Coating-Dependent Effects of Silver Nanoparticles on Tobacco Seed Germination and Early Growth

Silver nanoparticles, AgNPs, are used in a wide range of consumer products because of their excellent antimicrobial properties. AgNPs released into the environment are prone to transformations such as aggregation, oxidation, or dissolution so they are often stabilised by coatings that a ect their physico-chemical properties and change their e ect on living organisms. In this study we investigated the stability of polyvinylpyrrolidone PVP and cetyltrimethylammonium bromide CTAB coated AgNPs in an exposure medium, as well as their e ect on tobacco germination and early growth. AgNP-CTAB was found to be more stable in the solid Murashige and Skoog MS medium compared to AgNP-PVP. The uptake and accumulation of silver in seedlings was equally effcient after exposure to both types of AgNPs. However, AgNP-PVP induced only mild toxicity on seedlings growth, while AgNP-CTAB caused severe negative e ects on all parameters, even compared to AgNO3. Moreover, CTAB coating itself exerted negative e ects on growth. Cysteine addition generally alleviated AgNP-PVP-induced negative e ects, while it failed to improve germination and growth parameters after exposure to AgNP-CTAB. These results suggest that the toxic e ects of AgNP-PVP are mainly a consequence of release of Ag+ ions, while phytotoxicity of AgNP-CTAB can rather be ascribed to surface coating itself