Effects of seed deterioration on physiological traits, antioxidant enzymes and S-nitrosylation of proteins in two cultivars of canola (Brassica napus L.)

This study was conducted as a factorial experiments based on a completely randomized design with two factors cultivars (Modena and Okapi), aging level (0, 24 and 72 hours at temperature of 40˚c and relative humidity of saturated) and four replications to evaluate germination rate and percentage (GP), vigor index (SV), electrical conductivity (EC), catalase (CAT), ascorbate peroxides (APX), glutathione reductase (GR) and S-nitrosothiol (SNO) at the Ferdowsi University of Mashhad, 2019-20. Accelerated Aging (AA) treatments made significant decline in germination indices and biochemical characteristics (except EC) of canola seeds. Also, Modena cultivar was stronger in germination traits while Okapi cultivar was better in biochemical activities, which can be explained by difference in the primary genetic of the cultivars. According to the results, in the treatments of 72 hours of AA compared to the control, GP has decreased by 86%, CAT 88%, APX 89% and SNOs 36%. On the top of that, there was a positive correlation between SNOs and enzymes. In conclusion, Nitric oxide (NO) is likely to indirectly affect the antioxidant enzymes by SNOs in aged canola seeds. Seed aging targets the cell physiology by reducing the activities of antioxidant enzymes and NO and therefore increasing the rate of cell mortality.