title: Effects of Titanium Dioxide Nanoparticles on Red Clover and Its Rhizobial Symbiont.
abstract: Titanium dioxide nanoparticles (TiO2 NPs) are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two TiO2 NPs, i.e., P25, E171 and a non-nanomaterial TiO2. Growth of both organisms individually and their symbiotic root nodulation were investigated in liquid and hydroponic systems. While 23 and 18 mg l(-1) of E171 and non-nanomaterial TiO2 decreased the growth rate of R. trifolii by 43 and 23% respectively, P25 did not cause effects. Shoot length of red clover decreased between 41 and 62% for all tested TiO2 NPs. In 21% of the TiO2 NP treated plants, no nodules were found. At high concentrations certain TiO2 NPs impaired R. trifolii as well as red clover growth and their symbiosis in the hydroponic systems.
authors.affiliation: Institute for Sustainability Sciences ISS, Agroscope, Zurich, Switzerland.|Plant-Microbe-Interactions, Department of Biology, Utrecht University, Utrecht, the Netherlands.
authors.forename: Janine
authors.initials: J
authors.lastname: Moll
authors.affiliation: Institute for Sustainability Sciences ISS, Agroscope, Zurich, Switzerland.
authors.forename: Annette
authors.initials: A
authors.lastname: Okupnik
authors.affiliation: Institute for Sustainability Sciences ISS, Agroscope, Zurich, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Gogos
authors.affiliation: Federal Office for Agriculture FOAG, Berne, Switzerland.
authors.forename: Katja
authors.initials: K
authors.lastname: Knauer
authors.affiliation: Institute for Sustainability Sciences ISS, Agroscope, Zurich, Switzerland.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Bucheli
authors.affiliation: Institute for Sustainability Sciences ISS, Agroscope, Zurich, Switzerland.|Plant-Microbe-Interactions, Department of Biology, Utrecht University, Utrecht, the Netherlands.|Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
authors.forename: Marcel G A
authors.initials: MG
authors.lastname: van der Heijden
authors.affiliation: Institute for Sustainability Sciences ISS, Agroscope, Zurich, Switzerland.
authors.forename: Franco
authors.initials: F
authors.lastname: Widmer
mesh_terms: D003470:Culture Media / Q000737:chemistry; D018527:Hydroponics; D018519:Meristem / Q000187:drug effects; D053758:Nanoparticles / Q000633:toxicity*; D009587:Nitrogen Isotopes; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects / Q000648:ultrastructure; D018520:Plant Shoots / Q000033:anatomy & histology / Q000187:drug effects; D012231:Rhizobium / Q000187:drug effects / Q000502:physiology*; D013559:Symbiosis / Q000187:drug effects*; D014025:Titanium / Q000633:toxicity*; D029921:Trifolium / Q000187:drug effects / Q000254:growth & development / Q000382:microbiology*
chemical_list: D003470:Culture Media; D009587:Nitrogen Isotopes; C009495:titanium dioxide; D014025:Titanium