Effect of acid salicylic on germination indices, kernel vigor and activity of some antioxidant enzymes of sunflower (Helianthus annuus L.) cultivar Armavireski under drought stress

Since the production of oily plants can be affected by environmental factors such as water restriction, so treatment with acid salicylic as a growth regulator can increase drought tolerance in plants. In order to investigate the effect of acid salicylic on some biochemical and seed germination of sunflower seeds under drought stress conditions, an experiment was conducted as factorial in a completely randomized design with three replications in the physiology lab at the Islamic Azad University of Kaleiber Branch in 2017.The treatments consisted of different concentrations of acid salicylic in four levels (0, 0.5, 1 and 1.5 mM) and different levels of drought stress with polyethylene glycol 6000 at five levels with Zero potential of (distilled water), -5, -10, -15 and -20 megapascal). The results showed that the effect of drought stress and different concentrations of acid salicylic on germination and antioxidant enzymes was significant at 1% probability level. Interaction of stress and acid salicylic on the activity of superoxide dismutase enzymes, ascorbate peroxidase, seed vigor, root length and stem length were significant. In drought stress conditions, the plant has been shown to increase the activity of antioxidant enzymes to reduce the effects of oxidative stress. The results of the mean comparison of the data showed that with increasing drought stress, the percent and speed of germination decreased and the activity level of antioxidant enzymes increased. In the present study, acid salicylic pre-treatment with concentrations of 1 and 0.5 mM significantly increased the activity of malondialdehyde, superoxide dismutase, glutathione peroxidase, catalase, ascorbate peroxidase enzymes and germination components in comparison with the control.The overall results of this experiment showed that acid salicylic spraying, especially at 1 mM concentration, reduced the oxidative stress caused by drought and improved the antioxidant enzymes activity in sunflower seeds.