Evaluation of Melatonin Concentrations on Germination and Seedling Traits of Rice against Drought Stress

Abstract

Background: Rice is the world’s third most important food crop, particularly in Asia. Drought stress has varying degrees of impact on its production. New plant growth regulators have been studied in recent years as a way to overcome physiological limitations and increase productivity. Melatonin has been investigated for its potential advantages in boosting plant resistance to environmental stresses. In this study, the precise processes and functions of melatonin with respect to germination and early seedling establishment during drought were investigated. Methods: Rice seeds were subjected to different pretreatment of melatonin (0, 50, 100, 150, 200 and 250 µM) prior to experiencing drought stress characterized by a water potential of -0.4 MPa. Germination and physiological traits, including germination speed, shoot length, root length, promptness index, vigor index, stress index, fresh and dry weight were assessed. Result: These findings demonstrated that pretreatment of melatonin effectively mitigated the detrimental impacts of drought stress by enhancing germination percentage, seedling growth and physiological traits. Among the various concentration, 200 µM of melatonin proved to be the ideal concentration that has the ability to improve rice seed germination, early seedling growth and minimize the negative consequences of drought stress.