title: Photosynthesis limitations in three fern species.
abstract: Maximum photosynthesis rates in ferns are generally lower than those of seed plants, but little is known about the limiting factors, which are crucial to understand the evolution of photosynthesis in land plants. To address this issue, a gas exchange/chlorophyll fluorescence analysis was performed in three fern species spanning high phylogenetic range within Polypodiopsida (Osmunda regalis, Blechnum gibbum and Nephrolepis exaltata) to determine their maximum net photosynthesis (AN ), stomatal (gs ) and mesophyll (gm ) conductances to CO2 , and the maximum velocity of carboxylation (Vc,max ). The in vitro Rubisco specificity factor (SC /O ) was also determined. All three species had values for SC /O similar to those typical of seed plants, but values of AN , gs , gm and Vc,max were within the lowest range of those observed in seed plants. In addition, gs was unresponsive to light and CO2 , as already described in other fern species. On the contrary, gm varied with changes CO2 . A quantitative photosynthesis limitation analysis suggested that early land plants (ferns) presented not only stomatal limitations-which were less adjustable to the environment-but also restricted gm and Vc,max , resulting in limited maximum photosynthesis rates.
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gago
authors.affiliation: Forest Ecophysiology Laboratory, Conservation, Biodiversity and Territory Institute, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
authors.forename: Rafael E
authors.initials: RE
authors.lastname: Coopman
authors.affiliation: Centro de Ecología Aplicada Ltda. Av. Príncipe de Gales 6465, Santiago, Chile.
authors.forename: Hernán Marino
authors.initials: HM
authors.lastname: Cabrera
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Hermida
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Arántzazu
authors.initials: A
authors.lastname: Molins
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Miquel À
authors.initials: MÀ
authors.lastname: Conesa
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Jeroni
authors.initials: J
authors.lastname: Galmés
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Miquel
authors.initials: M
authors.lastname: Ribas-Carbó
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterrànies, Departament de Biologia, Universitat de les Illes Balears, Palma, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Flexas
mesh_terms: D005075:Biological Evolution; D002245:Carbon Dioxide / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D029624:Ferns / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D058503:Mesophyll Cells / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D054046:Plant Stomata / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism
chemical_list: D002734:Chlorophyll; D002245:Carbon Dioxide; D012273:Ribulose-Bisphosphate Carboxylase