بررسی اثر گابا (گاما آمینو بوتیریک اسید) بر بهبود تحمل تنش خشکی در زعفران مزروعی (Crocus sativus L.)

             Drought stress is one of the major environmental concerns associated with various defects in plant growth and development. Environmental stressors trigger a wide range of reactions in plants, ranging from changes in gene expression level and cell metabolism to alteration in growth rate and plant function. Application of certain chemicals, such as gamma amino butyric acid (GABA), is suggested to minimize the detrimental effects of drought stress. To investigate the effect of GABA in vegetative characteristics and resistance indices of saffron (Crocus sativus L.) plants under water deficit condition, current experiment was conducted in research greenhouse at Tehran University of Sciences. The experiment was performed in factorial pattern based on the completely randomized block design. In this experiment GABA was applied on plants at three concentrations of ۰, ۲۵ and ۵۰ μM under three levels of polyethylene glycol (PEG)(۰%, ۱۰% and ۱۵%) as drought stress inducer. The results showed that water deficit conditions decreased fresh and dry weight of shoot and root, leaf number, leaf area, photosynthetic pigments and protein content. Besides, physiological parameters such as proline content and antioxidant enzyme activity increased under drought stress conditions. Application of GABA in this experiment generally improved the morphological characteristics (including leaf number and leaf area, fresh and dry weight of leaves and roots), photosynthetic pigments and soluble protein content. GABA application improved qualitative and biochemical properties including anthocyanin, total phenol and flavonoid content under drought stress conditions. GABA exposure resulted in decreased MDA activity and increased antioxidant superoxide dismutase (SOD) functionality. GABA increased the plant's resistance to water deficit stress by affecting the activity of catalase enzyme activity in stressed plants compared to those of control. This effect was very significant under ۱۵% PEG and ۵۰ μM GABA treatments. Our findings indicate that GABA application can increase plant yield under drought stress conditions. According to these results and positive effect of the GABA application on induction of drought resistance in saffron, it is recommended to use GABA as an effective compound to diminish the detrimental effects of drought stress in saffron plants.  

کلیدواژه ها:

Water deficit stress ، Saffron ، GABA ، Drought resistance ، تنش کم آبی ، زعفران ، گابا ، مقاومت به خشکی