Impact of salicylic acid and sodium hydrosulfide applied singly or in combination on drought tolerance and grain yield in wheat plants

Climate change-induced drought stress (DS) poses a significant threat to crop production, emphasizing the need for innovative strategies to mitigate its adverse effects. Prior studies have demonstrated the distinct capacities of salicylic acid (SA) and sodium hydrosulfide (NaHS) to augment plant resilience against drought-related stressors. However, little is known about how they work together or the specific processes by which they increase DS tolerance. The purpose of this research was to determine how SA and NaHS affected the performance of wheat plants during the growing seasons of 2021–2022 and 2022–2023, when there was a drought. The research employed a block-randomized experimental layout with split plots, where the primary factors included two irrigation levels: full irrigation (IW1, 100% of water requirement) and deficit irrigation (IW2, 50% of water requirement). Secondary factors included the application of mock control, 0.5 mM SA, and 0.3 mM NaHS, an H₂S donor, either individually or in combination, administered before the onset of DS. The application of SA, NaHS, or their combination significantly enhanced wheat plant resistance to DS. Significant increases in a number of physiological markers, including proline content, relative water content (RWC), Fv/Fm, chlorophyll content, and antioxidant enzyme activity, demonstrated this improvement. Furthermore, in drought-stressed wheat plants, SA and NaHS treatments decreased the amounts of hydrogen peroxide (H₂O₂), malondialdehyde (MDA) content, and electrolyte leakage (EL). In conclusion, our study highlights the possibility of SA and NaHS, whether applied individually or in combination, to improve drought resistance in wheat plants, presenting a viable approach to lessen the effects of climate change on agricultural yield.