摘要
综合评述了氮素对土壤氧化甲烷的抑制机制。包括 :( 1)竞争甲烷单氧化酶的竞争抑制机制 ,( 2 )代谢产物的毒害抑制机制 ,( 3)外源盐引起的微生物生理缺水抑制机制和 ( 4)氮素周转作用引起的抑制机制。提出了氧化菌竞争利用土壤空气有限O2 的竞争抑制机制 ,即氨氧化菌利用更多的土壤有限氧气→产生优势氨氧化菌→形成优势菌群→限制甲烷氧化菌繁殖和功能发挥的氨长期抑制土壤氧化大气甲烷的机制 。
The following mechanisms of nitrogen fertilizers suppressing atmospheric methane oxidation in soils by methanotrophs have been reviewed:(1) competition between ammonium and methane for MMO's active sites;(2) toxicity of metabolites such as organic acids and NO 2 - to methanotrophs;(3) methanotrophs suffering physiological lack of water due to addition of nitrogen fertilizer into the soil fixing free soil water; and (4) nitrogen turnover in soils.Based on the research reports available in the world, the mechanism of ammonium suppressing atmospheric methane oxidation is supposed to be that both methanotrophs and ammonium oxidizing bacteria compete for limited amount of oxygen in soil air, if the amount of nitrogen added to the soil exceeds the soil capacity.What we have proposed successfully explains the reason why exogenous nitrogen can suppress atmospheric methane oxidation, that is, there exists a dynamic balance between ammonium oxidizing bacteria and methanotrophs in non fertilized soils called natural soils, but a large amount of nitrogen added to the soil will stimulate the activity and growth of ammonium oxidizing bacteria, which, in turn, outdoes methanotrophs in competition for limited oxygen in the soil and becomes dominant bacteria as compared with methanotrophs. So it is very difficult for methanotroph to outgrow ammonium oxidizing bacteria again and maintain the previous balance in fertilized soils, and however they can arrive at new balance,at which there are less methanotrophs but more ammonium oxidizing bacteria compared with that before nitrogen application. This may be the reason why soils fertilized with ammonium will gradually lose the ability to oxidize atmospheric methane.
出处
《农村生态环境》
CSSCI
CSCD
北大核心
2001年第3期30-34,共5页
Rural Eco-Environment
基金
中国科学院知识创新工程项目重要方向(KZCX2 -30 2 )
国家重点基础研究发展规划项目(G19990 1180 5 )
关键词
甲烷氧化菌
氨氧化菌
大气甲烷氧化
氮肥
抑制机制
土壤氧化
大气污染
ammonium oxidizing bacteria
atmospheric methane oxidization
methanotrophs
nitrogen fertilizer
suppression mechanism
