摘要:宁夏自治区是我国受到土壤次生盐渍化危害的重点区域，然而对该地区盐碱化形成机制及影响因素的研究资料较少。在宁夏石嘴山地区采集土壤样本，采用基于16S rRNA的PCR-DGGE技术对不同深度土壤的细菌群落多样性和优势种群进行分析，以期从土壤生态角度探索该地盐渍化成因及改良措施。带谱相似性和UPGMA聚类结果表明，表层（D < 20 cm）土壤和底层（D > 80 cm）土壤样本中细菌菌群相似程度较高；而中间层（20 cm < D < 80 cm）土壤样本中细菌菌群相似程度很低。多样性指数分析显示，随着地层深度的增加，菌落的丰富度和多样性均趋于下降；而均匀程度变化幅度不大。对其中5个优势条带进行测序比对的结果表明，该地区土壤可识别优势细菌菌群为变形细菌门Proteobacteria和拟杆菌门Bacteroidetes，但大部分条带未可识别。结果表明该地区盐碱土壤中的细菌菌群多样性程度较高，且优势菌群不尽相同；土壤深度与细菌菌落多样性在一定程度上存在线性关系。为深入研究次生盐渍化土壤的形成机制以及影响因素提供理论参考。



Abstract:As a key area affected by secondary soil salinization in China, there is limited relevant research data on the formation mechanisms, as well as their influencing factors, in the Ningxia Autonomous Region. In this study, soil samples were collected at various soil depths in the Shizuishan area, Ningxia. A 16S rRNA-related PCR-DGGE technique was used to analyze bacterial diversity and dominant populations at different depths to explore the causes of salinization and its improvement measures from the perspective of soil ecology. Results from band similarity and UPGMA clustering indicated that the degree of bacterial diversity in the surface (D < 20 cm) and bottom (D > 80 cm) layers were similar and relatively high, whereas it was low in the middle layer (20 cm < D < 80 cm). The diversity indices analysis demonstrated that with increasing depth, the degree of richness and diversity tended to decline; whereas the degree of uniformity did not change considerably. Sequence comparison of five clones showed that the most predominant bacterial communities in this region were Proteobacteria and Bacteroidetes, whereas the remaining bands were not identified. The results of this study indicated that the degree of microbial diversity in saline-alkali soil in this area is very high, and the predominant bacterial flora is not the same. Generally, the bacterial diversity showed a linear relationship with depth, which is possibly related to the soil moisture content. However, more profound and in-depth data is needed to support this study. This study aimed to provide a theoretical reference for further in-depth study on secondary salinized soil formation mechanisms and their influencing factors.





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