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研究不同类型稻田土壤自养微生物数量和多样性差异及其影响因子,对全面认识稻田生态系统的固碳潜力及其机制具有重要意义.鉴于此,本文选取4种典型稻田土壤,通过室内培养实验对具备卡尔文循环途径碳同化微生物进行了研究.利用荧光定量PCR(qPCR)、克隆文库以及末端限制性长度多态性分析(T-RFLP)技术,研究了卡尔文循环关键酶(1,5二磷酸核酮糖羧化酶/加氧酶Rubis CO)的2种编码基因(cbbL和cbbM)的丰度和多样性.结果表明,与培养前相比,培养45 d后碳同化自养微生物数量有所增加,cbbL基因丰度比cbbM基因高3个数量级.不同稻田土壤中碳同化功能微生物优势种群存在差异,且这些微生物大多不能归类到已知的细菌类群中,部分可归类的与变形菌和放线菌有较高相似度.RDA分析结果显示土壤有机碳(SOC)、阳离子交换量(CEC)、pH、黏粒、粉粒和砂粒含量对碳同化功能微生物群落结构有显著影响.本文的研究结果对于理解微生物在碳循环过程中的作用具有一定的科学意义,也可以为稻田土壤肥力科学化管理和构建低碳农业提供科学依据.
Studying the differences in the number and diversity of soil autotrophic microbes and their influencing factors in different types of paddy fields is of great significance for the comprehensive understanding of the potential of carbon sequestration in rice paddy ecosystems and their mechanisms. In view of this, four typical paddy soils were selected in this study. The carbon assimilation microorganisms with Calvin cycle pathway were studied.Using fluorescent quantitative PCR (qPCR), cloning library and terminal restriction fragment length polymorphism (T-RFLP) The abundance and diversity of two kinds of coding genes (cbbL and cbbM) of Rubisco (COB) were investigated.The results showed that compared with those before culture, the carbon assimilation autotrophic microorganisms The abundance of cbbL gene was 3 orders of magnitude higher than that of cbbM gene.The dominant populations of carbon assimilation functional microorganisms were different in different paddy soils and most of these microorganisms could not be classified into known bacterial groups, And Proteus and actinomycetes have higher similarity.RDA analysis showed that soil organic carbon (SOC), cation exchange capacity (CEC), pH, clay, silt and grit content of carbon assimilation functional microflora The results of this study have certain scientific significance for understanding the role of microorganisms in the carbon cycle and also provide a scientific basis for the scientific management of paddy soil fertility and the construction of low-carbon agriculture.