Abstract: Allozyme analysis of Davidia involucrata var. vilmoriniana was carried out with 78 individuals in four populations by means of horizontal starch gel electrophoresis technique. Eleven enzyme systems and 21 loci were investigated. The results show that there is high genetic diversity in Davidia involucrata var. vilmoriniana. At population level, the percentages of loci polymorphic (P)are variable from 28.6%-47.6%.

Key words: Davidia

摘要： 基因分化系数FST=01928，说明光叶珙桐居群间分化小。各项指标表明光叶珙桐的遗传多样性水平较高，比原变种珙桐高，外部环境可能是影响珙桐分布格局的重要因素。昭通与宝兴的遗传多样性明显高于其他两个居群，遗传多样性保存较为完整，而处于分布区东、西两侧边缘(云南西北部和湖北五峰)遗传多样性则相对较低，推测四川盆地边缘山地是该种的遗传多样化中心，可能是在地质灾难中(如第四纪冰期)，光叶珙桐真正的避难所。分布区东西两侧的居群可能是从四川盆地边缘山地扩散而来。

关键词: 珙桐属, 等位酶, 遗传多样性, 生物地理