title: Effects of uncoated and citric acid coated cerium oxide nanoparticles, bulk cerium oxide, cerium acetate, and citric acid on tomato plants.
abstract: Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato (Solanum lycopersicum L.) plants were cultivated for 210days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO2, CA+nCeO2) bulk cerium oxide (bCeO2), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500mg/kg, both the uncoated and CA+nCeO2 increased shoot length by ~9 and ~13%, respectively, while bCeO2 and CeAc decreased shoot length by ~48 and ~26%, respectively, compared with MPW (p≤0.05). Total chlorophyll, chlo-a, and chlo-b were significantly increased by CA+nCeO2 at 250mg/kg, but reduced by bCeO2 at 62.5mg/kg, compared with MPW. At 250 and 500mg/kg, nCeO2 increased Ce in roots by 10 and 7 times, compared to CA+nCeO2, but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO2 nor CA+nCeO2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO2 at 62.5mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO2 on tomato plants.
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States.
authors.forename: Ana Cecilia
authors.initials: AC
authors.lastname: Barrios
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, United States.
authors.forename: Cyren M
authors.initials: CM
authors.lastname: Rico
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States.
authors.forename: Jesica
authors.initials: J
authors.lastname: Trujillo-Reyes
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, United States.
authors.forename: Illya A
authors.initials: IA
authors.lastname: Medina-Velo
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States; Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, United States.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Peralta-Videa
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States; Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 W. University Avenue, El Paso, TX 79968, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, United States. Electronic address: jgardea@utep.edu.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Gardea-Torresdey
mesh_terms: D000085:Acetates / Q000378:metabolism*; D002563:Cerium / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D019343:Citric Acid / Q000378:metabolism*; D020099:Coated Materials, Biocompatible / Q000378:metabolism*; D005638:Fruit / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000502:physiology; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development / Q000502:physiology; D053768:Metal Nanoparticles; D010940:Plant Proteins / Q000378:metabolism
chemical_list: D000085:Acetates; D020099:Coated Materials, Biocompatible; D010940:Plant Proteins; D002734:Chlorophyll; D019343:Citric Acid; D002563:Cerium; C030583:ceric oxide
keywords: Cerium oxide nanoparticles; Fruit production; Surface coating; Tomato plant life cycle