Mediation of Growth and Metabolism of Pisum sativum in Salt Stress Potentially Be Credited to Thiamine

We explored how two pea varieties, Sarsabz (V1) and Meteor (V2), showed resistance to salt stress by modulating their mechanism under thiamine application. The experiment was performed to evaluate the effect of three levels of foliarly applied thiamine (0, 250, and 500 ppm) on biochemical and morpho-physiological parameters of pea varieties under salt stress (150 mM). Both morpho-physiological and biochemical responses were examined such as growth attributes, chlorophyll contents, total sugars, total proteins, proline content, phenolic content, and antioxidant activities. One hundred fifty millimolar of salinity caused significant reduction in growth and photosynthetic pigments in both pea varieties. The highly significant effect was noted after application of 500 ppm of thiamine in V1 on shoot and root weights, lengths, and photosynthetic pigments as compared to the control. The V2 accumulated the highest Na+, Cl−, and Ca2+ under stressed conditions compared to V1; its homeostasis appeared to be more affected. The results indicated that 500 ppm alleviated the detrimental effects of salinity in both pea varieties by supporting different components of the defense mechanism. Both varieties differed significantly for total soluble sugars, proline, and phenolics. Our results showed that the mitigating effects of 500 ppm of thiamine against salinity proved to be more promising in comparison with other levels. The exogenous supply of thiamine not only protected growth and development but also supported biochemical attributes in terms of detoxification responses for fighting against the stressed conditions.