【摘要】 土壤养分和微生物对环境变化十分敏感,能快速对土壤生态变化作出反应。分析土壤养分和微生物对不同碳源利用能力的差异,明确鄱阳湖湿地土壤微生物群落变化特征,对中国湿地健康状况评价及可持续利用具有重要意义。基于2014-2017年对鄱阳湖湿地不同植物群落(沉水植物区、湿生植物区、挺水植物区、湖滨高滩地)土壤生境的调查数据,利用Biolog微平板法和磷脂脂肪酸甲酯法(FAMEs)系统研究土壤微生物多样性群落特征。鄱阳湖湿地不同植物群落土壤养分和有效养分基本表现为沉水植物区>湿生植物区>挺水植物区>湖滨高滩地。鄱阳湖湿地不同植物群落土壤微生物群落代谢平均颜色变化率(AWCD)随培养时间延长而逐渐增加,土壤微生物群落代谢活性表现为沉水植物区>湿生植物区>挺水植物区>湖滨高滩地。土壤微生物对不同种类碳源的利用强度存在较大差异,碳水化合物和羧酸类碳源是鄱阳湖湿地不同植物群落土壤微生物的主要碳源,其次为氨基酸类、酚酸类和聚合物类,胺类碳源的利用率最小。土壤微生物群落的物种丰富度指数(H)、均匀度指数(E)、优势度指数(D_s)和碳源利用丰富度指数(S)总体以沉水植物区为最高,湖滨高滩地最低,优势度指数在鄱阳湖湿地不同植物群落差异不显著(P>0.05)。主成分分析结果表明,从31个因素中提取的与碳源利用相关的主成分1、主成分2分别能解释变量方差的63.152%和15.174%,在主成分分离中起主要贡献作用的是胺类和氨基酸类碳源;土壤微生物多样性指数与土壤养分之间呈正相关,与pH呈负相关,而土壤全碳和全氮含量对土壤微生物多样性贡献较大,是土壤微生物群落功能多样性差异的主要影响因子。物种丰富度指数(H)、均匀度指数(E)和碳源利用丰富度指数(S)与土壤养分各指标的相关系数绝对值均高于优势度指数(D_s),说明土壤养分对土壤微生物群落优势度指数的影响作用较小。更多还原

【Abstract】 Soil nutrients and microbes are very sensitive to the environment and can quickly respond to the changes in soil environment. Analyzing the utilization differences of soil microbes to diverse carbon sources, and clarifying the variation of soil nutrients and microbial communities in Poyang Lake, is crucial to assess the health status of alpine meadow and maintain its sustainable utilization. In order to study the variation of soil nutrients and microbial community diversity in the wetland of Poyang Lake, four plant communities were selected as the research object by three years, based on the soil habitat, the structure and function of soil microbial community were studied by using Biolog plate and phospholipid fatty acid methyl ester(FAMEs), respectively. Soil nutrients availability showed submerged plant area>wetland plantsbog plant area>emerged plant area>lake shoal. The average well color development(AWCD), which directly reflected microbial activity and functional diversity, first increased and then decreased with the order of submerged plant area>wetland plantsbog plant area>emerged plant area>lake shoal. The mostly used carbon sources by soil microbes were carbohydrates and carboxylic acids, followed by amino acids, phenolic acids and polymers, the lowest was amines. Simpson index, Shannon-Wiener index, richness index and McIntosh index showed submerged plant area>wetland plantsbog plant area>emerged plant area>lake shoal. Principal component analysis(PCA) identified two factors in relation to carbon sources,they explained 63.152% and 15.174% of the variation, respectively. The carbon sources used by soil microbial communities were different. Amino acids and amides were the two main carbon sources separated by the two principal component factors. Correlation analysis showed that soil microbial diversity index was significantly or very significantly positive correlation with soil nutrients, and was negative correlation with pH, that was the soil nutrients had the more positive contribution to soil microbial diversity and soil pH had the negative contribution, which were the reason of variation of soil microbial community diversity in the wetland of Poyang Lake.更多还原