-->Plant Physiology and Genetic Breeding

Explant selecting and anti-browning of Magnolia sinostellata in tissue culture

2017/10/1 18:46:41

Magnolia sinostellata is one of the endangered plants in Magnoliaceae, and is also facing the challenge of tissue culture for browning. Therefore, the leaf, stem with bud and root of M. sinostellata as explants were treated in different disinfection time(8, 10, 12, 14 min), light and dark condition, pretreated by PVP and Vc, and the basic media was MS(Murashige and Skoog )+0.5 mg·L^-1 6-BA+0.3 mg·L^-1 IAA, pH5.8)in this study. And then, three explants were treated by the basic media with 0.5, 1, 2 g·L^-1 anti-browning substance(Vc, PVP, CA, AgNO₃, Na₂S₂O₃)for getting the optimal tissue culture methods. All culture processes were put in 25 ℃ condition. The results showed that 14 min was the best sterilization time for the leaves and stems with bud, and 8 min was the optimal sterilization time for the roots under 0.1% HgCl₂ disinfection. The browning rates of leaves and stems were the lowest at 7 d during the early stage under dark culture condition, which was 60.00% and 56.67% respectively, and the browning rate of root was 45.00% at 14 d. Soaking explants in 1 g·L^-1 PVP for 6 h as pretreatment can significantly reduce the browning rate(P<0.05), the browning rate of leaves, stems with buds and roots were reduced to 45%, 28.33% and 63.33% respectively. Anti-browning agents and concentrations can effectively reduce the degree of browning of the explants in M. sinostellata. The best anti-browning substance for leaves was 0.02 g·L^-1 AgNO₃ and its browning rate reduced to 16.67%, the survival rate was 11.67%; 2 g·L^-1 CA was the optimal anti-browning substance for stems with buds and root, the browning rate were 30% and 50%,the survival rate was 50.00% and 76.67%. In conclusion, we found that the stem segment with bud and root were the best explants for tissue culture of M. sinostellata. This research had obtained the best scheme for preventing the browning of explants in M. sinostellata, which is helpful for the rapid propagation technique of M. sinostellata, and to provide reference for the study of other species of Magnoliaceae.

Expression patterns of JcOle14.3 and JcOle16.6 in different developmental stages of Jatropha curcas seeds

2017/10/1 18:46:41

The oleosin gene is very important to the formation of oil body in seeds, present study analyzed the expression patterns of oleosin genes JcOle14.3 and JcOle16.6 in different development stages of Jatropha curcas seeds by quantity RT-PCR, and the results showed that the expression levels of JcOle14.3 and JcOle16.6 were increased gradually at the early development stage(10-30 d)of seeds, but the levels were low. However, on the 40th day after pollinated, the expression levels of these two genes increased dramatically and arrived the highest, and the levels were reduced at the late development stage(50-55 d)of seeds. The results could be presumed that the expression 1evels of JcOle14.3 and JcOle16.6 may have the positively correlation with the lipid accumulation in the seeds.

Transgene by pollen-tube pathway of Dendrobium officinale

2017/10/1 18:46:41

The transgenic technology of Dendrobium officinale was studied by using pollen-tube pathway with plasmid and agrobacterium vectors as target genes delivery. The main results were summarized as follows:(1)The minimum lethal concentration of kanamycin to seed germination and protocorm growth were 90 and 150 mg·L^-1 respectively. Further study showed that 100 and 150 mg·L^-1 kanamycin could be added for selecting transgenic seeds and protocorms during selective culture in vitro respectively.(2)Plasmid and agrobacterium contained GFP or GUS gene was transferred into D. officinale via pollen-tube pathway. The technology and method were summarized as follows: Collected target plasmid(pSuper1300 and pBI121)and agrobacterium which contained GFP or GUS gene; resuspended the plasmid pSuper1300 and pBI121 to concentration of 100 ng·μL^-1 with thrice distilled water, while resuspended the agrobacteria which carried plasmid pSuper1300 and pBI121 to OD₆₀₀=0.7-0.8 with the solution of 2% sucrose+1/2MS+0.1% silwet-77+0.1% AS or 5% sucrose+0.1% silwet-77+0.1 mmol·L^-1AS respectively; during 0.5-2.5 h after artificial pollination, used stigma dripping method to transfer into plasmids and agrobacteria which contained target genes; collect the mature seeds; selective culture and PCR certificated that the resistant materials of almost all treatments were integrated GFP and GUS genes. Moreover, compared with agrobacterium as target gene delivery, the plasmid gene delivery could harvest more fruits.

