Effects of extracellular polymeric substances on silver nanoparticle bioaccumulation and toxicity to Triticum aestivum L

Chemosphere. 2021 Oct;280:130863. doi: 10.1016/j.chemosphere.2021.130863. Epub 2021 May 18.ABSTRACTThe potential effects of extracellular polymeric substances (EPS) on the behavior and toxicity of silver nanoparticle (Ag-NPs) and silver sulfide nanoparticle (Ag2S-NPs) remains ambiguous. The interaction of EPS from Bacillus subtilis with Ag2S-NPs, metallic Ag-NPs, or ionic Ag, and the associated plant safety had been examined in this study. The biological impacts of Ag-NPs and Ag2S-NPs were Ag form-dependent and highly influenced by microbial EPS. Compared with metallic Ag-NPs, Ag2S-NPs exert inert biological impacts, as revealed by 3.44 times lower Ag bioaccumulation in wheat (Triticum aestivum L.) seedlings and nearly reduce plant biomass when wheat was subjected to 1.0 mg-Ag L-1 of Ag-NPs and Ag2S-NPs with the transfer factors of 151.56-930.87 vs. 12.52-131.81, respectively. These observations were coincident with the low dissolved Ag ([Ag]diss) in the Ag2S-NPs treatment than the Ag-NPs treatment (114.0 vs. 0.0791, μg L-1). Compared with the enhanced toxicity of Ag2S-NPs to wheat, Bacillus subtilis EPS significantly alleviate the phytotoxicity of Ag-NPs, as revealed by the relative root elongation (7.15-45.40% decrease vs. 2.39-11.75% increase), and malondialdehyde (1.47-83.22% increase vs. 8.57-25.25% decrease) and H2O2 (11.27-71.78% increase vs. 5.16-36.67% decrease) contents. These constrasting plant responses of B. subtilis EPS are mainly caused by their complexation p...
Source: Chemosphere - Category: Chemistry Authors: Source Type: research