Dual role of abscisic acid on antioxidative defense in grass pea seedling (Lathyrus sativus L.)
2006
You-Caixiong (Lanzhou Univ. (China). Key Laboratory of Arid Agroecology) | Xing, G. (Chinese Academy of Sciences, Beijing (China). Inst. of High Energy Physics) | Gong, C. (Lanzhou Univ. (China). Key Laboratory of Arid Agroecology) | Li, F. (Lanzhou Univ. (China). Key Laboratory of Arid Agroecology) | Wang, S. (Shihezi Univ. (China). Key Laboratory of Oasis Eco-Agriculture of Xingjiang Bintuan) | Li, Z. | Wang, Y.
The effects of exogenous abscisic acid (ABA) application on the antioxidant defenses were investigated in grass pea (Lathyrus sativus L.) seedlings. Four treatment combinations of ABA (1x10-3 nM ABA) and PEG (10 % polyethylene glycol, PEG 6000) were designed to evaluate their short-term (48 h) effect: (1) Well-watered group (Control group1), (2) PEG treatment, (3) ABA treatment, and (4) PEG + ABA treatment. In addition, 2 other treatments were used to evaluate the long-term (15 d) effect of ABA: well-watered group (Control group2) and ABA treatment. Time-course analyses of ABA content, the production of malondialdehyde (MDA) and H2O2, and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and peroxidase (POD) in water-stressed leaves showed that a significant increase in ABA content preceded that of MDA and H2O2 in long term experiment, which was followed by a substantial increase in the activities of four antioxidant enzymes. Under the short-term drought stress, ABA application promoted the activities of antioxidant enzymes, and reduced the accumulation of MDA and H2O2 significantly. On the contrary, long-term application of exogenous ABA increases the generation of MDA and H2O2 significantly. It could be argued that during a successive application of exogenous ABA, ABA played a dual role by which the beneficial role in the initial stage shifted to a detrimental one under prolonged treatment in up-regulating protective defense strategies in plants.
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