More than the Ions: The Effects of Silver Nanoparticles on Lolium multiflorum

TitleMore than the Ions: The Effects of Silver Nanoparticles on Lolium multiflorum
Publication TypeJournal Article
Year of Publication2011
AuthorsYin, LY, Cheng, YW, Espinasse, BP, Colman, BP, Auffan, M, Wiesner, MR, Rose, J, Liu, J, Bernhardt, ES
JournalEnvironmental Science & Technology
Date PublishedMar 15
ISBN Number0013-936X
Accession Number
Keywordscells, engineered nanoparticles, environment, Exposure, Oxidative stress, Toxicity

Silver nanoparticles (AgNPs) are increasingly used as antimicrobial additives in consumer products and may have adverse impacts on organisms when they inadvertently enter ecosystems. This study investigated the uptake and toxicity of AgNPs to the common grass, Lolium multiflorum. We found that root and shoot Ag content increased with increasing AgNP exposures. AgNPs inhibited seedling growth. While exposed to 40 mg L(-1) GA-coated AgNPs, seedlings failed to develop root hairs, had highly vacuolated and collapsed cortical cells and broken epidermis and rootcap. In contrast, seedlings exposed to identical concentrations of AgNO(3) or supernatants of ultracentrifuged AgNP solutions showed no such abnormalities. AgNP toxicity was influenced by total NP surface area with smaller AgNPs (6 nm) more strongly affecting growth than did similar concentrations of larger (25 nm) NPs for a given mass. Cysteine (which binds Ag(+)) mitigated the effects of AgNO(3) but did not reduce the toxicity of AgNP treatments. X-ray spectro-microscopy documented silver speciation within exposed roots and suggested that silver is oxidized within plant tissues. Collectively, this study suggests that growth inhibition and cell damage can be directly attributed either to the nanoparticles themselves or to the ability of AgNPs to deliver dissolved Ag to critical biotic receptors.

Alternate JournalEnviron Sci Technol