Imperative roles of salicylic acid and nitric oxide in improving salinity tolerance in Pisum sativum L.

This study was undertaken to scrutinize efficacy of salicylic acid (SA) and/or sodium nitroprusside [SNP, source of nitric oxide (NO)] to mitigate injury symptoms of saline stress in Pisum sativum L. Exposure to sodium chloride (NaCl) was found to be injurious to germinating P. sativum L. (var. Shubhra IM-9101) and a direct correlation between severity of toxicity and NaCl-concentrations could be discernible. Both SA and NO serves as signal molecules in plant stress responses, and play crucial roles in key regulatory pathways of growth, development and metabolism. The limiting effects of salinity on radicle length and biomass accumulation were considerably released by SA and/or SNP and among which their combined application was found to be the most promising. Supplemented SA and/or SNP, particularly their cocktail, resulted in a substantial decline in reactive oxygen species accumulation, which later caused reduced accumulations of malondialdehyde, 4-hydroxy-2-nonenal and protein carbonyl, in NaCl subjected germinating P. sativum L. seeds. SA and/or SNP had significant inducing effects on activities of superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase. Additionally, exogenous SA and/or SNP led to the higher proline, sugar and glycinebetaine contents, than that of the control. On the basis of accumulated results, it could be concluded that the cocktail of SA and SNP may be efficiently used to overcome the adverse signatures of salinity stress.