title: Soil organic matter influences cerium translocation and physiological processes in kidney bean plants exposed to cerium oxide nanoparticles.
abstract: Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0-500mg/kg cerium oxide nanoparticles (nano-CeO2) under greenhouse condition. After 52days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65-111% with increasing nano-CeO2 concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5-250mg/kg nano-CeO2 led to an enhancement in the transpiration rate and stomatal conductance, but to a simultaneous decrease in carotenoid contents by 25-28%. Chlorophyll a in the OMES leaves also decreased by 27 and 18% on exposure to 125 and 250mg/kg nano-CeO2. In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO2 exposed plants, with respect to control. Thus, this study provides clear evidence that the properties of the complex soil matrix play decisive roles in determining the fate, bioavailability, and biological transport of ENMs in the environment.
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), El Paso, TX, USA.
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Majumdar
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), El Paso, TX, USA.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Peralta-Videa
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA.
authors.forename: Jesica
authors.initials: J
authors.lastname: Trujillo-Reyes
authors.affiliation: Texas AgriLife Research Center at El Paso, Texas A&M University System, 1380 A & M Circle, El Paso, TX 79927, USA.
authors.forename: Youping
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Barrios
authors.affiliation: Texas AgriLife Research Center at El Paso, Texas A&M University System, 1380 A & M Circle, El Paso, TX 79927, USA.
authors.forename: Genhua
authors.initials: G
authors.lastname: Niu
authors.affiliation: Autonomous University of Ciudad Juarez, Departamento de Química y Biología, Instituto de Ciencias Biomédicas, Anillo envolvente PRONAF y Estocolmo, Ciudad Juarez, Chihuahua 32310, México.
authors.forename: Juan P Flores-
authors.initials: JPF
authors.lastname: Margez
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; Environmental Science and Engineering PhD Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), El Paso, TX, USA. Electronic address: jgardea@utep.edu.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Gardea-Torresdey
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002338:Carotenoids / Q000378:metabolism; D002563:Cerium / Q000009:adverse effects*; D002734:Chlorophyll / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D053768:Metal Nanoparticles / Q000009:adverse effects*; D027805:Phaseolus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D012989:Soil Pollutants / Q000009:adverse effects*; D013054:Spectrophotometry, Atomic
chemical_list: D000975:Antioxidants; D012989:Soil Pollutants; D002734:Chlorophyll; D002563:Cerium; D002338:Carotenoids; C030583:ceric oxide
keywords: Cerium oxide nanoparticles; Gas exchange; Kidney bean; Photosynthetic pigments; Phytotoxicity; Soil organic matter