Organogenesis approaches in tissue culture of Dysosma versipellis

2017/10/1 18:46:41

To study the organic regeneration pathway of tissue culture of Dysosma versipellis, we used callus, adventitious buds and roots induced from in vitro leaves and petioles of D. versipellis on MS medium to analyze it, based on the technique of serial paraffin slices. The results showed that the parenchyma cells which were near the epidermis recovered cell division ability through the hormone stimulation. Originally cells of the stationary state altered cell metabolism after they were stimulated, and cell division became active. The parenchyma cells were continued to culture and formed meristemoid with cells division potential of totipotency of plant cell, which could form a lot of differentiation centers. Histological observation of D. versipellis proved that the bud primodium derived from the subsurface layers of callus and grew away from the middle of callus, so the buds which produced by dedifferentiation originated in exogenous way, formed the adventitious buds. Furthermore, the root primodium originated from parenchyma cells in the pith and partial vascular cambium cells in the depth of tissue, which raised towards the phloem liked spherical or wedge. It would continue growing and break epidermis, then adventitious buds were formed. This way was endogenous. Organogenesis type was the conventional way for D. versipellis to regenerate in vitro. Adventitious buds were induced at first during the growth process of tissue culture seedling, which was followed by the formation of adventitious roots. Because of vascular bundle of adventitious roots being originated from callus must link vascular bundle of stem and branch, it played an important role in supporting small plant development. At last, the vascular bundle formed from callus would connect the two into a complete plant. The research result has important guiding significance for scale planting cultivation of D. versipellis while protecting of germplasm resources.

Changes of super oxygen anion in mulberry varieties under water stress

2017/10/1 18:46:41

We used six mulberry varieties in Sichuan Province as the research object, by using physiological method and used NBT test to determine the activities of SOD and to study the changes of super oxygen anion(O^-₂·)in the leaf blade tissues under different drought conditions. The results showed that the SOD content of six mulberry varieties were significantly higher than those of the controls. The change trend of SOD activity was raised and then fell later, and super oxide anion grew steadily. Possible reasons were that reactive oxygen beyond a certain threshold, which led to SOD activity decreased. Under different drought conditions, from normal stress treatment to middle stress, the SOD content of six mulberry varieties also demonstrated rapid growth. Jiulonggui and Husang 32 showed a rising trend and increased by 62.7% and 60.1% obviously; followed by Yunsang 1 and Heyebai 1 raised to 52.2% and 58.2%; Yousang and Chongsang were increased to 50.8% and 47.4%, respectively. This showed that the SOD played an active and effective role to reduce O^-₂·. After moderate stress level of SOD and active oxygen showed the opposite trend, which showed significant degradation effect, and had a mechanism of active oxygen injury. Super oxide anion spread around the veins, area of super oxide anion gradually increased, which were observed by transmission electron microscope. It is obeserved that Husang 32 has its ability to eliminate the superoxide free radical, and its drought resistance abilities and leaf blade surface hairs were higher than that of Heyebai 1. Hence, it can be inferred that the length of leaf blade surface hairs has a certain relationship with drought resistance.

Correlation and regression analysis of fresh fruit bunch yield components in oil palm(Elaeis guineensis)

2017/10/1 18:46:41

Oil palm is the most important oil crop all over the world, its production is 30% of the world's total vegetable oil, but there is still room for improving the yield. In order to verify relationship among fresh fruit bunch yield components, correlation between fresh fruit bunch yield and other traits were studied by using correlation, regression and path analysis. The results indicated that fresh fruit weight, number of bunch were the most closely related with fresh fruit bunch yield. Moreover, breeder should focused on average weight of fresh fruit bunch, number of fresh fruit bunch in each plant, fruit length, fruit width and oil content of mesocarp, and balance interaction among these characters was related with fresh fruit bunch yield in the high yield oil palm varieties breeding. Analysis of variance and correlation showed that the average shell thickness had the most coefficient of variation(CV=88.34%), average fruit length had the least coefficient of variation(CV=11.99%), fresh fruit bunch yield had extremely significant positive correlation with average fresh fruit bunch weight, number of bunch produced, average fruit weight(r=0.882**, 0.714**, 0.439**), and had significant positive correlation with average fruit length(0.334*). Multiple regression and path analysis showed that practical regression equation x1=-281.511+2.787x4+3.455x5-2.672x6+0.411x7+6.690x8+ 3.664x9 was established by comparing parameters related with multiple linear regression equation. Average fresh fruit bunch weight and number of bunch had maximum direct effects(0.670, 0.439), other characters were relatively less, average fruit weight and average fruit length had maximum indirect effects(0.335, 0.322). The results provide information for the high yield varieties breeding.

