Effects of Physiological Regulation of γ-aminobutyric Acid on the Salt Tolerance in Xanthoceras sorbifolia Bunge

The leaf cuttings of Xanthoceras sorbifolia Bunge were used as the test materials, the four stress treatments, 1% NaCl, 5 mm^ol·L^-1 GABA+1% NaCl, ¹⁰ mmol·L^-1 GABA+1% NaCl^{, a}nd 15 mmol·L^-1 GABA+1% NaCl were set.Morphological indexes, root activity, endogenous GABA content, protective enzyme activity, malondialdehyde（MDA_）^,superoxⁱde anion ■ and Na⁺ contents were determined.The effects of γ-aminobutyric acid（GABA） on the physiological characteristics of Xanthoceras sorbifolia Bunge under salt stress were studied, in order to provide reference for the study on the salt tolerance of Xanthoceras sorbifolia Bunge.The results showed that under salt stress, the plant growth rate, plant fresh weight, leaf area, root dry weight, stem dry weight and leaf dry weight were significantly lower than the control, while the main root length was significantly higher ^than the control.10 mmol·L^-1 GABA significantly alleviated the growth and development of Xanthoceras sorbifolia Bunge under salt stress.In particular, the external morphology of Xanthoceras ^sorbifolia Bunge under 15 mmol·L^-1 GABA treatment was basically restored to the control level.Exogen^ous GABA significantly inhibited Na⁺ accumulation and increased the activities of superoxide dismutase（SOD）,peroxidase（POD） and catalase（CAT） in the roots of Xanthoceras sorbifolia Bunge under salt stress, thus decreasing the accumulation of MDA.In conclusion, exo^genous GABA significantly inhibited Na⁺ accumulation in roots of Xanthoceras sorbifolia Bunge under salt stress, improved protective enzyme activity and root activity, reduced plasma membrane oxidative damage of roots, and alleviated salt stress.