栌菊木的等位酶分析及其在生物地理和保护生物学上的意义

对我国西南特有的菊科单种属植物栌菊木10个居群、149个个体、11个酶系统及16个酶位点的水平淀粉凝胶电泳分析表明，栌菊木的遗传多样性水平在特有种中较高，在居群水平上，平均每个位点的等位基因数A=1．1—1．4，多态位点百分数P=6．3％—43．8％，实际杂合度Ho=0．063～0．250，期望杂合度He=0．043～0．194；物种水平上A=1．6，P=37．5％，Ho=0．143，He=0．141。居群间遗传一致度I=0．902—1．000，杂合性基因多样度比率FST为0．2395。栌菊木居群间分化程度较大，云南南盘江流域碧云寺居群遗传多样性较低，明显低于金沙江流域的居群。栌菊木可能是来自冈瓦纳古陆祖先的后裔，可能是古地中海退却以后在金沙江干热河谷分化出来的特有属，并且可能由于湿度等生态因子的限制，其分布区未能进一步扩大，仅在南盘江流域形成零散分布。等位酶分析结果还表明栌菊木遗传多样性总体水平较高，建议对遗传多样性较高的金沙江流域的居群加以保护。

Allozyme Analysis of Nouelia insignis and Its Sig nificance on Biogeography and Conservation Biology

Allozyme analysis of Noulia insignis ,which is a rare species and monotypic genus endemic to southwestern China,was carried out with 149 individuals in 10 populations,throughout the entire distribution of the species by means of horizontal starch gel electrophoresis technique.Eleven enzyme systems and 16 loci are studied.The results showed that genetic diversity was relatively high in population level as an endemic species ( A =1 1-1 4, P =6 3%-43 8%, H o =0 063-0 250, H e =0 043-0 194).And at species level it was higher ( A =1 6, P =37 5%, H o =0 143, H e =0 141).Genetic identity between populations ranges from 0 902 to 1 000. F ST (0 2395) indicates genetic differentiation among populations is high.The genetic diversity of Biyunsi population of Nanpan River valley,SC Yunnan is lower than that of Jinsha River valley N & NW Yunnan.Ecological factors especially humidity may be one reason that restrict the distribution of Nouelia and influence its genetic differentiation. Nouelia was probably a descendant from Gondwana,it was differentiated from diploid ancestor after Tethys retreat in Jinsha (Yangtze) River Valley,only a few scattered population dispersal to Nanpan River (SC Yunnan).But it could not further expand the distribution area for some restrictive ecological factors such as humidity.The results also showed that genetic diversity of Nouelia insignis as a whole is high.Furthermore,the results suggested that the populations of Jinshan (Yangtze) River,which have higher genetic diversity,should be further protected.