title: Monitoring CO2emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi.
abstract: Quantification of carbon (C) fluxes in mycorrhizal plants is one of the important yet little explored tasks of mycorrhizal physiology and ecology.13CO2pulse-chase labelling experiments are increasingly being used to track the fate of C in these plant-microbial symbioses. Nevertheless, continuous monitoring of both the below- and aboveground CO2emissions remains a challenge, although it is necessary to establish the full C budget of mycorrhizal plants. Here, a novel CO2collection system is presented which allows assessment of gaseous CO2emissions (including isotopic composition of their C) from both belowground and shoot compartments. This system then is used to quantify the allocation of recently fixed C in mycorrhizal versus nonmycorrhizal Medicago truncatula plants with comparable biomass and mineral nutrition. Using this system, we confirmed substantially greater belowground C drain in mycorrhizal versus nonmycorrhizal plants, with the belowground CO2emissions showing large variation because of fluctuating environmental conditions in the glasshouse. Based on the assembled13C budget, the C allocation to the mycorrhizal fungus was between 2.3% (increased13C allocation to mycorrhizal substrate) and 2.9% (reduction of13C allocation to mycorrhizal shoots) of the plant gross photosynthetic production. Although the C allocation to shoot respiration (measured during one night only) did not differ between the mycorrhizal and nonmycorrhizal plants under our experimental conditions, it presented a substantial part (∼10%) of the plant C budget, comparable to the amount of CO2released belowground. These results advocate quantification of both above- and belowground CO2emissions in future studies.
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.
authors.forename: Renata
authors.initials: R
authors.lastname: Slavíková
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.|Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, 252 43, Průhonice, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Püschel
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.|Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, 252 43, Průhonice, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Janoušková
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.
authors.forename: Martina
authors.initials: M
authors.lastname: Hujslová
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.
authors.forename: Tereza
authors.initials: T
authors.lastname: Konvalinková
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Gryndlerová
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic.
authors.forename: Milan
authors.initials: M
authors.lastname: Gryndler
authors.affiliation: Faculty of Science, Department of Botany, Charles University in Prague, Benátská 2, 128 01, Prague 2, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Weiser
authors.affiliation: Laboratory of Fungal Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, 14220, Prague 4, Czech Republic. jansa@biomed.cas.cz.
authors.forename: Jan
authors.identifier: http://orcid.org/0000-0002-0331-1774
authors.initials: J
authors.lastname: Jansa
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000737:chemistry / Q000378:metabolism*; D055137:Glomeromycota / Q000502:physiology*; D046913:Medicago truncatula / Q000378:metabolism* / Q000382:microbiology*; D038821:Mycorrhizae / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism
chemical_list: D002245:Carbon Dioxide; D002244:Carbon
keywords: 13C isotope labelling; Belowground carbon (C) allocation; Glomeromycota; Medicago truncatula; Rhizophagus irregularis; Shade