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作 者 ：杨慧;陈媛媛;徐永星;李作洲

期 刊 ：植物科学学报 2011年 29卷 3期 页码：319-330

关键词：水韭；迁地保护；遗传多样性；基因流；遗传管理；

Keywords:Isoetes, Ex-situ conservation, Genetic diversity, Gene flow, Genetic management,

摘 要 ：采用微卫星分子标记对中华水韭(Isoetes sinensis)安徽休宁、浙江建德和东方水韭(I.orientalis)浙江松阳三个孑遗居群的迁地保护居群开展了遗传多样性检测与遗传结构分析。7对多态性微卫星引物在36个迁地保护亚居群的720个样本中共检测到59个等位基因,每位点平均等位基因数(A)为8.43。迁地保护亚居群均维持很高的遗传多样性,多态信息含量(PIC)平均为0.707。迁地保护亚居群间遗传分化较低,遗传分化系数G_ST仅为0.070,居群间具有较大基因流(N_m=3.59)。单因素方差分析发现水韭孢子或孢子体在沿主要水流方向上的长距离传播能力要强于弱水流方向上的短距离传播能力,水流动态对水韭植物的基因流有重要影响。这与UPGMA聚类分析中迁地保护亚居群按邻近位置或水流相通程度优先聚类的结果相一致,水流所带动的强大基因流导致了不同孑遗居群来源的迁地保护亚居群间的遗传混杂。建议在开展水韭植物的迁地保护或回归自然重建时,对具有地方适应分化或者显著性进化的水韭植物居群应相互隔离而不宜配置在一起,以避免远交衰退的遗传风险。

Abstract:Genetic diversity and population structure of ex-situ conservation populations from two remnant Isoetes sinensis populations and one remnant I.orientalis population were investigated using microsatellite markers.A total of 56 alleles were identified in 720 individuals across the seven microsatellites,with a mean value of 8.43 alleles per locus.High genetic diversity was found in subpopulations with the mean polymorphism information content(PIC) of 0.707.Low genetic differentiation was revealed among conservation subpopulations(G_ST = 0.070),which may be due to higher gene flow among ex-situ subpopulations(N_m=3.59).Gene flow between subpopulation pairs was significantly affected by the relative position and water flow state among subpopulations under ex-situ conservation.One-way ANOVA indicated that the dispersal ability of Iseotes spores or sporophytes along the main flow direction was stronger than that along the weak flow direction,which suggested water flow had a great impact on the gene flow of Isoetes.This was in accordance with UPGMA analysis,which revealed that the subpopulations tended to cluster with the neighbor subpopulations connected by water flow.The results indicated that genetic mixing or genetic assimilation may have occurred among ex-situ conservation populations from different remnant populations of I.sinensis and I.orientalis,suggesting a possible risk of out-breeding depression if genetic enhancement was implemented by translocation of individuals from different remnant populations.Therefore,translocation among these remnant populations with local adaptation or significant evolution is not recommended to construct ex-situ conservation or reintroduction populations.

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