云南特有濒危植物馨香木兰的遗传多样性研究

摘要

为研究云南特有濒危植物馨香木兰的遗传多样性水平,采用随机扩增多态 DNA 技术(RAPD),对云南省馨香木兰4个居群,即文山州广南县、西畴县新街、西畴县亚坪等3个天然居群及昆明树木园1个人工居群,进行遗传多样性分析。随机筛选出重复性好的8条随机引物,对70个样品的基因组 DNA 进行扩增,建立RAPD 分析图谱。扩增结果为,共检测出84个多态位点。遗传多态位点百分率为61.90%(文山广南)、76.19%(西畴新街)、71.43%(昆明树木园)和66.67%(西畴亚坪)。遗传多样性 Shannon 指数为0.5686,其中30.55%来自种群间,69.45%来自种群内；Nei’s 指数为0.3903,种群间的遗传分化系数(GST)为0.2216。文山广南和西畴亚坪之间的遗传距离最大,昆明树木园与西畴亚坪之间的遗传距离最小。结果显示,与木兰科等其他濒危植物相比较,馨香木兰遗传多样性相对较高。根据各种群遗传背景研究结果,提出了该物种迁地保护种群遗传资源管理建议。%In order to study the genetic diversity of the endemic and endangered plant of Magnolia odorati-ssima in Yunnan Province,we collected 4 populations including one artificial population from Kunming Tree’s Garden (KM),and three wild populations from Guangnan (G),Xinjie (XCD)and Yapin (XPB) of Wenshan Prefecture.Eight RAPD primers were selected to screen 70 samples of M.odoratissima Among 84 detected sites,rpolymorphic percentage of the four populations were 61.90 % (G),76.19 % (XCD),71.43% (KM)and 66.67 % (XPB)respectively.Species diversity indicated by Shannon index was 0.568 6,among which 30.55 % was from the inter-populations and 69.45 % was from the inner-populations.The species diversi-ty indicated by Nei index was 0.390 3 and the coefficient of gene differentiation among the populations was 0.221 6.Genetic distance between Guangnan and Yapin was the longest,while the one between Kunming Tree’s Garden and Yapin was the shortest.The results showed that M.odoratissima had higher genetic diversity than other en-dangered and endemic plants of magnoliaceae.Based on the research,relevant management suggestion on ex-situ conservation of M.odoratissima genetic resources was proposed.