水田中水稻、稗草和异型莎草甲烷排放的生物学特性

比较了生长于淹水田间的水稻、稗草和异型莎草甲烷排放的生物学特性。结果表明，三种植物的甲烷排放量次序为稗草＞水稻＞异型莎草，前两者的甲烷排放量分别为后者的１１倍和８．４倍。但这个次序刚好与这三种植物根系甲烷形成活性的次序相反。观察了三种植物甲烷排放的日周期变化。稗草和水稻根际土壤的产甲烷活性高于非根际土壤，而异型莎草的根际和非根际土壤的产甲烷活性之间无明显差异。还观察到稗草和水稻的叶鞘和茎杆连接节处的间隙是甲烷逸入大气的主要途径，而异型莎草则未见有可供甲烷排放的间隙与气孔。

BIOLOGICAL CHARACTERISTICS OF METHANE EMISSION THROUGH ORYZA SATIVA,PANICUM CRUS-GALLI AND CYPERUS DIFFORMIS GROWING IN PADDY SOIL

Biological characteristics of methane emission were compared among Oryza sativa, Panicum crus-galli and Cyperus difformis growing in paddy soil.The order of the amounts of methane emitted was P.crus-golli>0.sativa>C.difformis, with the former two being 11 and 8 times as much as that of the latter,respectively ,and the order war just opposite to that of the methane-forming activities of roots of the three plants.The diurnal changes of methane emission of the three plants were relatively consistent with the valleys during 11:00-14:00 and midnight and peaks during 8:00-1:00,14:00-20:00 and about 5:00 early morning. The methanogenic activites of P.crus-galli and O.sativa in rhizospheric soils were higher than those in nonrhizospheric soils, but C.difformis was not found with obvious difference. The pathways of methane release of P.crus-galli and O.sativa were probably through the top gaps near the junctions of stems and leaves, however in C. difformis the top gaps and stomas from which methane could escape into atmosphere were not found.