title: To duckweeds (Landoltia punctata), nanoparticulate copper oxide is more inhibitory than the soluble copper in the bulk solution.
abstract: CuO nanoparticles (CuO-NP) were synthesized in a hydrogen diffusion flame. Particle size and morphology were characterized using scanning mobility particle sizing, Brunauer-Emmett-Teller analysis, dynamic light scattering, and transmission electron microscopy. The solubility of CuO-NP varied with both pH and presence of other ions. CuO-NP and comparable doses of soluble Cu were applied to duckweeds, Landoltia punctata. Growth was inhibited 50% by either 0.6 mg L(-1) soluble copper or by 1.0 mg L(-1) CuO-NP that released only 0.16 mg L(-1) soluble Cu into growth medium. A significant decrease of chlorophyll was observed in plants stressed by 1.0 mg L(-1) CuO-NP, but not in the comparable 0.2 mg L(-1) soluble Cu treatment. The Cu content of fronds exposed to CuO-NP is four times higher than in fronds exposed to an equivalent dose of soluble copper, and this is enough to explain the inhibitory effects on growth and chlorophyll content.
authors.affiliation: Department of Land, Air, and Water Resources, University of California, Davis, CA 95616, United States. jiyanshi@gmail.com
authors.forename: Jiyan
authors.initials: J
authors.lastname: Shi
authors.forename: Aamir D
authors.initials: AD
authors.lastname: Abid
authors.forename: Ian M
authors.initials: IM
authors.lastname: Kennedy
authors.forename: Krassimira R
authors.initials: KR
authors.lastname: Hristova
authors.forename: Wendy K
authors.initials: WK
authors.lastname: Silk
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D019684:Magnoliopsida / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D053758:Nanoparticles / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D003300:Copper; C030973:cupric oxide