Evaluation of phytotoxicity and genotoxicity of TMA-stabilized iron-oxide nanoparticle in corn (Zea mays) young plants.

Engineered iron oxide nanoparticles (IONPs) have potential applications in agriculture, but their effects vary depending on their composition, concentration, and plant species. In this study, we investigated the biological effects of iron oxide nanoparticles stabilized with tetramethylammonium hydroxide (TMA-IONPs) on Zea mays (corn). The nanoparticles were characterized by transmission and scanning electron microscopy (TEM, SEM), revealing an average diameter of 10.78 nm, and by ATR-FTIR spectroscopy, which confirmed TMA binding and colloidal stability in an aqueous medium. Corn seeds were germinated directly in aqueous solutions of TMA-IONPs at six concentrations ranging from 7.6 to 45.6 mg/L. Seedlings were grown under controlled environmental conditions, and all analyses were performed on day seven of seedling development. The following parameters were assessed: germination rate; seedling growth (shoot and root length); chlorophyll content; antioxidant enzyme activity (catalase and peroxidase); and mitotic index in root meristematic cells. Concentrations up to 45.6 mg/L significantly enhanced germination, biomass accumulation, chlorophyll biosynthesis, and enzymatic antioxidant activity. The highest mitotic index was observed at 38 mg/L with a low incidence of chromosomal aberrations. These findings suggest that low concentrations of TMA-IONPs promote corn seedling growth by stimulating cell division and modulating oxidative stress response. Further research is required to assess the broader agricultural potential and safety of these nanoparticle formulations.