人工与自然恢复条件下地被层优势种大羽藓的遗传多样性比较

基于随机扩增多态性DNA(RAPD)方法比较了川西米亚罗地区3个人工云杉林样地和3个天然次生林样地大羽藓(Thuidium cym bifolium)种群的遗传多样性及分化程度。人工林种群的平均多态位点百分比(PPL)为12.7%,Ne i’s基因多样性(HE)为0.042,Shannon’s信息指数(S)为0.064,种群内遗传一致度(I)为0.952;天然次生林种群则依次为10.0%、0.027、0.043和0.960。人工林种群和天然次生林种群Gst分别为0.592和0.702,Fst分别为0.639和0.695;结合UPGMA聚类和PCA分析,发现种群间的基因交流极少。单因素方差分析显示,人工林下大羽藓种群的遗传多样性水平显著高于天然次生林下种群(p<0.05),表明在皆伐迹地上通过人工造林能有效地促进林下物种遗传多样性的恢复。

A Comparison of Genetic Diversity of the Ground Layer Dominant Species Thuidium cymbifolium in Planted and Naturally Regenerated Forests

Genetic diversity and differentiation of populations of Thuidium cymbifolium between 3 planted spruce stands(PSS) and 3 naturally regenerated stands(NRS) were compared using random amplified polymorphic DNA(RAPD) marker.For PSS and NRS,the average percentage of polymorphic loci(PPL=12.7%,10.0%),Nei's genetic diversity(HE = 0.042,0.027) and Shannon's information index(S=0.064,0.043) were revealed by POPGENE,respectively.The results of population differentiation among the populations from PSS(Gst=0.592,Fst=0.639) and NRS(Gst=0.702,Fst= 0.695),together with the results of UPGMA cluster analysis and of principal components analysis showed that gene flow between populations was limited.AMOVA revealed a significantly higher level of population genetic diversity existed in PSS than that in NRS,which indicated that artificial reforestation after forest clearcut was effective in promoting the recovery of genetic diversity of the recolonized moss species.