title: Differential Toxicity of Bare and Hybrid ZnO Nanoparticles in Green Pea (Pisum sativum L.): A Life Cycle Study.
abstract: The effect of surface or lattice modification of nanoparticles (NPs) on terrestrial plants is poorly understood. We investigated the impact of different zinc oxide (ZnO) NPs on green pea (Pisum sativum L.), one of the highest consumed legumes globally. Pea plants were grown for 65 d in soil amended with commercially available bare ZnO NPs (10 nm), 2 wt% alumina doped (Al2O3@ZnO NPs, 15 nm), or 1 wt% aminopropyltriethoxysilane coated NPs (KH550@ZnO NP, 20 nm) at 250 and 1000 mg NP/kg soil inside a greenhouse. Bulk (ZnO) and ionic Zn (zinc chloride) were included as controls. Plant fresh and dry biomass, changes in leaf pigment concentrations, elements (Zn, Al, Si), and protein and carbohydrate profile of green pees were quantified upon harvest at 65 days. With the exception of the coated 1000 mg/kg NP treatment, fresh and dry weight were unaffected by Zn exposure. Although, all treated plants showed higher tissue Zn than controls, those exposed to Al2O3@ZnO NPs at 1000 mg/kg had greater Zn concentration in roots and seeds, compared to bulk Zn and the other NP treatments, keeping Al and Si uptake largely unaffected. Higher Zn accumulation in green pea seeds were resulted in coated ZnO at 250 mg/kg treatments. In leaves, Al2O3@ZnO NP at 250 mg/kg significantly increased Chl-a and carotenoid concentrations relative to the bulk, ionic, and the other NP treatments. The protein and carbohydrate profiles remained largely unaltered across all treatments with the exception of Al2O3@ZnO NPs at 1000 mg/kg where sucrose concentration of green peas increased significantly, which is likely a biomarker of stress. Importantly, these findings demonstrate that lattice and surface modification can significantly alter the fate and phytotoxic effects of ZnO NPs in food crops and seed nutritional quality. To the authors' knowledge, this is the first report of a life cycle study on comparative toxicity of bare, coated, and doped ZnO NPs on a soil-grown food crop.
authors.affiliation: Environmental Science and Engineering, The University of Texas at El PasoEl Paso, TX, USA; University of California Center for Environmental Implications of Nanotechnology, The University of Texas at El PasoEl Paso, TX, USA.
authors.forename: Arnab
authors.initials: A
authors.lastname: Mukherjee
authors.affiliation: Texas A&M AgriLife Research Center at El Paso El Paso, TX, USA.
authors.forename: Youping
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Environmental Science and Engineering, The University of Texas at El PasoEl Paso, TX, USA; University of California Center for Environmental Implications of Nanotechnology, The University of Texas at El PasoEl Paso, TX, USA.
authors.forename: Erving
authors.initials: E
authors.lastname: Morelius
authors.affiliation: Environmental Science and Engineering, The University of Texas at El PasoEl Paso, TX, USA; University of California Center for Environmental Implications of Nanotechnology, The University of Texas at El PasoEl Paso, TX, USA.
authors.forename: Carlos
authors.initials: C
authors.lastname: Tamez
authors.affiliation: Environmental Science and Engineering, The University of Texas at El PasoEl Paso, TX, USA; University of California Center for Environmental Implications of Nanotechnology, The University of Texas at El PasoEl Paso, TX, USA.
authors.forename: Susmita
authors.initials: S
authors.lastname: Bandyopadhyay
authors.affiliation: Texas A&M AgriLife Research Center at El Paso El Paso, TX, USA.
authors.forename: Genhua
authors.initials: G
authors.lastname: Niu
authors.affiliation: Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station New Haven, CT, USA.
authors.forename: Jason C
authors.initials: JC
authors.lastname: White
authors.affiliation: Environmental Science and Engineering, The University of Texas at El PasoEl Paso, TX, USA; University of California Center for Environmental Implications of Nanotechnology, The University of Texas at El PasoEl Paso, TX, USA; Department of Chemistry, The University of Texas at El PasoEl Paso, TX, USA.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Peralta-Videa
authors.affiliation: Environmental Science and Engineering, The University of Texas at El PasoEl Paso, TX, USA; University of California Center for Environmental Implications of Nanotechnology, The University of Texas at El PasoEl Paso, TX, USA; Department of Chemistry, The University of Texas at El PasoEl Paso, TX, USA.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Gardea-Torresdey
keywords: ZnO nanoparticles; bare; coated; dissolution; doped; phytotoxicity; seed quality