鄂尔多斯台地盐沼滩地微生物群落与土壤条件分析

Microbial communities and soil conditions in the salt marshes of Ordos platform

【背景】我国北方内陆区与平原区土地盐碱化问题严重,针对微生物如何在极端盐碱地植被演替过程中发挥作用的研究鲜有报道。【目的】研究鄂尔多斯台地5种不同植被类型的盐沼湿地微生物群落与土壤条件的关系,筛选出耐盐碱菌群及影响耐盐碱菌群的土壤环境因子。【方法】采用高通量测序技术,对其微生物细菌群落组成进行了比对分析。【结果】鄂尔多斯盐沼湿地5种植被类型土壤细菌群落丰度为:苔草草甸>杂类草草甸>禾草草甸>肉质耐盐草甸>盐沼裸地;多样性的排序为:苔草草甸>杂类草草甸>肉质耐盐草甸>禾草草甸>盐沼裸地;变形菌门均为5种植被类型样地土壤细菌群落丰度最高的菌种,随4种盐沼滩涂湿地的演替,变形菌门相对丰度存在先增大后减小的趋势,与异常球菌-栖热菌门的变化趋势相反;土壤黏粒与芽单胞菌门呈极显著正相关关系,随土壤粒径增大,厚壁菌门与其相关性也逐渐增加;鄂尔多斯台地盐沼滩地的土壤化学指标与细菌群落相关性大小排序是AK>TP>SOC>TN>AN>AP>pH。【结论】变形菌门为鄂尔多斯盐沼湿地各植被演替阶段丰度最高的菌群,放线菌纲、α-变形菌纲、芽单胞菌纲为其纲水平最耐盐菌群;苔草草甸细菌多样性及丰度最高,盐碱地区细菌群落对粒径大小的适应性各不相同,鄂尔多斯台地盐沼湿地细菌群落结构影响最大的土壤环境因子是AK。

[Background]Land salinization is serious in inland and plain areas of north China,and the role of microorganisms in the vegetation succession of extreme saline-alkali land has been seldom reported.[Objective]To study the relationship between soil conditions and microbial community in the salt marshes with five types of vegetation(S1:bare;S2:succulent;S3:carex;S4:grass;S5:weeds)on the Ordos plateau,and screen out salt-tolerant bacteria and the soil factors affecting salt-tolerant bacteria.[Methods]Illumina MiSeq high-throughput sequencing was performed to analyze the microbial community composition.[Results]The soil bacterial abundance and diversity in the Ordos salt marshes with 5 different types of vegetation ranked in the order of S3>S5>S4>S2>S1 and S3>S5>S2>S4>S1,respectively.Proteobacteria was the most abundant phylum in the soil bacteria of the 5 vegetation types,and its relative abundance first increased and then decreased with the succession of the 4 salt marshes,which was contrary to the trend of Deinococcus-Thermus.Soil clay particle had a significantly positive correlation with Gemmatimonadetes,and its correlation with Firmicutes increased gradually with the increase in soil particle size.The soil chemical properties showing high correlations with bacterial community were in the order of AK>TP>SOC>TN>AN>AP>pH.[Conclusion]Proteobacteria was the most abundant bacterial phylum in Ordos salt marshes experiencing vegetation succession,and Actinomycetes,Alphaproteobacteria,and Blastomonas were the classes with stronger salt tolerance.The diversity and abundance of bacteria in S3 were the highest,and the adaptability of bacterial community varied regarding the soil particle size in salt-alkali areas.AK was the most significant soil factor affecting the bacterial community structure in the salt marshes of Ordos platform.