Effects of pipeline trunk transfusion and drip on iron deficiency chlorosis of apple trees

2017/10/1 18:46:41

In order to explore the simple and labor-saving program of preventing iron deficiency chlorosis in fruit trees, we studied the effects of Fe-N solutions of different concentrations by pipeline transfusion and drip, contrasted by conventional management by determining the leaf SPAD value, hecto-leaf weight, hecto-leaf thickness, the content of total iron and active iron and so on. The results showed that the treatment of iron fertilizer pipeline transfusion significantly increased leaf SPAD value, hecto-leaf weight and hecto-leaf thickness, the content of total iron and active iron in leaves, while the chlorophyll fluorescence parameters also had a major impact. In addition, SPAD value and the content of active iron had a good linear relationship, and the correlation coefficient reached 0.899 through analyzing different grades yellow leaves. This result suggested that there was certain reliability with SPAD value as the way of diagnosing iron deficiency in apple, and it also explained that the yellowing leaf was mainly caused by the shortage of iron. The SPAD value, hecto-leaf weight, hecto-leaf thickness, the content of total iron and active iron in leaves were markedly improved by pipeline transfusing the solution of 16.4 × 10^-3 mol·L^-1, which were increased by 89.66%, 20.42%, 9.26%, 158.0% and 277.4% in the experiment, and the fluorescence parameters also reached the optimum level. The result showed that the technology of pipeline infusion dripping trunk significantly improved the index level of apple leaves, and the results laid the foundation for the application of pipeline trunk transfusion and drip in the prevention and treatment of iron deficiency chlorosis in apple.

Effects of string-harvest on ethylene production and storage quality in post-harvest tomato fruit

2017/10/1 18:46:41

Ethylene is a very important plant hormone, would cause rapid fruit ripening and softening. Keeping fruit freshness through regulation of ethylene biosynthesis and signal transduction is well studied. Tomatoes are typical climacteric fruits, very sensitive to ethylene action, so their post-harvest ethylene responses always cause fruit deterioration during storage periods. Tomato string-harvest is to harvest a cluster of fruits with the stem, which is more applicable to the cherry tomato fruit type. String-harvest shows its superiorities like high yield and labor saving in tomato productions, and fruits are sold at higher prices because of their longer shelf-life. This study aimed to clarify the effects of string-harvest trials on the ethylene production and storage quality in post-harvest tomato fruit, and to develop methods of extending tomato shelf-life. Cherry tomatoes graft-cultivated with two rootstocks(No. 1 and No. 3)from two production areas(Ⅰ and Ⅱ)in Tianyang County of Guangxi Zhuang Autonomous Region in China, were taken as experimental materials. Tomatoes harvested by string(treatment)or single fruit(control), were analyzed for their changes in the rate of ethylene production, content of carotenoid, lycopene, ascorbic acid, soluble sugar and titratable acids. Moreover, results indicate that throughout storage periods, ethylene production in string-harvest tomatoes with different rootstocks and cultivation areas were significantly lower than controls. The ethylene production rate in string-harvest tomato with Rootstock No.1 in Area I decreased rapidly to the minimum(0.35 nL·g^-1·h^-1)5 d after harvest, significantly lower than its control(1.36 nL·g^-1·h^-1), and other string-harvest tomatoes in different areas with different rootstocks reached their minimum 15 d after harvest. And, the content of natural antioxidants such as carotenoid, lycopene and ascorbic acid in string-harvest tomatoes increased significantly in the early storage period. Additionally, the string-harvest treatment also inhibited the post-harvest accumulation of soluble sugar and degradation of titratable acid to a certain extent. Finally, string-harvest treatment inhibited the fruit ethylene production, increased carotenoid, lycopene and ascorbic acid level, and delayed post-harvest changes of sugar and acid content, to extend tomato shelf-life and improve commodity quality. This work proposes to explain the physiological mechanisms of the fruit freshness regulation by string-harvest trials, provide basal knowledge and evidence for development of new post-harvest technologies, as well as offer guidelines to improving tomato storability and quality, which are meaningful to the tomato production industry.

Effects of light intensity and planting substrates on the growth of Begonia ningmingensis ‘Ningming Silver', a new begonia cultivar

