Exogenous Application of GABA Alleviates Alkali Damage in Alfalfa by Increasing the Activities of Antioxidant Enzymes

Alfalfa (Medicago sativa L.) is a widely grown and important forage crop. However, alkali stress detrimental to alfalfa yield nutritional quality. Gamma-aminobutyric acid (GABA) signaling molecule, it participates in responds metabolic regulation related plant growth development stress. In this study, we clarify the effect of spraying seedlings with GABA on tolerance seedlings. We determined that exogenous application at 75 mmol/L improved resistance caused by exposure 100 NaHCO3, pH 8.5. Exogenous significantly increased chlorophyll content, accumulation soluble sugars plants, decreased their relative electrical conductivity, malondialdehyde (MDA), superoxide anion (O2−) hydrogen peroxide (H2O2) contents, activities antioxidant enzymes catalase (CAT), dismutase (SOD), peroxidase (POD). GAD GABA-T, content glutamate endogenous GABA, regulated expression genes MsGAD, MsGABA-T MsGDH. plants survived for long time, compared control group, root length fresh weight were higher. had positive stress, was closely associated GABA-T activity, levels antioxidants. This work provides new method cultivation early-stage under low or moderate conditions through GABA.