Exogenous Application of Melatonin Induces Tolerance to Salt Stress by Improving the Photosynthetic Efficiency and Antioxidant Defense System of Maize Seedling

Melatonin-Induced Water Stress Tolerance in Plants: Recent Advances

“…Water stress tolerance (drought stress and waterlogging) may be attributed to structural and functional adaptations at the cellular and whole-plant levels, including root enhancement, growth promotion, oxidative damage alleviation, osmotic potential modulation, leaf water potential, cell wall elasticity control, stomatal closure, and the accumulation of osmolytes, thereby easing the harmful impacts of such destructive stresses [ 4 , 14 ]. Melatonin may be considered a core part of the regulatory network controlling all of these mechanisms, and it represents a promising material for future studies and practical use [ 18 , 107 , 108 ]. Melatonin research has been experiencing hypergrowth in the last two decades; however, its roles in water stress tolerance need further investigation.…”

“…In this respect, the endogenous melatonin levels change with the alteration of the environmental conditions of plant growth. The melatonin level is increased, with a protective role, in response to different abiotic stressors such as cold, heat, heavy metals, UV radiation, water deficit, and waterlogging [ 18 , 22 ]. Thus, the expressions of the biosynthesis enzyme transcripts ( TDC , SNAT , ASMT , and COMT genes) occur in stressful situations, producing a burst in the levels of endogenous melatonin.…”

“…All in all, as shown in Figure 1 , it can be concluded that once the plants feel water scarcity under drought conditions, the protective and regulatory role of melatonin, in parallel with other anti-stress strategies, will start to prevent, alleviate, or stop the harmful effects of the stress [ 18 , 79 ]. At the cellular level, stress signals from the cell membrane inform the nucleus that “cell life is under threat” to cope with the drastic effects of the drought [ 77 , 80 ].…”

“…Previous publications have stated that the various plant responses to water stress are mediated by essential regulators such as phytohormones [ 15 ]. Among them, melatonin is a unique antioxidant and plant master regulator that protects plants from oxidative stress and regulates various plant responses to environmental disorders, especially water stress [ 16 , 17 , 18 ]. Although accumulating reviews about the beneficial effects of melatonin have been published over the last decade, it still needs more discussion in order to update and discover melatonin functions, especially under biotic and abiotic stresses [ 19 , 20 , 21 ].…”

Melatonin-induced Water Stress Tolerance in Plants: Recent Advances

“…Previous publications stated that the various plant responses to water stress are mediated by essential regulators such as phytohormones [16]. Among them, melatonin is a unique antioxidant and plant master regulator that protects plants from oxidative stress and regulates various plant responses to environmental disorders, especially water stress [17][18][19]. Although accumulating reviews about the beneficial effects of melatonin have been published over the last decade, it still needs more discussion to update and discover melatonin functions, especially under biotic and abiotic stresses [20][21][22].…”