COMBINED APPLICATION OF SODIUM NITROPRUSSIDE AND MELATONIN ENHANCED PHOTOSYNTHETIC AND ANTIOXIDANT CAPACITY OF WHEAT UNDER DROUGHT STRESS

Exogenous application of sodium nitroprusside (SNP) and Melatonin improved drought Wheat's ability to withstand stress (Triticum aestivum L.) plants. Therefore, the current study investigated how melatonin and nitric oxide (NO) could improve the tolerance of wheat under drought stress. Treatments used for wheat plants included control, drought stress, SNP, melatonin treatment, combination SNP and melatonin treatment, abiotic stress with SNP, abiotic stress with melatonin, and abiotic stress with combined SNP and melatonin. The concentration of both SNP and melatonin used in the treatments for wheat plants was 100 μM, while the level of drought stress applied was at a standard level. In this study, the relationships between shoot length and a range of physiological parameters are investigated quantitatively. The results showed that there are significant positive correlations with tillers per plant (r = 0.918), SPAD value (r=0.977), chlorophyll-a (r=0.974), chlorophyll-b (r=0.718), and protein content (r=0.864). Still, there were negative correlations between enzyme activities and oxidative stress markers. Significant variations (p<0.05) were found between the treatments for shoot length, tillers per plant, SPAD value, chlorophyll-a, and chlorophyll-b, indicating a strong influence of SNP, melatonin and their combinations on plant growth, development, and photosynthetic activity under drought stress. Moreover, using SNP, melatonin, and their combination treatment restored these enzymes' activity, demonstrating their potential to strengthen antioxidant defence systems. This study concludes that NO and melatonin application significantly affected wheat development and reduced the adversative consequences of drought stress. Besides, the potential of these chemicals to be used as useful approaches to increase wheat tolerance to drought stress, hence advancing the development of sustainable agricultural methods.