Seed Priming with Sodium Nitroprusside and H2O2 Confers Better Yield in Wheat Under Salinity: Water Relations, Antioxidative Defense Mechanism and Ion Homeostasis

To mitigate the deleterious effects of abiotic stresses signaling molecules play a significant role. The present study was aimed to assess the responses of two differentially salt-tolerant wheat genotypes (Fsd-2008 and S-24) to exogenously applied sodium nitroprusside (SNP) (donor of nitric oxide), hydrogen peroxide (H2O2) as well as their combined application as seed priming under saline stress. Before sowing seeds were primed with each treatment as soaking for 16 h. Salinity markedly decreased the growth, nutrient uptake and yield, while enhanced the H2O2, malondialdehyde, osmolytes accumulation, antioxidative defense mechanism and Na+ uptake in both wheat cultivars. Comparatively less increase in Na+ uptake was recorded in genotype S-24 in comparison with genotype Fsd-2008. Seed priming with H2O2 and SNP improved the growth and yield, in association with increment in leaf photosynthetic pigments, water relations as well as accumulation of osmolytes. The content of non-enzymatic antioxidant components as well as activities of antioxidant enzymes were also further increased by the seed priming with signaling molecules in both wheat genotypes. Improvement in K+/Na+ ratio due to seed priming was also found in both wheat genotypes but more improvement was in genotype S-24. In conclusion, SNP and H2O2 applied salt tolerance was associated with improved photosynthetic pigments, water relations, osmolytes accumulation, antioxidative defense mechanism, and improved Na+ discrimination.