2017/10/1 18:46:42

Begonia is a world famous ornamental plant, and the different species or cultivars may require different favorable conditions, including planting substrate, light intensity, temperature and humidity for better growth performance. Begonia ningmingensis ‘Ningming Silver' is a newly released cultivar with high ornamental value and market potential. However, the suitable conditions of growing this cultivar have not been established. In order to screen the optimum substrate and light intensity for growing ‘Ningming Silver', the effects of four gradient light intensities(45%, 60%, 75% and 90% shading, respectively)and four types of substrates(peat: perlite = 1:1, peat:perlite:pine bark = 1:1:1, leaf mold:perlite:pine bark = 1:1:1 and maize straw:perlite:pine bark = 1:1:1)on plant growth performance were evaluated in a potted culture experiment at a shadehouse of Shanghai Chenshan Botanical Garden. The results showed that the leaf number, maximum leaf area, fresh and dry mass of the aboveground part, and dry mass of the underground part of ‘Ningming Silver' reached the highest at a treatment of 45% of light shading and substrate with equal proportion of leaf mold, perlite and pine bark. The lowest relative water content root/shoot ratio and the highest relative chlorophyll content also occurred in the same treatment. Therefore, 45% light shading and substrate with equal proportion of leaf mold, perlite and pine bark were the optimum conditions in this study for soilless culture of ‘Ningming Silver', which will provide a good reference for commercial container production of this new cultivar.

Effects of waterlogging stress on growth and physiological characteristics of Phalaris arundinacea seedlings

2017/10/1 18:46:42

The water depth gradient can be determined to be crucial ecology factor on controlling the growth and distribution of plant along with lake-land ecotone. In order to clarify the morphological and physiological characteristics of Phalaris arundinacea under different waterlogging depths, based on the P. arundinacea seedlings, the eight experimental groups [0, 10, 20, 30, 40, 50 cm, completely submerged and control(normal watering)groups] were set up by double basin method, and the plant height the number of leaves, the content of SPAD and MDA, the activity of SOD, POD and CAT, the content of solube protein of P. arundinacea were measured respectively. The results were as follows: The experiment of waterlogging stress was conducted about 36 d,(1)The waterlogging stress could inhibit the growth of P. arundinacea, with the increasing of waterlogging depth, the growth rate slowed and the number of leaves and the chlorophyll relative content decreased.(2)With the waterlogging time extended, the MDA content of different waterlogging groups of P. arundinacea rised constantly; The waterlogging depth of 0-30 cm, SOD and POD contents increased gradually, while the CAT content increased firstly and then decreased; The waterlogging depth of 40-60 cm, the SOD and CAT contents raised, while the POD content decreased firstly and the increased.(3)The content of soluble protein was increased with the time extended, but the waterlogging stress was not determined to be key factor that had a considerable influence on the soluble protein content. P. arundinacea growth was damaged by waterlogging stress, mainly manifest the slowing of growth rate, the increase of membrane lipid peroxidation, the destruction of antioxidant enzyme system and the gradual death of plants. It can provide some scientific reference for effective exploitation and utilization of P. arundinacea.

Physiological responses of three cultivar seedlings of Bougainvillea under drought stress

2017/10/1 18:46:42

Seedlings of Bougainvillea buttiana ‘Miss Manila', B. glabra ‘Imperial Delight' and B. peruviana ‘Thimma' were treated to study the physiological responses under drought stress. The results showed that the plant leaves began to droop, gradually shrink, yellow in color, and fell off, all of the treatment seedlings died finally under the long drought. The results showed that the peroxidase activities(POD)were increased at beginning, and decreased finally, while the superoxide dismutase(SOD)activities were gradual decreased, but the reduction rates were different in the three cultivar seedlings. The research on chlorophyll fluorescence parameters showed that qP value was decreased, while qN value was increased, and the photochemical efficiency of PS Ⅱ reaction center(Fv/Fm)and potential activity of PS Ⅱ(Fv/Fo)were decreased under drought stress. This study provides information for breeding application and choosing ulltivars of Bougainvillea.

Effects of silkworm excrement fast-rotting on rice habitat and security growth

2017/8/27 16:49:46

In this study, the self-developed silkworm excrement deodorant special preservative was used and the silkworm excrement was treated by field composting in order to realize safely silkworm excrement quick safety decomposing and utilization of cleaner fertilizer in paddy field and ecological nutrient of rice growth. The treated silkworm excrement organic fertilizer was applied as rice base fertilizer and tillering fertilizer for the study on rice habitat and security growth under excrement fast-rotting. The results showed that the temperature of the compost after the silkworm excremen transformation promoter was increased rapidly, and could convert stinky organics degradation or conversion into antioxidants. The heater temperature showed that the temperature of 5 d during the treating 10 d could maintain above 60 ℃. Rapid decomposition process, could effectively inhibit the growth of harmful microorganisms and kill pathogenic microorganisms silkworm excrement. After the quick-rot, we conducted a safety test, the Escherichia coli showed a descending trend. The odor eliminated after 4-5 d silkworm excrement fast rot. After application of this fertilizer to paddy fields, leaf chlorophyll content was 30.9% higher at the tillering stage, nitrate reductase activity increased by 48.9%, root activity increased by 21.3%, dry matter increased by 26.5%. Paddy yield increased 10.8%-22.9% and paddy soil permeability increased. Silkworm excrement fast-rotting to promote security growth and health utilization of rice growth is a safe, ecological, and healthy method, and the application effect is good.

