Facile microwave-assisted synthesis of NiO nanoparticles and its effect on soybean (Glycine max).

NiO nanoparticles in high purity, 15 ± 0.5 nm in size, were prepared via solid-state microwave irradiation. The [Ni(NH₃)₆](NO₃)₂ complex as a novel source was decomposed in the presence of microwave irradiation for a short time (10 min). The present method is facile, safe, and low-cost. This method exhibits other advantages; there is no need of a solvent, fuel, surfactant, expensive material, or complex instrument. Synthesised NiO nanoparticles were determined by various analyses. Also, for the first time, NiO nanoparticle effects on biochemical factors in soybean were investigated. Seeds of soybean were grown in the Murashige and Skoog agar medium containing different concentrations of NiO nanoparticles (0, 200, and 400 mg/L) for 21 days under growth chamber conditions. Estimates of malondialdehyde, hydrogen peroxide contents, and antioxidant enzymes (catalase and ascorbate peroxidase) under treatment of NiO nanoparticles were assayed. The result showed that by significantly increasing the concentration of NiO nanoparticles, the activity of catalase and ascorbate peroxidase enzymes was enhanced. Malondialdehyde and hydrogen peroxide contents significantly increased in the presence of NiO nanoparticles. In this study, the increasing activity of catalase and ascorbate peroxidase was not enough for radical oxygen species detoxification.