外源ABA对GalLDH超表达转基因水稻种子萌发和生理指标的影响

Effects of Exogenous ABA on Seeds Germination and Physiological Indicators of GalLDH-overexpressing Rice

采用5 μmol·L^-1的脱落酸(ABA)溶液对GalLDH(L-半乳糖内酯脱氢酶)基因超表达转基因水稻(GO-2)和粳稻野生型品种中花11(WT)的去壳种子进行处理,研究外源ABA对GO-2和WT种子萌发过程中抗坏血酸(AsA)含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性以及种子萌发率的影响。结果表明:正常培养条件下,GO-2种子的内源AsA含量在萌发前期比WT提高了16%,在萌发中后期提高了35%,差异显著,萌发率也高于WT。另外,ABA处理对处于萌发前期的WT种子抑制作用更为明显,说明内源AsA含量与水稻种子萌发密切相关,内源AsA含量的提高可能打破了种子萌发相关的激素之间的平衡,提高了种子的萌发率。此外,在种子萌发过程中,GO-2和WT的SOD和POD活性变化以及对外源ABA的响应存在差异,充分说明内源AsA与抗氧化酶系统共同参与调控水稻种子的萌发,进一步证实了内源AsA在水稻种子活力保持以及种子萌发中的重要作用。

In order to investigate the effects of abscisic acid(ABA) with 5 μmol·L^-1 concentration on ascorbic acid(AsA) content,the activities of superoxide dismutase(SOD) and peroxidase(POD) and the seed germination rate between GalLDH(L-galactosolactone dehydrogenase gene)-overexpressing rice(GO-2) and the wild-type rice zhonghua 11(WT),these physiological indices were determined after ABA treatment.The results showed that the endogenous AsA content in GO-2 seeds increased by 16% compared with WT at the early stage of germination under normal conditions,while AsA content in former increased by 35% compared with the latter at the late stage of germination with a significant difference.However,ABA treatment generated a more significant inhibitory effect on WT seeds at the early stage of germination,which indicated that endogenous AsA content was closely related to rice seed germination.Also,the increase of endogenous AsA content might break the balance of seed germination-related hormones and improved the seed germination rate.Additionally,there were significant differences in SOD and POD activities of GO-2 and WT in response to exogenous ABA during seed germination,which indicated that endogenous AsA and antioxidant enzymes were jointly involved in the regulation of rice seed germination. And further confirmed the important role of endogenous AsA in the maintenance of rice seed vitality and seed germination.