Effects of TiO(2) Nanoparticles Incorporation into Cells of Tomato Roots

In this study, tomato plants were grown in vitro with and without incorporation of TiO(2) nanoparticles in Murashige and Skoog (MS) growth medium. The aim of this study was to describe the morphological (area and roundness cell) and mechanical (Young’s Modulus) change in the different tissue of tomato root, epidermis (Ep), parenchyma (Pa), and vascular bundles (Vb), when the whole plant was exposed to TiO(2) nanoparticles (TiO(2) NPs). light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), wavelength dispersive X-ray fluorescence (WDXRF) techniques were used to identify changes into the root cells when TiO(2) NPs were incorporated. TiO(2) NPs incorporation produces changes in the area, roundness, and Young’s Modulus of the tomato root. When tomato root is exposed to TiO(2) NPs, the Ep and Vb area size decreases from 260.92 µm(2) to 160.71 µm(2) and, 103.08 µm(2) to 52.13 µm(2), respectively, compared with the control area, while in Pa tissue the area size was increased considerably from 337.72 mm(2) to 892.96 mm(2). Cellular roundness was evident in tomato root that was exposed to TiO(2) NPs in the Ep (0.49 to 0.67), Pa (0.63 to 0.79), and Vb (0.76 to 0.71) area zones. Young’s Modulus in Pa zone showed a rigid mechanical behavior when tomato root is exposed to TiO(2) NPs (0.48 to 4.98 MPa control and TiO(2) NPs, respectively). Meanwhile, Ep and Vb were softer than the control sample (13.9 to 1.06 MPa and 6.37 to 4.41 MPa respectively). This means that the Pa zone was stiffer than Ep and Vb when the root is exposed to TiO(2) NPs. Furthermore, TiO(2) NPs were internalized in the root tissue of tomato, accumulating mainly in the cell wall and intercellular spaces, with a wide distribution throughout the tissue, as seen in TEM.