How Can Salicylic Acid and 24-epibrassinolide Improve Productivity and Oil Quantity and Quality of Black Mustard Under Salt Stress?

This research work was carried out to find out whether the foliar application of salicylic acid (1 mM SA) and 24-epibrassinolide (0.1 μM 24-EBL) can mitigate the adverse impacts of salinity (0, 5, 10 and 15 dS/m NaCl as non-saline and low, moderate and high salinities) on performance of black mustard (Brassica nigra L.)? Pods per plant, grains per pod and grains per plant significantly decreased with increasing salinity, while 1000-grain weight increased under saline conditions. Grain yield per plant, oil percentage and yield decreased as a result of salinity increment. Foliar application of SA and 24-EBL slightly, but not significantly, enhanced 1000-grain weight and grain yield per plant compared to untreated plants. Salt stress increased percentages of palmitic and stearic acids, while reduced percentages of other fatty acids and unsaturation index (UI) of oil. Treatment of plants with SA and 24-EBL similarly decreased percentages of palmitic and stearic acids, whereas increased percentages of a saturated (erucic acid) and three unsaturated (oleic, linoleic, linolenic acids) fatty acids, leading to a high UI. Therefore, foliar applications of salicylic acid and 24-epibrassinolide could be suggested as effective methods to enhance oil quality of black mustard through increasing UI under saline and non-saline conditions.