中文摘要：

采用超薄平板聚丙烯酰胺等电聚焦电泳,对湖北西部药用植物天麻（Gastrodia elata Bl.）的4种变型进行了等位酶遗传变异的初步分析。在6个酶系统共检测到17个清晰位点和37个等位基因,其中多态位点11个,位点最大等位基因数为4,位点Acp-4和Prx-2的等位基因表现出变型特异性。遗传多样性分析结果表明：天麻在物种水平维持着较高遗传多样性,平均多态位点比率P=56.3%,每位点平均等位基因数A=2.1,平均预期杂合度He=0.222;但其变型水平遗传多样性较低（P=42.2%,A=1.7,He=0.146）,其中乌天麻遗传多样性最高,药天麻最低。天麻变型间遗传分化系数（GST）达0.3595,平均基因流（Nm）仅为0.4450,说明天麻变型间遗传分化较大,缺乏基因交流。聚类分析结果表明,天麻居群以变型为单元优先聚类而非地域优先聚类,揭示各天麻变型在遗传上是相对独立的进化显著单元,支持天麻种内变型的划分。红天麻与乌天麻两变型最为近缘,火天麻与药天麻两类群有着较近的遗传关系。

英文摘要：

Gastrodia elata（Orchidaceae）,a rare and endangered medicinal plant,is a polymorphic species with more than six forms.Allozymic variation of four form in G.elata from Hubei provinces was analyzed using isoelectric focusing in thin-layer polyacrylamide slab gels.Thirty-seven alleles of 17 loci in six enzyme systems were examined,in which 11 loci were polymorphic.The maximum number of alleles in a locus was four.Form specificity was found in alleles of loci Acp-4 and Prx-2.A high genetic diversity was observed at species level with mean number of alleles per locus A=2.1,mean percentage of polymorphic loci P=56.3% and average expected heterozygosity He=0.222,while a lower genetic diversity was found at form level（P=42.2%,A=1.7,He=0.146）.Among the four forms investigated,the highest level of genetic variation was found in G.elata f.glauca（P=50.0%,A=2.1,He=0.184）,and the lowest in an unidentified G.elata form named as＇Yao Tianma＇ by local farmers（P=25.0%,A=1.4,He=0.093）.A high genetic differentiation among different forms was revealed（GST=0.3595）,which may be due to restricted gene flow among forms（Nm=0.445）.Cluster analysis using UPGMA based on Nei＇s genetic distances revealed that populations from the same form tended to cluster together,suggesting that each form of G.elata was an indepen-dent evolutionarily significant unit in genetics,and the intra-species subdivision of G.elata are well supported by the present study.Results of this study also revealed that G.elata f.elata had a closest genetic relationship with G.elata f.glauca,while the unidentified form ＇Yao Tianma＇ is closest to another unidentified form named ＇Huo Tianma＇.