The effect of salicylic acid, glycine betaine and gamma amino butyric acid foliar spray on Carla antioxidant activity under water deficit stress

In order to evaluate the effect of salicylic acid, glycine betaine and gamma_ aminobutyric acid foliar spray on anti-oxidant activity of enzymes and non-enzymatic agents of Carla (Momordica charantia L.) under water deficit stress, an experiment was conducted as split plots based on randomized complete blocks design with three replications at Research Farm University of Zanjan during 2017. The treatments consisted of three levels of irrigation (50, 75 and 100% field capacity) as the main plots and two levels of salicylic acid (2 and 4 mM), glycine betaine (50 and 100 mM), and gamma aminobutyric acid (GABA) (10 and 20 mM) plus control were used as sub plots. Based on the results, increasing of water deficit stress, significantly increased the activity of catalase, peroxidase and antioxidant activity of leaf, as well as total phenol and flavonoid content and antioxidant activity of fruit, but the amount of vitamin C decreased. The interaction of irrigation regimes with experimental treatments caused a significant increase in measured traits. The highest level of leaf and fruit antioxidant activity was obtained using 4 mM salicylic acid and 100 mM glycine, respectively, in 75% field capacity. Considering that in this study, plants treated with salicylic acid, glycine betaine and GABA in different irrigation regimes had higher enzymatic and non-enzymatic antioxidant activity than control plants, therefore it seems that application of these materials can be effective in producing Carla under water deficit stress resistance.