Arabidopsis At1g10300 gene regulates leaf morphology and flowering time

2017/8/27 16:49:46

Nucleolar G protein 1(NOG1)is a highly conserved eukaryotic GTPase. NOG1 plays a significant role in the assembly of pre-60S ribosomal subunits. In yeast and animals, depletion of NOG1 results in reduced levels of 60S ribosomal subunits, aberrant pre-rRNA processing, and blockage of 60S ribosomal subunit export. A recent study in Caenorhabditis elegans found that knock-down NOG1 expression causes slower growth, smaller body size and increased life span, whereas over-expression of NOG1 results in decreased lifespan. However, the plant NOG1 has not been characterized. The Arabidopsis At1g10300 gene was annotated as NOG1-2. However, its role in Arabidopsis growth and development is still unknown. In this study, we used physiological, genetics and molecular tools to analyze the biological roles of the Arabidopsis At1g10300 gene. We firstly used semi-quantitative RT-PCR to investigate the transcriptional levels of At1g10300 gene in various tissues of Arabidopsis, including 7-day-old seedling, rosette leaf, cauline leaf, stem, bud and flower. The transcription of the At1g10300 gene was detected in seedlings, cauline leaves and blooming flowers. Among them, the highest transcriptional level was detected in blooming flowers. We then isolated a T-DNA insertion mutant allele of the At1g10300 gene. Phenotypic analysis found that the At1g10300 mutant had compact rosette and reduced ratio of leaf length/width compared to wild type. However, there was no significant difference in leaf area or plant height between the At1g10300 mutant and wild type. These data indicated that leaf morphology of At1g10300 mutant was altered. The At1g10300 mutant also displayed a late bolting phenotype under the condition of long-day photoperiod. To determine the molecular mechanism of this late flowering phenotype, we used quantitative RT-PCR to analyze the transcriptional levels of key genes of the flowering time pathway, including FLOWERING LOCUS T(FT), CONSTANS(CO), GIGANTEA(GI)and FLOWERING LOCUS C(FLC). The results showed that the transcriptional levels of the flowering promoting factors FT, CO and GI were down-regulated in the mutant plants compared with the wild type, whereas the transcription levels of the flowering inhibiting factor FLC was up-regulated. Taken together, these results suggest that mutation of At1g10300 gene delays flowering time by regulating the expressions of FT, CO, GI and FLC genes in Arabidopsis. Our data indicate that like its ortholog in worms, loss-of-function of At1g10300 gene also affects Arabidopsis rosette size and lifespan.

Selection of reference genes for RT-qPCR and expression of genes involved in homoglutathione anabolism in soybean under stress of phosphorus deficiency

2017/8/27 16:49:46

Selection of stable reference gene(s)is the prerequisite for RT-qPCR analysis. Homoglutathion plays an important roles in utilization of phosphate in plants. In this study, the expression of fifteen candidate reference genes were determined in two soybean varieties differing in phosphorus efficiency under normal and stress of low phosphorus availability. Fifteen candidate reference genes were validated by GeNorm, NormFinder, BestKeeper and ΔCt comparision and RefFinder analysis, and out of those, the three most stable genes, PSC, TUB and 18sRNA, were used to normalize the expression of two genes, γ-glutamylcysteine synthetase (γ-ECS)and homoglutathione synthetase(hGSHS), involved in homoglutathion anabolism. In the low P efficient soybean variety GX1, the expression fold changes(FC, as compared to normal)of γ-ECS and hGSHS in roots and leaves all decreased with the rise of stress duration; while in the high P efficient variety GX2, the FCs of γ-ECS in roots and leaves, as well as hGSHS in roots increased with the increase of stress duration; except that hGSHS in leaves decreased. The results suggest that the difference of gene expression might account to the phosphorus utilization efficiency.

