【作者】 康明；

【导师】 黄宏文；

【作者基本信息】 中国科学院研究生院（武汉植物园） ， 植物学， 2006， 博士

【摘要】 濒危植物的保育遗传学研究是揭示物种致濒机制和制定濒危物种保育策略的理论基础。本文选取了我国三种受人为干扰严重的濒危植物—华东经济发展快速地区的毛柄小勾儿茶和中华水韭与三峡库区的荷叶铁线蕨为代表，采用等位酶、AFLP、cpRFLP、cpSSR和SSR等分子标记，分别研究了这三种濒危植物的遗传多样性和遗传结构，主要结果如下： 1．毛柄小勾儿茶（Berchemiella wilsonii var．pubipetiolata）是一种只分布于我国浙江天目山地区和安徽大别山地区的濒危木本植物。生境破坏已经导致了该物种现有居群的片断化和局部居群的灭绝。我们初步采用超薄平板微型聚丙烯酰胺等电聚焦技术，对毛柄小勾儿茶4个现存居群的等位酶变异进行了研究，在9个酶系统、20个酶位点的检测结果表明，毛柄小勾儿茶在物种水平和居群水平上都存在较高的遗传多样性，但所有居群都缺乏低频率（小于0.1）等位基因，这可能是毛柄小勾儿茶遗传侵蚀的一个先期表征。等位酶的水平上对杂合子的选择和／或严重的近交衰退可能是导致所有居群都表现杂合子过剩的原因。 2．考虑到等位酶标记的一些缺陷，我们之后采用AFLP标记和cpDNA标记相结合的方法分析了毛柄小勾儿茶居群的遗传结构和生境片断化带来的影响。AFLP结果显示，毛柄小勾儿茶现存居群有中等水平的遗传多样性（H_s=0.141-0.172）。将cpRFLP和cpSSR相结合在88个个体中确定了6种单倍型，单倍型总的多样度为H_E=0.700。AMOVA分析结果显示地区间和地区内具有显著的AFLP遗传分化(φ_ST=0.196，φ_CT=0.396)。对于cpDNA单倍型来说，地区间有强烈的遗传分化，而地区内却没有显著的遗传分化。研究结果表明，毛柄小勾儿茶居群间的基因流较低。AFLP和cpDNA标记都揭示了不同地区居群间具有很强的遗传分化，这说明两地区的毛柄小勾儿茶居群是两个不同的进化谱系，在制定对毛更多还原

【Abstract】 Conservation genetic studies of endangered plants are a key part in the conservation effort for endangered species. Using several molecular markers, genetic variation and population structure of three endangered plant species which were severely disturbed by anthropogenic activities were studied. These baseline data should be essential to understand historical demographic and genetic events, and their interactions on endangered species. The main results are highlighted in the following:1. Berchemiella wilsonii (Schneid.) Nakai var. pubipetiolata Qian (Rhamnaceae) is distributed in fragmented habitat patches in eastern China. It is highly endangered because of severe disturbance by anthropogenic activities. Allozyme variation of population genetic diversity and structure of four extant populations was investigated by using isoelectric focusing in thin-layer polyacrylamide slab gels. Based on 20 loci scored from the nine enzymes examined, a high genetic diversity was detected at both the species and population levels, while there was a loss of low frequency alleles (<0.1) in all populations, possibly due to a recent decrease in population size, and genetic drift in small populations has resulted in a loss of alleles occurring at low frequency.. Most loci showed deviation from Hardy-Weinberg equilibrium due to excess of heterozygotes in all populations, suggesting that selection for heterozygotes and/or severe inbreeding depression have occurred in this species.2. AFLP and cpDNA markers were further used to determine the population structure of remnant populations of B. wilsonii var. pubipetiolata and assess the genetic effects of更多还原