【摘要】 用最大可能数（ＭＰＮ：ＭｏｓｔＰｒｏｂａｂｌｅＮｕｍｂｅｒ）法，测定了太湖五里湖敞水区及各种生态类型水生高等植物群落内的反硝化、硝化、亚硝化和氨化细菌的分布，并分析探讨了它们的作用．结果表明，反硝化细菌的最大可能数［ｎ（ＭＰＮ）］，在水生高等植物群落内水体中较敞水区湖水高２～５个数量级，差异极显著（Ｐ＜０．０１），漂浮植物群落内水体的反硝化细菌ｎ（ＭＰＮ）较沉水和浮叶植物群落内水体高２～３个数量级，差异极显著（Ｐ＜０．０１）；硝化细菌ｎ（ＭＰＮ），敞水区湖水高于凤眼莲、水花生群落内水体，差异显著（Ｐ＜０．０５），菱群落与其他群落比较，亦有极显著性差异（Ｐ＜０．０１）；亚硝化细菌ｎ（ＭＰＮ），在水生高等植物群落内的水体中较敞水区高３～４个数量级，差异极显著（Ｐ＜０．０１）；氨化细菌ｎ（ＭＰＮ），在水生高等植物群落内的水体中高于敞水区水体．除硝化细菌外，反硝化、亚硝化及氨化细菌均在根际处最为密集，且由根际向外呈现递减趋势．各种水生高等植物群落内氮循环细菌分布及微环境的差异，促进了有机氮的分解、铵态氮的硝化和挥发、硝酸盐氮的反硝化作用．室内培养试验结果表明，水生高等植物生长区水样的氨化产气量为敞水区的２倍左右?更多还原

【Abstract】 The distribution and role of four nitrogen cycle bacteria, including ammonifying bacteria, denitrifying bacteria, nitrobacteria and nitrosobacteria, were determined with MPN method in the Taihu Lake. The most probable number [ n (MPN)] of denitrifying bacteria in the water covered by Alternanthera philoxeroides and Eichhornia crassipes are about 2～3 and 2～5 order of magnitudes higher than those in the water vegetated with other macrophytes and in the unvegetated water, respectively. There is a significant difference between them ( P <0.01). The n (MPN) of ammonifying bacteria in vegetated water are markedly higher than those in the unvegetated water. The n (MPN) of nitrosobacteria in the vegetated water are notably higher than those in the unvegetated water ( P <0.01). The n (MPN) of nitrobacteria and nitrosobacteria in the water vegetated with submerged plants are higher than those in the water covered by floating plants. The n (MPN) of ammonifying and denitrifying bacteria, nitrosobacteria are very dense in rhizosphere and present a decreasing tendency from root surface to outside. The results demonstrate that the differences in distribution of the four nitrogen bacteria among the different aquatic macrophytes play a significant role in nitrogen removal. The results of culture experiment show that the volume of the gas produced by ammonification in the vagetated water is about 2 times as much as that in the unvegetated open water. The volumes of the gas produced by deitrification in the water covered by water peanut and hyacinth are 6.2 and 4.8 times as much as those in the unvegetated water. It indicates that nitrogen is liable to emit to atmosphere from the vegetated water.更多还原