Genetic diversity of the progeny population of different levels of improvement in Pinus massoniana

2017/8/27 16:49:46

The effects of genetic improvement on the genetic diversity of Pinus massoniana forest were studied, by using three improved levels of progeny of seed production populations as the research material, and the natural population as the control. The genetic diversity of the experimental groups was analyzed by sixteen pairs of SSR primers. The results were as follows: Shannon's information index(I)of natural populations, progeny of seed production area, offspring of Generation 1 seed orchard and Generation 1.5 seed orchard of P. massoniana were 0.53, 0.53, 0.53 and 0.46; observed heterozygosity(Ho)0.36, 0.36, 0.39, 0.35 respectively; expected heterozygosity(He)0.32, 0.32, 0.33, 0.27 respectively. There were no significant difference among the offsprings of seed production areas of Generation 1 and Generation 1.5 seed orchards of P. massoniana on the three main genetic diversity indexes. It showed that the genetic diversity of improved varieties was not affected significantly by the improved selection in the process of genetic improvement of P. massoniana in Guangxi. Compared with the plantations and natural forest, we knew that there was no significant decrease in the three main indexes of the improved varieties, which indicated that the three kinds of main populations in Guangxi had good group buffer capacity and individual buffer capacity. The results of the study have important significance for the scientific development of breeding strategy in P. massoniana, and provide important data support for the research of high generation breeding of P. massoniana

cDNA cloning and expression analysis of shaggy-like protein kinase(KdSK)gene in Kalanchoe daigremontiana

2017/8/27 16:49:46

Shaggy-like protein kinase(SKs)plays numerous roles during the plant development, such as organ development, phytohormone conduction, abiotic stress and biotic stress. Kalanchoe daigremontiana is an attractive model system for the study of the molecular mechanisms of somatic embryogenesis and organogenesis competence because of its ability to form embryos and to acquire organogenic competence through plantlets. To better understand the molecular mechanisms of plantlet formation involved in K. daigremontiana, a shaggy-like protein kinase, KdSK, was identified using rapid amplification of cDNA end(RACE)PCR. KdSK gene consists of an ORF of 1 272 bp that was predicted to encode a 483 amino acid residue-long protein of 47.79 kD with an isoelectric point of 8.37. The sequence analysis of the KdSK revealed homology to Cucumis sativus shaggy-related protein kinase kappa. Phylogenetic analysis showed that KdSK gene was closely related to Medicage sativa protein(MSK4)and formed a subgroup with Arabidopsis thaliana(AtSK4-1, AtKSK4-2), all clustered to Clade Ⅳof GSK3/shaggy kinases family. Conservation domain structure analysis indicated that KdSK protein had typical structure of the protein kinase domain, including ATP domain and Serine/Threonine protein kinases active-site signature. Real-time PCR analysis revealed that KdSK transcript was expressed the highest in root and upregulated under osmotic stress. This study characterized the novel KdSK gene from Kalanchoe daigremontiana for the first time and the results will be useful for further functional determination of the gene.

Effects of culture conditions on the growth and accumulation of saponin in Panax notoginseng callus

2017/8/27 16:49:46

It is well known that the growth and secondary metabolites accumulation of plant cells cultured in vitro are determined by many factors, such as culture conditions, nutrients supply, phytohormone application, etc. This study aims to explore the affecting factors during Panax notoginseng callus culture. On the basis of MS, modulations of phytohormone combination, nitrogen resource and illumination strength were carried out, and then the changes in saponins content during culture of P. notoginseng callus were measured and analyzed with spectrophotometry and HPLC. The results showed that the culture conditions had an considerable effect on the saponin accumulation in Panax notoginseng callus, in detail, combination of phytohormone had significant effects on saponin content with a peak of 4.72% ± 0.29% from the callus cultured on MS supplemented with 0.5 mg·L^-1 2,4-D+1.0 mg·L^-1 6-BA; The total N source concentration was maintained at 60 mmol·L^-1, the saponin accumulated at the highest level of 4.71% ± 0.17% in the callus under the ratio of NO₃^-/NH₄⁺=7:1(45 mmol·L^-1 KNO₃+7.5 mmol·L^-1 NH₄NO₃); When cultures grown in the light(1 000 lx and 500 lx for 12 h·d^-1, respectively)versus dark, their saponin content were calculated as 1.94% ± 0.31%, 2.38% ± 0.12% and 3.57% ± 0.27%, respectively. In addition, greening and cell differentiation were observed on the surface of callus under light, might be the main cause resulting in the inhibition of saponins synthesis and accumulation in callus. Saponins of P. notoginseng have been acknowledged to be the major compounds functioning in medical treatment of diseases, herein they are employed as the indicator of callus evaluation. Four kinds of saponins including Rg₁, Re, Rb₁ and Rd were identified from both the P. notoginseng callus and root by HPLC, and R₁ could not be detected in the former, however, presence in the latter, the reason for which needs to be further investigated. The above results are likely to provide technical support for the production of natural compounds through callus culture in large scale instead of field cultivation partly in the future, furthermore, which would also be a potential alternative to wild medicinal plant resources for its merits of sustainable and rational exploitation.

