γ-aminobutyric acid enhances the antioxidant defense system and photosynthetic performance of wheat seedlings under cadmium stress

In this paper, I elucidated the influence of γ-aminobutyric acid (GABA) on wheat cadmium (Cd) tolerance. Research results manifested that Cd stress increased superoxide dismutase, catalase, peroxidase, ascorbate peroxidase and glutathione peroxidase activities, and ascorbic acid (AsA) and glutathione (GSH) contents. However, Cd stress decreased AsA/ dehydroascorbic acid (DHA) and GSH/oxidised glutathione (GSSG) ratios, and inhibited photosynthetic performance and plant growth. Compared to Cd alone, GABA plus Cd improved wheat Cd tolerance by increasing the activities of above antioxidant enzymes, AsA and GSH contents, and AsA/DHA and GSH/GSSG ratios. Meanwhile, compared with Cd alone, GABA plus Cd also enhanced the photosynthetic performance by improving chlorophyll (Chl) and carotenoid (Car) contents and Car/Chl ratio, photosynthetic rate, transpiration rate, stomatal conductance, intercellular carbon dioxide concentration, and Chl fluorescence parameters maximum photochemical efficiency of PSII, photochemical quenching, nonphotochemical quenching and quantum efficiency of PSII photochemistry, which further promoted plant height and biomass. Compared to control, GABA alone also improved above indicators. Current results suggested that GABA can be applied as an anti-cadmium agent in wheat production practice.