野生地椒的斑块多样性及空间结构

Patch diversity and spatial structure of wild Thymus quinquecostatus

将ISSR、SRAP分子标记与空间自相关分析技术相结合,对我国野生百里香属植物分布最南端的怀远3个地椒居群进行了以斑块为单位的遗传多样性、克隆多样性和克隆结构、空间结构的研究.结果表明:地椒野生居群内不同斑块间存在较高的遗传多样性和克隆多样性,多样性条带百分率为75.75%,Nei基因多样性指数为0.2537,Shannon信息多样性指数为0.3811,基因型比率平均为0.61,Simpson指数平均为0.96,Fager均匀性指数平均为0.91.居群间的遗传分化较低,在总的遗传多样性中,90.35%来自居群内斑块间的变异,居群间占9.65%.野生地椒居群间无共有基因型斑块,居群内不同斑块间在一定范围内具有镶嵌性,克隆斑块间的分布范围主要集中在0～25m.该地区地椒居群除了在部分位点呈现一定相关性外,总体缺乏空间结构.该地区野生地椒种群斑块的建立应为种子入侵所致,其后克隆繁殖对斑块的发展及种群的扩张起到了主要作用.

With the combination of ISSR （ inter-simple sequence repeats）, SRAP （ sequence-related amplified polymorphism） and spatial autocorrelation, the genetic diversity and spatial structure per unit patch of three Huaiyuan populations of Thymus quinquecostatus in southeast China were an- alyzed. The results showed that there existed higher levels of genetic and clonal diversity among the patches within the wild T. quinquecostatus populations, with the percentage of polymorphic loc being 75.75 % , Nei＇ s gene diversity being 0. 2537, Shannon＇ s information index being 0. 3811, percent of genetype （G/N） being 0.61, Simpson index （D） being 0.96, and Fager index （E） being 0.91. Analysis of molecular variance （AMOVA） showed that only 9.65% of genetic variation resi- ded among the populations, while 90. 35% of it resided among the individuals within the popula- tions. No genotypc patches in common were observed among the three populations. The spatial dis- tribution of the same patches showed a concentrated distribution about 0-25 m, and that of different patches showed an inlaid distribution. Except for some locations that showed par correlations in the Huaiyuan populations of T. quinquecostatus, most locations lacked in spatial structure according to spatial autocorrelation analysis. The possible mechanism causing the establishment of the patches of T. quinquecostatus populations was due to seed dispersing, and the following clonal reproduction played important roles in patch development and population expanding.