Nitrogen assimilation and transpiration: key processes conditioning responsiveness of wheat to elevated [CO2] and temperature |
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| Authors: | Iván Jauregui Ricardo Aroca María Garnica Ángel M. Zamarreño José M. García‐Mina Maria D. Serret Martin Parry Juan J. Irigoyen Iker Aranjuelo |
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| Affiliation: | 1. Dpto. Ciencias del Medio Natural, Universidad Pública de Navarra, Mutilva Baja, Spain;2. Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (CSIC), Granada, Spain;3. R&D Department, CIPAV‐Timac Agro Roullier Group, Navarra, Spain;4. Departament de Biologia Vegetal. Facultat de Biologia, Universidad de Barcelona, Barcelona, Spain;5. Plant Biology and Crop Science, Rothamsted Research, Herts, UK;6. Grupo de Fisiología del Estrés en Plantas (Dpto. de Biología Ambiental), Unidad Asociada al CSIC, EEAD, Zaragoza e ICVV, Logro?o, Facultades de Ciencias y Farmacia, Universidad de Navarra, Pamplona, Spain;7. Department of Plant Biology and Ecology, Faculty of Science and Technology, University of Basque Country (UPV‐EHU), Bizkaia, Spain;8. Instituto de Agrobiotecnología (IdAB), Universidad Pública de Navarra‐CSIC‐Gobierno de Navarra, Campus de Arrosadía, Spain |
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| Abstract: | Although climate scenarios have predicted an increase in [CO2] and temperature conditions, to date few experiments have focused on the interaction of [CO2] 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 CO2. The main goal of this study was to analyze the effect of interacting [CO2] and temperature on leaf photorespiration, C/N metabolism and N transport in wheat plants exposed to elevated [CO2] and temperature conditions. For this purpose, wheat plants were exposed to elevated [CO2] (400 vs 700 µmol mol?1) and temperature (ambient vs ambient + 4°C) in CO2 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 [CO2] 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 [CO2] and elevated temperature resulted in photosynthetic acclimation. The reduction in transpiration rates induced limitations in nutrient transport in leaves of plants exposed to elevated [CO2] and temperature, led to mineral depletion and therefore contributed to the inhibition of photosynthetic activity. |
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