Exogenous application of melatonin to mitigate drought stress-induced oxidative damage in seedlings.

BACKGROUND

Drought stress is a major prevalent environmental factor impairing growth. Melatonin mitigates the impacts of drought stress on plants. However, melatonin's role in () is unknown. We aimed to reveal the protective effects of melatonin on seedlings under drought conditions.

METHODS

Melatonin was sprayed under drought or normal water conditions. The parameters, including growth, physiological factors, and phytohormones of , were examined.

RESULTS

Compared to the normal control group, drought stress inhibited the growth of seedlings and significantly reduced the content of carotenoids, SOD, POD, APX, PPO, CAT, GR, and soluble sugars, and increased the contents of MDA, O , proline, soluble proteins, ABA, and JA-Me in seedlings. However, melatonin treatment significantly reversed the adverse drought-induced responses and promoted the seedling's growth. Moreover, the heatmap and principal component analysis suggested a high similarity in the behavior patterns of the six measured antioxidant enzymes in seedlings.

CONCLUSION

Our study reported for the first time that melatonin has a protective role in seedlings under drought-stress conditions. This role is related to ROS scavenging, activation of antioxidant enzymes, and crosstalk of phytohormones. This study provided a theoretical basis for improving the ability of adapted to arid environments.