Abstract
Cotton (
Gossypium
spp.) is a crucial industrial crop, particularly grown for fiber; however, its growth, development, and yield are substantially restricted by high salt stress. Salicylic acid (SA) is a crucial phytohormone, exhibiting a multifarious array of roles in the enhancement of plant growth, progression, and resilience to stress. In the current investigation, we provided persuasive evidence on the potential roles of exogenous SA in promoting salinity tolerance in cotton plants by investigating various morphological, biochemical, and physiological features. Our results showed that pre-application of SA to the root zones of cotton plants led to a substantial enhancement of plant biomass, individual leaf area, net photosynthetic rate, stomatal conductance, transpiration rate, water-use-efficiency, and chlorophyll, carotenoid and relative water contents in leaves, resulting in better growth performance of cotton under salt stress. SA pretreatment further diminished the salinity-induced accumulation of hydrogen peroxide, and the elevated levels of electrolyte leakage and malondialdehyde in the leaves of cotton plants. The SA-pretreated cotton plants experienced reduced oxidative burden because of improved antioxidant defense systems, as manifested by the enhanced activities of catalase, ascorbate peroxidase, peroxidase, and the levels of total flavonoids. Furthermore, the pretreatment with SA resulted in a remarkable elevation in the levels of total free amino acids and total soluble sugars in salt-stressed plants, indicating that SA utilized these compounds for optimal osmotic regulation in the plant tissues amidst adverse saline conditions. Importantly, the pretreatment with SA resulted in a substantial inhibition of Na
+
uptake and a remarkable increase in the uptake of K
+
, Mg
2+
, and Ca
2+
in both roots and leaves of cotton plants. Together, our findings suggest that SA pretreatment could be an effective strategy to increase the resiliency of cotton plants toward salinity, thereby enabling better performance of cotton plants in saline prone areas.