中文摘要：

采用水平淀粉凝胶电泳技术,对采自山东、山西、河北、辽宁4个省的6个花楸树天然群体的种子样本进行分析,所用同工酶多态位点分别为Pgm-1,Pgm-2,Pgm-3,Pgi-1,Pgi-2,Pgd-1,Pgd-2,Pgd-3,利用多位点异交率估算程序（MLT）估算6个群体的异交率。结果表明：花楸树各群体的花粉库与胚珠库中,各位点基因的配子比例差异不显著,基本处于平衡状态;各群体多位点异交率均在0.981以上,多位点异交率与单位点异交率平均值的差值（tm-ts）显示出花楸树各群体都存在轻度的自交或近交,说明花楸树属于混合交配类型,表现为高度异交。根据电泳数据计算的近交衰退δ=1,表明花楸树天然群体的近交衰退很大。

英文摘要：

Genotypes of six natural populations of Sorbus pohuashanensis were studied using horizontal starch gel electrophoresis and the mating system was analysed at eight loci（Pgm-1,Pgm-2,Pgm-3,Pgi-1,Pgi-2,Pgd-1,Pgd-2,Pgd-3）using MLT software.Results indicated that the gametes ratio of each locus in pollen and ovule pools was mainly in balance in the six populations.The multi-locus outcrossing rates were above 0.981.The margin of multi-locus minus single-locus outcrossing rate（tm-ts）showed that slight inbreeding existed in the populations.Therefore,the mating system of S.pohuashanensis in the 6 populations is predominantly outcrossing.The inferred inbreeding depression（δ=1）from the electrophoresis data indicated severe inbreeding depression in the natural populations of the species.