the role of ERF-Ⅶ(ethylene response factor group Ⅶ)transcription factors in Arabidopsis thaliana. Anthocyanin levels were measured in various genotypes exposed to submergence treatment conditions. In addition, protein-protein interaction assays, including yeast two-hybrid(Y2H)and bimolecular fluorescence complementation(BiFC), were conducted to examine physical interactions between ERF-Ⅶ members and known regulators of anthocyanin biosynthesis. In addition, to elucidate its regulatory pathway, a systematic analysis of the role of RAP2.12 in regulating anthocyanin biosynthesis was conducted at both genetic and molecular levels. The results were as follows:(1)Anthocyanin accumulation under submergence depended on MBW complex, composed of MYB, bHLH, and WD40 proteins, which served as a central regulatory hub in flavonoid biosynthesis.(2)RAP2.12 physically interacted with MYB75, MYB90, and MYB113, and these interactions synergistically activated the expression of anthocyanin biosynthetic genes such as DFR and LDOX, indicating a transcriptional co-activation mechanism.(3)The rap2.2 2.3 2.12 triple mutant exhibited reduced sensitivity to submergence-induced anthocyanin accumulation, while (MA)RAP2.12-HA overexpression lines showed hypersensitivity, indicating that RAP2.12 promotes anthocyanin biosynthesis under submergence and acts as a positive regulator in this stress-adaptive pathway.(4)Genetic analysis revealed that the regulatory function of RAP2.12 was primarily dependent on MYB transcription factors, as RAP2.12 alone could not activate downstream gene expression in the absence of functional MYB proteins. In conclusion, RAP2.12 regulates anthocyanin biosynthesis and accumulation in A. thaliana seedlings under submergence stress by physically interacting with MYB75. It enhances the transcriptional activity of the MBW complex, thereby promoting the expression of key structural genes in the anthocyanin biosynthetic pathway. These findings expand our understanding of the roles of ERF-Ⅶ transcription factors in plant adaptation to hypoxic environments. Furthermore, this work provides novel insights into how environmental signals are integrated through transcriptional regulators to coordinate secondary metabolism and stress responses. It also provides a theoretical basis for understanding the molecular mechanism of plant response submergence stress and crop breeding.

Sequence analysis of PP2C2 gene in Artemisia desertorum and its expression pattern under drought stress

2025/9/30 10:22:28
Protein phosphatase 2C(PP2C)play important roles in growth and development, cell cycle regulation, signal transduction, and responses to environmental stress. This study focused on Artemisia desertorum, a highly drought-tolerant and multifunctional plant native to arid desert regions, to investigate the functional role of PP2C2 gene in drought tolerance. Using A. desertorum as the experimental material, the PP2C2 gene was amplified, its sequence was subjected to bioinformatic analysis, and its protein structure was predicted. Additionally, the expression patterns of PP2C2 under various water stress conditions were analyzed, and the regulatory role of the PP2C2 gene in drought stress responses was elucidated. The results were as follows:(1)The PP2C2 gene in A. desertorum contained an open reading frame(ORF)of 1 404 bp, encoding a protein of 467 amino acids. Sequence alignment demonstrated that the gene shared high homology with PP2C genes from other plants, such as Erigeron canadensis.(2)Bioinformatic analysis revealed that the PP2C2 protein was localized in the nucleus, no signal peptide, and was classified as a non-secretory protein. Its secondary structure predominantly consisted of random coils, with strong hydrophilicity, no transmembrane helical region, and multiple potential modification sites.(3)Quantitative real-time PCR(qRT-PCR)analysis showed that the expression of the PP2C2 gene was responsive to varying levels of drought stress. Under drought conditions, its expression exhibited an overall up-regulation trend, while rehydration led to a significant reduction in expression levels. This study preliminarily reveals that the PP2C2 gene plays a significant role in the drought tolerance mechanism of Artemisia desertorum, offering a theoretical reference for further understanding of its drought resistance mechanism and potential application in genetic engineering.

Cloning, subcellular localization, and expression analysis of the RdNAC72 gene in Rhododendron delavayi

2025/9/30 0:00:00
NAC transcription factors play important roles in plant growth, development, and stress responses. However, the molecular mechanism of the RdNAC72 gene in Rhododendron delavayi involved in response to stress remains unclear. To investigate the the roles of the RdNAC72 gene in high temperature stress response and its potential regulation mechenism, we first designed primers for cloning the full length coding sequence of the RdNAC 72 gene using PCR technology. Subsequently, the gene's structure, function, and physicochemical properties were analyzed and predicted using bioinformatics method. The spatial and temporal expression characteristics of the RdNAC72 gene under heat stress and expression pattern under ABA stress were analyzed using quantitative real-time PCR(RT-qPCR). The results were as follows:(1)The RdNAC72 gene had a full length of 1 005 bp, encoding 334 amino acids with a relative molecular weight of 37.415 kDa. Subcellular localization analysis showed that the RdNAC72 protein was located in the nucleus.(2)Multiple sequence alignment and phylogenetic analysis indicated that the RdNAC72 was most closely related to the RdNAC72 in R. williamsianum. Additionally, cis-acting element analysis revealed that the gene contained elements associated with hormone response, light response, anaerobic response, low temperature response, and heat stress response.(3)High temperature stress could induce the expression of RdNAC72, exhibiting temporal and spatial expression specificity. After three days of high temperature stress treatment, the relative expression level of the RdNAC72 gene in leaves was significantly upregulated by 31.16-fold; while no significant change was observed in roots and stems. After six days of high temperature stress treatment, the relative expression levels of RdNAC72 roots, stems, and leaves were all significantly upregulated, with the highest observed in leaves(61.56-fold), followed by stems(50.14-fold), and roots(17.42-fold). Additionally, it was found that ABA could induce the expression of RdNAC72.(4)RT-qPCR analysis demonstrated a coordinated expression pattern between RdHSP17.2 and RdNAC72 with RdHSP17.2 containing multiple NAC recognition motifs(CATGTG)and core binding sequences(CACG)in its promoter region, indicating that RdNAC72 may be a downstream target gene of RdNAC72. Therefore, the RdNAC72, a transcription factor, localized in the nucleus, responds significantly to high temperature and ABA, potentially activating the RdHSP17.2 expression to confer heat resistance. This study enriches the biological functions of NAC transcription factors, and provides the reference for the future genetic and breeding of this plant.

Analysis on variety types and superior tree economic traits of Illicium verum from four origins in Guangxi

2025/9/30 10:22:28
To further clarify the distribution of different variety types and excavate superior germplasm of Illicium verum(star anise)in Guangxi, a survey was conducted on I. verum from four different regions, and the leaf and fruit traits of 36 initially selected superior trees were analyzed. The results were as follows:(1)The proportion of star anise individuals with light red and red flowers exceeded 90%, whereas those with yellow flowers were not identified in this study. The number of fruit segments in star anise ranged from 6 to 13, with 8 segments being the most common. It was only the fruits with 8 and 13 segments that were consistently observed on the entire plants.(2)The coefficients of variation(CV)for fresh fruit weight, oil content of fresh fruit, and fruit stalk length all exceeded 20% among the initially selected superior trees. In contrast, the CV for trans-anethole content was the smallest at 5.44%. Significant differences were observed in leaf shape index, leaf thickness, and oil content of fresh fruit among the four origins.(3)A significantly or extremely significantly positive correlation was found between leaf thickness/fresh leaf weight and fresh fruit width/weight. Relative humidity was significantly positively correlated with seven main traits. In contrast, flower color did not show a clear correlation with the main fruit traits.(4)In the cluster analysis, the individual from Shanglin(SL5)clustered separately, whereas other individuals did not cluster based on region. In conclusion, the two types of star anise with light red and red flowers were the main variety types in Guangxi. Among these variety types, the number of fruit segments ranging from 6 to 13 were considered normally, and that fruits with 8 segments were the common type. The initially selected superior trees displayed a high degree of trait variation, suggesting significant potential for genetic improvement in economic traits such as fresh fruit weight and oil content of fresh fruit. Relative humidity significantly influenced the growth and development of star anise. Those plants with thicker leaves generally to produce larger fruits. However, no clear correlation was observed between flower color and fruit quality. Cluster analysis results implied, significant genetic differentiation in traits among plants from different regions indicating complex genetic relationships among these variety types. This complexity might be attributed to variations in artificial cultivation methods and the inherent genetic characteristics of the plants. The study provides a theoretical reference for the future utilization of germplasm resources and offers guidance for further breeding and cultivation of star anise.

