Role of trehalose on antioxidant defense system and some osmolytes of quinoa plants under water deficit

Abstract

For scavenging reactive oxygen species, plant possess effective system that protect them from destructive oxidative reaction. Parts of this system as osmoprotectants and antioxidative enzymes are key elements in the defense mechanisms. A field experiment was conducted to evaluate the potential of foliar treatment of trehalose (Tre) with different concentrations (0, 0.1 mM, or 0.5 mM) in improving antioxidant defense system of quinoa plant under normal irrigation and drought stress conditions. Drought stress caused significant increases in some osmoprotectants as glucose, trehalose, TSS, free amino acids, and proline. Meanwhile, trehalose foliar treatment with different concentrations significantly decreases in free amino acids and proline contents. More accumulation of the tested organic solutes of leaves (glucose, sucrose, trehalose, TSS) of the trehalose-treated plant in both normal irrigated and drought-stressed quinoa plants as compared with the corresponding controls. Treating quinoa plants with trehalose resulted in significant decrease in lipid peroxidation, hydrogen peroxide contents, and LOX activity in normal irrigated and drought-stressed plants. These decreases correlated with significant increases in total phenolic contents as compared with untreated control. Different concentrations of trehalose resulted in significant increases in antioxidant enzymes. Maximum increase antioxidant enzymes were observed by treating plants Tre at 0.5 mM either under normal irrigation or drought conditions. It could be concluded that foliar spray of trehalose was effective in improving quinoa performance by reducing hydrogen peroxide free radical and by enhancing antioxidant compounds (phenolics), compatible osmolytes, membrane stability, and antioxidant enzymes.