Agricultural biology characters of anvil germplasm and grafting applicability in eggplant (Solanum melongena)cultivars

2018/8/27 10:59:57

Bacterial wilt is a soil-borne disease that occurs generally in tropical and subtropical regions. Grafting with disease-resistant rootstocks is an effective way to control bacterial wilt in eggplant vegetables. For the combination of eggplant rootstock with excellent resistance to disease and graft applicability, the germplasm of eleven eggplant cultivars collected at home and abroad were evaluated by agricultural biology and the identification of bacterial wilt resistance. The effects of different anvil germplasm on the growth of grafted seedlings were also studied. The results showed that fruit types were: oval 5, obovate 2, long oval 4; young fruit color had purple 7, lavender 1, green 1, light green 2; the color of the old ripe fruit was yellow; the main stems of germplasm J14, J15, J16, J17 were purple, the rest were green; petal color of J61 was white, the rest were purple or lavender. The graft survival rate of eggplant germplasm and high susceptibility wilt eggplant cultivars reached 80% and the highest was 97%. The disease resistance of rootstock to bacterial wilt were identified by rooting and root inoculation at seedling stage. There were nine seedstocks with high resistance(HR), the disease index was 3.67-12.33, and six rootstocks germplasm(BC01, BC03, BC04, BC06, J15, J16)were susceptible to disease(R)after grafting, and the disease index was 16.67-21.00. Nvil germplasm can significantly improve the growth of scions, and the growth rates of the biomass of grafted seedlings BC01, BC03, BC04, BC06, J15 and J16 were significantly higher than those of other germplasms. According to the comprehensive test results, the diversity of agricultural biology characters of anvil germplasm of eggplant cultivars can be divided into different ecological types. The disease-resistant rootstock grafted with high-susceptible scion was effective, the germplasm(BC01, BC03, BC04, BC06, J15, J16)were resistant to bacterial wilt, which could be used as a candidate parent for the combination of resistance to bacterial wilt rootstock.

Effects of α-linolenic acid on germination of rice seeds under drought stress

2018/8/27 10:59:57

As a member of ω-3 polyunsaturated fatty acids, α-linolenic acid(ALA)is a component of plant cell membrane. It was shown that plants release ALA to remodel the mobility of cell membrane under drought stress. However, it is not known whether exogenous ALA can increase the plant tolerance to drought stress. In this research, we studied the impact of additional ALA on the drought tolerance of rice seeds under PEG6000 during the germination and seedling stage. The result showed that under 14% and 16% PEG stresses, the germination of rice seeds was postponed and their seedlings growth were inhibited. After addition of 25 μmol·L^-1 or 250 μmol·L^-1 of ALA, the inhibiting effect owing to the drought stress was relieved. And the alleviatng effect became stronger as the stress became severer. Under drought stress with 16% PEG, 25 μmol·L^-1 and 250 μmol·L^-1 of ALA improved the root length by 34.3% and 29.1%, respectively, while improved the seedling length by 67.8% and 52.0%; the root weight was increased by 43.9% and 35.2%, and the seedling weight was increased by 59.1% and 43.6%, respectively. Analysis of α-amylase activity in rice grains under 14% and 16% PEG stress showed, after addition of 25 μmol·L^-1 and 250 μmol·L^-1 ALA, the activity was increased by 56.7%-70.7% and 36.8%-43.8%, respectively. Analysis of root activity showed that after addition of 25 μmol·L^-1 and 250 μmol·L^-1 of ALA, the root activity under 14% and 16% PEG stresses were increased by 11.4%-28.4% and 5.4%-22.2%, respectively. The change of α-amylase activity and root activity with different PEG concentrations were also discussed. Therefore, we propose that ALA can relieve the drought tolerance of rice seeds mainly by means of increasing α-amylase activity during seed germination and seedling growth stages, while with a limited effect on root activity of rice radicle.

Drought-resistance capability of six ferns from South China

2018/8/27 10:59:57

The drought-resistance capability of Cyclosorus parasiticus, Pteris vittata, P. linearis, Adiantum pubescens, Nephrolepis biserrata and Macrothelypteris torresiana in South China was studied under the condition of artificial soil desiccation in this paper, and indexes of absolute water content, relative water content, chlorophyll content SPAD value and photosynthetic parameters were measured under drought-stress condition. The results showed that as drought stress increased, the absolute water content of six ferns decreased generally, Macrothelypteris torresiana, Pteris vittataand, Nephrolepis biserrata decreased slightly, and Cyclosorus parasiticus decreased the most. SPAD value decreased as drought stress increased, C. parasiticus and Nephrolepis biserrata decreased slightly, the reduction of Pteris vittata was significantly larger than that of the others. Net photosynthetic rate, leaf transpiration rate and stomatal conductance decreased as drought stress increased. With the increase of intercellular CO₂ concentration, Macrothelypteris torresiana and Pteris vittata decreased less, Cyclosorus parasiticus decreased largely, while Pteris linearis increased, Macrothelypteris torresiana and Pteris vittata increased slightly. The drought resistance of six ferns was evaluated by membership function method based on the average rate of change in indexes. The drought resistance order was Pteris vittata > Macrothelypteris torresiana > Nephrolepis biserrata > Adiantum pubescens > Cyclosorus parasiticus > Pteris linearis.

