ABA对低温胁迫下水稻幼苗抗氧化酶活性的影响

以耐冷型水稻(Oryza sativa L.)品种东农418和冷敏感型水稻品种松粳9号为材料,在三叶期以脱落酸(ABA)及其合成抑制剂钨酸钠进行喷施处理,通过抗氧化酶活性的响应,探讨低温胁迫下ABA对水稻苗期耐冷性的调节作用。结果表明,低温处理使叶片SOD活性降低,POD活性和MDA含量升高;外施ABA减缓了叶片SOD活性的降低,并可减少POD活性和MDA含量升高的幅度,而钨酸钠处理则加剧了SOD活性降低及POD活性和MDA含量的升高,说明ABA提高了水稻幼苗耐冷性。低温胁迫以及ABA对水稻抗氧化酶活性的影响因品种而异,外施ABA对耐冷型品种的调节作用效果更明显。

Effects of ABA on Antioxidase Activity in Rice Seedlings under Low Temperature Stress

The rice varieties with different cold-tolerance ﹙cold-tolerant variey Dongnong 418 and cold-sensitive variey Songjing 9﹚ were treated with abscisic acid ﹙ABA﹚ and tungstate ﹙inhibitor of ABA biosynthesis﹚ at the stage of three leaves. The effects of ABA on antioxidase activity under low temperature stress were studied. The results showed that, compared with normal temperature control, the activity of superoxide dismutase ﹙SOD﹚ in rice seedling leaves decreased under the low tem-perature stress, in the meanwhile, peroxidase﹙POD﹚ activity and malondialdehyde ﹙MDA﹚ content increased significantly. Ex-ogenous ABA could effectively enhance the cold-tolerance abilities of rice seedlings under low temperature stress by slowing down the decrease of SOD activity and the increase of POD activity and MDA content. On the contrary, tungstate significant-ly accelerated the decrease of SOD activity and the increase of POD activity and MDA content. Generally, the effects of low temperature stress and ABA varied with different rice varieties, exogenous ABA was more effective on cold-tolerance varieties than cold-sensitive varieties.