中文摘要：

采用空间自相关分析方法对中华水韭（lsoetes sinensis）的安徽天然居群的小尺度空间结构进行了研究，以探讨其群体内遗传变异的分布特征及其形成机制．根据来自4个酶系统的4个多态位点所提供的7个等位基因（Acp-4α、Acp-4c、Mdh—1α、Pgm-2α、Pgm-2b、Pgm-2n和Prx-1α），运用等样本频率和等地理间隔两种方法分别对33株个体进行了空间自相关系数Moran’s I值的计算．结果表明：中华水韭的安徽居群的遗传变异具一定的空间结构，近距离内呈斑块状分布，远距离内呈渐变衰退或双向渐变模式，斑块的大小约为24m，并在69—223m和389—576m内存在间断分布，在大于360m的范围内，个体之间表现为明显不相似．这种分布格局的形成主要是生境隔离、随机漂变和繁殖方式共同影响的结果．本研究在等位酶分析的基础上，进一步探讨了中华水韭的濒危机制，为其保育策略的健全和实施提供了一定的科学依据．

英文摘要：

Rare and endangered plant Isoetes sinensis is a remnant species of heterosporous lycopsids. The background of spatial structure of genetic variation within populations is helpful to formulate an efficient conservation strategy for threatened species. In this paper, we investigated the spatial distribution patterns of population genetic variation of I. sinensis in Anhui, using allozyme markers. A total of 33 individuals were sampled from Anhui natural population and involved in spatial autocorrelation analysis in two approaches of equal gene frequency and equal distance interval correlograms with eight classes. Seven alleles（Acp-4a,Acp-4c,Mdh-1a,Pgm-2a ,Pgm-2b,Pgm-2n and Prx-1a） from 4 polymorphic loci were used to calculate Moran＇ s I spatial autocorrelation coefficient. The result revealed significant spatial structure of genetic variation within population of I. sinensis ： the significant positive autocorrelation was found over short distance class 0 - 24 m, while there were depression and double cline structures in longer distance classes; the large distance classes （69 - 223 m,389 -576 m） in equal gene frequency correlograms and no or few individuals in some distance classes in equal distance interval correlograms suggested island distribution resulting from habitat fragmentation; furthermore, from the distance class 360 - 432 m, the individuals showed significant negative autocorrelation, which indicated gene exchange was greatly limited from the distance 360 m. The spatial distribution patterns may be attributed to the isolation of small patches, genetic drift and reproductive system. Based on the results of the present study combined with the homogeneous genetic basis detected in allozyme analysis of I. sinensis population, possible mechanisms causing the endangerment of I. sinensis are discussed and conservation strategies are proposed.