利用ISSR分子标记分析来自11个天然珙桐种群的遗传多样性.从100条引物中筛选出5条引物能扩增出稳定、清晰且具多态性的条带,共扩增出77个条带.其中74个为多态,多态条带百分率( PPB)为96.10％；各种群PPB值为37.66％ ～ 63.64％,平均为54.07％.种内Shannon多样性指数(HSP)为0.484 9,种群内Shannon多样性指数(HPOP)为0.1886～0.327 4,平均为0.277 4.这表明珙桐在物种和种群水平上均维持较高的遗传多样性.分子方差分析显示,种群间与种群内遗传变异分别占总遗传变异的46.22％,53.78％,种群间呈高度遗传分化.种群间遗传距离与对应的地理距离呈显著正相关(r=0.546,P＜0.01).UPGMA法聚类分析将11个珙桐种群分为3组.研究结果为珙桐遗传资源保护策略制定提供有价值的种群遗传学信息.%Davidia involucrata is an endemic plant species native to Southwest China. The genetic diversity of 11 natural populations of this plant was assessed using inter-simple sequence repeat ( ISSR) markers. Of the 100 primers screened, 5 primers were generated stable, distinct and highly polymorphic bands. Of 77 total ISSR discernible bands, 74 were polymorphic. The percentage of polymorphic bands was 96. 10% . At the population level the percent of polymorphic bands ranged from 37. 66% to 63. 64% , and the average value was 54. 07% . The Shannon's information index within species (HSP) was 0. 484 9, while the values within population (HPOP) were from 0. 188 6 to 0. 327 4 and the mean value was 0. 277 4. The result showed there existed high level genetic diversity both at population and species level. Analysis of molecular variance( AMOVA) revealed that among and within population genetic variation accounted for 46. 22% and 53.78% of the total genetic variation, respectively. A high degree of genetic differentiation was also found among populations. Population genetic differentiation was significantly positive correlated with geographical distances(r =0. 546, P < 0. 01). These 11 populations were divided into 3 major groups based on the UPGMA cluster analysis. These results would provide a valuable basis for developing conservation strategies.
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