Salt Stress Mitigation on Seedling Establishment, Antioxidant Capacity, Ion Homeostasis of Maize by Seed Priming with Melatonin

The study was done at the Department of Laboratory, China. To examine the influence of melatonin priming in mitigating the harmful effect of salt stress on seedling growth of maize (Zea mays L.). Maize seeds were individually primed by 1000 μM of melatonin before germination for 20 h and after germinated at four-leaf-stage exposed to 150 and 300 mM of NaCl. Six doses were employed: CK: Control; M: 1000 μM of melatonin, ST1: 150 mM NaCl only; ST2: 300 mM NaCl only; M+ST1: melatonin+150 mM NaCl; M+ST2: melatonin+300 mM NaCl. The treatments were laid in a Randomized Complete Block Design (RCBD) with four replications. Characters calculated under study were statistically analyzed by SPSS (SPSS Inc, Chicago, IL). Means of significantly different of the calculated data were separated at the 0.05 probability level by Duncan’s Multiple Range Test (DMRT). The results demonstrated that salt stress lead to considerable reduction in shoot and root length, Fresh and dry weight of shoot and root, relative water (RWC) and soluble sugar concentrations of shoot and root, whereas melatonin priming alleviated these decline. Furthermore, salt stress decreased chlorophyll, carotenoid, and K+ contents, antioxidant activities; however melatonin priming lead to improved these parameters. Also we found that salt stress seedlings higher in reactive oxygen species (ROS) malondialdehyde (MDA), hydrogen peroxide (H2O2) concentrations, superoxide (O2-), proline, abscisic acid (ABA), and sodium (Na+) contents, whereas seed primed with melatonin lowered these characters. Then, priming seed with 1000 μM of melatonin expected to be a best alternative to mitigate harmful effects of salts stress at seedling establishment stage in maize.