Gamma-aminobutyric acid improves cold tolerance of wheat seedlings

To provide a new agent to enhance wheat cold tolerance, we investigated the impacts of gamma-aminobutyric acid (GABA) on wheat antioxidant and photosynthetic capacity and growth parameters under cold stress (CS). CS significantly improved superoxide dismutase, catalase, peroxidase, ascorbate peroxidase and gluathione reductase in wheat leaves. Meanwhile, CS also increased the contents of reduced ascorbate (AsA) and reduced glutathione (GSH). However, CS significantly increased electrolyte leakage (EL) and malondialdehyde (MDA) levels. Compared with CS, GABA + CS improved the activities of the above antioxidant enzymes and the contents of antioxidants. In this way, GABA improved wheat antioxidant capacity and decreased MDA content and EL under CS. Whereas CS significantly increased non-photochemical quenching coefficient (qN) and reduced soil and plant analyser development (SPAD) value, net photosynthetic rate (Pn), maximum photochemical efficiency of PSII (Fv/Fm), effective quantum yield of PS II (Y(II)), photochemical quenching coefficient (qP), plant height and biomass. Compared to CS, GABA + CS significantly promoted the photosynthetic capacity by reducing qN and increasing SPAD value, Pn, Fv/Fm, Y(II) and qP. In this way, GABA improved plant growth under CS. Our results indicated that GABA can be used as a new agent to improve wheat cold tolerance.