水稻氨基酸态氮营养效应及其机理研究

在＾１５无菌水培试验条件下水稻氨基酸态氮和铵态氮的营养效应及其氮营养贡献，氨基酸态氮的同化机理等问题作了比较研究。结果表明，等氮量（１０ｍｇ／Ｌ）无菌水培５１天后，甘氨酸态氮（Ｇｌｙ－Ｎ）单施或与硫酸铵态氮（ＮＨ４＾＋－Ｎ）配施处理的干物重、吸氮量均大于硫酸铵态氮单施处理；Ｇｌｙ－Ｎ对水稻干物重及吸氮量的促进作用大于ＮＨ４＾＋－Ｎ；Ｇｌｙ－Ｎ与ＮＨ４＾＋－Ｎ配施条件下，以吸氮总量为基础计算的Ｇｌｙ－Ｎ氮营养贡献率可达５５．６６％。采用Ｇｌｙ－Ｎ培养的籼、粳稻整株谷草转氨酸ＧＯＴ、谷丙转氨酶ＧＰＴ及谷氨酸脱氢酶ＧＤＨ活性均大于ＮＨ４＾＋－Ｎ，且根中ＧＯＴ和ＧＰＴ活性、叶中ＧＤＨ活性明显高于相同部位ＮＨ４＾＋－Ｎ培养的水稻。水稻ＧＯＴ、ＧＰＴ及ＧＤＨ活性受对应底物谷氨酸（Ｇｌｕ）营养的促进。

EFFECTS OF AMINO ACID-N ON RICE NITROGEN NUTRITION AND ITS MECHANISM

Effects of amino acid-N and ammonium-N on rice growth, N nutritional status and its mechanism were studied under sterilized aquiculture with 15N tracer technique in this paper. The results showed that the dry weights and N uptakes of the rice plants in the treatments of glycine-N (Gly-N) or mixture of glycine-N and ammonium sulfate-N (Gly-N＋NH＋4-N) were significantly higher than that in the treatment of ammonium sulfate-N (NH＋4-N) after 51 days of sterilized aquiculture. The positive effect of Gly-N on the dry weight and N uptakes of rice plants was larger than that of NH＋4-N. The percentage of N in the rice plants derived from Gly-N in the mixture of Gly-N and NH＋4-N could reach a level as high as 55.66%. The activities of glutamateoxaloacetate transaminase (GOT), glutamate-pyruvate transaminase (GPT) and glutamate dehydrogenase (GDH) of the rice plants of indica and japonica cultivars in the treatment in Gly-N were all higher than in the treatment of NH＋4-N, respectively. Moreover, the activities of GOT and GPT in the roots and GDH in the leaves in the treatments of Gly-N were obviously higher than those in the treatments of NH＋4-N. The activities of GOT, GPT and GDH of the rice plants were positively promoted by its substrate glutamic acid (Glu).