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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 variation of invasive alien species and the control measures established on this basis have drawn much attention. However, there are few studies on the genetic variation of locally weeds generated. The yellow broomweed in Compositae mainly relies on rhizomes and seeds for reproduction, and is a widely distributed weed in the alpine meadow ecosystem in the Tibetan Plateau. In this study, RAPD random amplified polymorphic DNA was used to study the genetic variation of 11 species in this species. The results showed that 81 random amplified bands were obtained from 13 random primers, with an average of 6.23 bands per primer and 74.07% (61 bands) of polymorphic bands. The polymorphic loci in the population varied from 19.45% to 60.49% and He was 0.1698 ± 0.03, indicating that the species had a moderate degree of genetic diversity. The RAPD phenotype (genotype) among the populations is very rich and varies greatly. Further analysis showed that 67.64% of the total genetic variation existed among the populations, while only 31.74% of the variation was within the population. In contrast to what was initially thought to be due to the fact that the species’s genetic diversity due to clonal propagation was less than the expected genetic differentiation, a very rich genetic variation and a high genetic differentiation were found that approach the average of non-clonal or non-invasive species . Sexual reproduction, long-distance dispersal and possible hybridization infiltration are the main causes of this local weed having a different genetic structure than other invasive weeds.