Antioxidant and biochemical response of canola to organic growth-regulating and calcium in moisture stress conditions

Drought is one of the most important environmental factors in reducing canola yield, especially in arid and semi-arid regions such as Iran. To Investigate the activity of rapeseed CV. Dhalgan antioxidant enzymes and some biochemical traits under drought stress conditions and foliar application organic growth-regulating and calcium, an experiment as split plots based on a randomized complete block design with three replications were performed in the Agricultural Research Institute of University of Zabol (Chah Nimeh). Experimental treatments included cut-off irrigation levels based on plant growth stages at three levels I1= control (complete irrigation throughout the growing season), I2= Irrigation up to stem elongation completion, and I3= Irrigation up to silique formation as the main factor and subsidiary factor included foliar application: F1= control (Pure water spray) and foliar application organic growth-regulating and calcium with concentrations of F2 = 0.1, F3 = 0.05, and F4 = 0.03. The increase of drought stress levels from the full irrigation treatment compared to the irrigation up to silique formation and after that irrigation up to stem elongation completion caused an increase in the activity of catalase, peroxidase, polyphenol oxidase, ascorbate peroxidase, phenol, flavonoids, carbohydrates, and proteins. and the highest activity of these traits from irrigation up to stem elongation completion combined with spraying at a concentration of 0.1 was obtained. Increased activity of catalase enzyme (82), peroxidase (90), polyphenol oxidase (72), ascorbate peroxidase (76), soluble carbohydrates (75), protein (28), phenol (73), and flavonoids (53) percent in from irrigation up to stem elongation completion combined with spraying at a concentration of 0.1 compared to the control and pure water spray. In general, it seemed that among the experimental treatments by foliar application organic growth-regulating and calcium with concentrations of 0.1 could mitigate the harmful effects of drought by activating the enzymatic and non-enzymatic antioxidant system.