生物多样性 ›› 2002, Vol. 10 ›› Issue (1): 1-6.DOI: 10.17520/biods.2002001

• 论文 •    下一篇

夏腊梅的遗传多样性及其保护

周世良,叶文国   

  1. 1 (中国科学院植物研究所系统与进化植物学开放实验室,  北京 100093)
    2 (浙江省天台县林业局,  浙江天台 317200)
  • 收稿日期:2001-09-11 修回日期:2001-12-24 出版日期:2002-02-20 发布日期:2002-02-20
  • 通讯作者: 周世良

The genetic diversity and conservation of Sinocalycanthus chinensis

ZHOU Shi-Liang,YE Wen-Guo   

  1. 1 Laboratory of Systematic and Evolutionary Botany , Institute of Botany , Chinese Academy of Sciences , Beijing 100093
    2 Forestry Bureau of Tiantai County , Tiantai , Zhejiang 317200
  • Received:2001-09-11 Revised:2001-12-24 Online:2002-02-20 Published:2002-02-20
  • Contact: ZHOU ShiLiang

摘要: 夏腊梅(Sinocalycanthus chinensis)是国家二级保护的珍稀濒危植物,夏腊梅属(Sinocalycanthus)的唯一代表,仅间断分布于我国浙江省临安市和天台县极狭小的范围内。本文采用等位酶淀粉凝胶电泳技术对采自上述两地的天然居群和天目山自然保护区引种的人工居群的553个样品进行了遗传多样性检测,并与浙江腊梅(Chimonanthus zhejiangensis)作对比。检测结果表明夏腊梅的遗传多样性极低。从14个酶系统检测到的23个位点看,在物种水平上每位点的等位基因平均数(A)为1.2,多态位点(P)占21.7%,观察杂合度(Ho)为0.010。在居群水平上,A=1.0~1.1,P=0~13.0%,Ho=0~0.014。而对照种浙江腊梅杭州植物园人工居群的上述指标分别为A=1.5,P=39.1%,Ho=0.071。夏腊梅的2个自然居群之间在Mdh-4、Pgd-3Sod-1发生显著的分化,但居群内亚居群间几乎没有分化。在天目山自然保护区引种的人工居群中没有检测到多态性,说明作为迁地保护的天目山自然保护区人工居群并没能有效地保护夏腊梅的遗传多样性。由于目前自然保护区基本上采用不加人为干预的经营方式,划入龙塘山自然保护区内的自然亚居群会因为森林的自然演替而灭绝。所以,自然保护区目前的这种经营方式不适合对夏腊梅的保护。夏腊梅的例子说明,当我们对保护对象的生物学特性缺乏认识时,我们既不知道应该保护什么,也不知道应该如何保护。

Abstract: Sinocalycanthus chinensis is the only representative in the genus Sinocalycanthus and an endangered species restricted in small areas of Lin′an City and Tiantai County, Zhejiang Province. Currently only two natural populations remain: the larger one is found in Lin′an City, consisting of seven subpopulations with nearly 1731 990 individuals in total; the smaller one is located at Tiantai County where 2000 individuals exist. The genetic diversity of the two natural populations and one recently introduced population at Tianmushan Natural Reserve, Lin′an City, Zhejiang Province, was assessed using allozyme markers. A population of Chimonanthus zhejiangensis from Hangzhou Botanical Gardens, Hangzhou City, Zhejiang Province, was included in this study for the purpose of comparison. The genetic diversity of S. chinensis turned out to be extremely low. Only five of 23 loci from 14 enzymes assayed were polymorphic. The polymorphism was largely due to alternative fixation of alleles on Mdh-4, Pgd-3 and Sod-1, and two mutations (Gpi-1 and Gpi-2) on one individual out of 553 in total. At species level the mean number of alleles per locus ( A ) was 1.2, the percentage of polymorphic loci ( P ) was 21.7%, and the observed heterozygosity ( Ho ) was 0.010. At population level the estimates were A =1.0~1.1, P =0~13.0%, and Ho =0~0.014. In contrast, the estimates for C. zhejiangensis were much higher ( A=1.5, P=39.1%, Ho =0.071) though there were only 16 individuals tested. Since no genetic variation was detected in the introduced population of S. chinensis at Tianmushan Natural Reserve, the introduction of the plant should not be considered as a success of ex situ conservation of the endangered species. Moreover, the range of subpopulations within Longtangshan National Natural Reserve is diminishing due to the growth of evergreen forests. So far no measures have been taken to stop this subpopulation from shrinking because of lack of knowledge of ecology and biology of the plant. This study exemplifies that we are unable to conduct in situ conservation and to practise ex situ conservation properly if we have no knowledge of the biology of the species we intend to conserve.