Abstract
The current study has been designed to investigate the effect of different concentrations (0, 25, 75, 100 ppm) amino acids including Methionine (Met), Tryptophan (Tryp), Glycine Betaine (GB) and Lysine (Lys) in alleviating the effect of salt stress. The experiment was performed on maize plants under two stress conditions (0, 120 mM NaCl). Effect of salinity reduced the morpho-physiological parameters along with antioxidant activities. Application of amino acids exhibit potential of tolerance for saline stress. All applications of amino acids increased the growth parameters, however, maximum shoot length, biomass of shoot was noted under the application of lysine while root length, number of leaves and biomass of root was improved by the application of glycine betaine, methionine and tryptophan respectively. Photosynthetic pigments were increased under the influence of glycine betaine. Amino acids also triggered the antioxidant activity and increase the production of metabolites. Phenolics, total soluble proteins (TSP) and superoxide dismutase (SOD) were improved by the application of glycine betaine, catalase (CAT), peroxidase (POD) and flavonoids were improved by the application of tryptophan, while total free amino acids (TFA) were more under the effect of methionine application. With increasing concentrations of amino acids the parameters were also in increasing pattern. Because of amino acids application, enhancement of studied parameters under saline environment is linked to increased photosynthetic pigments, improved metabolites and modulated antioxidants activites in Zea mays L.