濒危植物缙云卫矛的酯酶和超氧化物歧化酶同工酶变异的数量分析

The numerical analysis of isozymic variation of the endangered species Euonymus chloranthoides

采用酶电泳手段 ,测定了重庆北碚特产的缙云卫矛 (Euonymuschloranthoides) 3个居群 3 6个个体功能叶片的酯酶 (Es)和超氧化物歧化酶 (SOD)的同工酶谱带 ,并进行二群体态数据编码 ,然后采用Sokal-Michener结合系数的加权平均法 (WPGMA)对各酶谱带相关数据进行聚类分析 ,并结合遗传杂合度 (He)、遗传相似性系数(I)、遗传距离 (D)等遗传分化度量指标的分析 结果表明 ,来自同一居群的个体 ,同工酶谱带相似性高、遗传杂合度小、遗传相似性系数大、遗传距离小 ;显示出居群内个体遗传分化小 ,而居群间的个体则相反 究其原因 。

The ES and SOD isozymic variation in leaves of 36 plants from 3 isol ated populations of E. chloranthoides, which are endenic to North Hot Spring o f Chongqing were studied with the electrophoretic technique. The isozyme bands of the two enzymes are scored to construct the two～state data matrix which is cac ulated by the Sokal～Michener association coefficients clustered by WPGMA. The genetic h et erozygosity (He)、 genetic identity (I), and genetic distance(D) interpretated f rom the isozyme bands were further caculated. Results indicate that indviduals f rom the same population show higher similarity in isozymic bands and higher gene tic homogeneity, while individuals from different populations posse rather high genetic dissimilarities. E. chloranthoides individuals show nonspecific dif ferent iation. Those 3 small populations may come from a big population formed long ag o . The selective pressure from environment during long evolutionary history make s E. chloranthiodes distributed as spatially isolated small populations which are endemic to North Hot Spring of Chongqing. Such special isolation largely prohib i ts the gene exchangs among individuals from different populations and the adapto d genetic variation to those micro～habitats are selected and remained in the ev o lutionary process, which makes the genetic differentiation among populations be c oming more obivious. The vegetative reproduction of the species lead to the hig her genetic homogeneity among individuals from the same population.