濒危植物南方红豆杉遗传多样性的RAPD分析

采用RAPD技术检测了山西南部南方红豆杉8个种群的遗传多样性。利用21个10聚寡核苷酸引物共检测出134个位点，其中多态性位点123个，占91.79%，8个种群的遗传多态位点百分率分别为67.16%(红豆峡)、67.91%(凤凰谷)、66.42%(小梯河)、66.42%(蟒河)、50.75%(历山西峡)、43.28%(云蒙山)、78.36%(长治宾馆)、50.75%(磨河)。南方红豆杉的遗传多样性分析结果显示：Shannon指数为2.180，其中31.7%的遗传多样性来自种群间，68.3%来自种群内；Nei指数为0.571，种群间的遗传分化系数(Gst)为0.181。8个种群间的遗传相似性分析结果显示：壶关红豆峡和陵川凤凰谷种群间的遗传距离最小(0.109 2)，壶关红豆峡和陵川蟒河种群间遗传距离最大(0.55)。本研究结果揭示，南方红豆杉自然种群具有较高的遗传多样性，其遗传多样性不是导致该种群濒危的主要原因，导致南方红豆杉种群濒危的原因可能与南方红豆杉自然种群及群落所在生境的直接破坏及其本身生物学和生态学特性所导致的自然更新不良有着密切的联系。

Genetic Diversity of Rare and Endangered Plant Taxus chinensis var. mairei

Random amplified polymorphic DNA (RAPD markers) provides a powerful tool for investigation of genetic variation in natural and domesticated populations. We described genetic variations in eight Taxus chinensis var. mairei populations distributed in Shanxi province. Twenty-one arbitrary 10 base pair primers produced 134 amplification bands, 123 of which were polymorphic (91.79%). Polymorphic percentage of the eight populations was 67.16% (HDX), 67.91(FHG), 66.42% (XTH), 66.42% (MH), 50.75% (LSDX), 43.28% (YMS), 78.36% (CZBG), 50.75% (MOH), respectively. Species diversity indicated by Shannon index was 2.180, 31.7% of which was from the inter-populations, 68.3% of which was from the intra-populations. Species diversity indicated by Nei index was 0.571 and the coefficient of gene differentiation (Gst) among the populations was 0.181. The genetic distance between Hongdouxia and Mohe populations was the largest (0.55), Hongdouxia and Fenghuanggu was the smallest (0.109 2). It was concluded from the present study that there exists high genetic diversity in natural populations of T. chinensis var. mairei. Low genetic diversity is not a key factor in threatening its natural populations. The reasons that lead T. chinensis var. mairei to endangered plant are related to the destruction of habitat, innate biological, ecological characteristics and poor regeneration ability of natural populations.