Ibuprofen Improves Wheat Growth Under Salinity by Modulating Hormonal and Antioxidant Status

Pre-sowing seed treatment (priming) is a strategic tool for programming future crop yield, aimed at improving early plant development and enhancing stress resilience. This study investigated the effects of priming wheat seeds with 100 µM ibuprofen on early ontogeny under optimal conditions and salt stress (100 mM NaCl). An evaluation of germination energy, growth parameters, phytohormone levels (abscisic acid, indolylacetic acid, and cytokinins) and the status of the antioxidant system in 7-day-old seedlings demonstrated that ibuprofen treatment stimulates wheat growth and tolerance, despite its absence of accumulation in plant tissues. Modulation of hormonal balance plays a key role in these protective effects: under optimal conditions, ibuprofen elevates abscisic acid and indolylacetic acid levels, while under salt stress, it prevents excessive abscisic acid accumulation and mitigates the stress-induced decline in indolylacetic acid and cytokinins. Furthermore, ibuprofen promotes a coordinated increase in glutathione, ascorbate, and H₂O₂ levels, concomitant with the activation of key enzymes (glutathione reductase and ascorbate peroxidase), thereby enhancing the plants' antioxidant potential. Under saline conditions, ibuprofen pretreatment also reduces stress-induced dysregulation of this system. Therefore, ibuprofen acts as a hormetic preconditioning agent that improves seedling vigor and stress tolerance by fine-tuning hormonal signaling and redox metabolism.