Weak coordination between leaf structure and function among closely related tomato species.
Theory predicts that natural selection should favor coordination between leaf physiology, biochemistry and anatomical structure along a functional trait spectrum from fast, resource-acquisitive syndromes to slow, resource-conservative syndromes. However, the coordination hypothesis has rarely been tested at a phylogenetic scale most relevant for understanding rapid adaptation in the recent past or for the prediction of evolutionary trajectories in response to climate change. We used a common garden to examine genetically based coordination between leaf traits across 19 wild and cultivated tomato taxa. We found weak integration between leaf structure (e.g. leaf mass per area) and physiological function (photosynthetic rate, biochemical capacity and CO2diffusion), even though all were arrayed in the predicted direction along a 'fast-slow' spectrum. This suggests considerable scope for unique trait combinations to evolve in response to new environments or in crop breeding. In particular, we found that partially independent variation in stomatal and mesophyll conductance may allow a plant to improve water-use efficiency without necessarily sacrificing maximum photosynthetic rates. Our study does not imply that functional trait spectra, such as the leaf economics spectrum, are unimportant, but that many important axes of variation within a taxonomic group may be unique and not generalizable to other taxa.
Department of Biology, Indiana University, Bloomington, IN, 47405, USA.|Biodiversity Research Centre and Botany Department, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Christopher D
CD
Muir
Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Ctra. Valldemossa km 7.5 E-07122, Palma de Mallorca, Spain.
Miquel À
MÀ
Conesa
Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Ctra. Valldemossa km 7.5 E-07122, Palma de Mallorca, Spain.
Emilio J
EJ
Roldán
Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Ctra. Valldemossa km 7.5 E-07122, Palma de Mallorca, Spain.
Arántzazu
A
Molins
Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Ctra. Valldemossa km 7.5 E-07122, Palma de Mallorca, Spain.
Jeroni
J
Galmés
D002245:Carbon Dioxide / Q000378:metabolism; D002980:Climate; D004058:Diffusion; D007700:Kinetics; D018551:Solanum lycopersicum / Q000033:anatomy & histology* / Q000502:physiology*; D058503:Mesophyll Cells / Q000378:metabolism; D010641:Phenotype; D010788:Photosynthesis; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000502:physiology*; D021122:Protein Subunits / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D013045:Species Specificity; D013696:Temperature; D014867:Water
D021122:Protein Subunits; D014867:Water; D002245:Carbon Dioxide; D012273:Ribulose-Bisphosphate Carboxylase

Solanum
; CO2 diffusion; Rubisco; evolution; leaf economics spectrum; leaf gas exchange; leaf mass per area; photosynthesis