Fig. 5

Light microscopic images showing thick sections of Nicotiana tabacum root. Control root (a). 5 nm (Fe₃O₄) NPs-treated plants with 3, 10, and 30 mg/L (b, c, and d, respectively). 10 nm (Fe₃O₄) NPs treated plants with 3, 10, and 30 mg/L (e, f, and g, respectively). 20 nm (Fe₃O₄) NPs treated plants with 3, 10, and 30 mg/L (h, i, and j, respectively). 5 nm (Fe₃O₄) NPs treated plants showing deformation of the epidermis (EP) (arrow); cortical cells (CX) and thickened xylem (X) and showing major disruption in the organization of the cortical cells (CX) and vascular bundles [xylem (X) and phloem (P)]. Bar equals 0.04 mm