Exogenous application of liquiritin alleviated salt stress and improved growth of Chinese kale plants

Current research was designed to evaluate the role of exogenous liquiritin (750 ppm) in alleviation of salt stress in Chinese kale (Brassica oleracea var. alboglabra). Salt stress (2.5 and 5 dS m(-1)) caused ionic phytotoxicity through enhancing sodium content and decreasing plant nutrients such as potassium, calcium and magnesium. The 5 dS m(-1) salinity treatment significantly declined the root length, shoot length, total chlorophyll, total soluble proteins, leaf relative water content, water use efficiency, total glucosinolates, and ascorbic acid of Chinese kale plants by 39%, 35%, 28%, 15%, 26%, 29%, 35%, and 19% respectively as compared to untreated control. Neverthless, liquiritin supplemented plants showed obvious augmentation in the values of these growth parameters under toxic and non toxic regimes. Similarly, salinized plants showed higher amount of hydrogen peroxide (H2O2), malondialdehyde (MDA), flavonoids, total soluble proteins, proline phenolics and free amino acids in addition to activity of antioxidant enzymes including super oxidase, catalase and peroxidase. Never-theless, liquiritin alleviated salt induced oxidative stress through decreasing MDA and H2O2 level besides improving antioxidative machinery in treated plants. The salt stress assuagement in liquiritin treated plants was correlated to the elevated biosynthesis of total free amino acids, proline, and total glucosinolate content besides well-organized antioxidant system.