【摘要】 采用等位酶淀粉凝胶电泳技术对西藏雅鲁藏布江中游砂生槐 (Sophoramoorcroftiana) 10个天然居群的遗传多样性进行了研究。 13个酶系统 2 4个酶位点 ( 46个等位基因 )的检测结果表明 ,砂生槐具较低的遗传变异水平。居群水平上的遗传多样性指标分别为 :多态位点百分率Pp =2 5 .0 %～ 37.5 % ,等位基因平均数Ap=1.3～ 1.7,平均期望杂合度Hep=0 .112～ 0 .16 9;种水平上的遗传多样性 (Ps=37.5 % ,As=1.9,Hes=0 .171)低于长寿命木本被子植物的平均值 (Ps=5 9.5 % ,As=2 .10 ,Hes=0 .183)。居群遗传结构的分析显示 ,10个居群中随机交配的偏差为FIS=- 0 .0 0 71,表明砂生槐在居群水平上存在轻微的杂合子过量现象 ,偏离了Hardy Weinberg平衡 ;FST=0 .1748,表明砂生槐是居群间分化较大的一类多年生木本植物 ,主要原因是环境恶化和人类活动干扰 (过度砍伐、放牧等 )导致其生境片断化 ,从而影响了居群间基因交流而造成基因流水平较低 (Nm =1.180 2 )。砂生槐高海拔居群H2 (谢通门 )、H31(江当 1)、H32 (江当 2 )、H5 (朗塞岭 )包含着绝大部分等位基因 ,显示了相对较高的遗传多样性水平 ,应加以保护和管理 ,作为砂生槐种质资源就地保存的基地。更多还原

【Abstract】 The genetic diversity of ten populations of Sophora moorcroftiana in the middle reaches of the Yarlung Zangbo River, Tibet, China was assessed using allozyme analysis by horizontal sliceable starch gel electrophoresis. Twenty four loci (46 alleles) of 13 enzyme systems demonstrate low levels of genetic variation within populations, with the value of P p=25.0%～37.5%, A p=1.3～1.7 and H ep=0.112～0.169. At the species level, the genetic diversity of S. moocroftiana (P s=37.5%, A s=1.9, H es=0.171) was lower than the mean value of angiosperms of long-lived woody species (P s=59.5%, A s=2.10, H es= 0.183). Wright′s F statistics analysis indicated that F IS, a measure of the deviation from random mating within the 10 populations, was -0.0071, suggesting deviation from Hardy-Weinberg equilibrium and a slight heteroygote excess in some populations. The higher level of differentiation (F ST=0.1748) among populations than those of other long-lived woody plants may result from habitat fragmentation and low levels of gene flow (Nm=1.1802) caused by environmental deterioration and human disturbance, including over-felling and over-grazing. It was worth noting that populations H2 (Xietongmen), H31 (Jiangdang1), H32 (Jiangdang2), and H5 (Langsailing) harbored the majority of alleles and had high levels of genetic diversity, suggesting that these populations in particular should be conserved in situ.更多还原