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

摘要： 为探究链霉菌JD211菌剂对水稻生长发育及氮代谢关键酶活性的调控机制，明确链霉菌JD211对水稻氮吸收及产量的影响，采用盆栽试验，在常规施肥基础上设置不施加链霉菌JD211菌剂（CK）和施加1%链霉菌JD211菌剂（JD211）处理，研究链霉菌JD211菌剂对水稻生长发育、氮含量、氮代谢相关酶活性和产量及其构成因素的影响。结果表明，链霉菌JD211菌剂可有效促进水稻各生育时期的株高、基部茎粗、倒一叶的叶宽和叶长以及单株干质量的增加，显著提高水稻生育前中期叶片和根系中硝态氮、铵态氮及全氮含量。在苗期至成熟期，与CK相比，JD211处理水稻叶片中硝酸还原酶（NR）活性提高20.28%~124.26%，根系中NR活性除拔节期略下降外，其他生育时期提高20.12%~214.17%；叶片中亚硝酸还原酶（NIR）活性提高14.55%~63.89%，根系中NIR活性提高33.77%~94.75%；叶片中谷氨酸合成酶（GOGAT）活性除成熟期降低11.87%外，其他生育时期提高13.25%~139.64%，根系中GOGAT活性提高17.83%~46.78%；叶片中谷氨酸脱氢酶（GDH）活性提高2.86%~51.73%，根系中GDH活性除扬花期降低16.81% 外，其他生育时期提高16.56%~82.65%；叶片中谷氨酰胺合成酶（GS）活性成熟期降低14.06%，其他生育时期提高38.02%~108.36%，根系中GS活性提高5.05%~82.93%。链霉菌JD211菌剂可显著提高水稻穗长、穗粒数、单穗质量、产量，分别较CK提高8.54%、18.04%、19.55%、21.64%。水稻产量与成熟期单株干质量呈显著正相关；与成熟期根系中全氮含量呈极显著正相关，与铵态氮含量、硝态氮含量、GOGAT活性和GDH活性均呈显著正相关。综上，链霉菌JD211菌剂可有效促进水稻生长发育，增强氮代谢能力，促进水稻对氮素的吸收利用，进而提高产量。

关键词: 链霉菌JD211菌剂, 水稻, 生长发育, 氮代谢, 产量