Cloning and activity analysis of HbJAZ1.0 gene promoter from rubber tree

2025/9/30 10:22:28
The JAZ(jasmonate ZIM-domain)is a repressor protein in the jasmonic acid signaling pathway, inhibiting the expression of early jasmonic acid response genes by interacting with related transcription factors. To elucidate the characteristics and activity of the HbJAZ1.0 gene promoter, this study used the rubber tree variety ‘CATAS 7-33-97' as material and analyzed the cis-acting elements and expression activity of the HbJAZ1.0 gene promoter through PCR amplification, PlantCARE software, and Arabidopsis thaliana transgenetic techniques. The results were as follows:(1)A total of 1 501 bp promoter sequence upstream of the HbJAZ1.0 gene was isolated from the genomic DNA of the rubber tree.(2)Several key cis-acting elements had been identified within the HbJAZ1.0 gene promoter, including ABRE for abscisic acid, TCA-element for salicylic acid, as well as ACAT-motif, Box 4, G-box, GT1-motif, TCCC-motif, TCT-motif and chs-CMA1a for light responsiveness.(3)A plant expression vector containing the GUS reporter gene under the control of the HbJAZ1.0 gene promoter had been constructed and transformed it into A. thaliana using Agrobacterium tumefaciens-mediated transformation. Histochemical GUS staining demonstrated extensive expression of the HbJAZ1.0 gene promoter throughout various tissues of Arabidopsis thaliana, including roots, stems, leaves, flowers, and fruits. In conclusion, the results indicate the HbJAZ1.0 gene promoter has a constitutive expression activity and might be regulated by light and various plant hormones. The results of the study may lay the foundation for further study on the function of HbJAZ1.0 gene.

Effects of mixed plantation of Pinus massoniana and Castanopsis hystrix at different stand ages on litter and soil carbon storage

2025/9/30 10:22:28
Litter is an important part of forest productivity, and its productivity and stoichiometric ratio(high N and low C:N, C:P and N:P, which facilitate litter decomposition)are vital in regulating soil carbon dynamics through decomposition rate modulation and nutrient release optimization. Although mixed-species plantations are known to significantly alter litter production and soil carbon sequestration compared with monocultures, but how these mixing effects change across different stand age stages remains poorly understood. The objective of this study was four pure Pinus massoniana plantation with different stand ages(25, 36, 46 and 63 years old)and their corresponding mixed plantations with Castanopsis hystrix. We measured litter production, litter stoichiometric ratio, and soil carbon storage to assess how mixing broad-leaved tree species with pure Pinus massoniana affects these factors across different stand ages. The results were as follows:(1)Tree species mixing significantly increased litter production in mature forests(36 years old). The positive mixing effect on litter production mainly existed in near-mature forests(25 years old)and mature forests(36 years old). Consequently, the litter N content gradually increased with increasing stand age, whereas the P content firstly increased and then decreased. Except for the mature forest(46 years old), mixed plantations had lower C:N than pure plantations. In over-mature forests(63 years old), we observed maximal mixing effects on litter N content and N:P but minimal effects on C:N.(2)Mixing also promoted an increase in soil carbon storage for most stand ages, particularly in the 0-60 cm soil layer. We also observed that the over-mature forest exhibited maximal mixing effect values in each soil layer.(3)Spearman's correlation analysis showed strong association between mixing-influenced soil carbon storage variations and litter C, N, C:N and N:P. Thus, introducing Castanopsis hystrix into pure Pinus massoniana plantations can effectively increase litter production and quality, thereby increasing soil carbon storage and promoting nutrient cycling. Moderately extending the management cycle of mixed plantations is beneficial for maximizing their ecosystem functions.

Comprehensive evaluation of cold resistance of eight macadamia varieties under low temperature stress

2025/9/30 10:22:29
In order to assess the cold resistence of macadamia and select varieties with strong cold resistance. In this study, eight main cultivated varieties of macadamia in Guangxi were treated at -8 ℃ to determine physiological indices related to cold resistance, including superoxide dismutase(SOD)activity, peroxidase(POD)activity, soluble sugar(SS)content, soluble protein(SP)content, proline(Pro)content, malondialdehyde(MDA)content, relative electric conductivity(REC)and chlorophyll(Chl)content. The cold resistance of macadamia was comprehensively evaluated by correlation analysis, principal component analysis, membership function analysis and cluster analysis. The results were as follows:(1)A total of 10 physiological indices of cold resistance were significantly different under low temperature stress.(2)By principal component analysis, 10 physiological indices were converted into three new physiological indices, with a cumulative contribution rate of 90.194%. Combined with the correlation analysis results, SOD, POD, SS, SP, Pro, Chlb and Chl(a+b)were selected as the main for the identification of cold resistance of macadamia.(3)Based on the results of cluster analysis and D value of comprehensive cold resistance, eight macadamia varieties were divided into three categories according to the strength of cold resistance. The first group had the strongest cold resistance, including ‘Guireyin No. 4', ‘Guire No. 7', ‘HY', and ‘JW'; the second group had moderate cold resistance, including ‘Guire No. 5' and ‘Guire No. 1'; the third group had the weakest cold resistance, including ‘A16' and ‘Guire No. 6'. Among them, ‘Guireyin No. 4' had the strongest cold resistance; while ‘Guire No. 6' had the weakest cold resistance. The observation results of leaf morphology under low temperature stress were consistent with the clustering analysis results. These results provide a theoretical basis for the study of cold resistance of macadamia, which is of great significance for planting macadamia in the cold area of Guangxi and planting in the North of China.

Response of foxtail millet yield and relationship between elements to foliar application of selenium

2025/7/1 10:29:50
Selenium(Se)is an essential trace element for humans, and consuming selenium rich agricultural products is the best way to effectively supplement the Se needed by the human. In order to facilitate the large-scale production and quality improvement of selenium-rich crops, Setaria italica var. germanica(Zhangzagu-10)was selected as the research object, different concentrations of commercial Se fertilizer on the leaves during the jointing and filling stages were sprayed, Se content and yield of S. italica var. germanica were measured, and the interaction between plant elements was analyzed and elucidated. The results were as follows:(1)Exogenous foliar spraying of Se fertilizer could significantly increase the Se content in grains and millet yield.(2)Spraying 30.75 g·hm^-2(measured as Se)on the leaves once during the grain filling period could increase the Se content of the seeds by 3.7 times compared to the control, meeting the standards for Se rich agricultural products.(3)The ear weight and milling ratio of millet significantly increased by 11.31% and 17.34%, respectively.(4)Foliar spraying of Se significantly altered the element content and interrelationships in plant leaves, stems, leaf sheaths, and grains, with a significant increase in the proportion of positive correlations between elements.(5)Calcium and sulfur ions showed a decreasing trend with the increase of Se fertilizer concentration, while iron, copper, and zinc ions exhibited a low concentration promoting and high concentration inhibiting phenomenon. The decrease in sulfur ion content in leaves and grains might be closely related to the increase in Se content, and the two compete in transportation and metabolic pathways within the plant. In conclusion, the Se fertilizer used in this study can effectively increase the Se content and yield of S. italica var. germanica. During the production process, soil sulfur fertilizer should be appropriately increased to supplement the reduced sulfur element in the grains. The results of this study provide practical support for the improvement of selenium-enriched fertilizer ratio, the production and nutrition regulation of selenium-enriched S. italica var. germanica.

Correlation between soil factors and effective component contents of Lonicerae Japonicae Flos

2025/7/1 10:29:50
To investigate the impact of soil factors on the accumulation of effective components in Lonicerae Japonicae Flos in southern Shaanxi region, this study measured the contents of chlorogenic acid, 3,5-di-O-caffeoyl quinic acid, 4,5-di-O-caffeoyl quinic acid, total phenolic acids, galuteolin, and 12 inorganic elements in 27 batches of Lonicerae Japonicae Flos samples from different production areas in southern Shaanxi. Additionally, the contents of 5 fertility indicators and 12 inorganic elements in the corresponding planting soil were measured. The enrichment characteristics of inorganic elements in Lonicerae Japonicae Flos were analyzed, and the main factors affecting the effective components of Lonicerae Japonicae Flos were identified. The results were as follows:(1)Pearson correlation analysis revealed a positive correlation between the effective components of phenolic acids in Lonicerae Japonicae Flos with Se and organic matter in soil, while showing a negative correlation with Co, Fe, and Mn in soil.(2)The trend of element enrichment coefficients in soil by Lonicerae Japonicae Flos was as follows: Cd>Cu>Zn>Se>Ni>Mn>Hg>Cr>Co>As>Pb>Fe. Monitoring Cd element content in Lonicerae Japonicae Flos was crucial for cultivation.(3)The Se-abundant areas in Ankang showed potential in Se-abundant Lonicerae Japonicae Flos development. The contents of Se and Cd in soil, Lonicerae Japonicae Flos should be expressed concerns at the same time. In summary, these results indicate that applying organic fertilizer and Se fertilizer in soil can improve the effective components in the production practice of Lonicerae Japonicae Flos. The study can provide theoretical direction for standardized planting and Se-abundant product development of Lonicerae Japonicae Flos.

