采用RAPD 标记技术,对分布于江苏省(紫金山、牛首山和宝华山)及安徽省(皇藏峪和琅琊山)的5 个南京椴(Tilia miqueliana Maxim.)居群的遗传多样性进行了分析,并采用UPGMA 聚类方法研究了5 个居群的遗传关系。结果表明:使用10 条多态性引物从5 个居群的总DNA 中扩增出169 条带,其中多态性条带151 条,多态性条带百分率达89. 34%。各居群的多态性条带百分率(PPB)、有效等位基因数(Ne)、Nei’s 基因多样度(h)和Shannon’s 多样性指数(I)均有明显差异,其中,宝华山居群的各项指标均最高,紫金山和牛首山居群的PPB 值最低,琅琊山居群的Ne 值最低,紫金山居群的h 和I 值均最低。5 个居群的I、h 和Ne 值分别为0. 243 0 ~ 0. 335 1、0. 154 4 ~0. 218 2和1. 248 9 ~1. 362 7; 在种水平上的I、h 和Ne 值分别为0. 359 4、0. 223 6 和1. 352 9。居群内变异占总变异的75. 95%,居群间变异占总变异的24. 05%。居群内和居群间的基因多样度分别为0. 218 5 和0. 173 2,物种水平上的基因分化系数为0. 207 5,居群间的基因流为1. 909 3。各居群间的遗传距离差异较大;其中,皇藏峪与牛首山居群的遗传距离最近,仅为0. 026 5;宝华山与紫金山居群的遗传距离最远,为0. 134 4。通过聚类分析可将5 个南京椴居群分为3 支,宝华山和琅琊山居群各自独立为2 支,皇藏峪、紫金山和牛首山居群聚为1 支,且可进一步分为2 个亚支,皇藏峪居群为1 个亚支、紫金山和牛首山居群聚为1 个亚支。研究结果表明:南京椴居群内的遗传多样性较高,但居群内的变异占主导地位,居群间存在明显的遗传分化。

Genetic diversity of five populations of Tilia miqueliana Maxim. distributed in Jiangsu Province (Baohuashan Mountain, Zijinshan Mountain and Niushoushan Mountain) and Anhui Province (Huangcangyu and Langyashan Mountain) was analyzed by RAPD marker, and genetic relationship among five populations also was studied by UPGMA cluster method. Results show that 169 bands are amplified from total DNA of five populations by 10 polymorphic primers, in which 151 bands are polymorphic bands with 89. 34% of percentage of polymorphic band. Percentage of polymorphic band (PPB), effective number of alleles (Ne), Nei’s gene diversity (h) and Shannon’s diversity index (I) are obviously different among five populations, in which, all indexes of population in Baohuashan Mountain are the highest, PPB value of populations in Zijinshan Mountain and Niushoushan Mountain is the lowest, Ne value of population in Langyashan Mountain is the lowest, and h and I values of population in Zijinshan Mountain are the lowest. Values of I, h and Ne of five populations are 0. 243 0-0. 335 1, 0. 154 4-0. 218 2 and 1. 248 9-1. 362 7, respectively, and those in species level are 0. 359 4, 0. 223 6 and 1. 352 9, respectively. Genetic variation within population accounts for 75. 95% and that among populations accounts for 24. 05% of total genetic variation. Gene diversity within population and among populations is 0. 218 5 and 0. 173 2, respectively, gene differentiation coefficient is 0. 207 5 at species level, and gene flow among populations is 1. 909 3. Genetic distance among all populations differs obviously, in which, that between populations of Huangcangyu and Niushoushan Mountain is the nearest  (only 0. 026 5) while that between populations of Baohuashan Mountain and Zijinshan Mountain is the farthest (0. 134 4). Five populations can be divided into three groups by cluster analysis, in which, populations of Bohuashan Mountain and Langyashan Mountain are separate two groups, while three populations of Huangcangyu, Zijinshan Mountain and Niushoushan Mountain are gathered into one group, which can be divided into two sub-groups further, one is Huangcangyu population and another contains populations of Zijinshan Mountain and Niushoushan Mountain. It is suggested that genetic diversity within T. miqueliana population is higher, but genetic variation within population play a dominant role and there is obvious genetic differentiation among populations.