Exogenous myo-inositol enhances drought tolerance in maize seedlings by antioxidant defense, and photosynthetic efficiency
Yuqi Liu, Hao Sun, Xiaonan Guo, Tianyuan Song, Zongling Yu, Wei Li, Yaxin Lin, Yanci Zhou, Deguang Yang
Abstract
Introduction Drought stress severely impairs maize ( Zea mays L.) production, particularly during the seedling stage. Methods In this study, we aimed to investigate the role of exogenous myo-inositol (MI) in alleviating drought stress in maize seedlings. We established four treatments: control (CK), MI application under normal irrigation (G), drought stress (D), and MI application under drought stress (DG). Results The results demonstrate that MI significantly restored growth parameters under drought conditions, increasing shoot and root biomass by 40.74% and 28.30%, respectively, on Day 7. Additionally, MI enhanced photosynthetic efficiency (net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (gs), and photosystem II efficiency (Fv/Fm)) and upregulated osmotic regulators (e.g. proline and soluble sugars) in the leaves and roots. Furthermore, antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), and glutathione reductase (GR)) and ascorbic acid–glutathione (ASA–GSH) cycle components were synergistically activated by MI, reducing oxidative damage, as indicated by decreases in malondialdehyde (MDA), H 2 O 2 , and O 2 ·- . Principal component analysis highlighted the pivotal roles of osmotic adjustment and antioxidant systems in drought mitigation. Discussion These findings reveal that MI is a potent inducer of drought resilience in maize, offering a novel strategy for maize cultivation under water scarcity.