title: Arbuscular Mycorrhizal Symbiosis with Arundo donax Decreases Root Respiration and Increases Both Photosynthesis and Plant Biomass Accumulation.
abstract: The effect of arbuscular mycorrhiza (AM) symbiosis on plant growth is associated with the balance between costs and benefits. A feedback regulation loop has been described in which the higher carbohydrate cost to plants for AM symbiosis is compensated by increases in their photosynthetic rates. Nevertheless, plant carbon balance depends both on photosynthetic carbon uptake and respiratory carbon consumption. The hypothesis behind this research was that the role of respiration in plant growth under AM symbiosis may be as important as that of photosynthesis. This hypothesis was tested in Arundo donax L. plantlets inoculated with Rhizophagus irregularis and Funneliformis mosseae. We tested the effects of AM inoculation on both photosynthetic capacity and in vivo leaf and root respiration. Additionally, analyses of the primary metabolism and ion content were performed in both leaves and roots. AM inoculation increased photosynthesis through increased CO2diffusion and electron transport in the chloroplast. Moreover, respiration decreased only in AM roots via the cytochrome oxidase pathway (COP) as measured by the oxygen isotope technique. This decline in the COP can be related to the reduced respiratory metabolism and substrates (sugars and tricarboxylic acid cycle intermediates) observed in roots.
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Antònia
authors.identifier: http://orcid.org/0000-0002-2962-1594
authors.initials: A
authors.lastname: Romero-Munar
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Néstor Fernández
authors.initials: NF
authors.lastname: Del-Saz
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Miquel
authors.initials: M
authors.lastname: Ribas-Carbó
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Flexas
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Baraza
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg, 1, 14476, Potsdam-Golm, Germany.
authors.forename: Igor
authors.identifier: http://orcid.org/0000-0002-1862-7931
authors.initials: I
authors.lastname: Florez-Sarasa
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg, 1, 14476, Potsdam-Golm, Germany.
authors.forename: Alisdair Robert
authors.initials: AR
authors.lastname: Fernie
authors.affiliation: Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Gulías
mesh_terms: D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D055137:Glomeromycota / Q000502:physiology; D038821:Mycorrhizae / Q000502:physiology*; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology; D018517:Plant Roots / Q000382:microbiology / Q000502:physiology*; D006109:Poaceae / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D002734:Chlorophyll; D002245:Carbon Dioxide; D000077194:Chlorophyll A
keywords: arbuscular mycorrhizal colonization; metabolomics; net assimilation rate; oxygen isotope fractionation; plant growth