Synthesis, characterization, and ameliorative effect of iron oxide nanoparticles on saline-stressed Zea mays

High soil salinity induces osmotic and ionic stress that threaten crop production worldwide and affect food security. This study evaluated the ameliorative effects of iron oxide nanoparticles on salinized Zea mays. Iron oxide nanoparticles were synthesized using an aqueous leaf extract of Diodella sarmentosa, and the results of the characterization using Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), transmission electron microscope (TEM), UV–visible spectrophotometer, and scanning electron microscope (SEM) revealed the presence of polydisperse spherical iron oxide nanoparticles (FeONPs) with a light absorption peak at 290 nm, and a size ranging from 3.03 nm to 87.04 nm. Daily foliar application of FeONPs on the salinized Zea mays for 10 days, significantly (p < 0.05) improved the plant’s photosynthetic pigments (total chlorophyl (175.71 %), chlorophyll a (256.34 %), chlorophyll b (77.01 %), carotenoid (39.36 %), root length (9.87 %), and antioxidant enzyme activities, compared to the untreated and bulk FeCl₃·6H₂O-treated controls. Since iron is known to promote photosynthetic pigment synthesis, the enhanced photosynthetic indices observed in the FeONPs-treated pot compared to the bulk FeCl₃·6H₂O-treated pot, may have resulted from the size-aided absorption of the FeONPs more than FeCl₃·6H₂O From the findings, it can be deduced that FeONPs can improve the growth and development of saline-stressed Zea mays by enhancing the activities of the antioxidant enzymes, while improving the photosynthetic pigments of the plant.