Simultaneous Application of Ascorbic Acid and Proline as a Smart Approach to Mitigate the Adverse Effects of Salt Stress in Wheat (Triticum aestivum)

Abstract

The effects of exogenously applied ascorbic acid (AsA, 1 mM) and proline (Pro, 1 mM), were evaluated on the growth, nutritional behavior, some key biochemical attributes, oxidative damage indicators, osmolytes accumulation as well as antioxidant system in wheat seedlings (Triticum aestivum cv. Salammbô) grown in the presence of 100 mM NaCl. AsA or Pro supplementation ameliorated wheat seedlings’ growth and increased parameters that were reduced by salinity. Relative water content, total chlorophyll, K⁺ and total carbohydrates contents as well as K⁺/Na⁺ ratio and root-to-shoot K⁺ translocation were significantly increased. Osmoprotectant contents were remarkably accumulated, whereas Na⁺ content and root-to-shoot Na⁺ translocation were significantly declined. Additionally, exogenous AsA or Pro application enhanced the antioxidant defense system components and insured better oxidative stress tolerance, as indicated by reduced H₂O₂ production and lipid peroxidation, resulting in an increased membrane stability index. Such effects were further enhanced following the simultaneous application of AsA and Pro, resulting in a better growth, as compared to single applications of these substances. Taken together, findings of this study provide strong arguments highlighting the potential synergy between exogenously applied AsA and Pro in mitigating the adverse effects of salt stress of wheat plants at the early seedling stage.