Differences in physiological characteristics of leaf senescence during color transition period between Taxodium ascendens and T. distichum

2025/7/1 10:29:50
During the autumn and winter seasons, both Taxodium ascendens and T. distichum undergo a color transition period in which their leaves gradually turn orange or red, making them common ornamental trees with colored foliage in gardens. Analyzing the physiological characteristics of leaf color transition period in these two species is crucial for understanding the aging and coloring processes of these trees, providing valuable guidance for the application of ornamental trees with colored leaves in garden landscapes. This study conducted measurements on pigment content, antioxidant enzyme activity, osmoregulatory substance contents, malondialdehyde(MDA)content, and chlorophyll fluorescence parameters in aging leaves of T. ascendens and T. distichum during the color transition period. Statistical methods such as significant difference analysis, correlation analysis, linear fitting, and membership function analysis were employed to comprehensively evaluate the physiological state of aging leaves from both species. The results were as follows:(1)The AC/CHLa+b ratio in T. ascendens and T. distichum leaves increased rapidly with age reaching 11.46 and 7.13 respectively; this directly contributed to the orange-red hue observed in their foliage.(2)During aging processes, superoxide dismutase(SOD)and catalase(CAT)activities and soluble sugar content decreased while MDA content first increased and then decreased; however peroxidase(POD), ascorbate peroxidase(APX), and phenylalanine ammonialyase(PAL)activities increased, indicating a resistance effect against leaf senescence.(3)The photochemical conversion efficiency and heat dissipation ability could represent the change of physiological and biochemical indexes well, and reflect the aging process.(4)Comprehensive scores showed that at any given time T. ascendens consistently exhibited lower scores than T. distichum suggesting superior physiological status for T. ascendens. In conclusion, T. ascendens and T. distichum demonstrate similar physiological characteristics of leaf senescence but T. ascendens enteres into this phase earlier than T. distichum. In landscape applications combining plantings of T. ascendens alongside T. distichum can extend overall periods for colorful foliage display.

Function of R2R3-MYB Gene LcMYB113 on regulating anthocyanin biosynthesis in Loropetalum chinense var. rubrum

2025/7/1 10:29:50
Anthocyanins are one of the key factors affecting the formation of ornamental value of Loropetalum chinense var. rubrum. In order to investigate the molecular mechanisms of anthocyanin biosynthesis in L. chinense var. rubrum, an anthocyanin biosynthesis-related R2R3-MYB gene, named LcMYB113 with GenBank accession number OR344758, was cloned from L. chinense var. rubrum. The deduced amino acid sequence of LcMYB113 gene was analyzed by bioinformatics methods. The relative expression levels of LcMYB113 gene in leaves of L. chinense var. rubrum and L. chinense were tested by real-time quantitative RT-PCR method. The phenotypes of leaves and flowers of transgenic tobacco lines were recorded. The relative expression levels of anthocyanin biosynthetic structural genes in leaves of transgenic tobacco lines were examined. The results were as follows:(1)The open reading frame of LcMYB113 gene was 789 bp long, encoding 262 amino acids. Multiple alignment analysis showed that the N-terminal of LcMYB113 contained a canonical R2R3 DNA binding domain and a bHLH transcript factor binding motif [D/E]Lx₂ [R/K]x₃Lx₆Lx₃R. Two anthocyanin biosynthesis activator characteristic motifs ANDV and [K/R]P [Q/R]P [Q/R] were also found in the amino acid sequence of LcMYB113. Phylogenetic tree analysis indicated that LcMYB113 was closely related to anthocyanin specific R2R3-MYB subfamily transcription factors, including PsMYB58 of Paeonia &#215; suffruticosa and VvMYBA1 of Vitis vinifera.(2)The anthocyanin content and relative expression level of LcMYB113 gene in leaves of L. chinense var. rubrum were 7.4 and 101 times that of L. chinense respectively, which indicated that the relative expression level of LcMYB113 gene was correlated with the anthocyanin content in leaves.(3)The LcMYB113 gene overexpression vector was constructed and transformed into tobacco variety WS38. Heterologous expression of LcMYB113 gene in tobacco induced anthocyanin accumulation in leaves and flowers of transgenic lines. Further more, compared with wide type tobacco line, transgenic lines had remarkably higher relative expression levels of anthocyanin biosynthetic structural genes, such as NtANS, NtDFR and NtCHS. In summary, this research results indicate that LcMYB113 can regulate the biosynthesis of anthocyanin, providing theoretical support for leaf color breeding of L. chinense var. rubrum.

Effects of intercropped trees on the structure and function of soil fungal communities in tea gardens

2025/7/1 10:29:50
To explore the impact of different intercropped trees on fungal communities in tea garden soils in southern Henan, the study took the tea garden soils intercropped with Castanea mollissima, C. seguinii and Cunninghamia lanceolata in Xinyang, Henan as the test objects. The indoor chemical experiments and high-throughput sequencing technology were used to analyze the chemical properties of tea garden soils, fungal community structure and their relationship with soil nutrients under different intercropping patterns. The results were as follows:(1)The fungal species abundance and diversity in the tea garden soils intercropped with Castanea seguinii and Cunninghamia lanceolata were significantly higher than those intercropped with Castanea mollissima, and there were significant differences in fungal community composition among the three.(2)In terms of fungal community structure, the tea gardens intercropped with C. seguinii and Cunninghamia lanceolata exhibited high similarity. Further analysis revealed that Basidiomycota and Ascomycota were the main fungal phyla in the soil of three intercropped tea gardens. Among them, the relative abundance of Basidiomycota was higher in the tea garden soils intercropped with Castanea mollissima and Cunninghamia lanceolata, while Ascomycota dominated in the tea garden intercropped with Castanea seguinii. At the genus level, the relative abundance of Russula and Mortierella in the tea garden soils intercropped with Castanea mollissima was significantly higher than the other two intercropping types.(3)The study also found a significant correlation between the chemical properties of the tea garden soils and the fungal community structures. There were significant differences in nitrate nitrogen and available phosphorus contents in the soil of tea gardens intercropped with different trees, which further influenced the distribution and structure of the fungal community.(4)In terms of fungal nutrition types, the soil fungi in the tea gardens intercropped with Castanea mollissima and Cunninghamia lanceolata were dominated by ectomycorrhizal fungi, while that in the tea garden intercropped with Castanea seguinii was primarily undefined saprotrophic fungi. In summary, significant differences exist in the composition, diversity, and functions of fungal communities in the soil of tea gardens intercropped with Castanea mollissima, C. seguinii, and Cunninghamia lanceolata in southern Henan. These findings provide scientific evidence for the selection of intercropped tree species in tea gardens, contributing to the optimization of the ecological environment and the improvement of tea quality.

Growth and stoichiometry of Pinus yunnanensis seedlings in response to shade and drought interaction

2025/7/1 10:29:50
In order to investigate the growth of Pinus yunnanensis seedlings and the stoichiometric characteristics of carbon(C), nitrogen(N)and phosphorus(P)of different organs in response to shade and drought treatments and the adaptive mechanism, the growth of P. yunnanensis seedlings in shade and drought environments was measured and analyzed in a potting controlled experiment using 1-year-old P. yunnanensis seedlings as the target. The experiment was set up with two levels of 0% shade and 70% shade, and four moisture gradients of normal moisture(CK, 80%±5%), light drought(LD, 65%±5%), moderate drought(MD, 50%±5%)and severe drought(SD, 35%±5%)were set to determine the growth indexes of P. yunnanensis seedlings under shade and drought treatments, as well as the C, N, and P contents of leaf, stem, coarse root and fine root, and calculate the stoichiometric characteristics of their stoichiometric characteristics. The results were as follows:(1)Seedling height, diameter and biomass increment were the greatest under 0% shade and 70% shade conditions with LD; leaf biomass increment was significantly increased under the shade treatment(70% shade)compared with no shade treatment(0% shade)in all drought stress treatments.(2)Compared with the normal water treatment, with the increase of drought stress degree, the C content in each organ of P. yunnanensis seedlings under the shade and drought interaction did not change significantly; the N content in leaf was decreasing, the N contents in stem and coarse root were increasing, and the N content in fine root was decreasing and then increasing; the P content in leaf and coarse root was decreasing, and the P content in fine root was increasing.(3)The order of variability of each element was CP. yunnanensis seedlings. C content was negatively correlated between coarse root and fine root, N content were positively correlated between leaf and fine root, stem and coarse root, and coarse root and fine root, and P content was positively correlated between leaf and fine root. In summary, the growth of P. yunnanensis seedlings in drought environment is mainly limited by N element; shade slows down the growth of P. yunnanensis seedlings limited by N element. P. yunnanensis seedlings improve the habitat of seedlings by increasing the utilization efficiency of N and P, and can alleviate the damage caused by drought stress. It is recommended that appropriate shade be provided when cultivating P. yunnanensis seedlings in the forest understory in the future.

