高温胁迫下水稻氨基酸态氮与铵态氮营养效应研究

Effects of different nitrogen forms on rice seedlings under sterilized culture at high temperature

在高温胁迫无菌砂培条件下对无机氮 (硫酸铵 )、有机氮 (甘氨酸 ,谷氨酸和赖氨酸 )和缺氮 (对照 )培养的水稻植株干物重、总氮量及其根、叶谷草转氨酶 (GOT)和谷丙转氨酶 (GPT)活性作了研究。结果表明 ,有机、无机氮均被水稻吸收 ,且吸收量相当。低浓度无机氮 (N 10mg/L)或有机氮培养 2 0d后的水稻植株总氮量比对照的高 5 0 %以上 ;无机氮培养的植株干物重显著低于有机氮培养和对照 ,表明植株受NH+ 4 毒害。培养 15d后 ,多数有机氮培养的植株根或叶GOT或GPT活性显著高于对照 ,但根、叶间有较大差别 ;而无机氮培养的植株根GOT及根、叶GPT活性是对照的 2倍或以上。高浓度无机氮 (N 5 0 0mg/L)处理 6h后稻株根、叶GPT活性分别是对照的 2 5和4倍 ,而高浓度甘氨酸 ,谷氨酸和赖氨酸态氮 (N 5 0 0mg /L)处理 6h后 ,根、叶GPT活性分别是对照的 5 7、9 4、1 9倍及 1 8、2 3、1 4倍。

The effects of different N sources (ammonium sulfate,glutamate, glycine and lysine) on rice (Oryza sativa L )seedlings grown in high temperature(35 ～ 37℃ during lighting period and 30 ～ 33℃ during dark) and sterile sand culture was studied The dry matter of plants grown 20 days with ammonium as sole N source was significantly lower than that grown with amino acids, and also slightly lower than that grown with free N (control), indicating ammonium toxicity The total N of plant cultured with amino acids was similar to that with ammonium, and was 50% higher than control Compared with the control, root GOT and GPT activity of roots and leaves of plants grown with ammonium (N 10 or 500 mg/L) increased to twice, perhaps relative to ammonium toxicity Grown for 15 days in low N concentration (N 10 mg /L), GOT activity in leaves of plants with glutamate as sole N source significantly increased The activity of GPT in glycine fed plant roots and leaves and glutamate fed plant leaves significantly increased, but GOT activity in lysine fed plant leaves decreased Treated with high N concentration (N 500 mg /L) for 6 h, the activity of GPT was 5 7, 9 4, and 1 9 times control in roots, respectively, for glycine , glutamate and lysine treated plants, and was 1 8, 2 3 and 1 4 times control in leaves, respectively These results indicated that rice seedlings grown under higher temperature were able to take up organic nitrogen