Synergistic effects of hydrogen sulfide and nitric oxide in enhancing salt stress tolerance in cucumber seedlings

Salinity stress poses a significant threat to plant growth and agricultural productivity, affecting millions of hectares of land worldwide. The adverse effects of salt toxicity, primarily caused by high levels of sodium chloride in soil and water, disrupt essential physiological processes in plants, leading to reduced yields and degraded soil quality. The present study thoroughly investigated the potential involvement of hydrogen sulphide (H₂S) and nitric oxide (NO) in facilitating salt stress tolerance in cucumbers. In this investigation, NaHS (sodium hydrogen sulfide), which is the donor of H₂S, and SNP (sodium nitroprusside), which is the donor of NO, were used as treatments for cucumber seedlings exposed to salt stress. Additionally, L-NAME (N-nitro-L-arginine: 100 μM) and cPTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide), which are inhibitors and scavengers of NO respectively, were used to verify the involvement of NO in the presence of salinity. NaHS and SNP supplementation significantly boosted fresh weight, dry weight, plant height, and chlorophyll content, promoting growth under salt stress. These treatments raised endogenous H₂S and NO levels, upregulating antioxidative enzymes like SOD, CAT, APX, GR, GPX, and GSTs. This response reduced oxidative damages by lowering reactive oxygen species (ROS) and lipid peroxidation. The combined application of NaHS and SNP under salt stress offers a promising and cost-effective strategy to improve plant resilience to salinity, reduce oxidative stress, and ultimately enhance crop productivity. These findings provide important insights into the potential use of H₂S and NO donors for sustaining agricultural production in saline environments, addressing a critical global challenge for food security.