关键词: 链霉菌JD211菌剂, 水稻, 生长发育, 氮代谢, 产量

Abstract: In order to investigate the regulatory mechanism of Streptomyces JD211 agent on the growth and activities of nitrogen metabolism⁃related enzymes，and clarify the effects of Streptomyces JD211 agent on nitrogen uptake and yield of rice，a pot experiment was conducted.Two treatments were set up，including treatment without Streptomyces JD211 agent（CK） and treatment with 1% Streptomyces JD211 agent（JD211）based on conventional fertilization，and the effects of Streptomyces JD211 agent on growth and development，nitrogen content，activities of nitrogen metabolism⁃related enzymes，and yield and its components were studied. The results showed that Streptomyces JD211 agent could effectively promote the increase of plant height，basal stem diameter，leaf width and leaf length of the last leaf，and dry weight per plant of rice at all growth stage，and significantly increase the contents of nitrate nitrogen，ammonium nitrogen and total nitrogen in the leaves and roots of rice at earlier and middle stages.From seedling stage to mature stage，compared with CK，the nitrate reductase（NR）activity in rice leaves of JD211 treatment increased by 20.28%—124.26%，and increased by 20.12%—214.17% in roots，except for a slight decrease at jointing stage；the nitrite reductase（NIR）activity in leaves increased by 14.55%—63.89%，and increased by 33.77%—94.75% in roots；the glutamate synthase（GOGAT）activity increased by 13.25%—139.64% in leaves，and increased by 17.83%—46.78% in roots，except for a decrease of 11.87% at mature stage；the glutamate dehydrogenase（GDH）activity in leaves increased by 2.86%—51.73%，and increased by 16.56%—82.65% in roots，except for a decrease of 16.81% at flowering stage；the glutamine synthetase（GS）activity in leaves decreased by 14.06% at mature stage，increased by 38.02%—108.36% at other stages，and increased by 5.05%—82.93% in roots.The Streptomyces JD211 agent could significantly increase rice panicle length，grains number per panicle，single panicle weight，and yield，with increases of 8.54%，18.04%，19.55%，and 21.64% compared with CK，respectively.The rice yield was significantly positively correlated with the dry weight per plant at mature stage，extremely significantly positively correlated with the total nitrogen content in roots at mature stage，and significantly positively correlated with ammonium nitrogen content，nitrate nitrogen content，GOGAT activity，and GDH activity.In summary，the Streptomyces JD211 agent can effectively promote rice growth and development，enhance nitrogen metabolism，facilitate nitrogen absorption and utilization，and thus increase yield.

Key words: Streptomyces JD211 agent, Rice, Growth and development, Nitrogen metabolism, Yield