缺齿蓑藓(Macromitrium gymnostomum)的形态和遗传变异及其地理因素分析

Genetic and morphological variation patterns of Macromitrium gymnostomum and their geographical backgrounds

缺齿蓑藓(Macromitrium gymnostomum Sull.&Lesq.)广布于我国东南部,形态变异较大,与近缘种关系模糊。为了正确鉴定缺齿蓑藓形态变异范围,以及形态、遗传和地理因素三者的关系,对缺齿蓑藓11个地理居群106个样本配子体的13个形态性状进行了测定。结果显示,根据形态数据可将106份样本聚类成8个形态组。用13对ISSR引物获得了150个位点,其中148个为多态位点,多态位点百分率为98.67%; Nei's基因多样性在居群内占62.22%,在居群间占37.78%;居群间基因流(Nm)为0.8235,遗传分化指数(Gst)为0.3778。11个地理居群的遗传距离在0.0873～0.2363之间,平均为0.1508。基于148个多态位点可将106份样本聚成8个遗传组。缺齿蓑藓的形态变异有一定的遗传背景(r=0.159,n=106,P <0.2),地理因素对形态(r=0.309,n=106,P <0.01)和遗传(r=0.251,n=106,P <0.01)分化产生了极显著影响。

Macromitrium gymnostomum Sull.&Lesq.is widely distributed in southeastern China,with high morphological variation and confusion with allied species.To correctly define the morphological variation range of M.gymnostomum and the relationship among morphological patterns,genetics,and geographical factors,13 morphological traits based on 106 samples from 11 populations of M.gymnostomum were determined.The 106 samples were preliminarily clustered into eight groups based on the 13 morphological traits.Using 13 pairs of ISSR primers,150 ISSR bands were amplified,of which 148(98.67%)were polymorphic.The intra-population genetic diversity accounted for 62.22%,whereas the inter-population value accounted for 37.78%.Gene flow existed among populations,with a Nm index of 0.8235 and a Gst of 0.3778.The genetic distance among the 11 geographical populations varied from 0.0873 to 0.2363,with an average of 0.1508.Based on information from the 148 loci,the 106 samples were clustered into eight groups.The morphological variations of M.gymnostomum were genetically controlled to an extent(r=0.159,n=106,P<0.2).Distinctive geographical influences on morphological(r=0.309,n=106,P<0.01)and genetic differentiation(r=0.251,n=106,P<0.01)were also found.