Effect of seed pre-treatment with L-arginine on improvement of seedling growth and alleviation of oxidative damage in canola plants subjected to salt stress. Fatemeh Nasibi1, 2*, Khosrow Manouchehri Kalantari1, 2 and Adeleh Barand1

Soil salinity is one of the major abiotic stresses that adversely affect plant productivity and quality. Therefore, an experiment was conducted to investigate the effects of seed treatment with L-arginine on some morphological and physiological parameters of Brassica napus under salinity stress. The seeds of canola were pre-treated with three arginine concentrations (0, 5, and 10µM Arg) for 24 hours. Then they were subjected to three levels of salt treatments (0, 50, and 100 mMNaCl) for 7 days. Results of this experiment indicate that salinity stress caused a number of morphological and physiological changes in the canola plant, including decrease in root and shoot length. Hydrogen peroxide and malondialdehyde (MDA) content increased in leaves of canola plant under salt stress. Salt stress also induced changes in antioxidant enzymes activitiessuch as catalase (CAT), ascorbate peroxidase, (APX), and Guaiacol peroxidase (GPX). In conclusion, the adverse effects of salt stress on canola can be alleviated by the arginine pre-treatment through modulating activities of antioxidant enzymes.