ABSTRACT
Melatonin is an indoleamine that was first isolated and identified as a neurotransmitter in animals and proved to be very important in several indispensable biological processes. Scientists have now proved that this molecule is highly conserved among all the species across kingdoms. Though discovered first in animals, it was found in plants with significant physiological roles. The biosynthesis pathways, mode of action and metabolism and the regulatory mechanism of melatonin are continuously being explored. Melatonin exhibits many hormone-like activities in plants. It has significant functions in plant growth and development, such as enhancement of photosynthesis (carbon fixation), reproductive development, seed germination, root development and growth, circadian rhythms, senescence, post-harvest fruit ripening, maintenance of plant tissue structure and function, delay of senescence and responses to biotic and abiotic stresses. Its function also encompasses antioxidant activity. Recognizing its importance in highly diverse biological functions, some scientists mentioned melatonin as an autoregulatory compound and recommended the use of the name ‘Phyto melatonin’.
