西藏地区入侵植物曼陀罗(Datura stramonium L.)遗传多样性与种群分化研究

Genetic Diversity and Population Differentiation of Invasive Plant Datura stramonium L.in Tibet,China

曼陀罗(Datura stramonium)为茄科曼陀罗属一年生草本植物,曾作为药用植物引入中国,但由于长期缺乏规范性的管控措施,目前在中国各地均有扩散分布,被划分为入侵植物类,近年来在西藏地区人类干扰较大的生境中均发现其分布。入侵植物的遗传多样性和遗传结构与其入侵适应性机制有直接关联,掌握入侵植物的遗传多样性是了解其潜在适应机制的一项重要内容。该研究利用ISSR分子标记法对分布于西藏不同地区的曼陀罗15个种群的遗传多样性和种群分化进行分析。结果表明:Nei’s遗传多样性指数(H)平均值为0.1884,Shannon多样性指数(I)平均值为0.2828,基因流Nm为1.5640。AMOVA分析表明,曼陀罗种群遗传变异大部分来源于种群内部,种群间遗传分化系数(F_(st))为0.1380(F_(st)<0.25),表明种群间遗传分化不大;聚类分析结果表明,西藏地区曼陀罗种群没有表现出空间上的绝对地域性特征;Mantel检验结果表明,曼陀罗种群的遗传距离与地理距离之间没有显著相关性;曼陀罗遗传多样性与环境因子的相关性分析结果表明,年平均降雨量对曼陀罗遗传多样性具有显著影响。因此,曼陀罗的入侵扩散可能与自然扩散无关,而与人为有意或无意的多次引入有关。控制人为传播,并在曼陀罗开花授粉和果实成熟前对其进行拔除处理可能是目前防控曼陀罗入侵扩散的有效方法。

Datura stramonium is an annual herb of the genus Datura in family Solanaceae.It was once introduced to China as a medicinal plant,due to a long absence of standard control measures and management,it is now distributed throughout the country and classified as an invasive plant.In recent years,it has been found in habitats with high human disturbance in Tibet.The genetic diversity and genetic structure of invasive plants are directly related to their adaptive mechanisms,and studying the genetic diversity of invasive plants is an important aspect for understanding their potential adaptive mechanisms.However,the genetic diversity and genetic structure of D.stramonium distributed in Tibet are currently unknown.In this study,ISSR molecular markers were used to analyze the genetic diversity and population differentiation of 15 populations of D.stramonium collected different regions in Tibet.The results indicated that the mean of Nei's genetic diversity index(H)is 0.1884,Shannon's diversity index(I)is 0.2828 and gene flow Nm is 1.5640.The results of AMOVA analysis showed that the genetic variation of D.stramonium populations mainly comes from within the population and the coefficient of genetic differentiation(F_(st))between populations is 0.1380(F_(st)<0.25),and there is little genetic differentiation between populations.The results of cluster analysis indicated that D.stramonium in Tibet do not show absolute regionalism in space.The results of Mantel test showed that there is no significant correlation between genetic distance and geographical distance of D.stramonium population.The results of correlation analysis with environmental factors showed that the annual mean rainfall has a significant effect on the genetic diversity of D.stramonium.The invasion and spread of D.stramonium may not be related to natural diffusion,but rather to multiple intentional or unintentional introductions by human.The controlling human transmission and uprooting D.stramonium before flowering,pollination and fruit ripening may be the effective methods for preventing and controlling its invasion and spread.