title: Stomatal and mesophyll conductances to CO₂ in different plant groups: underrated factors for predicting leaf photosynthesis responses to climate change?
abstract: The climate change conditions predicted for the end of the current century are expected to have an impact on the performance of plants under natural conditions. The variables which are foreseen to have a larger effect are increased CO2 concentration and temperature. Although it is generally considered CO2 assimilation rate could be increased by the increasing levels of CO2, it has been reported in previous studies that acclimation to high CO2 results in reductions of physiological parameters involved in photosynthesis, like the maximum carboxylation rate (Vc,max), stomatal conductance (gs) and mesophyll conductance to CO2 (gm). On the one hand, most of the previous modeling efforts have neglected the potential role played by the acclimation of gm to high CO2 and temperature. On the other hand, the effect of climate change on plant clades other than angiosperms, like ferns, has received little attention, and there are no studies evaluating the potential impact of increasing CO2 and temperature on these species. In this study we predicted responses of several representative species among angiosperms, gymnosperms and ferns to increasing CO2 and temperature. Our results show that species with lower photosynthetic capacity - such as some ferns and gymnosperms - would be proportionally more favored under these foreseen environmental conditions. The main reason for this difference is the lower diffusion limitation imposed by gs and gm in plants having high capacity for photosynthesis among the angiosperms, which reduces the positive effect of increasing CO2. However, this apparent advantage of low-diffusion species would be canceled if the two conductances - gs and gm - acclimate and are down regulated to high CO2, which is basically unknown, especially for gymnosperms and ferns. Hence, for a better understanding of different plant responses to future climate, studies are urged in which the actual photosynthetic response/acclimation to increased CO2 and temperature of ferns, gymnosperms and other under-evaluated plant groups is assessed.
authors.affiliation: Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain. Electronic address: jaume.flexas@uib.es.
authors.forename: Jaume
authors.initials: J
authors.lastname: Flexas
authors.affiliation: Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Carriquí
authors.affiliation: Laboratorio de Ecofisiología para la Conservación de Bosques, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
authors.forename: Rafael E
authors.initials: RE
authors.lastname: Coopman
authors.affiliation: Applied Plant and Soil Biology, Faculty of Biology, University of Vigo, 36310 Vigo, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gago
authors.affiliation: Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
authors.forename: Jeroni
authors.initials: J
authors.lastname: Galmés
authors.affiliation: Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
authors.forename: Sebastià
authors.initials: S
authors.lastname: Martorell
authors.affiliation: Estación Experimental de Aula Dei (EEAD), CSIC, Dpto. Nutrición Vegetal, Apdo. 13034, E-50080 Zaragoza, Spain.
authors.forename: Fermín
authors.initials: F
authors.lastname: Morales
authors.affiliation: Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes 10, 41012 Sevilla, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Diaz-Espejo
mesh_terms: D000064:Acclimatization; D002245:Carbon Dioxide / Q000378:metabolism; D057231:Climate Change; D032462:Cycadopsida / Q000378:metabolism*; D029624:Ferns / Q000378:metabolism*; D058503:Mesophyll Cells / Q000378:metabolism; D008954:Models, Biological; D010788:Photosynthesis; D054046:Plant Stomata / Q000378:metabolism
chemical_list: D002245:Carbon Dioxide
keywords: Angiosperms; Climatic change; Diffusive limitations; Ferns; Mesophyll conductance; Photosynthesis