华山新麦草自然居群沿海拔梯度的遗传分化

华山新麦草为我国特有种 ,仅分布于陕西华山 ,是国家一级珍稀濒危植物和急需保护的农作物野生亲缘种。应用 RAPD技术 ,选取 8条引物对华山新麦草自然分布区的 3个山峪(种群 ) 1 1个样方 (亚居群 ) 79个华山新麦草个体的总 DNA进行随机扩增 ,共得到 65个RAPD位点。统计分析表明 ,在华山的 3个山峪 (居群 )中 ,黄埔峪 (居群 )与其它 2个山峪 (居群 )发生较显著的遗传分化 ;华山峪 6个亚居群的个体平均 RAPD位点数有随海拔的升高而下降的趋势 ;6个亚居群间的相似性系数也有随海拔的升高而下降的趋势 ;华山峪的高海拔亚居群和低海拔亚居群间表现出明显差异。主成分分析结果进一步证明了黄埔峪居群与华山峪居群和仙峪居群间、以及华山峪的高海拔亚居群与低海拔亚居群间已发生一定程度的分化。研究结果暗示海拔差异是导致华山新麦草自然居群遗传分化的主要因素 ,海拔差异造成的有限的基因流可能才是影响居群和亚居群遗传分化的主要因子 ,而亚居群内遗传变异程度则与该亚居群的所处的特定生境有关

Population differentiation of Psathyrostachys huashanina along an altitudinal gradient detected by random amplified polymorphic DNA

Psathyrostaotys huashanica Keng is a unique plant species of China and it distributes in Mountain Hua of Shaanxi Province only.It is the first class rare and endangered plant of the nation and need to be protected as a close relationship species to wheat.Presentation of here is the results from a study of 11 sub populations of Psathyrostachys huashanica sampled in 3 natural valleys of Mountain Hua along an altitudial gradient by means of random amplified polymorphic DNA.The statistical analysis revealed mean RAPD products per individual as well as similarity coefficient among sub populations decreased with the increase of altitude.In three valleys of Mountain Hua,cluster analysis showed a significant genetic differentiation resided between Huangpuyu population and the other two populations;additionally, a similar significant genetic difference was observed between sub populations at higher elevation and those at lower elevation in Huashanyu.The research results imply altitude function as a major selective force of genetic differentiation for natural population of Psathyrostachys huashanica .The restricted gene flow resulted from difference of altitude probably is the major factor influencing genetic differentiation of populations and sub populations.The level of genetic differentiation within sub populations relates to special ecological situation of its microhabitat.