Protective effect of a natural ally on simultaneous mild heat and salt episodes in maize seedlings

Abiotic stresses occur together in several combinations in nature and do not usually act alone. However, studies on plants mainly are limited to a single stress type. Yet, atmospheric trends make it indispensable to expand approaches to investigate physiological consequences under multiple abiotic stresses. The potential of Melatonin (Mel) hydropriming on photosynthetic machinery and antioxidant system was investigated in this study. Mel hydropriming (0.1mmol/mL) resulted in leaf photochemistry protection, which is characterized by maximum photochemical efficiency of PSII, photosynthetic pigments intactness, reactive oxygen species (ROS) scavenging enzymes activation accompanying depressed levels of endogenous hydrogen peroxide (H2O2) and membrane oxidation in maize seedlings at early vegetative stage under combination of 150mM NaCl and 37 +/- 3 degrees C mild heat. Mimicking nature by combining stresses is more realistic to study abiotic stress responses. High antioxidant capacity of melatonin can serve as a hydropriming substance to withstand simultaneous heat and salt stress.