Effects of Exogenous Gamma-Aminobutyric Acid on Absorption and Regulation of Ion in Wheat Under Salinity Stress

Abstract : Gamma-aminobutyric acid (GABA), a four-carbon non-protein amino acid, is a significant component of the free amino acid pool, there are numerous reports that rapid and large increases in GABA levels occur in plants, in response to a variety of biotic and abiotic stress. Based on its metabolism and putative roles in plants, GABA is considered a natural chemical to increase wheat salt-tolerance. So this study investigated the exogenous GABA on wheat seedling (Triticum aestivum L. cv. Changwu134 and zhouyuan9369) growth and absorption of salt ions under normal or salt-stressed conditions. The results demonstrated that salt stress inhibited growth of wheat seedlings, decreased dry weight and water content, altered ion balance within the stressed seedlings. Pretreatment with 50 mg/L GABA increased seedling biomass and K+ content in leaves, decreased Na+ content in leaves and roots under salt-stressed conditions by improving Na+ exclusion, K+ retention. These results indicated that exogenous 50 mg/L GABA improved seedling growth and alleviated the inhibition due to salt stress of wheat by altered ion balance. Exogenous GABA has the capability of restraining transportation of salt ions to leaves and sustaining normal function of leaves. And the effect of exogenous GABA is obvious in common variety (zhouyuan9369) than in salt-tolerance variety (changwu134).