Protective role of exogenous kinetin against oxidative stress induced by salt stress in rice genotypes
2016
Saeedipour, S. | Moradi, F.
Salinity is one of the most challenging problems adversely affecting the growth and development of plants. Plants adopt various strategies to overcome the adverse effect of salinity stress. This study sought to determine the role of the exogenous applications of the kinetin (KIN) in improving defense mechanisms in two genotypes of rice (FL485 and IR29, salt-tolerant and salt-susceptible, respectively) against NaCl stress. The results indicated that KIN led to an increase in abscisic acid (ABA) and indole-3-acetic acid (IAA)content in the flag leaves of the two rice cultivars under salt stress. Salt stress increased the content of ascorbic acid (AsA) in the leaves of the tolerant cultivar FL485, which suggested that the oxidative defense system in salt-stressed rice plants had been very operative. Exogenous application of KIN further increased the activities of AsA and ascorbate operative. Exogenous application of KIN further increased the ativities of AsA and ascorbate oxidase (ASO) in the salt-stressed FL485 but not in the susceptible cultivar IR29. KIN was found to be more effective in enhancing the activities of alpha-tocopherol in salt-stressed rice plants more efficiently that in the salt-tolerant cultivar. In addition, KIN led to a marked increase in hydrogen peroxide (H sub 2 O sub 2) concentration in both cultivars compared with the untreated plants. Lipid peroxidation levels of both cultivars under salt treatment showed no change with foliar applications of KIN.
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