Acid rain causes visible symptoms on foliage which can lead to severe economic loss to the growers. In this study, two cultivars of Beta vulgaris L. (Palak, an economically important leafy vegetable) were subjected to simulated acid rain (SAR) of pH 5.6, 5.0, and 4.5 to assess the cultivar-specific physiological, biochemical, growth, and nutritional responses at different growth stages compared to pH 7.0 (control). Higher SAR acidity caused enhanced accretion of reactive oxygen species and lipid peroxidation in both the cultivars but the degree of increase was higher in Anupama compared to Allgreen at the vegetative stage (VS). Both Allgreen and Anupama displayed leaf injury with more severity in Anupama leading to the greater loss of chlorophyll and the plant's photochemical efficiency. Antioxidative enzymatic activities (superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, and glutathione reductase) and non-enzymatic metabolites (total phenolics, flavonoids, ascorbic acids and thiol content) didn't show a significant effect of SAR upto pH 5.6 and thereafter variable responses were observed in both the cultivars at different growth stages. The cytoplasmic pH didn't alter in Allgreen at pH 5.6 whereas decreased significantly in Anupama. The decrease in cytoplasmic pH was more in Anupama compared to Allgreen at pH 5.0 and 4.5. The growth, biomass, and fresh weight of leaves enhanced in Allgreen at VS whereas reduced in Anupama at all growth stages under SAR. The soluble protein, starch and total soluble sugar were more suppressed in Anupama compared to Allgreen under SAR. The present findings demonstrate that SARs of pH < 5.6 induced foliar injury, and disturbed physiological and biochemical traits leading to reductions in the growth, yield, and quality of palak, however, Anupama was severely affected than Allgreen. This research may be utilized to understand the cultivar-specific responses of palak an important leafy vegetable known to be a "Mines of Minerals".
