Biodiv Sci ›› 2012, Vol. 20 ›› Issue (4): 460-469.DOI: 10.3724/SP.J.1003.2012.10011

• Original Papers • Previous Articles     Next Articles

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

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.