Abstract: 【Objective】 In order to understand the effects of nitrogen forms on endogenous plant hormones content in grains of Yumai 34（a strong gluten cultivar）and Yumai 50(weak gluten)．【Method】Pot experiments were completed in NH2--N, NH4+-N and NO3--N treatments which nitrification inhibitors dicyandiamide(DCD) was applied, and indoleacetic acid (IAA), gibberellins (GA3), abscisic acid(ABA), zeatin riboside (ZR) content in grains were investigated 5, 15, 20 and 25 days after anthesis respectively using method of the Enzyme-linked Immunosorbent Assay (ELISA)．【Result】When NH2--N was applied to Yumai34，ZR content in grains was promoted greatly in primary period of grains forming, IAA, GA3, ABA content in grains were increased evidently at the main period of grain filling and grain filling rate was higher in this period, and the grain weight was increased by5.74～9.16%． Applied with NH4+-N，ZR content in grains of Yumai50 was higher in primary period of grain forming, IAA, GA3 content in grains were higher at the main period of grains filling and grain filling rate was higher in this period．IAA content in grains was still higher in later period of grain filling , grains filling rate decreased slowly in this period．At last, the grains weight was increased by 3.88～11.52%．【Conclusion】This study showed that endogenous hormones content in grains of Yumai 34 and Yumai 50 responded differently to nitrogen forms which could regulate grain filling．When NH2--N was applied to Yumai34 and NH4+-N applied to Yumai50, grain filling was promoted by endogenous plant hormones content in grains and grains weight be increased．

Key words: nitrogen forms, wheat, genotype, grains, endogenous plant hormones