Rhododendron adaptation and characteristics under ex-situ conservation and provide research reference for self and cross fertility, especially aiming at the short of the natural pollination fertility and its multi-index comprehensive evaluation in the past study, this paper revealed the natural pollination fertility characteristics and adaptation of Rhododendron under ex-situ conservation conditions by collecting and analysing the data from the main bases at Dujiangyan(1 700 m above sea level), Yutang 700 m above sea level in Longchi of Sichuan Province and Dujiangyan(700 m above sea level)and Emeishan Biological Test Station(805 m above sea level)in Longchi of Sichuan Province. Thirty-seven species of Rhododendron natural pollination belonging to 15 subsections within 5 subgenera had been carried out for a period of four years with test the green seedling rate(Gs)as the main index, and green seedling coefficient(Gc), rate of capsul set(St)and unit number of fertility seed(Sf)as a secondary indexes. The results were as follows:(1)Except for R. lutescens to not get seeds, the other 36 species went through the life cycle of “from seed(seedling)to seed" to some extent in their conservation sites, among them twenty-two types of high fertility, eleven types of fertility and one type of low fertility.(2)The above four indicators, especially green seedling rate, green seedling coefficient and unit number of fertile seed from comparing the ex-situ conservation and field conditions, could reflect different levels of fertility fitness.(3)Within the 36 fertile species of Rhododendron in different degrees, 24 species of them occur an abortion phenomenon in various degree, and the cause might result in selfing and natural crossing for florescence overlaping of the same or dissimilar subsections with different degrees, which might be caused by genetic discomfort due to genetic selection restrictions or stress, this phenomenon is particularly prominent in some species of flowering individuals limited, so the number of the flowering individuals related most closely to the fertile fitness, ensuring “the minimum viable population(MVP)” for the genus conservation is important.(4)Each species of Rhododendron might exist in a range and upper limit of unit seed number and there are differences in the number among different groups and species.(5)The natural pollination results as the exploration of selfing and inter-specific hybridization offered a starting point of understanding and reference, and the index system and method of fertility comprehensive evaluation about Rhododendron plants was put forward.]]> 2017/8/27 16:49:45 ZHUANG Ping 5true Rhododendron under the ex-situ conservation conditions remains largely unclear due to the lacking of comparative study among the species in the genus. In this study, self-bred experiments on 32 species including 13 subsectiosns within 5 subgenera were carried out for a period of four years of data collection and analysis in the main bases of Longchi Dujiangyan(1 700 m above sea level), Yutang Dujiangyan(700 m), and Emeishan Biological Test Station(805 m). Using the green seedling rate(Gs)as the main index and green seedling coefficient(Gc), rate of capsul set(St)and unit number of fertility seed(Sf)as the auxiliary indexes, the experiment revealed the self-fertility characteristics of Rhododendron. The results were as follows:(1)Self fertility and sterility is two coexisting phenomena of Rhododendron sexual reproduction, and the former had more types than the latter. Of the 32 Rhododendron species, ten species were self-sterility, five species weak fertile type, seven species fertile type, and ten species high fertility type. Twenty-seven self-fertility species from sect. Rhododendron, subgen. Azaleastrum and subsect. Argyrophylla, the other four subsections in subgen. Hymenanthes and other groups were reported for the first time in China.(2)Through the comparison with natural pollination related fertility index, there were two distinct reflection found in fertility index of different species in inbred background: greatly reduced or increased, thus putting forward self fertility is an adaptation strategy for partial species of Rhododendron, or active in response to adverse environmental conditions.(3)Subsect. Fortunea considered as the most primitive taxa, with all types from self sterile to high fertility, may laid inherent genetic basis for the genus, and different regional climateand environment for the specific groups and species, through the long-term direct or indirect effects on pollinator, may be an external force that shape the diversification on self fertility of the genus ultimately.(4)The conservation, breeding and development of related disciplines were also discussed on the basis of the research results, the mechanism about post-zygotic abortion could not explain perfectly capsul aborted for some species and the polyploidy might not lead to self sterility in the genus.]]