Effects of hot water treatment on postharvest rot and physiological characteristics of kumquat fruits

2018/8/27 10:59:57

Kumquat was the type of tangerine fruit with the skin and pulp both edible, therefore the processing requirements for the postharvest treatments are extremely strict. The present research treated kumquat(Fortunella crassifolia)with hot water using three temperature gradient, 30, 40 and 50 ℃, respectively. The fruit rotting rate, weight loss rate, soluble solids, hardness, organic acid, cell permeability and the changes of antioxidant enzyme activity were investigated. The results showed that the total acid content was maintained at 0.3% during the storage process. After hot water treatment, the total acid content was slightly lower than that of the control, and the soluble solids content was around 18% and not significant compared to the control. The hardness of the treated fruits was first decreased and then increased during storage, but the hardness of the heat-treated fruit was higher than that of the control group during the whole storage. The leakage rate of cell membrane first increased and then decreased, and the hot water treatment could delay the peak time. The fruits CAT activity of the 40 ℃ and 50 ℃ hot water treatment were lower than that of the control. During the whole storage period, the fruits POD activity was lower than that of the control after hot water treatment. Hot water treatment could increase the kumquat fruit SOD activity, and with the increase of storage temperature, the effect was enhanced. Hot water treatment could increase the H₂O₂ content of the fruit and thus induce a series of physiological effects. However, the temperature and the duration of hot water treatment should be correspondingly adjusted. This study showed that, for the fruit harvested in March, if the hot water was higher than 40 ℃, the processing time should be longer than 5 min, which could effectively reduce the rate of fruit decay.

Adaptability observation and evaluation of nine new sugarcane cultivars in Guilin

2018/8/27 10:59:57

To explore the adaptability of new sugarcane, those cultivars with better adaptability and performance were screened for further demonstration in Guilin. Nine new sugarcane varieties of demonstration experimental station were evaluated for 1-year plant crop and 2-year ratoon crop, test materials and controls adjacent to each other with ROC22 as control. The germination rate, tillering rate, plant height, yield and sugar content of fourteen traits were observed and recorded, and comprehensively evaluated by DTOPSIS method. The results showed that Guitang 29, Guitang 31, Yunzhe 03-194, Yuntang 60, Funong 38 and Yuetang 55 were superior to ROC22 in aspect of comprehensive agronomic traits and yield traits, Guitang 29 had higher shooting cane, sugar yield and yield rate, except for pests occur, suggestions on strengthening pest control in the field; Guitang 31 had more effective stalks and high sucrose content, suggestions on strengthening the management of fat and water to increase yield rate; Yunzhe 03-194 had high germination rate, tidy seedling, more effective stalks, higher shooting cane, but its dead heart seedlings and smut incidence were rarely serious than those of other cultivars, suggestions on strengthening the management of disease and insect pests in the field; Yuntang 60 had higher sugar yield and strong lodging resistance, except for lower new plant rate, suggestion on increasing seedling quantity; Funong 38 had high sucrose content and good disease resistance, and could be used as an excellent disease resistant material; Yuntang 55 had higher shooting cane. Therefore, the six sugarcane cultivars above should be further extented and demonstrated in Guilin.

NaCl pretreatments improving cold tolerance of two Manilkara species

2018/8/27 10:59:57

Manilkara roxburghiana and M. zapota are precious tropical fruit trees with good development prospect. Based on the results that they had higher salt tolerance, three-year seedlings were treated under 9 ℃ and 3 ℃ cold stress after 10‰ and 20‰ NaCl pretreatment, and the changes of osmoregulation substance contentments and antioxidant enzyme activities were studied. The results showed that changing tendency was the same between the two species. The contentments of proline, soluble sugar, soluble protein and the activities of SOD, POD and CAT in the groups under 10‰ and 20‰ NaCl pretreatments were higher than those in the contrast. The capacities of cold tolerance were as followed: 10‰ > 20‰ > CK. It was deduced that NaCl pretreatments might effectively improve the cold tolerance of the two species. 10‰ NaCl pretreatment was most effective when the soil salinity of M. roxburghiana and M. zapota were 2.46‰ and 1.14‰ respectively. The results provided the theory direction and technology support for spread growth of the two species. Key words: Manilkara