Abstract: In this study, tall fescue (Arid 3) was used as the material to study the effect of preparation of γ-aminobutyric acid (25, 50, 100, 200 and 400 mg/L) on heat tolerance of tall fescue under heat stress. The results showed that different concentrations of GABA could alleviate the damage of high fescue seedlings under the heat stress of 42/30℃ (day/night). Further studies showed that exogenous GABA could not only reduce the accumulation of malondialdehyde (MDA) and H2O2 in seedlings under heat stress, but also enhance the activities of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). At the same time, it can also improve the soluble protein content in the seedlings and reduce the soluble sugar content and the relative conductivity of the leaf exudate. GABA at the concentration of 100 mg/L showed the best results.

Key words: γ-aminobutyric acid, tall fescue, heat stress, heat tolerance