Leaf hydraulic characteristics of 16 Cycas species

2025/7/1 10:29:50
Cycads of China are mainly distributed across diverse habitats in tropical and subtropical regions, with most species are highly endangered. The study of leaf hydraulic traits in cycads species enhances our understanding of their adaptation to the water environments and responses to climate change. We selected 16 native Cycas species from Nanning Botanical Garden and measured leaf morphological and anatomical characteristics, pressure-volume curves, hydraulic conductance, and cavitation resistance. Additionally, we collected leaf traits of tropical-subtropical angiosperms from the same region for comparative analysis. The results were as follows:(1)There was slight interspecific variation in hydraulic traits across the 16 Cycas species, and no significant differences were found in hydraulic traits between the two groups distributed in karst and non-karst.(2)Compared to angiosperms, Cycas species showed higher leaf maximum hydraulic conductance(K_leaf-max), lower cavitation resistance(P_50leaf), and smaller stomatal safety margin(HSM_tlp), tend to adopt a risky stomatal regulation strategy.(3)Different from angiosperms, we found a no significant trade-off between K_leaf-max and P_50leaf in Cycas species, which partly due to the fact leaf hydraulic traits of Cycas were less influenced by anatomical structure. This study reveals the hydraulic strategies of Cycas species, illustrates the high leaf hydraulic risk of Cycas, and recommends monitoring water relations of their field populations to improve the level of conservation.

Leaf hydraulic characteristics of 16 Cycas species

2025/7/1 10:29:50
Cycads of China are mainly distributed across diverse habitats in tropical and subtropical regions, with most species are highly endangered. The study of leaf hydraulic traits in cycads species enhances our understanding of their adaptation to the water environments and responses to climate change. We selected 16 native Cycas species from Nanning Botanical Garden and measured leaf morphological and anatomical characteristics, pressure-volume curves, hydraulic conductance, and cavitation resistance. Additionally, we collected leaf traits of tropical-subtropical angiosperms from the same region for comparative analysis. The results were as follows:(1)There was slight interspecific variation in hydraulic traits across the 16 Cycas species, and no significant differences were found in hydraulic traits between the two groups distributed in karst and non-karst.(2)Compared to angiosperms, Cycas species showed higher leaf maximum hydraulic conductance(K_leaf-max), lower cavitation resistance(P_50leaf), and smaller stomatal safety margin(HSM_tlp), tend to adopt a risky stomatal regulation strategy.(3)Different from angiosperms, we found a no significant trade-off between K_leaf-max and P_50leaf in Cycas species, which partly due to the fact leaf hydraulic traits of Cycas were less influenced by anatomical structure. This study reveals the hydraulic strategies of Cycas species, illustrates the high leaf hydraulic risk of Cycas, and recommends monitoring water relations of their field populations to improve the level of conservation.

Characteristics of soil seed bank after 32 years of different harvesting methods in evergreen broad-leaved forests

2025/7/1 10:29:50
Soil seed bank is both the genetic memory and the future in vegetation succession, and plays an important role in revealing the mechanism in the recovery process of disturbed forests and in predicting its successional direction. In order to reveal the role of soil seed bank in the process of forest restoration, the soil seed banks from secondary forests which undertook different modes of harvesting and have recovered ever since, were analyzed. The comparisons were conducted between forests naturally restored for 32 years after clear cutting(CC)or selective cutting(SC)in Tianjingshan Forest Farm, Guangdong, with non-cutting(NC)evergreen broad-leaved forests in the same area as controls. The distribution, density, species composition and diversity of the soil seed bank in these three types of forest were investigated through vegetation surveys and soil seed germination experiments, and the relationship between the soil seed bank and the above-ground vegetation was analyzed. The results were as follows:(1)The seed banks of understory soils of different harvesting methods were dominated by herbs, followed by shrubs and least by trees. The seed densities of trees and shrubs were in the order of NC>CC>SC, with NC significantly higher than CC and SC(P<0.05), and there was no significant difference between CC and SC; the seed densities of herbs were not significantly different among different harvesting methods.(2)A total of 43 plant species were found in the soil seed banks, most of which were light-damanded species, including 7 tree species(which were NC=CC>SC), 15 shrubs(which were NC>CC>SC), and 21 herbs(which were CC>NC>SC).(3)Shannon diversity index, Simpson diversity index and Pielou evenness index of trees in the seed banks were in the order of NC>CC>SC among different harvesting methods, the diversity indices and evenness indices of shrubs and herbs were mostly not significantly different among different harvesting methods.(4)The similarity between soil seed banks and above-ground vegetation was low of different harvesting methods, with four shared tree species including three in NC and one in SC, two shared shrub species, one each in SC and CC, and one shared herbaceous species in NC. In conclusion, the seed density, number of species and diversity indices in the soil seed banks after 32 years of natural recovery from logging in evergreen broad-leaved forests are still smaller than those in unharvested forests, the soil seed bank cannot support rapid natural recovery of disturbed forests. The results provide scientific basis and theoretical guidance for the management of subtropical secondary forests and the development of artificial restoration techniques

Effects of microwave treatment on germination of sugarcane seedcane setts and elimination of ratoon stunting disease pathogenic bacterium

2025/12/4 12:25:40
To study the effect of microwave treatment on the elimination of ratoon stunting disease(RSD)pathogenic bacterium, this study optimized conditions of microwave for sugarcane seedcane setts through systematic investigation of their placement modes, microwave temperature and duration. The temperature uniformity, germinative force, germination rate, shoot height, and positive rate of RSD were systematically analyzed. The results were as follows:(1)Among the five tested placement modes, circularly stacked shape resulted in the optimal spatial arrangement with superior microwave temperature field uniformity.(2)Appropriate microwave condition(54-56 ℃)was found to promote activity of sugarcane seedcane setts growth, while temperatures ≥58 ℃ caused significant damage to it.(3)Microwave treatment exhibited a significant effect on the elimination of RSD pathogenic bacterium, the positive rate of RSD in the sugarcane seedcane setts treated at 54 ℃ and 56 ℃ for 20 min and 30 min was reduced to 0, achieving complete elimination of pathogenic bacterium.(4)Under microwave treatment at 54 ℃ for 20 min, sugarcane seedcane setts achieved a 10-day germination rate of 100%, with an average shoot height of 11.67% higher than the control group. Furthermore, this treatment saved processing time and energy consumption compared to microwave condition of 54 ℃, 30 min, establishing it as the optimal microwave condition. This study utilized microwave technology for the elimination of RSD pathogenic bacterium, demonstrating advantages such as superior temperature uniformity, high elimination of pathogenic bacterium efficiency, and environmental friendliness. The findings offer a novel technical reference for the preparation and propagation of healthy sugarcane seedcane setts.

Effects of different propagation methods on the structure and function of endophytic microbial community in ratoon cane roots

2025/12/4 12:25:40
To investigate the effects of different propagation methods on the structures and functions of endophytic bacterial and fungi in ratoon cane roots, the ratoon cane roots were analyzed based on high-throughput sequencing technology. In this study, ratoon cane roots via tissue culture and conventional propagation methods were used as the materials. Meanwhile, the functions of bacterial and fungal communities were also predicted using PICRUSt and FUNGuild softwares, respectively. The results were as follows:(1)The dominant endophytic microbial communities in ratoon cane roots were different between conventional propagation and tissue culture propagation methods.(2)The unique dominant endophytic bacterial genera in ratoon cane roots under the conventional propagation method included Leifsonia, Phyllobacterium, norank_f__Micropepsaceae, Haliangium, Granulicella, Acidothermus, norank_f__Acetobacteraceae and norank_f__Magnetospirillaceae; meanwhile, the unique dominant endophytic fungal genera were Trechispora, Hypochnicium, unclassified_o__Trechisporales, Mycena, Chaetosphaeria, Cladophialophora and Trichoderma.(3)In the ratoon cane roots under the tissue culture propagation method, the unique dominant endophytic bacterial genera included Ralstonia,Amycolatopsis,unclassified_f__Pseudonocardiaceae, Devosia, Streptomyces, Lechevalieria and Kibdelosporangium, and the unique dominant endophytic fungal genera included unclassified_f__Marasmiaceae, unclassified_k__Fungi, Penicillium, Sarocladium, unclassified_c__Agaricomycetes and Setophoma. Compared with the conventional propagation method, the endophytic microbial compositions in ratoon cane roots could be altered by the tissue culture propagation method.(4)The numbers of unique operational taxonomic units(OTUs)of endophytic bacteria and fungi in ratoon cane roots under the tissue culture propagation method was greater than that under the conventional propagation method, indicating higher endophytic microbial diversity and abundance.(5)The functional prediction results showed that the functions of endophytic bacteria in ratoon cane roots were similar between conventional and tissue culture propagation methods, however, the endophyte-plant pathogen-undefined saprotroph group of endophytic fungi was significantly enriched under tissue culture propagation method. In conclusions, endophytic microbial community structures and functions in ratoon cane roots are affected by different propagation methods. All above results also provide a theoretical basis for the subsequent screening, development, and utilization of beneficial functional microbial populations.

