Interactive Effect of Tocopherol, Salicylic Acid and Ascorbic Acid on Agronomic Characters of Two Genotypes of Brassica napus L. Under Induced Drought and Salinity Stresses

Several agricultural systems are vulnerable to the harmful effects of climate change in today’s increasingly vulnerable world. Drought and salinity are two major factors in climate change that can severely slow down the development of many crops. This study determined the influence of induced drought and salinity on growth of two varieties of Brassica napus L. (Shiralee and Vanguard), after priming with salicylic acid, ascorbic acid and tocopherol. Seed priming significantly promoted seed germination and reduced the normal germination time of seeds under both induced stressors. Significant increase in shoot length, shoot and root fresh weight, dry shoot weight of seedling was found for all the primed seeds as compared to non-primed seeds of both cultivars. Results showed that absolute growth rate of both varieties were remarkably influenced by the imposed drought as compared to salinity treatments. Relative growth rate, net assimilation rate, seed germination index, Timson germination index were negatively affected by 150 mM NaCl concentration for the vanguard cultivar. According to results of scanning electron microscope (SEM), osmoprimed seeds increased stomatal physiology and epidermal vigor of both cultivars significantly by boosting the water potential. Response of both B. napus cultivars was found different under induced drought and salinity treatments. It has been concluded from the results that, seed priming with growth regulators such as tocopherol, ascorbic acid and salicylic acid is considered as useful technique for enhancing the germination and growth responses of B. napus under drought and salinity stresses.