Effects of exogenous melatonin on wheat quality under drought stress and rehydration

Melatonin (MT) regulates and enhances crop tolerance to drought stress. However, the effect of melatonin spraying on grain quality under drought–rehydration treatment is currently insufficiently evaluated. Here, the present study was conducted by spraying 100 μM MT before wheat grain filling and then drought–rehydration treatment was carried out. Rewatering after drought stress increased the appreciably wet gluten content, sedimentation index, total protein content, and gluten content of wheat grains and decreased the prolainm content, albumin content, and globulin content. And MT application effectively alleviated grain quality damage, reducing wet gluten content and gluten content. In addition, MT compensated for the oxidative damage and the membrane lipid peroxidation damage caused by drought–rehydration treatment. In addition, two drought stresses significantly reduced photosynthetic parameters. And MT effectively improved the photosynthetic efficiency. These results indicated that MT is feasible for enhancing wheat resistance and ameliorating grain quality during drought and rehydration.