ABSTRACT
ABSTRACT The antioxidant properties of melatonin (MEL) and its role in the maintenance of proper reduction-oxidation (redox) state are considered to be one of the most important functions in living cells. The effects of its action are not only caused by the direct elimination of reactive oxygen species (ROS) but also by the stimulation of the antioxidant enzyme activities and possible activation of other metabolic pathways, for example, polyphenol synthesis. Melatonin also affects the efciency of the photosynthesis process by (1) delaying chlorophyll degradation, (2) increasing the uptake of CO2, and (3) accelerating the electron transport. This indoleamine, similar to indole-3-acetic acid (IAA), could be involved in the regulation of plant growth and development. There are also reports that indicate the role of melatonin on plant circadian rhythms and photoperiodic responses; however, to explain exactly this phenomenon, further investigations are necessary.