> 2017/8/27 16:49:45 ZHUANG Ping 4true Rhododendron was studied for its tolerance to low temperature, and it was used as a green plant in Ningbo and surrounding cities. We used the excellent strains of “Fanjing” Rhododendron as the material with pot experiment, and the method of artificial cooling to study different low temperatures( 0, -3, -6 and -9 ℃ ), physiological and biochemical effects of growth state and leaf ultrastructure. The results showed that at the temperature -3 ℃ and 0 ℃, the chlorophyll content decreased slowly and before treatment did not change significantly at the temperature -9 ℃ and -6 ℃, the chlorophyll content was significantly lower than that before treatment and the control group, different low temperature treatments, photosynthetic rate of leaves decreased, until the end of the trial when the photosynthetic rate was directly proportional to the temperature. Under -9 ℃ and -6 ℃ low tempe-rature stress, the relative conductivity and malondialdehyde in leaves(Malondialdehyde, MDA)content increased most rapidly, and catalase( Cata-lase, CAT ), peroxidase( Peroxidase, POD )and superoxide dismutase( Superoxide Dismutase, SOD )activity decreased significantly; at -3 ℃ and 0 ℃ treatment, the content of MDA increased significantly, but soluble protein CAT, POD and SOD activity did not change significantly. Lower temperature had great effect on the ultrastructure of leaves of Rhododendron, when the temperature was at -3 ℃ and 0 ℃, the cell structure was normal; under -6 ℃ treatment, fuzzy starting structure of thylakoid, starch grains and osmiophilic particles become larger and more; under the -9 ℃ treatment, the cell membrane began to disintegrate and chloroplast membrane a serious lack of damage severity, hollowing out, some cells even become empty cells. Comprehensive indicators of changes in the si-tuation, excellent strains of Rhododendron can tolerate a lower temperature of -6 ℃. Therefore, it can be used as a good candidate material for Rhododendron in Ningbo and surrounding cities.]]> 2017/8/27 16:49:45 1,2, HE Jing-Wen^1,2, LU Dan², XIE Xiao-Hong², WU Yue-Yan^2*]]> MING Meng^1,2, HE Jing-Wen^1,2, LU Dan², XIE Xiao-Hong², WU Yue-Yan^2* 3true Rhododendron species are mostly distributed in high mountains, they favor cold environmental conditions, and high temperature has been the primary obstacle to cultivate them in most cities of China. In this study, R. simsii and R. ovatum with higher tolerance to heat stress were used as female parents, and crossed with sixteen wild Rhododendron species from subgen. Tsutsusi, subgen. Pentanthera, subgen. Rhododendron, subgen. Hymenanthes and subgen. Azaleastrum in order to breed new varieties with stronger heat resistance and higher ornamental value. The ovary-swelling rate, fruit-bearing rate and germination rate of hybrid seeds were investigated, the cross-compatibility among wild Rhododendron species and the effective evaluation indicators of cross-compatibility were discussed according to ovary-swelling rate, fruit-bearing rate and germination rate of hybrid seeds. The results showed that R. simsii as female parent had higher cross-compatibility than R. ovatum. When R. simsii was crossed with other species from the same subgenus, the cross-compatibility was higher. However, when R. simsii was crossed with the male parents from different subgenus, the cross-compatibility of these different cross combinations was obviously different. On the other hand, when R. ovatum was used as female parent, the hybridization affinity was not affected heavily by phylogenetic relationship. R. ovatum was crossed with R. ellipticum from the same subgenus, ovary-swelling rate was 43.4%, but fruit-bearing was not found, but when it was crossed with other species from different subgenra, some cross combinations had better cross-compatibility. Further data analysis indicated that there were positive correlations between ovary-swelling rate and fruit-bearing rate, between fruit-bearing rate and the number of seeds per capsule, but there was not significant correlation between ovary-swelling rate and the number of seeds per capsule. No direct connections were found between pollen viability(above 15%), SLR(male/female style length ratio)(0.50-2.12)and cross affinity.]]> 2017/8/27 16:49:45 *, ZHAO Hong-Juan, WU Ying-Qian, ZHANG Yue-Miao]]> GENG Xing-Min^*, ZHAO Hong-Juan, WU Ying-Qian, ZHANG Yue-Miao 2true Rhododendron praevernum', and its floral morphology and leaf size are described and supplemented in this paper. The number of stamens in R. praevernum, which are remarkably variations, and differences in existing description references result in its difficulty and confusion to identify. This paper will provide some valuable information for further taxonomic revision of R. praevernum.]]> 2017/8/27 16:49:45 1, YU Xun-Lin^2*, LUO Kai-Wen³]]> XIANG Jian-Feng¹, YU Xun-Lin^2*, LUO Kai-Wen³ 1true