Magnetopriming regulates antioxidant defense system in soybean against salt stress

The field experiment was conducted to study the influence of magnetopriming with static magnetic field (SMF of 200 mT for 1 h) on growth, nitrogen fixation, photosynthesis, antioxidative system and yield of soybean under salt stress. The results revealed the adverse effect of salinity on growth, photosynthesis, nitrogenase activity and yield. Salt stress significantly elevated the level of hydrogen peroxide (H2O2) and ascorbic acid (ASA) and the activities of superoxide dismutase (SOD), ascorbic acid peroxidase (APX), glutathione reductase (GR) and guaiacol peroxidase (POD) in leaves of soybean seedlings emerged from unprimed seeds. However, a-tocopherol content was reduced with the increase concentration of NaCl but it was enhanced in leaves emerged from magnetoprimed seeds. On the other hand leaf area, specific leaf weight, photosynthesis, nitrogenase activity and ASA/DHA ratio were significantly increased whereas H2O2, ASA and antioxidant enzymes were reduced significantly by SMF pre-treatment; which ultimately improved the biomass accumulation, yield and harvest index of soybean under both the saline and non saline conditions. These results indicated that SMF pre-treatment compensated for the negative effects of salinity stress, consequently soybean plants do not have to deflect their metabolic energy in detoxification of ROS produced under salt stress. Thus application of magneto-priming could scavenge or alleviates the harmful effects of salinity stress at the field performance of soybean plants and it can be used in agriculture to better growth and increased yield under adverse abiotic stress conditions.