微生境下羊草两种生态型种群的遗传多样性及遗传分化——等位酶分析

Genetic diversity and differentiation of two ecotypes of Leymus chinensis populations in microhabitat——Allozyme analysis

采用水平淀粉凝胶电泳技术 ,应用等位酶分析方法测定了松嫩平原南部微生境条件下羊草灰绿色和黄绿色两种生态型 9个种群的遗传多样性和遗传分化程度。羊草种、种群和生态型水平都维持较高的遗传多样性。两种生态型之间有明显的遗传多样性差异及遗传分化。灰绿型和黄绿型的多态位点百分率分别为 67.3 %和 57.1 % ,等位基因平均数分别是2 .2和 1 .9,期望杂合度分别为 0 .3 4 8和 0 .2 98。两种生态型种群之间平均遗传距离是 0 .1 8,而同一生态型种群间的遗传距离仅分别为 0 .0 4 5和 0 .0 99。灰绿型和黄绿型种群间遗传一致度为 0 .83 6,相同生态型种群间遗传一致度分别是 0 .956和 0 .91 4。

Leymus chinensis (Trin.) Tzvel.is a rhizome grass species,which has two ecotypes,a gray green type and a yellow green type,in the south of the Songnen Plain of China.Levels of allozyme diversity and genetic differentiation were assessed for 14 allozyme loci in 7 populations of the gray green type and 2 populations of the yellow green type (a total of 271 individuals). Leymus chinensis maintained relatively high genetic variation at the ecotype,population and species levels as compared with the average plant species.Significant differences of genetic diversity and genetic differentiation were found between the gray green and yellow green ecotypes.Percentage of polymorphic loci,mean number of alleles per locus and expected heterozygosities between the gray green type and the yellow green type were 67.3% and 57.1%,2.2 and 1.9,0.348 and 0 298 respectively.The means of genetic distance were 0.18 between the ecotypes,0 045 and 0 099 within the gray green type and the yellow green type respectively.While the means of genetic identity were 0 836 between the types,those within the gray green type and the yellow green type were 0 956 and 0 914 respectively.