TABLE 2.
Role of melatonin in inducing drought stress tolerance in different plant species.
| Crops | Stress conditions | MT application | Effects | References |
| Soybean | 30% field capacity | 100 μM | MT application improved the photosynthesis and reduced the ABA, MDA, and H2O2 accumulation by triggering the activities of APX, CAT, POD, and SOD | Imran et al., 2021b |
| Coffee | 40% field capacity | 100 μM | MT reduced the chlorophyll degradation, MDA accumulation, electrolyte leakage by increasing the activities of CAT and SOD. Moreover, MT suppressed the expression of chlorophyll degradation gene PAO and upregulated the gene AREB encoding ABA-responsive element-binding protein | Cherono et al., 2021 |
| Maize | 40% field capacity | 100 μM | MT application increased biomass production by reducing the ROS production and increasing the photosynthetic activity and activities of APX, CAT, and POD and accumulation of soluble proteins and proline | Ahmad et al., 2019 |
| Moringa oleifera | Drought stress was imposed by skipping irrigation at 45 and 60 days after sowing | 150 μM | Foliar application of MT improved moringa’s growth, yield, and quality by enhancing the photosynthetic pigments, phenolic contents, IAA accumulation and reducing the MDA and ROS accumulation by increasing the APX, CAT, and SOD activities | Sadak et al., 2020 |
| Flax | 50% field capacity | 7.5 mM | MT application improved the growth, yield, photosynthetic activities, IAA contents, soluble sugars, free amino acids, and activities of CAT and POD | Sadak et al., 2020 |
| Wheat | 40% field capacity | 500 μM | MT improved the photosynthetic rate, efficiency of PS-II, water holding capacity, and activities of APX, DHAR, GPX, GST, and genes expression of these antioxidant enzymes | Zhang et al., 2017a |
| Alfalfa | Drought stress was imposed by withholding irrigation for seven 7 days | 10 μM | MT application reduced the MDA contents ROS production and increased the activities of APX, CAT, GR, and SOD and genes expression | Antoniou et al., 2017 |
| Maize | Drought stress was imposed by withholding irrigation for 7 days | 100 μM | MT application improved the photosynthetic activities, stomatal conductance, turgor potential and reduced the MDA and H2O2 by increasing anti-oxidant activities | Ye et al., 2016 |