基于ISSR遗传多样性分析的云南蓝果树保护措施探索

Conservation of Nyssa yunnanensis Based on Genetic Diversity Analysis Using ISSR Markers

保存种群的遗传多样性和进化潜力是成功拯救保护濒危物种的关键。云南蓝果树（Nyssa yunnanensis W.C.Yin）是国家I级重点保护的极度濒危野生植物,也是国家实施极小种群野生植物保护工程的目的物种。为了制定针对性的保护措施,采用ISSR分子标记方法对64株极度濒危物种云南蓝果树子代个体进行遗传多样性分析。从100条引物中筛选出12条ISSR引物,共扩增出77个稳定、清晰的条带。其中58个为多态性条带,物种水平上的多态性条带百分率（PPL）变动范围为50.00%-87.50%,平均值为（74.65±0.01）%;等位基因观察值（Na）为1.7532;有效等位基因观察值（Ne）为1.5804;Nei＇s基因多样性指数（He）为0.3206,多态性信息含量指数（PIC）变动范围为0.15-0.44,平均值为0.27±0.01;Shannon＇s遗传多样性信息指数（I）随着样本数的增加而升高,但当样本数达到24及以上时,Shannon＇s指数的数值基本不再变化。基于遗传多样性分析结果,从地质历史原因和人为干扰因素等方面对云南蓝果树的濒危机制进行了探析,并提出了有针对性的云南蓝果树保护措施。

Preserving genetic diversity and evolution potentials of the population is a key factor to successfully conserve an endangered species. Nyssa yunnanensis,a critically endangered and range-restricted tree species under national Grade I protection in China,has been projected in the conservation of species with extremely small populations. To explore and draw up the pertinent conservation strategies,we examined the genetic diversity of 64 N. yunnanensis individuals using inter-simple sequence repeat（ ISSR） markers generated by 12 ISSR primers. The results showed that the genetic diversity of natural population of Nyssa yunnanensis（ PPL）ranged from 50. 00 % to 87. 50 % with a mean of（ 74. 65 ± 0. 01） %,alleles observed value（ Na） was1. 7532,effective alleles observed value（ Ne） was 1. 5804,Nei＇ s genetic diversity index（ He） was 0. 3206,polymorphism information content（ PIC） ranged from 0. 15 to 0. 44,with a mean of 0. 27. Moreover,Shannon＇ s index（ I） of phenotypic diversity raised as the population size increased. But Shannon＇ s index（ I）had not been changed until the number reached 24. Based on results of genetic diversity analysis,we clarified the endangered mechanism of N. yunnanensis on the viewpoints of both geological history and contemporary hu-man disturbances. Conservation measures were suggested to maintain and increase genetic diversity,evolution potentials,and environment adaptability of N. yunnanensis,so as to successfully conserve this critically endangered species.