控释氮肥对杂交水稻糙米蛋白质品质和氮代谢关键酶活性的影响

 以八两优100（杂交早稻）和威优46（杂交晚稻）为材料，研究了施用控释氮肥对稻米蛋白质含量、氨基酸含量及其组分以及叶片和籽粒中硝酸还原酶（NRase）、谷氨酰胺合成酶（GS）和蛋白水解酶活性的影响。结果表明，八两优100和威优46控释氮肥处理糙米蛋白质、复合蛋白含量均显著或极显著高于尿素处理，其中谷蛋白和谷蛋白/醇溶蛋白比值增幅明显。施控释氮肥的八两优100和威优46糙米氨基酸总量、必需氨基酸和限制性氨基酸含量均较施用尿素的明显提高。在施用尿素和控释氮肥条件下，供试两组合叶片中NRase、蛋白水解酶、GS以及籽粒中的GS活性的动态变化一致。施用控释氮肥有利于功能叶中NRase、GS、蛋白水解酶以及籽粒中的GS活性维持较高水平。控释氮肥对杂交水稻功能叶氮代谢关键酶活性和籽粒中蛋白质合成及氨基酸积累均有明显的调节作用。这可能是控释氮肥能显著提高杂交水稻产量和蛋白质及氨基酸含量的生理原因之一。

Effect of Controlled Release Nitrogen Fertilizer on Protein Quality of Brown Rice and Key Enzyme Activity Involved in Nitrogen Metabolism in Hybrid Rice

The protein and amino acids contents and components in brown rice,the activities of nitrate reductase(NRase),glutamine synthetase(GS)and protease in functional leaves and grains in hybrid rice as regulated by controlled release nitrogen fertilizer(CRNF)were analyzed by using Baliangyou 100(early hybrid rice)and Weiyou 46(late hybrid rice)as materials.There were three treatments:1)Control(no nitrogen applied,CK);2)Urea(90 kg N/hm2 in early hybrid rice,105 kg N/hm2 in late hybrid rice,2/3 N as basal application,1/3 N as top-dressing at the tillering stage,Urea);3)Controlled release nitrogen fertilizer(90 kg N/hm2 in early hybrid rice,105 kg N/hm2 in late hybrid rice,all N as basal application,CRNF).Results showed that total protein and complex protein contents in brown rice of both the early and late hybrid rice were significantly higher in CRNF treatment than in urea treatment.Glutelin and glutelin/prolamine ratio were increased significantly under CRNF treatment for both of the hybrid rice combinations.Total amino acids,essential amino acids and limited amino acids contents in brown rice under CRNF treatment for both of the hybrid rice combinations were increased greatly compared with urea treatment.Dynamic changes in NRase and protease activities in functional leaves and glutamine synthetase activities in grains for both of the hybrid rice combinations followed the same tendency.Moreover,CRNF application was favorable to maintain the activities of NRase,GS and protease at high level.CRNF application had obvious regulation for key enzyme activities involved in nitrogen metabolism in functional leaves and grains of hybrid rice,so it might contribute to a significantly enhanced grain yield,protein content and amino acids content of hybrid rice comparing with urea application.