半日花属片段化居群的遗传现状及保护启示

Genetic Status and Conservation Implications of Fragmented Populations of Helianthemum

利用ITS序列及叶绿体微卫星对我国西北荒漠半日花属所有自然居群进行遗传结构分析。研究结果表明:半日花属新疆地区的居群与内蒙古地区的居群之间发生了显著的遗传分化;在各自地区内,居群间也发生了显著的遗传分化。分析其遗传分化的原因可知:早更新世气候变化使半日花属两地区间居群呈间断化分布,地区间基因流中断,导致地区间的遗传分化;半日花产种率低,居群生境呈破碎化,存在多重地理障碍,自身传播能力有限,限制地区内居群间基因流;半日花属居群规模很小,小居群的遗传漂变与近交效应加剧地区内居群间的遗传分化。根据研究结果,提出加大宣传力度,对天然居群进行人工复壮,构建核心种质资源等保护建议。

This paper investigated the genetic structure across the whole distribution range of Helianthemum in northwestern desert of China using ITS sequence and chloroplast SSRs.The results showed that there was strong genetic divergence between Xinjiang region and Inner Mongolia region in Helianthemum;there was a significant genetic divergence between the populations in Xinjiang regionand Inner Mongolia region respectively.This paper speculated that the climate change during the early Pleistocene resulted in the discontinuous distribution of the populations and the interruption of gene flow,leading to genetic divergence between the two regions;the low seed production rate,fragmented habitat,multiple geographical barriers and limited self transmission capacity limited gene flow among populations;the genetic drift and inbreeding effect of small populations aggravated the genetic divergence among populations in the region.