生物多样性 ›› 2006, Vol. 14 ›› Issue (5): 410-420.  DOI: 10.1360/biodiv.060104

• 论文 • 上一篇    下一篇

樟科濒危植物思茅木姜子遗传多样性的ISSR分析

陈俊秋1, 2,慈秀芹1, 2,李巧明1,李捷1*   

  1. 1 (中国科学院西双版纳热带植物园昆明分部植物系统与保护生物学实验室, 昆明 650223)
    2 (中国科学院研究生院, 北京 100049)
  • 收稿日期:2006-05-25 修回日期:2006-07-24 出版日期:2006-09-20 发布日期:2006-09-20

Genetic diversity of Litsea szemaois, an endangered species endemic to China, detected by inter-simple sequence repeat (ISSR)

Junqiu Chen1, 2,Xiuqin Ci1, 2, Qiaoming Li1, Jie Li1*   

  1. 1 Laboratory of Plant Phylogenetics and Conservation Biology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223
    2 The Graduate School of the Chinese Academy of Sciences, Beijing 100049
  • Received:2006-05-25 Revised:2006-07-24 Online:2006-09-20 Published:2006-09-20

摘要: 本文采用ISSR标记对中国特有且仅在云南南部狭域分布的樟科濒危植物思茅木姜子(Litsea szemaois)现存8个居群的遗传多样性进行了研究。从96条引物中筛选出了10条, 对103个个体进行了扩增, 共扩增出77条条带, 其中多态性条带为67条。分析结果表明: (1) 思茅木姜子的遗传多样性水平很高。在物种水平上,多态位点百分率PPB =87.01%, 平均每个位点的有效等位基因数Ne=1.4006, Nei’s基因多样度指数H=0.2466, Shannon多样性信息指数Hsp=0.3826; 在居群水平上,PPB=37.99%, Ne=1.2500, H=0.1418, Shannon多样性信息指数Hpop=0.2088。(2) 居群间的遗传分化较低。基于Nei’s遗传多样性分析得出的居群间遗传分化系数Gst=0.3700; Shannon’s居群分化系数((Hsp–Hpop)/Hsp)为0.45。AMOVA分析显示: 思茅木姜子的遗传变异主要存在于居群内, 占总变异的72.99%, 居群间的遗传变异占27.01%, 表明思茅木姜子属于异交种。(3)两两居群间的Nei’s遗传一致度(I)的范围为0.8233–0.9761。经Mantel检测, 居群间的遗传距离和地理距离之间不存在显著的正相关关系(r=0.0925, P= 0.6931)。我们推断人类活动的干扰和生境的片断化是导致思茅木姜子濒危现状的主要因素。考虑到目前其遗传多样性水平虽然很高, 但各居群个体数量很少, 因此应该对思茅木姜子各居群的所有个体实施及时的就地保护; 而遗传变异大部分存在于居群内的个体间, 所以在迁地保护时应在各居群内大量采样。

关键词: 竞争, Neocheiropteris palmatopedata, 生长特性, 孢子萌发

AbstractLitsea szemaois is a critically endangered species endemic to southern Yunnan,China. We assessed the genetic variability within and among eight extant populations of this species using ISSR PCR (10 primers). We expected a low genetic diversity level, but our results revealed an extraordinarily high level of specific genetic diversity (at species level: percentage of polymorphic loci PPB=87.01%, effective number of alleles Ne=1.4006, Nei’s (1973) gene diversity H=0.2466, and Shannon’s Information index Hsp=0.3826; at population level: PPB=37.99%, Ne=1.2500, Nei’s (1973) gene diversity H=0.1418, and Shannon’s Informa-tion index Hpop=0.2088. The diferences among populations in levels of genetic diversity were very obvious, with the highest level (PPB=72.73%) in Mandian population and the lowest level (PPB=18.18%) in Jinghong population. A low level of genetic differentiation among populations was detected based on Nei’s genetic di-versity analysis (37%), Shannon’s diversity index (45%), and AMOVA (27.01%). This may result from out-breeding. Pairwise genetic identity (I) values among populations ranged from 0.8233 to 0.9761. There was no correlation between genetic and geographic distance among the populations studied. The influence of human activity and forest fragmentation may play a prominent role in creating this species’s current endan-gered status.