Mitigation of adverse effects of salt stress on germination, growth, photosynthetic efficiency and yield in maize (Zea mays L.) through magnetopriming

The efficiency of magnetopriming was evaluated for mitigation of the detrimental effects of salt stress on maize germination, growth, photosynthesis, and yield of maize plants. Maize seeds were pretreated with 200 mT of static magnetic field (SMF) for 1 h to assess the impact of SMF on the germination, seedling vigor, growth of plant, photosynthetic performance, ROS content, and yield under salt stress. The seedling characteristics of maize were negatively influenced by salt stress. However, SMF-pretreated maize seeds showed relatively higher germination percentage and germination stress tolerance index as compared to untreated seeds in saline and nonsaline conditions. The detrimental effect of NaCl induced salt stress was also observed on growth, yield, and different physiological characteristic of maize plants. The results showed that SMF-pretreated seeds enhanced seedling vigor, growth parameters such as plant height, leaf area, and biomass accumulation at different concentrations of NaCl (0, 25, 50, 75, and 100 mM) as compared to untreated seeds. Photosynthetic pigments, quantum yield of PSII photochemistry (Fv/Fm), phenomenological fluxes such as electron transport per leaf CS (ETo/CSm) and density of reaction centers (RC/CSm), the performance index (PI) were high in the leaves of plants that emerged from SMF-pretreated seeds as compared to untreated seeds. This stimulatory effect of SMF treatment of seeds was also revealed in the rate of photosynthesis and stomatal conductance, which results in improved yield of maize plants under saline conditions. The leaves from plants of SMF-treated seeds showed decreased hydrogen peroxide (H2O2) when compared with untreated seeds in both conditions. SMF ameliorates the adverse effect of salt stress in maize plants, by reducing H2O2 and increasing growth, photosynthetic performance, and yield under salt stress. For improvement of salt tolerance, magnetopriming with SMF of 200 mT for 1 h to dry seeds of maize can be efficiently used as a presowing treatment.