LAUSR

This research was carried out to evaluate the effects of salicylic acid (1 mM) and putrescine (1 mM) on mitigation of oxidative stress caused by different irrigation intervals (70; 70 → 90 → 110 → 130 → 150; 70 → 100 → 130 → 150 and 150 mm evaporation, respectively). Two experiments with split plot arrangements in three replications were performed in 2 consecutive years of 2017 and 2018. Although, the activities of peroxidase, catalase, superoxide dismutase, and ascorbate peroxidase were stimulated by drought stress, lipid peroxidation and H2O2 were also enhanced due to this stress. This was led to a reduction in relative water content of leaves, membrane stability, chlorophyll content, oil percentage, and grain and oil yields under stressful conditions. Foliar sprays putrescine and especially salicylic acid further increased the antioxidant enzymes activities, water content, membrane integrity and chlorophyll pigment under different irrigation intervals. These superiorities of salicylic acid and putrescine treatments were led to a high improvement in grain and oil yields of rapeseed. It was concluded that gradual water deficit and application of these growth regulators can alleviate some of the injuries of water deficit on field production of rapeseed.