Ascorbic Acid and α-Tocopherol Minimize Salt-Induced Wheat Leaf Senescence
2011
Farouk S.
Background Leaf senescence is an oxidative process, and most of the catabolic events involved in senescence are propagated irreversibly once initiated. Results Salinity hastened the senescence of wheat flag leaves, decreased the concentrations of chlorophyll, total carotenoids, ascorbic acid, total phenol, calcium, potassium, magnesium, K+/Na+ ratio and soluble proteins, as well as the activities of catalase and peroxidase. Conversely, salinity increased sodium, chloride, and the chlorophylla:b ratio, as well as membrane permeability, hydrogen peroxide, and malondialdehyde synthesis. Both antioxidants application reduced the hydrogen peroxide accumulation, lipid peroxidation, membrane permeability, sodium and chloride content over control plants. The antioxidants enzyme activities were significantly increased by antioxidant spray. Enhanced accumulation of ascorbate, phenol, carotenoids, calcium, potassium and magnesium was seen in antioxidants-sprayed plants compared with control plants at 65 days after sowing. Under moderate and sever salinity levels application of both antioxidants alleviated the harmful effects of salinity on leaf senescence related parameter. The higher levels of antioxidants and low level of H2O2 in flag leaf may be the prerequisite for delayed leaf senescence in antioxidants-sprayed plants. Conclusions It can be concluded that ascorbic acid-sprayed plants can postpone the leaf senescence by peroxide/phenolic/ascorbate system which is involved in scavenging the ROS produced during leaf senescence.
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