青藏高原入侵杂草黄帚橐吾种群内与种群间的遗传变异研究(英文)  

Genetic variation within and among populations of Ligularia virgaurea (Asteraceae),an invasive weed in the grassland ecosystem of the Qinghai-Tibetan Plateau

作　　者：司庆文 吴桂丽[2] 杨慧玲 周党卫 

机构地区：[1]中国科学西北高原生物研究所高原生物进化与适应重点实验室,青海西宁810008 [2]兰州大学干旱与草地生态重点实验室,甘肃兰州730000

出　　处：《草业科学》2010年第6期77-87,共11页Pratacultural Science

基　　金：The Natural Science Foundation of China(3000012);the Chinese Academy of Science Innovation Program(0954051211,095406121)~~

摘　　要：外来入侵物种的遗传变异以及在此基础上建立的控制措施受到了广泛关注,但是,对本地产生杂草的遗传变异却研究较少。菊科中的黄帚橐吾主要依赖根状茎和种子进行繁殖,是青藏高原高山草地生态系统中的广布杂草。本研究利用RAPD随机扩增的DNA多态性研究该物种11个种群的遗传变异。结果表明,13个随机引物获得了81条可重复的扩增带,每个引物平均产生6.23条带,74.07%(61条)的带是多态的。种群中多态位点变化为19.45%～60.49%,He是0.1698±0.03,表明该物种具有中等程度的遗传多样性。种群间的RAPD表型(基因型)十分丰富,并且变异较大。进一步分析发现,总遗传变异的67.64%存在于种群间,而只有31.74%的变异分布在种群内。与起初认为该物种由于克隆繁殖导致的遗传多样性与遗传分化均较小的预期相反,发现了十分丰富的遗传变异和较高的遗传分化,这些遗传参数接近非克隆或非入侵物种的平均值。有性繁殖、长距离扩散以及可能的杂交渗入是导致该本地杂草具有不同于其他入侵杂草遗传结构的主要原因。The genetic mechanism and subsequent control of exotic invasive species have received extensive attention within recent years,but little attention has been paid to native weeds restricted to local ecosystems.Ligularia virgaurea is a clonal species of Asteraceae and reproduces asexually by underground rhizomes and sexually by seeds,which distributes throughout alpine meadows of the Qinghai-Tibetan Plateau.In the present study,random amplified polymorphic DNA（RAPD）markers were used to evaluate genetic variation and clonal diversity of 11 populations of Ligularia virgaurea.A total of 81 amplified bands were scored from the 13 RAPD primers,giving a mean of 6.23 amplified bands per primer,and 74.07%（61 bands）were found to be polymorphic bands（PPB）,indicating a remarkable level of genetic variation at the species levels.The percentage of polymorphic loci within population ranged from 19.45% to 60.49%,and the mean Nei gene diversity（He）was 0.169 8,indicating a moderate variation in the genetic diversity of L.virgarea.RAPD phenotypes（genotypes）among populations were highly rich and variable.Moreover,an analysis of molecular variance（AMOVA）showed that 67.64% of the total genetic variation was found among individuals within population,while 31.74% was between populations.Contrary to the initial assumption that this clonal weed has a low diversity and population differentiation,results suggested that both the genetic diversity and among-population differentiation of L.virgarea are high comparing to the average of the other non-clonal or non-invasive species.We proposed that the sexual recruitment and long-distance colonization characteristics,perhaps in combination with genetic introgression,are responsible for such a pattern of genetic structure in this local weed.

关 键 词：黄帚橐吾 RAPD 遗传变异 种群结构 青藏高原 

分 类 号：S451[农业科学—植物保护]