不同生境夏蜡梅群体遗传多样性的RAPD分析

Genetic Diversity of Sinocalycanthus chinensis in Four Different Habitats Revealed by RAPD

利用RAPD技术对天台大雷山4个不同生境:灌丛、常绿阔叶林、杉木林和竹林中的夏蜡梅群体进行遗传多样性研究。12个随机引物在80个个体中共检测到182个可重复的位点,其中多态位点为49个,总的多态位点百分率为26.92%。4个群体的多态位点百分率在6.04%-11.54%之间,平均为8.93%,其中竹林群体最高,常绿阔叶林群体最低,大小顺序为竹林群体>灌丛群体>杉木林群体>常绿阔叶林群体,Shannon指数和Nei指数估算结果为灌丛群体最高,其次是竹林群体,第三是杉木林群体,最低的是常绿阔叶林群体。AMOVA分子差异分析表明夏蜡梅群体间遗传分化程度高,71.91%的变异存在于群体间,28.09%的变异存在于群体内,群体间的基因分化系数(GST)为0.627 4。夏蜡梅群体间的基因流很低,Nm=0.297 0。聚类分析结果表明杉木林群体和灌丛群体最先聚在一起,再与常绿阔叶林群体相聚,最后与竹林群体聚在一起。可见,夏蜡梅在各生境间有着不同的遗传多样性,且在各生境间发生了明显的遗传分化。

The genetic diversity of Sinocalycanthus chinensis populations in four different habitats, namely, scrub, evergreen broadleaved forest, Chinese fir forest and bamboo grove, was analyzed by polymorphic DNA technique. 12 primers were selected at random and 182 repeatable loci with 49 polymorphic loci were produced from 80 DNA samplings. The total average percentage of polymorphic loci was 26.92%. The percentage of polymorphic loci of four populations varied from 6.04% to 11.54% with an average of 8.93%, among which bamboo grove population was the highest and evergreen broad- leaved forest population was the lowest with the order as follows ： bamboo grove population 〉 scrub population 〉 Chinese fir population 〉 evergreen broadleaved forest population. The results of Shannon＇ s index and Nei＇s index were in the same trend, the highest was scrub population, followed by bamboo grove population, and then was Chinese fir population, the lowest was evergreen broadleaved forest population. Analysis of molecular variance （AMOVA） demonstrated that the genetic differentiation among population was high. Variation among population occupied 71.91%, while that within population occupied only 28.09%. The gene differentiation coefficient among populations was 0. 672 6. The gene flow among populations was very low, Nm = 0. 297 0. Cluster analysis showed Chinese fir population and scrub population got together first, then evergreen broadleaf forest population joined in, and the final population was the bamboo grove. It was obvious that different population had different genetic diversity, and there were remarkable genetic differentiation among populations.