Effect of polyamine precursors and antioxidants on growth and metabolism of salt-stressed barley

Abstract

Background: Salinity is a serious problem that reduces crop productivity by affecting seed germination and seedling growth. It affects plant growth by disrupting plant osmosis, causing ionic toxicity, and metabolic and physiological changes. The aim of the present study was to examine the effect of polyamine precursors, besides the effect of some antioxidants such as glutathione and ascorbate on growth, metabolism, and productivity of two barley cultivars, different in salt tolerance, when subjected to salt stress. Methods: Salt-tolerant G124 and salt-sensitive G119 barley cultivars had their seeds planted in plastic pots with clay and sand soil that measured 10 cm in diameter and 4 cm in height (2:1). The pots were divided into five categories: the grains were presoaked for 24 hours in distilled water, an amino acid solution (Arginine, Methionine, and Ornithine) (1 mM each), glutathione, or ascorbic acid (0.1 mM for each), seedlings were cultivated in 0.1 mM sodium chloride alone, seedlings were cultivated using a combination of salt and glutathione, seedlings were grown using a combination of salt and ascorbic acid, seedlings were cultivated using a combination of salt and amino acid mixture. Results: Salinity has resulted in a reduction in all growth parameters in both barley cultivars. In the seedling, pre-flowering, and yield stages, the exposure to salt decreased photosynthetic pigments, total soluble carbohydrates, weight, and the number of grains, whereas it showed an increase in the activities of catalase and peroxidase, proline content, malondialdehyde, and membrane leakage. Conclusion: The addition of glutathione, ascorbic acid, or amino acid mixture alleviated the harmful effect of sodium chloride and improved barley's defense mechanism against salt stress. The results showed that the alleviating effect was eventually reflected in plant growth, indicating that glutathione might be suggested as an effective treatment to reduce the impacts of salinity on barley.