Physiological Effect of 24-Epibrassinolide and Its Conjugate With Succinic Acid on the Resistance of Rapeseed Plants to Chloride Salinity

It has been shown for the first time that exogenous 24-epibrassinolide (EBL) and a conjugate synthesized on its basis, which is 2,3,22,23-tetraester of EBL and succinic acid, at a concentration of 10 nM almost equally mitigate the negative effects of salt stress (150 mM NaCl) on rapeseed plants, maintaining photosynthetic activity and growth parameters. Specificity of the action of the studied compounds in regulating the resistance of rapeseed plants to NaCl is noted. EBL against the background of chloride salinity increases the content of carotenoids, superoxide dismutase and peroxidase activity, while conjugate EBL increases only peroxidase activity. Pretreatment of plants for 4 hours before stress was more effective than the introduction of the studied regulators simultaneously with the stressor.