Multifaceted roles of melatonin: Investigating coffee leaf melatonin concentration as a potential indicator of vegetative growth

Abstract

This study investigates the melatonin profile in the leaves of Liberica (Coffea liberica) and Robusta (Coffea canephora) coffee plants, assessing its potential as a growth indicator during the vegetative phase. Our research posits that melatonin concentrations vary with leaf age and can be effectively detected through Thin Layer Chromatography (TLC) and Liquid Chromatography-Mass Spectrometry (LC-MS) analysis. Results showed that all leaf samples—young, middle-aged, and old—from both species exhibited melatonin, confirming its role in various physiological processes. LC-MS analysis revealed melatonin concentrations of 0.72% and 0.58% in young and middle-aged Liberica leaves, respectively. In contrast, Robusta leaves showed slightly higher levels in young leaves (0.73%) and lower in middle-aged leaves (0.51%). These findings suggest that melatonin is crucial in promoting growth and stress tolerance, particularly in young leaves. Furthermore, the variations in melatonin concentrations between the two species indicate potential species-specific adaptations related to photosynthesis and environmental resilience. The results underscore the pivotal role of melatonin in the developmental stages of coffee plants and propose its potential as a growth indicator. This finding paves the way for future research to refine and optimize the analytical methods for detection of melatonin, sparking further interest and exploration in this area.