Changes in Antioxidant Capacities and Antioxidant Enzyme Activities during Drought Stress in the Germination Period of Madura Local Corn Seeds (Zea mays L.)

One of the major environmental factors of plant growth and productivity is drought stress. A plant that grows under drought stress can have an adverse physiological, biochemical, and morphological effect. It is involved in metabolic responses such as signaling, physiological regulation, and defense responses. The effect of various polyethylene glycol (PEG) concentrations on induced drought stress on the antioxidant capacities and antioxidant enzyme activities was investigated on Madura local maize during germination. Seed samples were treated under 5%, 10%, and 15% of PEG for 6 days. The changes in the antioxidant capacities such as 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and hydroxyl radical scavenging; antioxidant enzyme activities including catalase (CAT) and ascorbate peroxidase (APX) and gene expression were observed during seeds germination. The result showed that the antioxidant activity capacities and enzymes exhibited significantly higher levels in drought-treated conditions. The most effective level of drought stress to elevate the capabilities and enzyme activity of antioxidants, as well as its gene expression, was observed at 15% PEG, whereas ABTS scavenging activity was increased by 20% over the control, hydroxyl scavenging activity up to 14%, CAT and APX activity increased 4 - 5 times over the control. Along with the presence of antioxidant mechanisms, including the capacities and activities of different types of ABTS+, hydroxyl, CAT, and APX, might play important roles during the germination phase and be able to manage reactive oxygen species to the normal level under stress conditions. It was concluded that the germination seeds could be used as natural antioxidant agents, and drought could improve antioxidant levels, so this information is beneficial for broader cultivation on suboptimal land.