The progress of nanotechnology presents many nanoparticles that are important in medicine, agriculture and industry. Quickly and entirely absorbed by plants, nano-compounds and remedy their nutrient deficiency and satisfy this need. Iron oxide nanoparticles with suitable surface chemistry can be used as a rich source of iron for plants due to its gradual release of Fe in a wide pH range (pH 3 to 11). The present study investigated the impact of iron oxide nanoparticles (Fe2O3NPs in 0, 10, 20 and 30 μM concentrations) on physiological parameters of peppermint (Mentha piperita) under salt stress (0, 50, 100 and 150 mM concentrations of NaCl). Fe2O3NPs caused increases in leaf fresh weight and dry weight, phosphorus, potassium, iron, zinc, and calcium contents of the peppermint under salinity stress but did not have an effect on the sodium element. 30 μM concentration of Fe2O3NP was more impressive. Lipid peroxidation and proline contents of the peppermint under salinity decreased significantly by applying Fe2O3NPs. The maximum activities of total antioxidant enzymes (I %), catalase, superoxide dismutase, and guailcol peroxidase were observed in plants treated with 150 mM of NaCl, but application of Fe2O3NPs declined these antioxidant activities. The results suggest that the appropriate concentration of iron nanoparticles could be used for stress resistance of the peppermint.
