Mesophyll diffusion conductance to CO2: an unappreciated central player in photosynthesis.
Mesophyll diffusion conductance to CO(2) is a key photosynthetic trait that has been studied intensively in the past years. The intention of the present review is to update knowledge of g(m), and highlight the important unknown and controversial aspects that require future work. The photosynthetic limitation imposed by mesophyll conductance is large, and under certain conditions can be the most significant photosynthetic limitation. New evidence shows that anatomical traits, such as cell wall thickness and chloroplast distribution are amongst the stronger determinants of mesophyll conductance, although rapid variations in response to environmental changes might be regulated by other factors such as aquaporin conductance. Gaps in knowledge that should be research priorities for the near future include: how different is mesophyll conductance among phylogenetically distant groups and how has it evolved? Can mesophyll conductance be uncoupled from regulation of the water path? What are the main drivers of mesophyll conductance? The need for mechanistic and phenomenological models of mesophyll conductance and its incorporation in process-based photosynthesis models is also highlighted.
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain. Electronic address: jaume.flexas@uib.es.
Jaume
J
Flexas
Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Private Bag 4011, Narellan, NSW 2567, Australia.
Margaret M
MM
Barbour
INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France.
Oliver
O
Brendel
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; Centro de Ecología Aplicada Ltda., Av. Suecia 3304, Ñuñoa, Santiago, Chile.
Hernán M
HM
Cabrera
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Marc
M
Carriquí
Instituto de Recursos Naturales y Agrobiología, IRNAS-CSIC, Apartado 1052, 41080 Sevilla, Spain.
Antonio
A
Díaz-Espejo
INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France; School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia.
Cyril
C
Douthe
INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France.
Erwin
E
Dreyer
Department of Crop and Forest Sciences, AGROTECNIO Center, Universitat de Lleida, Avda. Rovira Roure 191, 25198 Lleida, Spain.
Juan P
JP
Ferrio
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Jorge
J
Gago
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Alexander
A
Gallé
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Jeroni
J
Galmés
Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba 305-8604, Japan.
Naomi
N
Kodama
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Hipólito
H
Medrano
Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Ülo
Ü
Niinemets
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
José J
JJ
Peguero-Pina
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Alicia
A
Pou
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Miquel
M
Ribas-Carbó
Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
Magdalena
M
Tomás
Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia.
Tiina
T
Tosens
School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia.
Charles R
CR
Warren
D001692:Biological Transport; D002245:Carbon Dioxide / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D004058:Diffusion; D058503:Mesophyll Cells / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism*
D002734:Chlorophyll; D002245:Carbon Dioxide