氧气浓度调控稻田土壤氧化亚氮释放的微生物作用机理

The availability of oxygen in soil is one of the main factors regulating the release of nitrous oxide. Therefore, the study of the microbial mechanism involved in nitrous oxide emission under the regulation of soil oxygen in paddy soil is of great significance. Using the oxygen-controlled experiments under laboratorial condition, the inner link between soil nitrous oxide emission and soil water-filled porespace and organic matter was studied under different oxygen concentration in soil atmosphere, and the internal relations among the nitrous oxide yield and translation and the variations of amoA, narG and nosZ-containing communities involved in abundance, composition and gene expression were also investigated by the methods of the real-time PCR and the terminal restriction fragment length polymorphism (T-RFLP). In combination with the data of chemical parameters such as dissolved organic nitrogen (DON), dissolved organic carbon (DOC), ammonium, nitrate, nitrification potential, denitrification potential and redox potential, the microbial mechanism of nitrous oxide emission under the regulation of soil oxygen in paddy soil would be clearly explained, which would provide important theoretical basis for regulating nitrous oxide emission in paddy soil.

土壤氧气浓度是影响土壤氧化亚氮释放的关键因素，研究氧气浓度调控稻田土壤氧化亚氮释放的微生物作用机理对了解土壤氮素循环过程具有重要的科学意义。本研究通过设置控氧土壤培养试验，利用实时定量PCR与末端限制性片段长度多态性等分子生物学技术，结合测定土壤铵态氮、硝态氮、可溶性有机氮和可溶性有机碳浓度与土壤硝化势、反硝化势和氧化还原电位等参数，研究不同氧气浓度下稻田土壤氧化亚氮释放与土壤含水量和有机质水平的内在联系，以及稻田土壤氧化亚氮产生和转化与amoA、narG和nosZ功能种群的丰度和动态、群落的组成和演替以及功能基因的表达活性和多样性的耦合机制，从不同角度揭示土壤氧气浓度调控典型水稻土氧化亚氮释放的微生物作用机制。研究结果对调控水稻土氧化亚氮的排放具有重要的理论意义。