生境破碎对缙云卫矛种群遗传多样性的影响  

Effects of Habitat Fragmentation on Population Genetic Diversity of Endangered Plant Euonymus chloranthoides Yang

作　　者：胡世俊[1] 闫晓慧[1] 何平[2] 张春平[2] 

机构地区：[1]西南林业大学林学院国家林业局西南地区生物多样性保育重点实验室,昆明650224 [2]西南大学生命科学学院,重庆400715

出　　处：《重庆师范大学学报（自然科学版）》2013年第2期26-29,共4页Journal of Chongqing Normal University:Natural Science

基　　金：国家自然科学基金项目(No.30070080;No.31200319)

摘　　要：生境破碎是许多物种生存的主要威胁,不同物种对生境破碎的反应不同,破碎后种群遗传多样性的信息对物种的保护具有较大的指导意义;缙云卫矛(Euonymus chloranthoides Yang)为重庆地区特有濒危植物,由于公路修建、旅游景点开发等因素的影响,缙云卫矛种群遭受了严重的生境破碎,居群小且处于隔离状态。对位于缙云山的该物种4个居群的遗传多样性分析表明:59.38%的遗传变异存在于居群内,40.62%的遗传变异存在于居群间,居群之间表现出较高水平的遗传分化,居群间遗传分化较大与该物种居群间的长期隔离,花粉、种子的扩散距离较近有关;遗传多样性最高的居群的多态位点百分率为64.58%,但最小的板子沟居群多态位点百分率仅29.17%,表明小居群不利于遗传多样性的维持。居群间的基因流(Nm)偏小,为0.730 9,难以抵消遗传漂变引起的居群间的遗传分化;聚类分析显示距离最近的居群首先聚在一起,表明该物种居群间遗传分化大小受空间距离远近影响。研究认为对该物种的有效保护应加强对小种群的就地保护,增强居群间的基因流,防止小居群遗传多样性的进一步丧失。Habitat fragmentation is the main threat to the survival of many species, species response to habitat fragmentation differently; the information of genetic diversity has great significance to protect species. Euonymus chloranthoides Yang is an endangered plant endemic to Chongqing. The population of this plant in Jinyun Mountain has been fragmented seriously because of the highway construction, tour development and so on. Some populations are small and isolated. Four populations in Jinyun maintain were selected to study the effects of habitat fragmentation on population genetic diversity of E. chloranthoides. The results of ISSR experiment show that the Gsr is 0. 406 2 which means 59.38 % of the genetic diversity exists within the population, and 40.62 % of the genetic diversity exists among populations, the level of population differentiation is high due to long isolation, low dispersal distance of pollen and seed. The PPB of the population with highest genetic diversity is 64.58%, The genetic diversity of Banzigou population, the smallest one, is the lowest, and the PPB of this population is 29.17%, which means small population do harm to the mainte- nance of genetic diversity. The gene flow （Nm） is 0. 730 9, which is difficult to counteract the differentiation caused by genetic drift. Cluster analysis show he nearest populations cluster first, which mean that the genetic differentiation is affected by spatial distance. In-situ conservation should be strengthened to protect the small populations, and gene flow among populations should be improved to prevent the further genetic loss of small populations.

关 键 词：生境破碎 缙云卫矛 遗传多样性 濒危植物 

分 类 号：Q16[生物学—普通生物学]