生物多样性 ›› 2012, Vol. 20 ›› Issue (4): 460-469.DOI: 10.3724/SP.J.1003.2012.10011

• 研究报告 • 上一篇    下一篇

黄梅秤锤树孤立居群的遗传多样性及其小尺度空间遗传结构

阮咏梅1,2, 张金菊3, 姚小洪1, 叶其刚1*   

  1. 1中国科学院武汉植物园种质创新与特色农业重点实验室, 武汉 430074
    2中国科学院研究生院, 北京 100049
    3江西师范大学生命科学学院, 南昌 330022
  • 收稿日期:2012-01-12 修回日期:2012-04-05 出版日期:2012-07-20 发布日期:2012-09-12
  • 通讯作者: 叶其刚
  • 基金资助:

    狭果秤锤树片断化居群遗传多样性的维持机制与保育策略

Genetic diversity and fine-scale spatial genetic structure of different lifehistory stages in a small, isolated population of Sinojackia huangmeiensis (Styracaceae)

Yongmei Ruan1,2, Jinju Zhang3, Xiaohong Yao1, Qigang Ye1*   

  1. 1Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Science, Wuhan 430074

    2Graduate University of the Chinese Academy of Sciences, Beijing 100049

    3College of Life Sciences, Jiangxi Normal University, Nanchang 330022
  • Received:2012-01-12 Revised:2012-04-05 Online:2012-07-20 Published:2012-09-12
  • Contact: Qigang Ye

摘要: 研究濒危植物片断化孤立居群不同年龄阶段植株的遗传多样性和小尺度空间遗传结构有助于认识残存居群动态和制订保育策略。本研究选取黄梅秤锤树(Sinojackia huangmeiensis)的一个片断化孤立居群(面积160 m × 80 m)为研究对象, 对居群内60株成年个体、175株幼树和198株幼苗全部定位, 采用8个微卫星位点检测了居群内不同生活史阶段植株的遗传多样性、空间遗传结构, 并分析了花粉和种子传播距离和式样。结果表明, 黄梅秤锤树居群3种不同年龄阶段植株的遗传多样性之间无显著差异; 居群出现显著的杂合子缺失, 可能是由近交造成的; 在10 m以内成年个体、幼树和幼苗植株均呈现出显著的空间遗传结构, 说明种子扩散限制于成年母树周边; 种子和花粉传播的平均距离分别为9.07 ± 13.38和23.81 ± 23.60 m, 且花粉和种子传播式样均呈“L”型分布; 种子雨重叠少、有限的基因流、自疏以及近亲繁殖是造成各年龄阶段出现空间遗传结构的主要原因。本研究结果启示, 在采集秤锤树迁地保护材料时个体间距离应超过10 m, 以降低采样个体的遗传相似性; 同时在就地保护过程中需要人为促进基因流和加强幼苗管理, 以降低近交风险。

Abstract: Knowledge of genetic diversity and fine-scale spatial genetic structure (SGS) at different age stages of small isolated populations is important for understanding population dynamics and developing effective conservation measures for fragmented populations. In this study, we used a small, isolated population of Sinojackia huangmeiensi as a case study to investigate the change in the levels of genetic diversity and SGS at different age stages. We mapped and genotyped 60 adults,175 saplings, 198 seedlings using eight microsatellite markers to detect the genetic diversity, SGS and pollen and seed dispersal patterns in a 80 m × 160 m transect located in an original secondary forest surrounded by farmlands. No significant differences in genetic diversity were found among the three life stages, and a significant heterozygote deficiency in the population may result from substantial biparental inbreeding. We found significant fine-scale spatial structure at different age stages within 10 m, suggesting that seed dispersal mainly occurred near a mother tree. Seed dispersal distance and pollen dispersal distance were 9.07±13.38 and 23.81±23.60 m, respectively, and ‘L’ shaped curves were observed in both pollen dispersal and seed dispersal patterns. The spatial distribution of the different age stages is most likely the result of little overlap in seed rain, self-thinning, biparental inbreeding and limited gene flow. Our results have important implications for conservation of extant population of S. huangmeiensis. Measures for promoting pollen flow and increasing survival rate of seedlings should be considered for in situ conservation. The presence of SGS in this fragmented population implies that seeds for ex situ conservation should be collected from trees at least 10 m apart to reduce genetic similarity between neighboring individuals.