Abstract: The effects of S-3307 (Uniconazole) by soaking seeds and spraying the leaves at booting stage with different concentrations (0, 20 and 40 mg/kg) on the nitrogen metabolism of flag leaves and grain after flowering and grain protein content and yield were studied. S-3307 treatment increased soluble protein content in flag leaf at earlier period of grain filling; but the soluble protein content in flag leaf was no more, even lower than that of the control in mature period, indicating that S-3307 accelerated the accumulation of nitrogen in leaf and export to grain. S-3307 increased glutamine synthetase activities in superior and inferior grains and non-protein nitrogen content in superior grains at earlier stage of grain development, and promoted non-protein nitrogen transforming into protein nitrogen. The non-protein nitrogen content in grain of S-3307 treated rice was lower than that of the control in mature period, and the protein nitrogen content of treated rice grain was higher than that of control during the total grain filling period, thus both protein nitrogen percentage and amount of protein nitrogen in grain were enhanced. S-3307 significantly increased crude protein content and protein yield of rice grain. Compared with check the application of S-3307 by soaking seeds and spraying the leaves raised the crude protein content by an average of 7.2% and 8.3%, and increased protein yield by an average of 13.1% and 13.4%, respectively.

Key words: rice, uniconazole, nitrogen metabolism, protein

摘要： 以杂交稻组合汕优63为材料，探讨了烯效唑处理对水稻开花后剑叶和籽粒氮代谢、稻米蛋白质含量及产量的影响。结果表明，烯效唑处理后，籽粒灌浆前、中期剑叶内可溶性蛋白质含量提高，而成熟期其含量与对照基本相同，甚至略低于对照；烯效唑提高了强、弱势粒中谷氨酰胺合成酶活性以及强势粒发育前期的非蛋白氮含量，并促进其向蛋白氮的转化，使成熟期非蛋白氮含量低于对照，而各时期蛋白氮含量均高于对照，成熟期强、弱势粒中蛋白氮含量和单粒蛋白氮绝对积累量均得以提高；烯效唑提高了稻米内蛋白质含量和蛋白质产量，浸种和喷施处理蛋白质含量平均分别比对照高7.2%和8.3%，蛋白质产量平均分别比对照高13.1%和13.4%。

关键词: 水稻, 烯效唑, 氮代谢, 蛋白质