浙江天台山不同海拔高度七子花种群遗传多样性及其与环境因子的相关性分析

Analysis of the genetic diversity of Hepatacodium miconioides at different altitude in Tiantai mountain in Zhejiang Province and its relationship with environmental factors

采用RAPD技术对浙江天台山3个海拔高度的七子花(Hepatacodium miconioides)天然种群的遗传多样性、遗传分化以及与环境因子的相关性进行了研究.12种随机引物在60株个体中共检测到122个可重复的位点.3个种群多态位点百分率为18.85%～23.77%,平均为21.86%,表明各种群的遗传多样性水平比较低.3个种群Shannon和Nei指数平均为0.132 9、0.092 5,其值较低.虽然3个种群所分布的地理范围小,但种群间存在明显的遗传分化,Shannon指数所显示的总遗传多样性中,种群内占33.58%,种群间占66.42%.Nei指数显示的种群间遗传分化系数为0.654 6.种群间的基因流很小,仅为0.265 6.3个七子花种群间的遗传相似度平均为0.712 6,遗传距离平均为0.341 2.海拔990 m种群与海拔780 m种群的遗传相似度较高,海拔500 m种群与其它两种群的相似度较低.七子花种群内的遗传多样性与土壤总氮呈极显著的正相关.

The genetic diversity within populations and genetic differentiation among populations of Hepatacodium miconioides at three different altitudes in Tiantai mountain in Zhejiang Province were analyzed by random amplified polymorphic DNA (RAPD) technique. The relationships between the genetic diversity and the environmental factors were analyzed. 12 random primers were selected in the amplification of 60 plants and 122 repetitive loci were produced. The percentage of polymorphic loci of three populations ranged from 18.85% to 23.77% with an average of 21.86% indicating the relatively low genetic diversity of H. miconioides. The averages of Shannon index of phenotypic diversity (0.132 9) and Nei index (0.092 5) within populations were relatively low. The distinct genetic differentiation existed among populations of \%H. miconioides\% in spite of the relatively small geographical distribution. Estimated by Shannon index of phenotypic diversity, the average genetic diversity within populations of H. miconioides accounted for 33.58% of the total genetic diversity while the genetic diversity among populations accounted for 66.42%. The genetic differentiation among populations of H. miconioides, as estimated by Nei index, was 0.6546. The gene flow estimated from Gst was only 0.265 6, indicating that the gene flow among populations of H. miconioides was relatively low. The average of the genetic identity among populations of H. miconioides was 0.712 6 and the average of genetic distance of H. miconioides was 0.341 2. The genetic identity between population at the altitude of 990 m and populations at the altitude of 780 m was the highest. The genetic identity between populations at the altitude 500 m and other two populations was relatively low. The correlation analysis showed that the genetic diversity within populations was significantly positively related with the soil total nitrogen.