Mesophyll conductance to CO2 and Rubisco as targets for improving intrinsic water use efficiency in C3 plants |
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Authors: | J. Flexas A. Díaz‐Espejo M. A. Conesa R. E. Coopman C. Douthe J. Gago A. Gallé J. Galmés H. Medrano M. Ribas‐Carbo M. Tomàs Ü. Niinemets |
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Affiliation: | 1. Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears, Spain;2. Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain;3. Ecophysiology Laboratory for Forest Conservation, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile;4. Applied Plant and Soil Biology, Faculty of Biology, University of Vigo, Vigo, Spain;5. Bayer CropScience NV, Innovation Center, Zwijnaarde, Belgium;6. Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia;7. Estonian Academy of Sciences, Tallinn, Estonia |
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Abstract: | Water limitation is a major global constraint for plant productivity that is likely to be exacerbated by climate change. Hence, improving plant water use efficiency (WUE) has become a major goal for the near future. At the leaf level, WUE is the ratio between photosynthesis and transpiration. Maintaining high photosynthesis under water stress, while improving WUE requires either increasing mesophyll conductance (gm) and/or improving the biochemical capacity for CO2 assimilation—in which Rubisco properties play a key role, especially in C3 plants at current atmospheric CO2. The goals of the present analysis are: (1) to summarize the evidence that improving gm and/or Rubisco can result in increased WUE; (2) to review the degree of success of early attempts to genetically manipulate gm or Rubisco; (3) to analyse how gm, gsw and the Rubisco's maximum velocity (Vcmax) co‐vary across different plant species in well‐watered and drought‐stressed conditions; (4) to examine how these variations cause differences in WUE and what is the overall extent of variation in individual determinants of WUE; and finally, (5) to use simulation analysis to provide a theoretical framework for the possible control of WUE by gm and Rubisco catalytic constants vis‐à‐vis gsw under water limitations. |
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Keywords: | aquaporins carbonic anhydrase gene modification leaf anatomy mesophyll conductance Rubisco stomatal conductance stomatal manipulation Vcmax WUE |
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