Mitigating the adverse effects of drought stress on sunflower plants via foliar application of salicylic acid

Sunflower is the primary oilseed crop of Pakistan, valued for its edible oil and high yield potential under favorable conditions. However, drought stress is a major limiting factor affecting sunflower productivity, causing significant yield reductions. The present study aimed to evaluate the potential role of salicylic acid in enhancing the growth and physiological performance of sunflowers under drought stress. Drought stress was applied 20 days after sowing, with three experimental treatments conducted in five replications: (a) control (normal conditions), (b) drought stress, and (c) drought stress supplemented with 250 mg L? salicylic acid. Key findings revealed that the foliar application of 250 mg L? salicylic acid significantly improved various growth parameters, including shoot length (24.92%), root length (18.97%), fresh shoot weight (15.78%), dry shoot weight (24.15%), fresh root weight (21.32%), and dry root weight (26.72%). Moreover, chlorophyll content increased by 32.90%, stomatal conductance by 19.52%, relative water content by 20.84%, and membrane stability index by 41.79%. Moreover, salicylic acid markedly mitigated oxidative damage, reducing malondialdehyde levels by 32.81% and hydrogen peroxide levels by 17.80% compared to untreated plants. Furthermore, the treatment enhanced the activity of antioxidant enzymes, with superoxide dismutase activity increasing by 17.25%, catalase by 40.05%, and peroxidase by 10.41%. In conclusion, the foliar application of 250 mg L? salicylic acid effectively enhances the growth and physiological parameters of sunflower under drought stress, offering a sustainable and reliable strategy to mitigate the adverse effects of water scarcity on crop production.