Exogenous melatonin confers drought stress by promoting plant growth, photosynthetic efficiency and antioxidant defense system of pea (Pisum sativum L.)

One important environmental condition that negatively impacts plants is drought stress. Melatonin had the potential to enhance drought tolerance in plants. So, the purpose of this study was to explore the benefits of exogenous melatonin on drought-stressed pea. Pea plants were exposed to severe drought by only providing half of the water they needed. Treatment with melatonin was given through foliar spray at various concentrations (0, 30, 60, and 90 µM). The current findings demonstrated that the plant growth metrics, including plant height, root length, and fresh biomass, were dramatically lowered by drought stress. The unfavorable impacts of drought stress on plant growth were, however, lessened by melatonin treatment, which led to better growth and production. Melatonin-treated plants exhibited enhanced antioxidant defense mechanisms, as indicated by increased levels of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione (GR) activities. Melatonin supplementation effectively reduced hydrogen peroxide (H2O2) and malondialdehyde (MDA), thereby minimizing oxidative damage caused by drought stress.The photosynthetic system in drought-stressed pea plants was considerably inhibited by melatonin. Exogenous melatonin may be able to mitigate the negative effects of drought-related stress on pea. These findings point to melatonin as a potential tool for improving pea drought resistance. As a signaling molecule, melatonin promotes plant development while also governing photosynthesis, the antioxidant defense system, and oxidative stress. To fully understand the molecular principles behind the melatonin-mediated drought-resistant response in plants, more investigation is needed.