泡沙参复合体(桔梗科)的物种生物学研究Ⅳ.等位酶水平的变异和分化

BIOSYSTEMATIC STUDIES ON ADENOPHORA POTANINII KORSH. COMPLEX (CAMPANULACEAE) Ⅳ. ALLOZYME VARIATION AND DIFFERENTIATION

利用聚丙烯酰胺凝胶电泳技术，对采自泡沙参复合体整个分布区的１５个天然居群进行了等位酶分析。７种酶系统共１０个等位酶基因位点的检测表明，本复合体植物具有高水平的遗传变异性，居群水平上的遗传多样性指标分别为：多态位点百分率Ｐ＝０４０～０７０，等位基因平均数Ａ＝１．５～２．５，平均期望杂合度Ｈｅ＝０．１０２～０．２９１。３个类群在居群水平上的平均多样性水平由高至低依次为：Ａ．ｗａｗｒｅａｎａ（Ａ＝２．１０，Ｐ＝０６３，Ｈｅ＝０．２３７），Ａ．ｌｏｂｏｐｈｙｌａ（Ａ＝１．８５，Ｐ＝０６０，Ｈｅ＝０．２０４）和Ａ．ｐｏｔａｎｉｎｉ（Ａ＝１．８３，Ｐ＝０６０，Ｈｅ＝０．１８８）。居群遗传结构和交配系统的分析表明，本复合体植物的大部分遗传变异存在于居群之内，ＦＳＴ＝０．１７６（Ａ．ｗａｗｒｅａｎａ）和０．１１５（Ａ．ｐｏｔａｎｉｎｉ），并以异交为主，异交率估计值分别为ｔ＝０．８６（Ａ．ｗａｗｒｅａｎａ），０．７４（Ａ．ｐｏｔａｎｉｎｉ）和０．６３（Ａ．ｌｏｂｏｐｈｙｌａ），这是本复合体植物具有丰富遗传变异的主要原因之一。根据１５个居群的遗传一致度（Ｉ）值进行聚类分析发现，１５个居群可分为明显的２支，由Ａ．ｌｏｂ?

Fifteen natural populations representing all the taxa in Adenophora potaninii complex were investigated using vertical slab polyacrylamide gel electrophoresis. Allozyme data for ten loci of seven enzymes demonstrate high levels of genetic variation within populations, with the values of P=0 40～0 70, A=1.5～2.5 and He=0.102～0.291. At specific level, there existed the highest variation in A. wawreana (A=2.10, P=0 63, He=0.237), followed by those of A. lobophylla (A=1.85, P=0 60, He=0.204) and A. potaninii (A=1.83, P=0 60, He=0.188). Based on Wright's F statistics, the outcrossing rates(t) were 0.86(A. wawreana ), 0.74 (A. potaninii) and 0.63(A. lobophylla). The analysis on population genetic structure indicates that most variation resided within populations, which is consistent with the high rate of outcrossing rates in the complex. On the basis of genetic identity(I), cluster analysis shows that there was high genetic divergence between A. lobophylla populations and A. wawreana A. potaninii clade, while no clear genetic difference was found between A. wawreana populations and A. potaninii populations. Consequently, the present allozyme data justify the establishment of A. lobophylla, but give no support for treating A. wawreana and A. potaninii as a separate species.