Inter simple sequence repeat (ISSR) molecular technique was used to analyze the genetic diversity of 84 Stemona sessilifolia individuals from 4 natural populations. The 15 selected ISSR primers generated a total of 184 fragments, 153 of which were polymorphic. Based on results of ISSR analysis,high levels of genetic variation were revealed both at the species level and population level,percentage of polymorphic fragments PPF=83. 15%,effective number of alleles (Ae) 1. 425,Shannon information index (Ⅰ) 0. 388,and Nei's gene diversity index (Hpop) 0. 254. At population level, PPF= 63. 04% ,Ae= 1. 351, Ⅰ= 0. 310, Hpop = 0. 206. Analysis of molecular variance (AMOVA) demonstrated that 87. 37% of genetic diversity was found within populations. The genetic differentiation coefficient ( GSt ) among populations was 0. 191 1. High level of gene flow was found among populations (Nm = 2. 116 6). The UPGMA cluster analysis and principal components analysis (PCA) revealed that 4 populations formed 2 distinct groups, and taishan population was clearly separated from other populations. However, with S. tubenrosa and S. japoni-ca used as outgroup,the UPGMA cluster analysis supported that S. shandongensis should be treated as a synonym of S. sessilifolia. The Mantel test revealed that an insignificant positive correlation (r=0. 625 8,P = 0. 074) existed between genetic distance and geographical distance.%利用ISSR分子标记,对直立百部4个居群的84个样本进行遗传多样性研究,探讨山东百部种的地位.结果表明:(1)15个引物共检测到184条清晰的谱带,其中多样性条带153条；直立百部的遗传多样性水平较高,其物种水平多样性条带百分率(PPF)为83.15％,有效等位基因数(Ae)为1.425,Shannon多样性指数(I)为0.388,Nei's多样性指数(Hpop)为0.254.(2)居群平均水平上多样性条带百分率为63.04％,有效等位基因数为1.351,Shannon多样性指数为0.310,Nei's多样性指数为0.206.(3)AMOVA分析显示直立百部居群间遗传分化水平(φST)为0.126 3,POPGENE分析显示居群间的遗传分化系数(GST)为0.191 1,二者均表明居群内变异大于居群间变异；直立百部居群间的基因流(Nm)为2.116 6,说明居群间的基因交流较频繁.(4)聚类及主成分分析显示,直立百部4个居群聚为两支,其中泰山居群与其他居群关系较远,以蔓生百部和大百部为外类群分析的结果支持将山东百部作为直立百部的异名,Mental检测显示居群间遗传距离与地理距离间没有显著相关性.
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