Photosynthesis Research

, Volume 117, Issue 1, pp 45–59

Diffusional conductances to CO2 as a target for increasing photosynthesis and photosynthetic water-use efficiency

  • Jaume Flexas
  • Ülo Niinemets
  • Alexander Gallé
  • Margaret M. Barbour
  • Mauro Centritto
  • Antonio Diaz-Espejo
  • Cyril Douthe
  • Jeroni Galmés
  • Miquel Ribas-Carbo
  • Pedro L. Rodriguez
  • Francesc Rosselló
  • Raju Soolanayakanahally
  • Magdalena Tomas
  • Ian J. Wright
  • Graham D. Farquhar
  • Hipólito Medrano
Review

DOI: 10.1007/s11120-013-9844-z

Cite this article as:
Flexas, J., Niinemets, Ü., Gallé, A. et al. Photosynth Res (2013) 117: 45. doi:10.1007/s11120-013-9844-z

Abstract

A key objective for sustainable agriculture and forestry is to breed plants with both high carbon gain and water-use efficiency (WUE). At the level of leaf physiology, this implies increasing net photosynthesis (AN) relative to stomatal conductance (gs). Here, we review evidence for CO2 diffusional constraints on photosynthesis and WUE. Analyzing past observations for an extensive pool of crop and wild plant species that vary widely in mesophyll conductance to CO2 (gm), gs, and foliage AN, it was shown that both gs and gm limit AN, although the relative importance of each of the two conductances depends on species and conditions. Based on Fick’s law of diffusion, intrinsic WUE (the ratio AN/gs) should correlate on the ratio gm/gs, and not gm itself. Such a correlation is indeed often observed in the data. However, since besides diffusion AN also depends on photosynthetic capacity (i.e., Vc,max), this relationship is not always sustained. It was shown that only in a very few cases, genotype selection has resulted in simultaneous increases of both AN and WUE. In fact, such a response has never been observed in genetically modified plants specifically engineered for either reduced gs or enhanced gm. Although increasing gm alone would result in increasing photosynthesis, and potentially increasing WUE, in practice, higher WUE seems to be only achieved when there are no parallel changes in gs. We conclude that for simultaneous improvement of AN and WUE, genetic manipulation of gm should avoid parallel changes in gs, and we suggest that the appropriate trait for selection for enhanced WUE is increased gm/gs.

Keywords

PhotosynthesisWater-use efficiencyStomatal conductanceMesophyll conductanceMeta-analysis

Supplementary material

11120_2013_9844_MOESM1_ESM.xls (89 kb)
Data compilation in different species and conditions (see Online Resource 3 for a complete list of the references used). Supplementary material 1 (XLS 89 kb)
11120_2013_9844_MOESM2_ESM.doc (46 kb)
Complete list of references from which data in Online Resource 2 and 4 were compiled. Supplementary material 2 (DOC 46 kb)
11120_2013_9844_MOESM3_ESM.xls (34 kb)
Data compilation for specific genetic manipulations. Supplementary material 3 (XLS 34 kb)
11120_2013_9844_MOESM4_ESM.doc (524 kb)
The relationship between gm/gs and gm in a multi-species dataset. Data and symbols as in Fig. 1. Supplementary material 4 (DOC 523 kb)

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Jaume Flexas
    • 1
  • Ülo Niinemets
    • 2
  • Alexander Gallé
    • 1
    • 3
  • Margaret M. Barbour
    • 4
  • Mauro Centritto
    • 5
  • Antonio Diaz-Espejo
    • 6
  • Cyril Douthe
    • 1
  • Jeroni Galmés
    • 1
  • Miquel Ribas-Carbo
    • 1
  • Pedro L. Rodriguez
    • 7
  • Francesc Rosselló
    • 8
  • Raju Soolanayakanahally
    • 9
  • Magdalena Tomas
    • 1
  • Ian J. Wright
    • 10
  • Graham D. Farquhar
    • 11
  • Hipólito Medrano
    • 1
  1. 1.Research Group on Plant Biology under Mediterranean Conditions, Departament de BiologiaUniversitat de les Illes BalearsPalma de MallorcaSpain
  2. 2.Institute of Agricultural and Environmental SciencesEstonian University of Life SciencesTartuEstonia
  3. 3.Bayer CropScience NVZwijnaardeBelgium
  4. 4.Faculty of Agriculture, Food and Natural ResourcesThe University of SydneyNarellanAustralia
  5. 5.Institute for Plant ProtectionNational Research CouncilSesto FiorentinoItaly
  6. 6.Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC)Irrigation and Crop Ecophysiology GroupSevillaSpain
  7. 7.Instituto de Biología Molecular y Celular de PlantasConsejo Superior de Investigaciones Científicas-Universidad Politécnica de ValenciaValenciaSpain
  8. 8.Computational Biology and Bioinformatics Research Group, Departament de Ciències Matemàtiques i InformàticaUniversitat de les Illes BalearsPalma de MallorcaSpain
  9. 9.Science and Technology BranchAgriculture and Agri-Food Canada, Indian HeadSaskatchewanCanada
  10. 10.Department of Biological SciencesMacquarie UniversityNorth RydeAustralia
  11. 11.Research School of BiologyThe Australian National UniversityCanberraAustralia