淹水水稻土消耗N2O能力及机制  

N_2O Consumption Ability of Submerged Paddy Soil and the Regulatory Mechanism

作　　者：王玲[1,2] 邢肖毅[1,2] 秦红灵[1] 刘毅[1] 魏文学[1] 

机构地区：[1]中国科学院亚热带农业生态研究所桃源农业生态试验站,亚热带农业生态过程重点实验室,长沙410125 [2]中国科学院大学,北京100049

出　　处：《环境科学》2017年第4期1633-1639,共7页Environmental Science

基　　金：国家自然科学基金项目(41330856,41271280);国家自然科学基金青年科学基金项目(41301274)

摘　　要：大量研究表明淹水厌氧状态下的水稻田等湿地生态系统中N_2O负排放量巨大,对缓解大气温室气体效应有重要意义,但水稻土壤对大气N_2O的吸收消耗潜力以及调控潜力发挥的微生物机制却鲜见报道.本实验以表层渍水水稻土壤(0~5cm)为研究对象,通过室内厌氧培养手段,分析环境N_2O浓度的提高对土壤N_2O消耗能力的影响以及nosZ基因丰度的变化规律.结果表明,淹水厌氧状态下的水稻土壤中nosZ基因绝对丰度(以干土计)在DNA水平上达到108copies·g^(-1),具有很强的N_2O转化还原潜力.回归分析结果显示环境N_2O浓度与土壤N_2O消耗速率显著线性正相关(r2=1,P<0.001),土壤N_2O消耗能力可被高浓度的环境N_2O极大程度激发,达到4 567.99μg·(m^2·h)^(-1).与此同时较高水平的nosZ基因丰度在不同浓度N_2O处理间无显著差异,说明DNA水平上的nosZ基因丰度可能已经不是限制N_2O还原的关键因子,微生物调控因子需进一步探索.A large number of researches showed that the N_2O negative emissions from flooding paddy fields,peatlands and other wetlands ecosystem were frequent and considerable,which is of great significance on alleviating the greenhouse gas effect.However,there are few reports about the transformation and microbial mechanism of N_2O between atmosphere and paddy soil.The slurry of surface paddy soil（0-5 cm） was incubated in laboratory conditions,and the effect of enhanced N_2O concentrations in headspace on the N_2O consumption capacity of submerged paddy soil and the response of nosZ gene abundance were explored.The results showed that,paddy soil under flooding and anaerobic conditions harbored very strong potential of N_2O reduction along with a relatively high nosZ gene abundance（108copies·g^-1dry soil at DNA level）.Regression analysis presented the N_2O concentrations in headspace were positively correlated（r2= 1,P〈0.001） to the N_2O consumption rates of paddy soil slurry,indicating the high N_2O concentration could stimulate the N_2O consumption power,to a very high rate of 4 567.99 μg·（m^2·h）^-1.Meanwhile,there were no significant differences in the high abundance of nosZ gene among N_2O treatments,demonstrating the nosZ gene abundance at DNA level might not be the main controller of N_2O consumption ability in submerged paddy soil and further study on the key microbial factor is needed.

关 键 词：水稻土 厌氧 N2O浓度 N2O消耗 NOSZ 

分 类 号：X144[环境科学与工程—环境科学]