The responses of soil microbial taxonomic diversity on vegetation communities and seasons in karst area
The responses of soil microbial taxonomic diversity on vegetation communities and seasons in karst area
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作者：
H. Xun
摘 要：以环江县土壤微生物分类多样性随不同植被和季节响应的假设为基础，对草丛（T）、灌木（S）、次生林（SF）和原始林（PF）4个演替群落进行了检验。提取土壤微生物总DNA，扩增细菌16S和真菌18S rDNA，并通过变性梯度凝胶进行指纹图谱分析。与土壤细菌群落相反，土壤真菌群落表现出明显的优势系统型，但在演替过程中不具有连续性。植被对土壤微生物多样性的香农指数（分别为p0.05、p0.001）有显着影响，但在演替过程中没有显着趋势。细菌和真菌多样性也受季节影响显着。细菌多样性变化(分别为p0.001,p0.001),除SF和PF土壤外,T土中的微生物多样性变化(p0.01)均存在,同时,植被与季节之间也存在一定的交互作用。T土中微生物分类多样性存在显着的季节变化(p0.01),而SF和PF土壤中则未检测到。细菌与细菌之间存在显着正相关。土壤微生物分类多样性随着植被演替而趋于稳定，在喀斯特地区退化生态系统恢复初期，土壤中存在大量但不稳定的微生物多样性。
The hypotheses that soil microbial taxonomic diversity responds with different vegetations and seasons,four successional communities:Tussock(T),shrub(S),secondary forest(SF)and primary forest(PF),were tested in Huanjiang county,southwest China.The total soil microbial DNA was extracted,following the amplification of bacterial 16S and fungal 18S rDNA,and get fingerprinting by denaturing gradient gel electrophoresis(DGGE)in order to determine for these communities.In reverse with the soil bacterial communities,the soil fungal ones presented obviously dominant phylotypes but no continuity along successional ongoing.Significant effects of vegetation on soil microbial diversity measured by Shannon index(p0.05,p0.001,respectively),but no prominent trends along successional process,were examined.Bacterial and fungal diversity also significantly affected by seasonal exchanges(p0.001,p0.001,respectively),further more,these shifts(p0.01)of diversity in T soil other than in SF and PF soils were observed.Meanwhile,there exist some interaction effects between the vegetation and the season.Significant seasonal shifts(p0.01)in microbial taxonomic diversity in T soil,but not SF and PF soils were detected.Significant positive correlations were found between bacterial and fungal taxonomic diversities.Soil microbial taxonomic diversity gets steadier along vegetation succession and,in early restoration stage of degradation ecosystem in karst area,large but unstable microbial diversity exists in soils.