Poster Presentation 24th Australian Conference on Microscopy and Microanalysis 2016

Effect of coated silver nanoparticles on cell ultrastructure and their localization in tobacco cells (#261)

Petra Peharec Štefanić 1 , Kristina Majsec 1 , Petra Cvjetko 1 , Biljana Balen 1
  1. Division of Molecular Biology, Department of Biology, Faculty of Science, University of Zagreb, 10 000 Zagreb, Croatia
Nanoparticles (NPs) research is currently an area of intense scientific surveys, due to a variety of their potential applications. However, the characteristics making NPs attractive for their exploitation in new products have led to concerns that NPs may pose a risk for environment and human health. Silver NPs (AgNPs) are of particular interest because of their well-known antibacterial and antifungal properties. Therefore, they can be found in various consumer products. Since plants play a significant role in accumulation and biodistribution of many environmentally released substances, they could be influenced by AgNPs, serving as a potential pathway for AgNP-transport and bioaccumulation into food chains. The aim of the study is to reveal effects of differently coated AgNPs: neutral PVP-AgNP, negatively charged citrate-AgNP and positively charged CTAB-AgNP on tobacco cell ultrastructure. Two months-old plants grown on a solid MS medium were exposed to aqueous solution of 100 µM of each AgNPs for 7 days. For localization and ultrastructural analyses, tobacco leaf and root tissues were fixed with 1% glutaraldehyde and postfixed with 1% OsO4 in cacodylate buffer (pH 7.2). After dehydration in ethanol, the tissue was embedded in Spurr's resin. Ultrathin sections were examined using a FEI Morgagni 268D electron microscope. Ultrastructural studies revealed changes in root meristematic cells and leaf chloroplasts in AgNP-treated plants. In the presence of all AgNPs root meristematic cells became highly vacuolated. In leaf cells the chloroplasts of citrate-AgNP treated plants were bigger but with less-developed thylakoid system. Plants treated with PVP-AgNP were characterized with thinner and longer chloroplasts with stacked thylakoids compared to controls. In CTAB-AgNP treated plants, chloroplasts were well developed with higher content of plastoglobules compared to control. The obtained results show the impact of AgNPs on the ultrastructure of root meristematic cells and leaf chloroplasts, which is also dependent on the applied coating.