Research on pollen morphology and germination characteristics of Camellia oleifera ‘Changlin'

2025/12/4 12:25:40
To observe the pollen morphological characteristics and explore the influence of nutritional elements on the germination of C. oleifera ‘Changlin' pollen through in vitro culture. In this experiment, three nationally approved Camellia oleifera ‘Changlin' series of Camellia, planted in East Guizhou Province, were used as materials. A single-factor and orthogonal tests were conducted using the agar medium germination method. This study was to research the effects of different concentrations of KH₂PO₄, H₃BO₃, MgCl₂, and CO(NH₂)₂ on in vitro germination of C. oleifera pollen, screen the optimum nutrient ratio for promoting pollen germination and observe the pollen morphology by scanning electron microscope(SEM). The results were as follows:(1)The pollen morphology of C. oleifera ‘Changlin' was subprolate or spheroidal, the polar view was trilobate-circular, the equatorial view was subprolate or nearly circular, the pollen had three germination furrows, and the outer wall pattern was cerebroid.(2)The single-factor test showed that 0.10-0.15 g·L^-1 KH₂PO₄ had the best effect on pollen germination. The optimal concentrations of the other three elements were 0.05-0.10 g·L^-1 for H₃BO₃, 0.05-0.08 g·L^-1 for MgCl₂, and 0.15 g·L^-1 for CO(NH₂)₂.(3)The orthogonal test results showed that the treatment effect of 0.10 g·L^-1 KH₂PO₄+0.15 g·L^-1 H₃BO₃+0.08 g·L^-1 MgCl₂+0.15 g·L^-1 CO(NH₂)₂ was the best, which was the best ratio for promoting pollen germination of C. oleifera. The results can provide a reference for assisted pollination of C. oleifera by drone, promoting pollen germination and nutrient solution formulation, and germplasm identification of C. oleifera.

Transcriptome analysis of the molecular mechanism of Rhododendron delavayi responding to high temperature stress

2025/12/4 12:25:40
In order to investigate the molecular mechanisms underlying the response of Rhododendron delavayi seedlings to high-temperature stress, we performed RNA-seq analysis on R. delavayi seedlings treated at high temperatures to identify differentially expressed genes(DEGs). Then, we performed Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses to identify significantly enriched signaling pathways and transcription factors. The results were as follows:(1)We obtained 90.54 Gb of clean data from the transcriptome analysis of R. delavayi leaf samples, and by analyzing the DEGs, and identified 5 435 genes that were differentially expressed after three and six days of high-temperature stress.(2)We performed GO enrichment analysis of the identified DEGs and found that genes differentially expressed after three days of high-temperature stress were primarily enriched in physiological processes such as organic matter synthesis, response to stimuli, and lipid metabolism. In contrast, genes differentially expressed after six days of high-temperature stress were mainly enriched in processes related to phosphorus metabolism, phosphorylation, and plasma membrane function.(3)Through KEGG enrichment analysis, we found that the DEGs after three and six days of high-temperature stress were predominantly enriched in pathways related to biosynthesis of secondary metabolites, starch and sucrose metabolism, and plant hormone signal transduction.(4)By analyzing the plant hormone signal transduction pathway, we found that high-temperature stress triggered an overall upregulation of abscisic acid(ABA), jasmonic acid(JA), and salicylic acid(SA)signaling pathways.(5)Furthermore, we identified several transcription factor families, including NAC, MYB, WRKY, and bHLH, as potential key regulators of the response of R. delavayi to heat stress. These results enhance our understanding of the regulatory mechanisms underlying heat stress tolerance in R. delavayi and provide a theoretical reference and genetic resources for developing more heat-tolerant cultivars.

Comparison on stem and leaf traits between common relict gymnosperms and broad-leaved tree species in Dayao Mountains, Guangxi

2025/12/4 12:25:40
A variety of relict gymnosperms are distributed in the evergreen broad-leaved forest in Dayao Mountains, Guangxi. Understanding their environmental adaptations is essential for developing rational conservation strategies. To compare and analyze the differences in stem and leaf traits between relict gymnosperms and the dominant broad-leaved tree species coexisting with them, this study selected four common relict gymnosperm species and six broad-leaved tree species from the local evergreen broad-leaved forest. Considering the characteristics of the montane environment, this study measured the leaf low temperature semi-lethal temperature, specific leaf area, sapwood-specific conductivity, wood density, saturated water content(of leaves and stems), and bending strength. The results were as follows:(1)There were significant inter-specific differences in the stem and leaf traits among the 10 woody plant species. The leaf low temperature semi-lethal temperature ranged from -23.13 to -9.46 ℃, specific leaf area varied from 56.80 to 154.00 cm²·g^-1, saturated water content ranged from 0.81 to 1.25 g·g^-1, sapwood-specific conductivity ranged from 0.74 to 1.77 kg·m^-1·MPa^-1·s^-1, wood density was 0.48-0.67 g·cm^-3, and bending strength was 61.55-138.14 N·mm^-2.(2)There were no significant differences in the means of all measured traits between relict gymnosperms and broad-leaved tree species.(3)Except for the correlation between wood density and saturated water content, there were no significant correlations between the other pairs of measured traits. These results indicate that relict gymnosperms and angiosperms exhibit diverse combinations of stem and leaf traits, which is beneficial for their coexistence in the subtropical montane evergreen broad-leaved forest. This study contributes to maintaining the integrity of mountain ecosystems and provides a theoretical basis for the conservation of relict gymnosperms.

Comparison on stem and leaf traits between common relict gymnosperms and broad-leaved tree species in Dayao Mountains, Guangxi

2025/12/4 12:25:40
A variety of relict gymnosperms are distributed in the evergreen broad-leaved forest in Dayao Mountains, Guangxi. Understanding their environmental adaptations is essential for developing rational conservation strategies. To compare and analyze the differences in stem and leaf traits between relict gymnosperms and the dominant broad-leaved tree species coexisting with them, this study selected four common relict gymnosperm species and six broad-leaved tree species from the local evergreen broad-leaved forest. Considering the characteristics of the montane environment, this study measured the leaf low temperature semi-lethal temperature, specific leaf area, sapwood-specific conductivity, wood density, saturated water content(of leaves and stems), and bending strength. The results were as follows:(1)There were significant inter-specific differences in the stem and leaf traits among the 10 woody plant species. The leaf low temperature semi-lethal temperature ranged from -23.13 to -9.46 ℃, specific leaf area varied from 56.80 to 154.00 cm²·g^-1, saturated water content ranged from 0.81 to 1.25 g·g^-1, sapwood-specific conductivity ranged from 0.74 to 1.77 kg·m^-1·MPa^-1·s^-1, wood density was 0.48-0.67 g·cm^-3, and bending strength was 61.55-138.14 N·mm^-2.(2)There were no significant differences in the means of all measured traits between relict gymnosperms and broad-leaved tree species.(3)Except for the correlation between wood density and saturated water content, there were no significant correlations between the other pairs of measured traits. These results indicate that relict gymnosperms and angiosperms exhibit diverse combinations of stem and leaf traits, which is beneficial for their coexistence in the subtropical montane evergreen broad-leaved forest. This study contributes to maintaining the integrity of mountain ecosystems and provides a theoretical basis for the conservation of relict gymnosperms.

Differences of functional traits of Camphora officinarum and C. glandulifera branches

2025/12/4 12:25:40
Camphora officinarum and C. glandulifera both belong to the genus Camphora in the Lauraceae. In order to explore whether the two species exhibit the same or similar functional traits and covariant characteristics, the biennial branches of C. officinarum and C. glandulifera were used as research objects to measure 18 traits, including branch morphology, component biomass and water content. The descriptive statistical analysis, correlation analysis, allometric scaling analysis and plant trait network analysis were used to explore the differences in biomass and water allocations, allometric relationships between morphological traits, individual size-dependent characteristics and functional trait network relationships between the two species. The results were as follows:(1)The biennial branches of C. glandulifera had higher morphological traits and biomass of each component than C. officinarum. The biomass indices for C. officinarum and C. glandulifera demonstrated moderate variability, while the water content indices displayed weaker variability. The proportions of lamina biomass to total leaf biomass of C. officinarum(93.6%)and C. glandulifera(92.5%)were close. However, C. glandulifera(39.0%)had a larger proportion of stem biomass to total branch biomass than C. officinarum(15.5%). There was no significant difference in the water content percentage of inner leaves between C. officinarum(92.11%)and C. glandulifera(92.32%). However, the water content percentage in the inner stems of C. glandulifera(40.43%)was significantly higher than that of C. officinarum(19.64%).(2)Allometric relationships were observed between component biomasses, morphological traits and water contents of C. officinarum and C. glandulifera branches, and many allometric relationships with allometric scaling exponent not equal to one were found for C. glandulifera branch components.(3)At the leaf level, the biomass and water allocations of C. officinarum and C. glandulifera had similar individual size-dependent characteristics; however, at the branch level, different individual size-dependent characteristics of the two species existed.(4)Trait network analysis showed that C. glandulifera branch trait network was more complex than C. officinarum, that is, C. glandulifera branch traits were more closely related; the covariant relationship between morphological and biomass traits was high, but the water traits were relatively independent. In conclusion, the branch traits and trait associations of C. officinarum and C. glandulifera of the same genus exhibited not only great differences, but also a certain similarity, which may be mainly related to their different intrinsic growth property.

