title: Soil contamination with silver nanoparticles reduces Bishop pine growth and ectomycorrhizal diversity on pine roots.
abstract: Soil contamination by silver nanoparticles (AgNP) is of potential environmental concern but little work has been carried out on the effect of such contamination on ectomycorrhizal fungi (EMF). EMF are essential to forest ecosystem functions as they are known to enhance growth of trees by nutrient transfer. In this study, soil was experimentally contaminated with AgNP (0, 350 and 790 mg Ag/kg) and planted with Bishop pine seedlings. The effect of AgNP was subsequently measured, assessing variation in pine growth and ectomycorrhizal diversity associated with the root system. After only 1 month, the highest AgNP level had significantly reduced the root length of pine seedlings, which in turn had a small effect on above ground plant biomass. However, after 4 months growth, both AgNP levels utilised had significantly reduced both pine root and shoot biomass. For example, even the lower levels of AgNP (350 mg Ag/kg) soil, reduced fresh root biomass by approximately 57 %. The root systems of the plants grown in AgNP-contaminated soils lacked the lateral and fine root development seen in the control plants (no AgNP). Although, only five different genera of EMF were found on roots of the control plants, only one genusLaccariawas found on roots of plants grown in soil containing 350 mg AgNP/kg. At the higher levels of AgNP contamination, no EMF were observed. Furthermore, extractable silver was found in soils containing AgNP, indicating potential dissolution of silver ions (Ag+) from the solid AgNP.
authors.affiliation: Environmental Sustainability Research Centre, College of Life and Natural Sciences, University of Derby, Kedleston Road, Derby, DE22 1GB UK.
authors.forename: M J
authors.identifier: 0000-0003-4983-8333
authors.initials: MJ
authors.lastname: Sweet
authors.affiliation: School of Biology, Newcastle University, Ridley Building, Newcastle upon Tyne, NE1 7RU UK ; School of Life, Sport and Social Sciences, Edinburgh Napier University, Sighthill campus Sighthill Court, Edinburgh, EH11 4BN UK.
authors.forename: I
authors.initials: I
authors.lastname: Singleton
keywords: AgNP; Environmental effects; Fungi; Nanoparticle; Pine