双季稻田甲烷排放与土壤产甲烷菌群落结构和数量关系研究

Relationship Between Methane Emission and the Community Structure and Abundance of Methanogens Under Double Rice Cropping System

为揭示南方双季稻田甲烷排放与土壤产甲烷菌群落结构和数量的关系,监测了双季稻田甲烷排放规律,并采用PCR-DGGE和荧光原位杂交法(FISH)分别分析了水稻不同生育期土壤产甲烷菌群落结构和数量的变化特征。结果表明:早晚稻生育期内的甲烷排放总量分别为9.28g·m-2和7.78g·m-2。早晚稻生育期内产甲烷菌的群落结构和种群数量均存在一定的季节变化,以水稻生长旺盛期群落结构复杂、数量多,其中水稻移栽20d左右土壤产甲烷菌数量最多,早、晚稻分别为1.14×107个·g-1干土和6.72×106个·g-1干土,均显著高于当季其他生育期。早稻生育期内产甲烷菌的群落结构多样性比晚稻复杂,数量比晚稻多,这与双季稻田的甲烷排放规律一致。稻田甲烷排放量与稻田土壤产甲烷菌的数量存在显著的正相关关系,而与群落结构没有显著相关性。因此,控制稻田产甲烷菌数量可以有效减少甲烷的排放量。

A field experiment was carried out to study the relationship between methane emission and the community structure and abundance of methanogens under a double rice cropping system in Southern China. Several relevant parameters were measured including methane emis- sion determined by closed static chamber technique, community structure of methanogens by PCR denaturing gradient gel electrophoresis （PCR-DGGE） and the population of methanogens by fluorescence in situ hybridization （FISH）. The results showed that the amounts of methane emission were 9.28 g· m-2 and 7.78 g· m-2 at early and late rice growing stage, respectively. The community structure and abundance of methanogens changed greatly with rice growing period for both early and late rice, but the main methanogens species existed in paddy field sostenuto. The diversity and abundance of methanogens in vigorous rice growing stage（20 days after rice transplanting） were higher than oth- er stages. The peak abundance of methanogens were 1.14~107 In. g-1 dry soil and 6.72~106 In＂ g-~ dry soil for early and late rice growing season, respectively; which was significantly higher than other growing stages in the same growing season. The diversity and abundance of methanogens of early rice was higher than that of late rice, consistent with the methane emission pattern. The methane emission was signifi- candy eorrelated with the abundance of methanogens, however, there was no significant correlation with the diversity of methanogens. In conelusion, reducing the abundance of methanogens will be an effective way to reduce the methane emission in paddy field.