8个栽培水杉居群遗传多样性的等位酶分析  

Allozyme analysis of genetic diversity in eight cultivated populations of Metasequoia glyptostroboides

作　　者：李晓东[1] 杨佳[1] 史全芬[1] 李建强[1] 

机构地区：[1]中国科学院武汉植物园,武汉430074

出　　处：《生物多样性》2005年第2期97-104,共8页Biodiversity Science

基　　金：国家重点基础研究发展规划项目(G2000046806);中国科学院方向性项目 (KSCX2 -SW-104 );中国科学院武汉植物园资助项目(01035123; 01035107)

摘　　要：水杉(Metasequoiaglyptostroboides)是我国特有的活化石植物,有 50多年的栽培历史。栽培水杉在多大程度上涵盖了野生水杉的遗传多样性,是评价水杉保育策略成功与否的关键所在。为了评估水杉栽培居群的遗传变异水平,作者采用超薄平板微型聚丙烯酰胺等电聚焦电泳方法对水杉的 8个人工栽培居群的等位酶变异和遗传多样性进行了研究。对 9个酶系统 23个酶位点的检测结果表明: 有 8个酶位点的等位基因频率分布差异非常显著,在 2个居群中存在稀有等位基因;平均等位基因数A=1.375,多态位点百分率PPL=33.15,平均预期杂合度He=0. 161。与孑遗居群相比, 栽培水杉的遗传变异水平偏低,表明栽培居群的遗传多样性不能完全涵盖孑遗居群。将采于潜江的 9个丛枝水杉(Metasequoiaglyptostroboidesvar. caespitosa)样品与分别采自潜江、武汉和上海的各 9个水杉样品的等位酶资料进行了UPGMA单株聚类分析,并将丛枝水杉作为一个居群与其他 8个水杉居群作UPGMA聚类分析,其结果不支持将丛枝水杉作为水杉的一个变种的分类处理。Metasequoia glyptostroboides , a “living fossil” plant endemic to China, has been cultivated for more than fifty years. In order to evaluate to what extent the cultivated populations have conserved the genetic variation of the wild ones, we estimated the allozymic variation and genetic diversity in eight cultivated populations using isoelectric focusing in thin layer polyacrylamide slab gels. Twenty three loci of nine enzyme systems were detected and used for estimating population genetic diversity. Obvious difference in allele frequency was observed in eight of 23 loci, and rare alleles were detected in two populations. Genetic variability of cultivated M. glyptostroboides was low ( PPL = 33.15%, A = 1.375, H e = 0.161), and the genetic diversity was lower in cultivated populations than in relict ones, indicating that genetic diversity of cultivated populations could not completely cover that of relict M. glyptostroboides . Based on the allozymic variation data, a UPGMA dendrogram was constructed, comprising nine individuals of Metasequoia glyptostroboides var. caespitosa from Qianjiang of Hubei Province and nine individuals from each of three M. glyptostroboides populations, i.e., Qianjiang, Wuhan and Shanghai. Moreover, the genetic relationships among the population of M. glyptostroboides var. caespitosa and eight populations of M. glyptostroboides were analyzed. These analysis suggested that Metasequoia glyptostroboides var. caespitosa should not be treated as a variety of M. glyptostroboides .

关 键 词：遗传多样性 等位酶分析 水杉 UPGMA聚类分析 平均等位基因数 栽培居群 遗传变异 活化石植物 等位酶变异 聚丙烯酰胺 栽培历史 保育策略 电泳方法 等电聚焦 频率分布 检测结果 多态位点 分类处理 薄平板 酶系统 百分率 杂合度 

分 类 号：S718[农业科学—林学]