Morpho-physiological changes in carrots by foliar γ-aminobutyric acid under drought stress

The present study was aimed to investigate the effects of foliar spray of gamma-aminobutyric acid (GABA) on the morpho-physiological traits of water-stressed carrot cultivars (Supertaj and Bharat). The different levels of GABA (0, 1, 2, and 4 mM) were sprayed after 20 days of carrot germination grown under 100% and 50% field capacity of soil moisture. The samples were taken after 2 weeks of GABA application and morphological characteristics, integrity of cell-membrane, photosynthetic pigments, and enzymatic antioxidants were measured. The results revealed that the foliar application of GABA improved the vegetative growth and significantly increased the levels of free amino acids, plastid pigments, enzymatic antioxidants, and the relative water content in the roots grown under 50% field capacity as compared to control. Additionally, the GABA application decreased the electrolyte leakage of ions and malondialdehyde content in carrot leaves. The protein contents of GABA-treated carrot plants did not significantly vary with untreated plants. In conclusion, the application of GABA for the production of carrots may help plants to mitigate the adverse effects of water deficit stress.