不同氮源对水稻幼苗根氨同化酶的影响

将氮索含量相同、但来源不同的氮源分别加入到水稻培养液中，分析了不同氮源对水稻幼苗根氨同化酶活性的影响．与无氮培养的水稻根相比，(NH4)zSO4，NH4NO3，KNO3，谷氨酸(Glu)和谷氨酰胺(Gin)都能分别促进水稻根谷氨酰胺合成酶(GS)、依赖于NADH的谷氨酸合酶(NADH-GOGAT)和依赖于NADH的谷氨酸脱氢酶(NADH-GDH)活性．(NH4)2SO．对GS和NADH-GOGAT活性促进最为显著，而Gln对GS和Glu对NADH-GOGAT的活性分别影响最小．Glu对NADH-GDH活性的诱导稍强于其它氮源．这些结果提示，不同氮源对水稻根氨同化酶活性影响的差别也许反映了这些物质对水稻根部氮索代谢的影响以及对这些酶诱导能力的不同．

Effect of Different Nitrogen Sources onAmmonia-assimilating Enzymes of the Roots in Rice Seedlings

The same amount of nitrogen from the different sources was added to the nutrition solutions of rice plant growth, respectively. The effect of different nitrogen sources on ammonia\| assimilating enzymes of the roots in rice seedlings was studied. As compared with the roots of rice seedlings grown in N\|free nutrition solution, the activities of glutamine synthetase (GS), NADH\|dependent glutamate synthase (NADH\|GOGAT), and NADH\|dependent glutamate dehydrogenase (NADH\|GDH) were stimulated by (NH 4) 2SO 4, NH 4NO 3, KNO 3, glutamic acid (Glu), and glutamine (Gln). The stimulation of (NH 4) 2SO 4 for the activities of GS and NADH\|GOGAT was more remarkable, but the effect of Gln on GS as well as Glu on NADH\|GOGAT was little, respectively. The stimulation of Glu to NADH\|GDH was more obvious than other nitrogen sources. The results suggested that the different effect of these nitrogen sources on ammonia\|assimilating enzymes might reflect the discrepancy of the nitrogen metabolism and the distinction of the induced ability for these enzymes in roots of rice seedlings.