低温胁迫下外源ABA对开花期水稻叶鞘激素含量及抗寒生理的影响

为了探讨低温条件下外源ABA对水稻叶鞘内源激素含量和抗寒生理指标的调控效应,以水稻品种龙稻5(耐冷型品种)和龙粳11(冷敏型品种)为材料,于开花期喷施ABA后,在人工气候室进行低温(15℃,分别持续1,2,3,4,5 d)处理。结果表明,开花期低温可导致水稻花粉活力和结实率显著降低,冷敏型品种尤为严重,喷施ABA可有效抑制花粉活力和结实率的降低。低温处理可引起水稻叶鞘MDA、可溶性糖、可溶性蛋白和脯氨酸含量及相对电导率的提高,同时导致SOD、POD和CAT活性发生变化;外源ABA具有降低MDA含量和相对电导率的作用,同时促进可溶性糖、可溶性蛋白、脯氨酸含量和保护酶活性的提高。研究证实外源ABA具有提高水稻抗冷的作用,对优化东北地区水稻生产抗冷方法,建立寒地水稻生产的抗冷技术体系,达到保产增产的目的有积极意义。

Effect of exogenous ABA on the endogenous hormone levels and physiology of chilling resistance in the leaf sheath of rice at the flowering stage under low temperature stress

This research investigated the effect of exogenous abscisic acid (ABA) applied to the leaf sheath of rice at low temperature, on endogenous hormone levels, and on a cold hardiness physiology index of two rice varieties. Potted plants of rice varieties, LD5 (cold tolerant) and LJ11 (cold sensitive) were exposed to low temperature (15 ℃; 1, 2, 3, 4, or 5 d) in a climate chamber, at the flowering stage. Low temperature at flowering significantly decreased pollen vigor and seed set, and these effects were particularly serious in the cold sensitive varieties. The exogenous ABA effectively inhibited the decrease of the seed setting rate. Low temperature increased the levels of malondialdehyde (MDA), soluble sugar, soluble protein, and proline, and the relative conductivity of the leaf sheath, and also led to changes in the activities of superoxide dismutase, peroxidase and catalase. Exogenous ABA reduced the level of MDA and the relative conductivity, and promoted an increase in soluble sugar, soluble protein and proline levels, and promoted improvements in protective enzyme activity. This study confirmed that exogenous ABA improves the cold resistance of rice. Enhancement of low temperature resistance in rice will be very significant in facilitating increased rice production in the colder northeast east regions of China.