title: Elevated CO2levels modify TiO2nanoparticle effects on rice and soil microbial communities.
abstract: Evidence suggests that CO2modifies the behavior of nanomaterials. Thus, in a few decades, plants might be exposed to additional stress if atmospheric levels of CO2and the environmental burden of nanomaterials increase at the current pace. Here, we used a full-size free-air CO2enrichment (FACE) system in farm fields to investigate the effect of elevated CO2levels on phytotoxicity and microbial toxicity of nTiO2(0, 50, and 200mgkg-1) in a paddy soil system. Results show that nTiO2did not induce visible signs of toxicity in rice plants cultivated at the ambient CO2level (370μmolmol-1), but under the high CO2concentration (570μmolmol-1) nTiO2significantly reduced rice biomass by 17.9% and 22.1% at 50mgkg-1and 200mgkg-1, respectively, and grain yield by 20.8% and 44.1% at 50mgkg-1and 200mgkg-1, respectively. In addition, at the high CO2concentration, nTiO2at 200mgkg-1increased accumulation of Ca, Mg, Mn, P, Zn, and Ti by 22.5%, 16.8%, 29.1%, 7.4%, 15.7% and 8.6%, respectively, but reduced fat and total sugar by 11.2% and 25.5%, respectively, in grains. Such conditions also changed the functional composition of soil microbial communities, alerting specific phyla of bacteria and the diversity and richness of protista. Overall, this study suggests that increases in CO2levels would modify the effects of nTiO2on the nutritional quality of crops and function of soil microbial communities, with unknown implications for future economics and human health.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Wenchao
authors.initials: W
authors.lastname: Du
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, TX 79968, United States; Environmental Science and Engineering PhD program, The University of Texas at El Paso, El Paso, TX 79968, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, El Paso, TX 79968, United States.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Gardea-Torresdey
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Ji
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China.
authors.forename: Kaihua
authors.initials: K
authors.lastname: Gu
authors.affiliation: Department of Chemistry, The University of Texas at El Paso, TX 79968, United States; Environmental Science and Engineering PhD program, The University of Texas at El Paso, El Paso, TX 79968, United States; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, El Paso, TX 79968, United States.
authors.forename: Jose R
authors.initials: JR
authors.lastname: Peralta-Videa
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210046, China. Electronic address: hyguo@nju.edu.cn.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Guo
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis*; D053758:Nanoparticles / Q000032:analysis; D012275:Oryza / Q000254:growth & development*; D012987:Soil; D012988:Soil Microbiology; D014025:Titanium / Q000032:analysis*
chemical_list: D012987:Soil; D002245:Carbon Dioxide; C009495:titanium dioxide; D014025:Titanium
keywords: CO(2); Microbial communities; Phytotoxicity; Rice; TiO(2) nanoparticles