外源聚γ-谷氨酸对水稻幼苗耐旱性和渗透调节的影响

EFFECTS OF EXOGENOUS POLY γ-GLUTAMIC ACID ON DROUGHT TOLERANCE AND OSMOTIC ADJUSTMENT OF RICE SEEDLINGS

在水培条件下添加聚乙二醇-6000(PEG-6000)模拟干旱胁迫,研究聚γ-谷氨酸(γ-PGA)对杂交稻品种金优38幼苗耐旱性和渗透调节的影响,探讨γ-PGA在提高水稻耐干旱中的效果和生理作用机制。结果表明,在12.5%PEG-6000胁迫下,使用100、200mg/L外源γ-PGA后,水稻幼苗的叶枯率降低,叶鲜重、干重和叶片活力明显提高,水稻幼苗的耐旱性较未添加γ-PGA处理(CK)增强。经外源γ-PGA处理后,水稻幼苗叶片中活性氧的累积量减少,脯氨酸、游离氨基酸和可溶性总糖的含量较对照分别提高1.3%～8.6%、0.2%～10.7%、13%～28.6%,差异达显著水平(P<0.05);外源γ-PGA可明显减缓干旱胁迫下钾离子含量降低的速率。外源γ-PGA可能通过参与水稻幼苗的渗透调节而提高水稻的耐旱能力。

To explore drought-tolerance improvement effects and its action modes of poly γ-glutamic acid（γ-PGA） on rice seedlings,effects of γ-PGA on growth and osmotic adjustment of hybrid rice Jinyou 38 under polyethylene glycol 6000（PEG-6000） simulated drought stress in a hydroponics culture were investigated.When 100 and 200mg /L exogenous γ-PGA were applied under 12.5% PEG-6000 stress,withering rates of rice seedlings decreased,fresh weight,dry weight and vigor of leaves improved obviously.Furthermore,accumulation of reactive oxygen species were strongly reduced,the contents of organic osmotic substances,such as proline,free amino acids and soluble sugar,increased by 1.3% ～ 8.6%,0.2% ～ 10.7% and 13% ～ 28.6%,respectively,compared with control.Also,the decrease rates in potassium ions were apparently alleviated under drought stress.These indicated that γ-PGA probably improved the drought tolerance of rice seedlings through participation in osmotic adjustment.