Effect of exogenous Gama-aminobutyric acid on physiological tolerance of wheat seedlings exposed to chilling stress . Praviz Malekzadeh*, Jalil Khara and Reza Heidari

Accumulation of γ -aminobutyric acid (GABA) is associated with stress factors in plant systems. The objective of the current study was to compare GABA concentration in wheat plants under chilling stress. After 48 h treatments of seedlings under chilling stress combined stresses with and without GABA, morphological and biochemical assays were conducted. It was observed that the inhibition of seedling roots elongation caused by chilling stress was significantly mitigated by GABA. The activities of antioxidant enzymes were changed; the content of malondialdehyde was increased in chilling stress but reduced in GABA treated seedlings. GABA can alleviate oxidative damage caused by chilling stress in wheat seedlings by activating antioxidant defense responses.