Seedling Priming with Sodium Nitroprusside Rescues Vigna radiata from Salinity Stress-Induced Oxidative Damages

The main focus of this manuscript was to highlight the efficacy of seedling priming with 0.06 mM sodium nitroprusside (SNP), a potent NO donor in the alleviation of salt-induced oxidative and ionic stress in Vigna radiata. Treatment of seedlings with 100 mM NaCl reduced their overall growth and severely affected the basic growth and physiological parameters such as fresh weight, dry weight, root, shoot and leaf length, and relative water content and led to chlorophyll loss, accumulation of H2O2 and malondialdehyde (MDA) and induced the ascorbic acid oxidase (AAO) activity. Priming with SNP enhanced the level of protective metabolites such as proline, reducing sugars, total amino acids and total phenolics, lowered the AAO activity, and modulated the activity of antioxidative enzymes such as catalase, ascorbate peroxidase, superoxide dismutase and guaiacol peroxidase that efficiently scavenged the H2O2 formed, lowered the MDA level and chlorophyll loss, and improved the overall physiological traits. The activity of polyphenol oxidase, nitrate reductase and alpha-amylase was also induced in presence of SNP during salt stress that ensured better utilization of polyphenolic compounds for defence, and improved the nitrogen assimilation efficiency with better mobilization of stored starch, so as to facilitate germination and enhance seedling tolerance in response to salinity. Our communication clearly established the prospects of seedling priming with SNP as a cost-effective strategy to develop salt-tolerant V. radiata seedlings with better survival capacity.