Metal Oxide Nanoparticles (Tio2, Zno, and Fe2 O3) Change the Functional Groups, but not the Plant Tissue Content of Common Bean Plants Grown in a Greenhouse

Abstract

The impact of nanoparticles (NPs) on the morphological characteristics, functional groups, and chemical and microstructural features of plant tissues were evaluated using common bean (Phaseolus vulgaris L.) plants. Beans plants were grown for 90 days in an agricultural soil amended with TiO2, ZnO, and Fe2 O3 NPs at 150 or 300 mg kg-1. Controls consisted of soil without NPs amendments. After 60 days of sowing (DAS), TiO2 NPs significantly reduced stem and root length compared to control treatments. Additionally, changes were observed in the FTIR-ATR spectra signals, mainly in the root spectra at 30 and 90 DAS. Significant differences were observed in the different plant structures regarding Ti, Zn, and Fe absorption and accumulation. A higher accumulation of Ti was observed in the roots at 90 DAS. Moreover, plants had a higher accumulation of Zn and Fe in leaves, stems, and roots when grown in soil amended with ZnO or Fe2 O3 NPs, respectively, at 30 and 90 DAS. In the microstructural analysis of tissue showed no evidence of absorption or translocation of NPs. Therefore, the accumulation of ionic forms of Ti, Zn, and Fe in the plant can be explained by the dissociation and dissolution of the NPs in the rhizosphere, facilitating their adsorption.