Bacteria diversity study on rhizosphere soil of Arenaria bryophylla in Qiangtang Plateau region

2025/12/4 12:25:40
Arenaria bryophylla, which is mainly distributed in extreme environments at an altitude of about 5 000 m, is one of the important Xizang medicinal plants in the plateau region. To explore the bacterial diversity in the rhizosphere soil of A. bryophylla in the Qiangtang grassland of northern Xizang, China, this study used high-throughput sequencing technology to investigate the diversity and community composition of rhizosphere soil bacteria from A. bryophylla at different sites. The results were as follows:(1)There was no significant difference in the α-diversity of rhizosphere soil bacteria among the three sampling sites, but the bacterial community composition was significantly different(P<0.05). The dominant phyla of the bacterial communities in the rhizosphere soil at all three sampling sites were Proteobacteria and Firmicutes, while the composition of dominant genera differed. Correlation network analysis showed that the connections within the rhizosphere soil bacterial communities were mainly positive, indicating synergistic effects.(2)Light intensity, ammonium nitrogen, available phosphorus, and organic matter significantly affected the composition of bacteria in the rhizosphere soil of A. bryophylla(P<0.05), with light intensity having the highest explanatory power.(3)Predictions of COG functional gene families and KEGG metabolic pathways showed that amino acid transport and metabolism, and carbohydrate transport and metabolism were the dominant functions, and there were significant differences in the dominant functional genes among different regions(P<0.05). In conclusion, there are significant differences in the composition of the bacterial community in the rhizosphere soil of A. bryophylla in different regions of the Qiangtang Plateau. Environmental factors such as light intensity significantly affect the bacterial community composition, and the functions of rhizosphere soil bacteria in different regions show differentiation. This study provides a theoretical basis for the research on A. bryophylla as a traditional Xizang medicine on the Qinghai-Xizang Plateau, and also provides a reference for further understanding the adaptive evolution of A. bryophylla to the harsh environment of the Qinghai-Xizang Plateau.

Effects of fence enclosure on soil seed bank and aboveground plant communities in alpine grasslands with different degradation levels

2025/12/4 12:25:40
Fence enclosure is one of the primary restoration measures for degraded grasslands on the Qinghai-Xizang Plateau, demonstrating significant effectiveness in restoring lightly or moderately degraded grasslands but limited success in desertified grasslands, the reasons for which remain unclear. This study focused on lightly degraded and desertified(sand patches)alpine meadows and alpine steppes in Nagqu, Xizang, systematically analyzing the characteristics of soil seed banks and their relationship with aboveground vegetation in grasslands of different degradation levels inside and outside fence. The study specifically investigated the scientific hypothesis that the poor restoration effect of fence on desertified grasslands is related to the lack of target plant species in the soil seed bank. The results were as follows:(1)The soil seed bank densities of alpine meadow and alpine steppe ranged from 184 to 2 162 seeds·m^-2 and 74 to 812 seeds·m^-2, respectively. Notably, in alpine meadow, the soil seed bank density of desertified grassland was significantly higher than that of lightly degraded grassland, while the opposite was observed in alpine steppe. Fence significantly increased the soil seed bank density of lightly degraded grasslands in both grassland types but had no significant effect on desertified grasslands. The high species similarity between inside and outside fences of the soil seed bank suggested minimal differences in species composition.(2)Overall, grassland type, degradation level, and fence had no significant impact on soil seed bank species diversity.(3)Regardless of fence, although the soil seed banks of alpine meadow and desertified alpine steppe contained seeds of target plants beneficial for restoration, but their densities were far lower than those of weed species.(4)The similarity coefficients between soil seed banks and species composition of aboveground plant communities ranged from 0.33 to 0.43 in alpine meadow and 0.22 to 0.33 in alpine steppe, both indicating low similarity and substantial differences in species composition. Therefore, this study confirms the critical role of the soil seed bank in the restoration of desertified grasslands, with the scarcity of target plant seeds being a key limiting factor for natural restoration of desertified grasslands. It is recommended that artificial interventions, such as reseeding target plant species, be implemented to enhance the ecological restoration of desertified grasslands.

Diversity of endolichenic fungal communities and functional prediction of Parmotrema in Fujian Wanmulin

2025/12/4 12:25:40
In order to study the community diversity and predict their functions of endolichenic fungi(ELF)of Parmotrema in Fujian Wanmulin, the fungal communities of P. reticulatum and P. tinctorum were compared and analyzed by a combination of isolation culture and high-throughput sequencing technology. The results were as follows:(1)There were significant differences in the classification ratios of ELF communities obtained by high-throughput sequencing and isolation culture.(2)A total of 70 strains were isolated from 16 samples, and 20 species-level taxa were identified by morphological observation and ITS sequencing. They belonged to 1 phylum, 2 classes, 6 orders, 8 families, 12 genera, and 20 species. Sordariomycetes was the most dominant fungal class, among which the dominant genera were Nemania and Xylaria.(3)The α diversity analysis showed that the endolichenic fungi community diversity in Parmotrema was very rich, and 9 phyla and 7 classes were identified, and in addition to Sordariomycetes, Dothideomycetes and Saccharomycetes also accounted for a large proportion.(4)The fungal community structure between the two species(P. reticulatum and P. tinctorum)tended to be consistent, and the community diversity was high and evenly distributed.(5)The results of functional prediction analysis of fungal communities using the FUNGuild database showed that the fungal functional groups in the genus Parmotrema mainly included pathotrophs, symbiotrophs and saprotrophs. This study suggests that the results of the two methods complement each other and can provide a theoretical reference for the subsequent functional research and utilization of endolichenic fungi.

Correlations of leaf functional traits of Persicaria hydropiper and its responses to climatic factors in Northwest Yunnan

2026/3/7 21:10:46
The study of the response of wetland plants to climate change is the foundation for understanding the response of wetland ecosystem to climate change. This study took Persicaria hydropiper, one type of emergent aquatic plant in the lakeside zone of Jianhu, Lashihai, Luguhu and Napahai in Northwest Yunnan, as the research object. The species' functional traits were measured, the altitude and climatic factors of four sampling sites were collected, and the relationship between functional traits of P. hydropiper and climatic factors was detected through redundancy analysis to explore climate response variations of these functional traits. The results were as follows:(1)The stomatal density and leaf mass per area of P. hydropiper significantly increased with the increase of altitude, however, stomatal conductance, conduit area, stomatal area, leaf carbon mass fraction, and leaf nitrogen mass fraction significantly decreased with increasing altitude(P<0.05).(2)The mean annual temperature, mean annual precipitation, and mean annual air relative humidity were the main climatic factors affecting the functional traits of P. hydropiper. The species preferred to grow in low altitude habitats with relatively high temperature, precipitation, and air humidity.(3)There was a functional correlation between the functional traits of P. hydropiper. Net photosynthetic rate was significantly and positively correlated with leaf vein density, leaf mass per area, and leaf phosphorus mass fraction, while it was significantly and negatively correlated with sieve tube area(P<0.05). Stomatal conductance and transpiration rate were significantly and positively correlated with stem diameter, stomatal size, and leaf carbon mass fraction. Transpiration rate was also significantly and positively correlated with plant height(P<0.05). This study reveals the main environmental factors that affect the functional traits of P. hydropiper, and provides scientific data for its functional adaptability in the context of climate change.

Short-term effects of warming on organic carbon content during leaf litter decomposition in subalpine fir forest of western Sichuan

2026/3/7 21:10:46
Global warming profoundly impacts the decomposition of surface litter in terrestrial ecosystems. Understanding the response of litter decomposition and its organic carbon components in alpine forests to warming is of great significance for comprehending forest carbon turnover under climate change. To explore the short-term impact of warming-induced hydrothermal changes on organic carbon components during litter decomposition, a one-year in-situ decomposition experiment was carried out in a subalpine fir forest in western Sichuan. The dynamic changes of leaf litter mass and its organic carbon components were monitored through continuous sampling using simulated warming in an open-top chamber(OTC). The results were as follows:(1)Compared with the control, simulated warming significantly increased soil temperature(+0.55 ℃), while significantly decreased litter water content by 7.46%, however, it had no significant effect on soil water content.(2)Simulated warming did not significantly change the mass remaining and the content of major organic carbon components(such as total organic carbon, hot water-soluble organic carbon, and non-structural carbon)of leaf litter. However, the content of dissolved organic carbon(DOC), dissolved sugar, and starch was significantly affected by the interaction between warming and the sampling period, indicating that litter mass remaining and the content of most organic carbon components are not sensitive to short-term warming.(3)The partial least squares structural equation model(PLS-SEM)analysis showed that although simulated warming did not alter the association pathways among soil temperature and water content, litter mass, and organic carbon components, it significantly strengthened the negative correlation between litter water content and organic carbon components. This suggests that future temperature increases in subalpine areas of western Sichuan may affect the input of litter organic carbon into soil as a source of nutrients by altering the moisture status of surface litter. This study emphasizes that future research should focus more on the impact of warming on litter moisture dynamics and its role in carbon turnover. These findings provide an important basis for a deeper understanding of the carbon cycle in alpine ecosystems and for optimizing forest response prediction models under future global climate change scenarios.

