若尔盖高原湿地不同退化阶段的土壤细菌群落多样性

Soil bacterial community diversity under different stages of degradation in zoige wetland

采用传统分离培养和基于16S rDNA的变性梯度凝胶电泳(Denaturing gradient gel elec-trophoresis,DGGE)方法,研究了若尔盖高原湿地不同退化阶段土壤类型(泥炭土、沼泽土、草甸土、风沙土)和土壤深度(0-20 cm、20 cm-40 cm、40 cm-60 cm)中微生物的数量、细菌群落结构及其多样性。结果表明:微生物数量总体上不仅随着土壤类型的改变而减少(泥炭土>草甸土>沼泽土>风沙土),也随着土壤深度的增加而递减(0-20 cm>20 cm-40 cm>40 cm-60 cm)。细菌群落结构受土壤类型的影响比土壤深度大。细菌群落多样性大体上随土壤类型的变化而减少(泥炭土>风沙土>草甸土>沼泽土),而在土壤深度方面无明显的递变趋势。另外,微生物总数与土壤有机质、全氮和pH显著相关,而细菌群落多样性与土壤pH呈极显著负相关性。回收DGGE图谱中10个优势条带进行测序分析,结果显示,其中7个鉴定为γ-Proteobacteria(γ-变形菌纲),1个鉴定为α-Proteobacteria(α-变形菌纲),其余2个属于Bacteroidetes(拟杆菌门),说明Proteobacteria(变形菌门)为若尔盖湿地土壤中的优势细菌类群。

Both culture-dependent and culture-independent methods,denaturing gradient gel electropho-resis（DGGE） based on the sequence of 16S rDNA,were used to examine the microbial quantity,bacterial community structure and diversity in different soil types（Peat soil,Swamp soil,Meadow soil and Sandy soil） and soil detphs（0-20 cm,20 cm-40 cm and 40 cm-60 cm） under different stages of degradation in Zoige Wetland.Experimental results showed that total microbial quantity decreased with the soil types（Peat soilMeadow soilSwamp soilSandy soil） and declined with soil depths（0-20 cm20 cm-40 cm40 cm-60 cm）.Bacterial community structure was affected by soil type more primarily than by soil depth.Bacterial community diversity generally declined with soil types（Peat soilSandy soilMeadow soilSwamp soil）.However,no significant tendency was found for the soil depth.In ad-dition,the total microbial quantity was strongly correlated with organic matter,total nitrogen and pH,and bacterial community diversity exhibited significant negative correlation with pH.Ten bands were excised from the DGGE gel and re-amplified for 16S rDNA sequencing.Based on the sequencing re-sults,seven bands can be identified as related to γ-Proteobacteria,one close to α-Proteobacteria,and the other two belong to Bacteroidetes.These results provide evidence that Proteobacteria are the domain bacterial communities in the soil of Zoige Wetland.