Mitigation of drought-induced stress in sunflower (Helianthus annuus L.) via foliar application of Jasmonic acid through the augmentation of growth, physiological, and biochemical attributes.

Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely cultivated oilseed crop with considerable potential globally. Jasmonic acid, a plant growth regulator, plays a crucial role in alleviating the adverse impacts of drought stress on the morphological, biochemical, and physiological characteristics of crops. Experimental detail includes sunflower varieties (Armani Gold, KQS-HSF-1, Parsun, and ESFH-3391), four drought stress levels (0, 25%, 50%, and 75% drought stress), and three levels (0, 40ppm, 80ppm) of jasmonic acid. The 0% drought stress and 0ppm jasmonic acid were considered as control treatments. The experimental design was a completely randomized design with three replicates. Drought stress significantly reduced the growth in all varieties. However, the exogenous application of jasmonic acid at concentrations of 40ppm and 80ppm enhanced growth parameters, shoot and root length (1.93%, 19%), shoot and root fresh weight (18.5%, 25%), chlorophyll content (36%), photosynthetic rate (22%), transpiration rate (40%), WUE (20%), MDA (6.5%), Phenolics (19%), hydrogen peroxide (7%) proline (28%) and glycine betaine (15-30%) under water-stressed conditions, which was closely linked to the increase in stomatal activity stimulated by jasmonic acid. Furthermore, JA 80 ppm was found to be the most appropriate dose to reduce the effect of water stress in all sunflower varieties. It was concluded that the foliar application of JA has the potential to enhance drought tolerance by improving the morphological, biochemical, and physiological of sunflower.