Fine-scale spatial genetic structure in predominantly selfing plants with limited seed dispersal： a rule or exception？  

作　　者：Sergei Volis Danara Ormanbekova Irina Shulgina 

机构地区：[1]Key Laboratory of Biodiversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China [2]Department of Agricultural Sciences, University of Bologna, Via Zamboni, 33, 40126 Bologna, Italy

出　　处：《植物分类与资源学报》2016年第2期75-81,共7页Plant Diversity

摘　　要：Gene flow at a fine scale is still poorly understood despite its recognized importance for plant population demographic and genetic processes.We tested the hypothesis that intensity of gene flow will be lower and strength of spatial genetic structure(SGS) will be higher in more peripheral populations because of lower population density.The study was performed on the predominantly selfing Avena sterilis and included:(1) direct measurement of dispersal in a controlled environment;and(2) analyses of SGS in three natural populations,sampled in linear transects at fixed increasing inter-plant distances.We found that in A.sterilis major seed dispersal is by gravity in close(less than 2 m) vicinity of the mother plant,with a minor additional effect of wind.Analysis of SGS with six nuclear SSRs revealed a significant autocorrelation for the distance class of 1 m only in the most peripheral desert population,while in the two core populations with Mediterranean conditions,no genetic structure was found.Our results support the hypothesis that intensity of SGS increases from the species core to periphery as a result of decreased within-population gene flow related to low plant density.Our findings also show that predominant self-pollination and highly localized seed dispersal lead to SGS at a very fine scale,but only if plant density is not too high.Gene flow at a fine scale is still poorly understood despite its recognized importance for plant population demographic and genetic processes. We tested the hypothesis that intensity of gene flow will be lower and strength of spatial genetic structure （SGS） will be higher in more peripheral populations because of lower population density. The study was performed on the predominantly selfing Arena sterilis and included： （1） direct measurement of dispersal in a controlled environment; and （2） analyses of SGS in three natural populations, sampled in linear transects at fixed increasing inter-plant distances. We found that in A.sterilis major seed dispersal is by gravity in close （less than 2 m） vicinity of the mother plant, with a minor additional effect of wind. Analysis of SGS with six nuclear SSRs revealed a significant autoeon＇elation for the distance class of 1 m only in the most peripheral desert population, while in the two core populations with Mediterranean conditions, no genetic structure was found. Our results support the hypothesis that intensity of SGS increases from the species core to periphery as a result of decreased within-population gene flow related to low plant density. Our findings also show that predominant self-pollination and highly localized seed dispersal lead to SGS at a very fine scale, but onlv if plant density is not too high.

关 键 词：Gene flow Neighborhood size Spatial genetic structure Range position Core PERIPHERY 

分 类 号：Q948[生物学—植物学]