中文摘要：

应用RAPD技术研究了祁连山中段中国沙棘（Hippophae rhamnoides ssp．sinensis）4个居群和1个对照居群的遗传多样性水平，探讨中国沙棘边缘居群的遗传变异以及天然屏障祁连山对中国沙棘居群遗传结构的影响。结果显示，祁连山地区中国沙棘居群水平的Nei＇基因多样度（h）和Shannon多态信息指数（I）分别为0．2070和0．2974，基因分化系数（Gst）为0．3193，均高于中国沙棘整个分布区的平均值，表明该地中国沙棘边缘居群遗传多样性水平及居群间的遗传分化都有增加的趋势；居群间每代迁移数（Nm=1．0659）显著低于异交风媒植物（Nm=5．380），表明祁连山的隔离对中国沙棘居群间的基因交流有限制作用，造成了该地中国沙棘边缘居群间较高的遗传分化。

英文摘要：

The genetic diversities of four Hippophae rhamnoides ssp. sinensis populations and one control population in the middle part of Qilianshan Mountain were examined by RAPD to explore the effects of the genetic variations in marginal H. rharnnoides ssp. sinensis populations and Qilianshan Mountain as a natural segregating barrier on genetic structures of H. rharnnoides ssp. sinensis populations. The results showed that in H. rharnnoides ssp. sinensis populations of Qilianshan Mountain,Nei＇ gene diversity （h） and Shannon index （I） and the coefficient of genetic differentiation among populations were respectively 0. 207 0, 0. 297 4 and 0. 319 3,all higher than that in the whole area covered by H. rharnnoides ssp. sinensis populations,which indicated that in the region in question,the genetic diversity in marginal H. rharnnoides ssp. sinensis populations and the genetic differentiation among the populations tended to increase ;The number of migration per generation （Nrn = 1.0659） among the populations was significantly lower than that （Nrn= 5.380） among the populations of wind-pollinated outcross plants,which showed that as a segregating barrier,Qilianshan Mountain limited the gene exchanges among H. rharnnoides ssp. sinensis populations thereby resulting in high genetic differentiation among marginal H. rharnnoides ssp. sinensis populations in the region in question.