Nutrient storage and allocation pattern in a savanna ecosystem, Yuanjiang dry-hot valley, Southwest China

2026/3/7 21:10:46
Nutrient storage and allocation patterns in plant communities are critical for understanding nutrient utilization and cycling within ecosystems. The dry-hot valleys of Southwest China, characterized by their extreme climatic conditions of high temperatures and low precipitation, support a unique savanna vegetation type. To investigate nutrient element storage and allocation patterns in this region, this study took the savanna ecosystem in the Yuanjiang dry-hot valley of Yunnan Province as the research object and systematically analyzed the storage and allocation patterns of five nutrient elements: nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), and magnesium(Mg). The results were as follows:(1)The total nutrient storage of nitrogen(N), phosphorus(P), potassium(K), calcium(Ca), and magnesium(Mg)was 8.337 7 t·hm^-2, with Ca having the highest storage(2.587 8 t·hm^-2)and P having the lowest storage(0.297 3 t·hm^-2). Compared to other forest ecosystems, nutrient storage in this savanna system was relatively low.(2)Vertically, nutrient distribution showed a clear hierarchy: the tree layer contributed the most(84.29%), followed by the grass layer(9.65%)and shrub layer(5.69%), with minimal contribution from the litter layer(0.37%).(3)Notably, belowground nutrient storage accounted for 47.81% of the total, indicating a significant allocation of nutrients to roots and other subterranean components.(4)The region's low annual rainfall and prolonged seasonal droughts imposed severe constraints on plant growth, leading to the observed low nutrient storage in this savanna ecosystem.(5)As an adaptive strategy to long-term drought stress, the savanna plants in this region allocate a greater proportion of nutrients to belowground structures such as roots to maintain ecological adaptability. This study reveals the characteristics of nutrient storage and spatial allocation in the dry-hot valley ecosystem, providing an important basis for understanding material cycling patterns in this region, scientific guidance for the restoration and reconstruction of degraded ecosystems, and valuable reference for in-depth exploration of plant adaptation strategies and ecosystem management practices in arid and semi-arid regions.

Characteristics of the Bauhinia bohniana community, a unique vegetation in the Jinsha River valley

2026/3/7 21:10:46
The dry-warm valley shrubland is a significant vegetation type in the middle Jinsha River valley. The Bauhinia bohniana shrubland is a recently discovered relic endemic community of this type. Current research on valley shrubland has largely focused on dry-hot valley vegetation, and there is a lack of research on the community and ecological characteristics of dry-warm valley vegetation. This study used drone photography and the quadrat method to investigate the characteristics and current distribution of the B. bohniana community. The results were as follows:(1)A total of 22 surveyed B. bohniana community quadrats recorded 194 vascular plant species belonging to 57 families and 120 genera. Fabaceae and Poaceae were the dominant families, while Carex and Selaginella were the dominant genera; the flora showed a tropical-temperate transitional pattern, with 56.52% tropical and 43.48% temperate genera; at the species level, Chinese endemics dominate, including 51 indicator species of the Jinsha River dry-warm valleys, reflecting relict evolution and specialization driven by the Tethys retreat and the uplift of the Qinghai-Tibet Plateau.(2)The community exhibited a distinct vertical structure, with shrub layer cover ranged from 30% to 70%, herb layer from 10% to 50%, and interlayer from 1% to 3%; it had a typical drought-deciduous appearance, turning sparse and yellow in the dry season and regreening in the rainy season, with a significantly delayed phenology compared to surrounding areas; the species diversity index of the shrub layer was higher than that of the herb layer.(3)The life-form spectrum was dominated by hemicryptophytes(41.24%)and phanerophytes(34.54%). Prominent adaptive traits included a predominance of small leaves(microphyll, 50.52%), chartaceous(64.06%), and a deciduous habit, which indicated convergent adaptation to drought stress. The community shared adaptive strategies with African savannas community and Mediterranean shrubland but had a higher proportion of temperate genera(43.48%), highlighting its transitional nature. This study is of great significance for revealing the historical evolution of the Jinsha River valley, and provides a scientific basis for the ecological conservation of its middle reaches.

Effects of different nitrogen additions on growth and leaf nutrient uptake of Ochroma lagopus plantation

2026/3/7 21:10:46
To investigate the effects of different nitrogen applications on the growth and leaf nutrient uptake of Ochroma lagopus plantations, one- and a-half-year-old O. lagopus trees were used as experimental materials. Five treatments set up: 0(N0), 50 kg·hm^-2 urea(N1), 100 kg·hm^-2 urea(N2), 50 kg·hm^-2 slow-release nitrogen fertilizer(PCU1), and 100 kg·hm^-2 slow-release nitrogen fertilizer(PCU2); tree height, diameter at breast height(DBH), and leaf carbon(C), nitrogen(N), phosphorus(P), chlorophyll, and non-structural carbohydrates(NSC)contents were measured. The results were as follows:(1)Compared with the N0 treatment, tree height, DBH, chlorophyll a, chlorophyll b, and chlorophyll(a+b)contents were significantly increased by 28.66%, 50.72%, 50.17%, 50.71%, and 50.25%, respectively, under the N2 fertilization treatment(P<0.05).(2)Compared with the N0 treatment, leaf N content significantly increased by 60.16%(P<0.05)under the N2 fertilization treatment; P content showed a decreasing trend. Under the N0 treatment, leaf N/P<14, indicating that O. lagopus growth was limited by N element. After nitrogen addition, N/P>14, indicating that nitrogen fertilization altered the N-element limitation on O. lagopus growth.(3)Compared with the N0 treatment, leaf soluble sugar and NSC contents were significantly increased by 78.98% and 52.49%, respectively, under the N2 fertilization treatment(P<0.05).(4)Under urea application, the leaf soluble sugar content showed significant positive correlations with N content, C/P, and N/P, and a significant negative correlation with P content; under slow-release fertilizer application, the leaf starch content showed a significant negative correlation with P content and a significant positive correlation with N/P; under nitrogen application, the leaf soluble sugar and starch contents showed significant positive correlations with N content and N/P.(5)The phenotypic plasticity indices for leaf N, N/P, C/P, soluble sugar content, and soluble sugar/starch were all relatively high. The cumulative variance contribution rates of principal component 1(PC1)and principal component 2(PC2)were 66.3%. In summary, nitrogen addition significantly promotes the growth of O. lagopus and leaf nutrient absorption, with the N2 fertilization treatment yielding the best results; nitrogen addition alleviates the limiting effect of nitrogen on O. lagopus growth; O. lagopus promotes growth by increasing chlorophyll content, improving leaf utilization efficiency of nitrogen and phosphorus, and thereby altering the distribution of leaf soluble sugar and starch contents.

Effects of temperature and wind on growth and physiology of Pinus yunnanensis var. tenuifolia seedlings

2026/3/7 21:10:46
Exploring the growth and physiological adaptability of the offspring of Pinus yunnanensis var. tenuifolia(Pyt)populations to high temperature and strong wind environment in their typical habitats is of great significance for understanding the adaptive evolution and developmental potential of this species. Pyt is one of the main tree species in the dry-hot valleys located at the junction of Yunnan, Guizhou, and Guangxi in the upper reaches of the Pearl River. It is very important to maintain water, soil, and vegetation ecology in this area. This study conducted seedling cultivation experiments using natural populations of Pyt seeds collected from the Nanpanjiang-Hongshui River basin, along with one natural population of P. massoniana (Pm)from the adjacent eastern region. The 25 ℃ windless environment group was used as the control, while the 30 ℃ windless environment group and the 25 ℃ environment with a wind speed of 1.2 m·s^-1 were established to investigate the adaptive responses of seedling growth and physiology to high temperature and wind environment. The results were as follows:(1)Compared to Pm, Pyt seedlings exhibited superior growth and physiological performance under a temperature of 30 ℃ and a wind speed of 1.2 m·s^-1. Additionally, the offspring of certain Pyt populations performed significantly better than those of Pm. These findings demonstrate that Pyt possess superior ecological suitability compared to Pm in dry-hot habitats.(2)The 30 ℃ environment significantly increased ground diameter(+11.9%, P<0.05)and total root average diameter(+9.41%, P<0.05), along with a marked reduction in peroxidase activity(-68.1%, P < 0.01)compared to 25 ℃ environment. A wind speed of 1.2 m·s^-1 significantly enhanced the total root average diameter(+11.1%, P < 0.05)and decreased malondialdehyde content(-44.9%, P < 0.05)compared to a windless environment, indicating that high temperature and windy environment promote the growth of Pyt seedlings by enhancing the adaptation of their roots and stems to dry-hot, and windy enviromment, thereby achieving a lower stress response.(3)Overall, antioxidant enzyme activities and peroxidation product contents showed negative correlations with annual mean temperature, monthly average temperature, and wind speed, while showed positive correlations with altitude and annual precipitation, indicating that the physiological adaptability of seedling growth was mainly influenced by the synergistic selections of temperature, precipitation, wind, and altitude. In conclusion, the dry-hot environment combined with strong wind environment in the Nanpanjiang-Hongshui River valley is a critical factor driving the development and evolution of Pyt.

