Under drought stress, exogenous application of GABA can significantly increase the activities of SOD, POD, and CAT in maize leaves, and reduce the accumulation of MDA, thereby alleviating the damage to the cell membrane caused by drought stress and reducing the relative conductivity of leaves.
In addition, the increase of the content of osmotic adjustment substances can improve the water absorption and water retention capacity of cells and maintain the normal shape of cells.
At the same time, exogenous application of GABA can significantly reduce the photochemical damage of leaves, alleviate the negative effects of drought stress on chlorophyll and photosynthesis, and restore the growth of maize seedlings.
Exogenous application of GABA can also increase the transpiration rate, net photosynthetic rate, and stomatal conductance of leaves, alleviate the effect of drought stress on the photosynthesis of seedlings, and improve the adaptability of plants under drought stress.
γ-aminobutyric acid (γ-aminobutyric acid, GABA) is a four-carbon non-protein amino acid that exists in various organisms in a free state.
In the abiotic stress of crops, GABA has the functions of maintaining the C/N balance in crops, acting as a signal transduction substance, improving the activity of antioxidant enzyme systems, and increasing the content of osmotic adjustment substances, so it is closely related to the regulation of crop stress resistance.
Under mild and severe drought stress, exogenous application of GABA can significantly increase the plant height, stem diameter, leaf area and whole plant dry and fresh weight of muskmelon seedlings, and alleviate the growth inhibition caused by drought stress.
In our study, exogenous application of GABA under drought stress can significantly restore the growth of maize seedlings and alleviate the inhibitory effect of drought stress, and the GABA concentration is the best when the concentration is 1mmol·L-1. The significant decrease in the root-to-shoot ratio also indicated that GABA promoted the aboveground part more than the underground part under drought stress.