不同氮源对大豆硝酸还原酶和谷氨酰胺合成酶活性及蛋白质含量的影响

利用硝态氮(NO3--N)、铵态氮(NH4 -N)及混合态氮对4个栽培大豆品种结荚期植株进行诱导处理,研究不同氮源对叶片硝酸还原酶(NR)、谷氨酰胺合成酶(GS)活性以及子粒蛋白质含量的影响.结果表明,NO3--N增加4个品种NR活性效果最好,其次是混合态氮,而NH4 -N的效果较差.从4个品种叶片的GS活性看,混合态氮和NH4 -N的处理效果好,而NO3--N的效果差;三种氮源处理4个基因型的子粒蛋白质含量都有不同程度的增加,增加的顺序与提高NR活性的顺序相同.说明施用三种氮肥能增加大豆品种子粒的蛋白质含量,而以施用硝酸钾的效果最佳.相关分析表明,大豆叶片NR活性与子粒蛋白质含量之间呈极显著正相关(r=0.663**),可以把结荚期叶片的硝酸还原酶活性作为选择高蛋白大豆材料的参考指标之一.

EFFECTS OF DIFFERENT NITROGENS ON ACTIVITIES OF NITRATE REDUCTASE,GLUTAMINE SYNTHETASE AND SEED PROTEIN VONTENTS IN SOYBEAN VULTIVARS

Effects of different nitrogens(NO 3 --N,NH 4 +-N,NO 3 --NH 4 +)on nitrate reductase (NR) and glutamine synthetase(GS) activities, and seed protein contents of soybean cultivars during pod-bearing period were investigated. The experimental results indicated that NR activities of leaves in four soybean genotypes treated by NO 3 --N were obviously enhanced. However, NR activities of these genotypes treated by NH 4 +-N were the lowest in three kinds of nitrogens. GS activities induced by NO 3 --NH 4 + and NH 4 +-N were remarkably increased. Seed protein contents of four genotypes induced by three kinds of nitrogens were higher than those done by H 2O(CK). The correlation between leaf NR activity and seed protein content was extremely significant (r= 0.633 *). Hence it is suggested that high NR activity in soybean leaves should be one of bio-chemical index for selecting soybean germplasms with seed high protein.