-->Physiology and Ecology

Phenotypic and genetic diversity of sugarcane ( Saccharum L. )protospecies and landraces

Triterpene biosynthesis in Euphorbia pekinensis induced by methyl jasmonate

Effects of fertilization on nutrient concentrations of different root orders' fine roots in Cinnamomum camphora seedings

Influence of soil covered cultivation on shoot quality of Phyllostachys prominens

Growth and physiological responses of Leucobryum juniperoideum to different nitrogen stresses

Variation for morphology and biomass of Gentiana rigescens in agroforestry system

Above-and below-ground biomass distribution of main alpine meadow plants and impact of degradation on root/shoot ratio and root area

Comparative study concerning the effects of rare species treatments on RDA ordination

Effects of different altitudes on plant growth and quality of chrysanthemum at high altitude

Sunipia nigricans, a new recorded species of Orchidaceae from Yunnan, China

A newly naturalized plant in Qinghai-Tibetan Plateau

Carbon, nitrogen and phosphorus stoichiometry of typical plants in karst area of Maocun, Guilin

Habitat adaptation of two dominant tree species in a subtropical monsoon forest: leaf functional traits and hydraulic properties

Determination of the stable carbon isotope composition in atmospheric carbon dioxide based on plants cultured in bidirectional tracers

Species diversity and floristic composition of the fern flora of Yunnan, China

Cloning and functional analysis of a flavonoid-3-O- glucosyltransferas gene from Indosasa hispida

Didymoplexiella Garay, a newly recorded genus of Orchidaceae from Guangxi, China

Leaf structure traits and their correlation of five tree seedlings of Fagaceae family

Diurnal variation of photosynthetic characteristics of five kinds of arbor dominant species in Napahai

Air negative ion concentrations and their affecting factors in Guangdong Chebaling National Nature Reserve

Steady-state and dynamic photosynthetic performance in the shade-demanding plant Amorphophallus xiei under different levels of growth irradiance

Effects of AMF inoculation on the growth and chlorophyll fluorescence of Sorghum bicolor × S. sudanense in coal wastes

Population structure and dynamics of the endemic plant Acer guizhouense in Guizhou Province

Genetic diversity and genetic structure of the northern margin populations of Hippophae neurocarpa

Effects of different calcium levels on photosynthesis and protective enzyme activities of colorful Hosta

Comparative study on the photosynthetic light response characteristics of Dysosma guangxiensis and D. versipellis

Damage characteristics of Phyllostachys violascens forests and relationship with bamboo status and mulching management exposed to freezing stresses

Outstanding universal value of plant diversity and conservation in Emeishan World Heritage Site

Transformation of Siraitia grosvenorii with 2A11-iaaM gene

Light-response of PS Ⅱ fluorescence parameters on Vallisneria natans and Potamogeton malaianus to various water depths in Poyang Lake

Effects of arbuscular mycorrhizal fungi on growth, lateral root number and root endogenous hormones of Camellia sinensis ‘Fuding Dabaicha'

Allelopathic effects of Eupatorium adenophorum leaf aqueous extracts to Vicia faba

Effects of clonal integration on patterns of nitrogen allocated to photosystem in Phyllostachys bissetii under heterogeneity light environment

Effects of Fe fertilizer siphon transfusion on photosynthetic parameters and organelle structure of iron chlorosis in apple trees

Micropropagation in vitro of Actinidia chinensis ‘Yangshi Jinhong 50'

Effects of UV-B radiation on biosynthesis of terpenoids and expression of related genes in Chrysanthemum indicum var. aromaticum

cDNA-AFLP analysis of differentially expressed genes during flowering in Osmanthus fragrans

Effects of copper stress on growth and antioxidant enzymes in sugarcane

Effects of light quality and seed size on fourteen species of plants in Puer region

Rooting and transplanting techniques of tissue culture plantlets of Vaccinium dunalianum

Effect of soil water content and inoculation with Funneliformis mosseae on growth of Bretschneidera sinensis seedlings

Schima argentea communities in the middle Luoxiao Mountains

Effects of water Cu pollution on growth and chlorophyll fluorescence characteristics of Vallisneria natans

Effects of Cd stress on physiological characteristics of alfalfa and its Cd enrichment

Effects of saline-alkali stress on growth of Chrysanthemum morifolium ‘Hanluhong'

Effects of slow-released sand selenium on selenium enrichment and growth of green cabbage

Community characteristics of Castanopsis platyacantha, Schima scinensis forest in Wumeng Mountain

Characteristics of CO2 flux and concentration in coniferous and broad-leaved mixed forest in Dinghu Mountain

New discovery of floristic region of Central China

An introduction to the main forest vegetation types of mainland SE Asia(Indochina Peninsula)

Overview of forage plant resources in rocky desertification area and its development and utilization analysis

Allelopathic effects of aqueous extract of Ageratina adenophora on seven native plant seedlings in growth and chlorophyll

Characteristics and spatial distribution of forest gap in a northern tropical karst seasonal rainforest in Nonggang, Guangxi, South China

Variation of total organic carbon flux in forest hydrological processes in karst experimental site, Guilin

Features of soil mineral elements in man-made forest of Guizhou karst mountain area

Plant diversity and composition of ecological floating bed affect domestic sewage purification

Effects of different regeneration modes on understory plant functional group in Eucalyptus plantations

Plant growth-promoting traits of yeasts on Jatrophacurcas under lead and cadmium stresses

Photoinhibition and recovery of photosystem Ⅱ of three broad-leaved evergreens under low temperature stress

Absorption of poorly soluble phosphorus by sugarcane seedlings and its response to low phosphorus stress

Effects of gallic acid on cell structure of Xanthomonas oryzae pv. oryzicola

Recalcitrance of Quercus wutaishanica seeds— Sensitivity to desiccation and low temperature

Effects of heavy metal nickel stress on physiological and biochemical characteristics of Helianthus annuus seedlings

Species abundance distribution feature and protection priority area of the national protected wild plants in Guizhou Province

Hypochaeris albiflora and Solanum diphyllum, two newly naturalized plants in mainland China

Effects of exogenous ascorbic acid on alleviating aluminum stress in rice seedlings

Global transcriptome analysis of Botrychium ternatum and screening of its plant hormone signal transduction related genes

A comparative study on diversity and composition of greening tree species in parks of different ages in Chongqing

Effects of culture conditions on induction of Panax quinquefolium adventitious roots

Geographic variation of seed and seedling traits of Dalbergia odorifera from different places

Effects of different calcium ion concentrations on photosynthetic and physiological indexes of calcicole-type and calcifuge-type golden Camellia

Effects of drought-rewatering on leaf water potential of two Dendrobium plants

Effects of selenate at different concentrations on growth and physiological indexes of tea tree

Morphological and photosynthetic physiological characteristics of Melia azedarach seedlings under

Effects of Sophora moorcroftiana endophytic bacteria on germination of black highland barley seeds and seedling growth

Variation analysis of flavonoid contents in seeds and yield traits on recombinant inbred line population of tartary buckwheat

Physiological response of Thuarea involuta under salt stress

Variation analysis of leaf morphology and growth characteristics of Cinnamomum camphora with different provenances

Contents and potential ecological risk assessment of heavy metals in soil and Siraitia grosvenorii at the hilly region in Longsheng County Taking Baozeng Village as an example

Characteristics of CO₂ flux and concentration in coniferous and broad-leaved mixed forest in Dinghu Mountain

Spatial distribution and habitat characteristic of Pinus kwangtungensis in the Guangdong Nanling 20 hm² forest dynamics plot

Effects of Cr⁶⁺ on photosynthetic characteristics and trace element absorption of Coix lacryma-jobi in constructed wetland

Effects of water content on sugar metabolism of Malus × robusta seed cryopreservation