title: Nitrogen assimilation and transpiration: key processes conditioning responsiveness of wheat to elevated [CO2] and temperature.
abstract: Although climate scenarios have predicted an increase in [CO(2)] and temperature conditions, to date few experiments have focused on the interaction of [CO(2)] and temperature effects in wheat development. Recent evidence suggests that photosynthetic acclimation is linked to the photorespiration and N assimilation inhibition of plants exposed to elevated CO(2). The main goal of this study was to analyze the effect of interacting [CO(2)] and temperature on leaf photorespiration, C/N metabolism and N transport in wheat plants exposed to elevated [CO(2)] and temperature conditions. For this purpose, wheat plants were exposed to elevated [CO(2)] (400 vs 700 µmol mol(-1)) and temperature (ambient vs ambient + 4°C) in CO(2) gradient greenhouses during the entire life cycle. Although at the agronomic level, elevated temperature had no effect on plant biomass, physiological analyses revealed that combined elevated [CO(2)] and temperature negatively affected photosynthetic performance. The limited energy levels resulting from the reduced respiratory and photorespiration rates of such plants were apparently inadequate to sustain nitrate reductase activity. Inhibited N assimilation was associated with a strong reduction in amino acid content, conditioned leaf soluble protein content and constrained leaf N status. Therefore, the plant response to elevated [CO(2)] and elevated temperature resulted in photosynthetic acclimation. The reduction in transpiration rates induced limitations in nutrient transport in leaves of plants exposed to elevated [CO(2)] and temperature, led to mineral depletion and therefore contributed to the inhibition of photosynthetic activity.
authors.affiliation: Dpto. Ciencias del Medio Natural, Universidad Pública de Navarra, Campus de Arrosadía, E-31192, Mutilva Baja, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Jauregui
authors.affiliation: Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, E-18008, Granada, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Aroca
authors.affiliation: R&D Department, CIPAV-Timac Agro Roullier Group, Orcoyen, E-31160, Navarra, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Garnica
authors.affiliation: R&D Department, CIPAV-Timac Agro Roullier Group, Orcoyen, E-31160, Navarra, Spain.
authors.forename: Ángel M
authors.initials: ÁM
authors.lastname: Zamarreño
authors.affiliation: R&D Department, CIPAV-Timac Agro Roullier Group, Orcoyen, E-31160, Navarra, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: García-Mina
authors.affiliation: Departament de Biologia Vegetal. Facultat de Biologia, Universidad de Barcelona, Av. Diagonal, 645, E-08028, Barcelona, Spain.
authors.forename: Maria D
authors.initials: MD
authors.lastname: Serret
authors.affiliation: Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts, AL5 2JQ, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Parry
authors.affiliation: Grupo de Fisiología del Estrés en Plantas (Dpto. de Biología Ambiental), Unidad Asociada al CSIC, EEAD, Zaragoza e ICVV, Logroño, Facultades de Ciencias y Farmacia, Universidad de Navarra, Irunlarrea 1, E-31008, Pamplona, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Irigoyen
authors.affiliation: Department of Plant Biology and Ecology, Faculty of Science and Technology, University of Basque Country (UPV-EHU), Apdo. 644, Bilbao, E-48080, Bizkaia, Spain.|Instituto de Agrobiotecnología (IdAB), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Campus de Arrosadía, E-31192-Mutilva Baja, Spain.
authors.forename: Iker
authors.initials: I
authors.lastname: Aranjuelo
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D018533:Biomass; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000032:analysis / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology; D018515:Plant Leaves / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism; D018526:Plant Transpiration / Q000502:physiology*; D013213:Starch / Q000378:metabolism; D013696:Temperature; D014908:Triticum / Q000502:physiology*
chemical_list: D000596:Amino Acids; D004798:Enzymes; D009587:Nitrogen Isotopes; D010940:Plant Proteins; D002245:Carbon Dioxide; D002244:Carbon; D013213:Starch; D009584:Nitrogen