On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)

Legumes such as alfalfa (Medicago sativa L.) are vital N2-fixing crops accounting for a global N2 fixation of ~35 MtNyear-1. Although enzymatic and molecular mechanisms of nodule N2 fixation are now well documented, some uncertainty remains as to whether N2 fixation is strictly coupled with photosyn...

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Autores: Molero Milán, Gemma, Tcherkez, Guillaume, Araus Ortega, José Luis, Nogués Mestres, Salvador, Aranjuelo Michelena, Iker
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2014
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/51963
Acceso en línea:https://hdl.handle.net/2445/51963
Access Level:acceso abierto
Palabra clave:Lleguminoses
Fotosíntesi
Adaptació (Biologia)
Isòtops estables en ecologia
Carboni
Efectes fisiològics
Legumes
Photosynthesis
Adaptation (Biology)
Stable isotopes in ecological research
Carbon
Physiological effect
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spelling On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)Molero Milán, GemmaTcherkez, GuillaumeAraus Ortega, José LuisNogués Mestres, SalvadorAranjuelo Michelena, IkerLleguminosesFotosíntesiAdaptació (Biologia)Isòtops estables en ecologiaCarboniEfectes fisiològicsLegumesPhotosynthesisAdaptation (Biology)Stable isotopes in ecological researchCarbonPhysiological effectLegumes such as alfalfa (Medicago sativa L.) are vital N2-fixing crops accounting for a global N2 fixation of ~35 MtNyear-1. Although enzymatic and molecular mechanisms of nodule N2 fixation are now well documented, some uncertainty remains as to whether N2 fixation is strictly coupled with photosynthetic carbon fixation. That is, the metabolic origin and redistribution of carbon skeletons used to incorporate nitrogen are still relatively undefined. Here, we conducted isotopic labelling with both 15N2 and 13C-depleted CO2 on alfalfa plants grown under controlled conditions and took advantage of isotope ratio mass spectrometry to investigate the relationship between carbon and nitrogen turn-over in respired CO2, total organic matter and amino acids. Our results indicate that CO2 evolved by respiration had an isotopic composition similar to that in organic matter regardless of the organ considered, suggesting that the turn-over of respiratory pools strictly followed photosynthetic input. However, carbon turn-over was nearly three times greater than N turn-over in total organic matter, suggesting that new organic material synthesised was less N-rich than pre-existing organic material (due to progressive nitrogen elemental dilution) or that N remobilisation occurred to sustain growth. This pattern was not consistent with the total commitment into free amino acids where the input of new C and N appeared to be stoichiometric. The labelling pattern in Asn was complex, with contrasted C and N commitments in different organs, suggesting that neosynthesis and redistribution of new Asn molecules required metabolic remobilisation. We conclude that the production of new organic material during alfalfa growth depends on both C and N remobilisation in different organs. At the plant level, this remobilisation is complicated by allocation and metabolism in the different organs. Additional keywords: carbon exchange, carbon isotopes, nitrogen fixation, nitrogen 15 isotopeCSIRO Publishing2014201420142014info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersion27 p.application/pdfhttps://hdl.handle.net/2445/51963Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésVersió postprint del document publicat a: http://dx.doi.org/10.1071/FP13189Functional Plant Biology, 2014, vol. 41, num. 4, p. 331-341http://dx.doi.org/10.1071/FP13189(c) Molero Milán, Gemma et al., 2014info:eu-repo/semantics/openAccessoai:recercat.cat:2445/519632026-05-29T05:05:01Z
dc.title.none.fl_str_mv On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
title On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
spellingShingle On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
Molero Milán, Gemma
Lleguminoses
Fotosíntesi
Adaptació (Biologia)
Isòtops estables en ecologia
Carboni
Efectes fisiològics
Legumes
Photosynthesis
Adaptation (Biology)
Stable isotopes in ecological research
Carbon
Physiological effect
title_short On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
title_full On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
title_fullStr On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
title_full_unstemmed On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
title_sort On the relationship between C and N fixation in nodulated alfalfa (Medicago sativa)
dc.creator.none.fl_str_mv Molero Milán, Gemma
Tcherkez, Guillaume
Araus Ortega, José Luis
Nogués Mestres, Salvador
Aranjuelo Michelena, Iker
author Molero Milán, Gemma
author_facet Molero Milán, Gemma
Tcherkez, Guillaume
Araus Ortega, José Luis
Nogués Mestres, Salvador
Aranjuelo Michelena, Iker
author_role author
author2 Tcherkez, Guillaume
Araus Ortega, José Luis
Nogués Mestres, Salvador
Aranjuelo Michelena, Iker
author2_role author
author
author
author
dc.subject.none.fl_str_mv Lleguminoses
Fotosíntesi
Adaptació (Biologia)
Isòtops estables en ecologia
Carboni
Efectes fisiològics
Legumes
Photosynthesis
Adaptation (Biology)
Stable isotopes in ecological research
Carbon
Physiological effect
topic Lleguminoses
Fotosíntesi
Adaptació (Biologia)
Isòtops estables en ecologia
Carboni
Efectes fisiològics
Legumes
Photosynthesis
Adaptation (Biology)
Stable isotopes in ecological research
Carbon
Physiological effect
description Legumes such as alfalfa (Medicago sativa L.) are vital N2-fixing crops accounting for a global N2 fixation of ~35 MtNyear-1. Although enzymatic and molecular mechanisms of nodule N2 fixation are now well documented, some uncertainty remains as to whether N2 fixation is strictly coupled with photosynthetic carbon fixation. That is, the metabolic origin and redistribution of carbon skeletons used to incorporate nitrogen are still relatively undefined. Here, we conducted isotopic labelling with both 15N2 and 13C-depleted CO2 on alfalfa plants grown under controlled conditions and took advantage of isotope ratio mass spectrometry to investigate the relationship between carbon and nitrogen turn-over in respired CO2, total organic matter and amino acids. Our results indicate that CO2 evolved by respiration had an isotopic composition similar to that in organic matter regardless of the organ considered, suggesting that the turn-over of respiratory pools strictly followed photosynthetic input. However, carbon turn-over was nearly three times greater than N turn-over in total organic matter, suggesting that new organic material synthesised was less N-rich than pre-existing organic material (due to progressive nitrogen elemental dilution) or that N remobilisation occurred to sustain growth. This pattern was not consistent with the total commitment into free amino acids where the input of new C and N appeared to be stoichiometric. The labelling pattern in Asn was complex, with contrasted C and N commitments in different organs, suggesting that neosynthesis and redistribution of new Asn molecules required metabolic remobilisation. We conclude that the production of new organic material during alfalfa growth depends on both C and N remobilisation in different organs. At the plant level, this remobilisation is complicated by allocation and metabolism in the different organs. Additional keywords: carbon exchange, carbon isotopes, nitrogen fixation, nitrogen 15 isotope
publishDate 2014
dc.date.none.fl_str_mv 2014
2014
2014
2014
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/51963
url https://hdl.handle.net/2445/51963
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Versió postprint del document publicat a: http://dx.doi.org/10.1071/FP13189
Functional Plant Biology, 2014, vol. 41, num. 4, p. 331-341
http://dx.doi.org/10.1071/FP13189
dc.rights.none.fl_str_mv (c) Molero Milán, Gemma et al., 2014
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) Molero Milán, Gemma et al., 2014
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 27 p.
application/pdf
dc.publisher.none.fl_str_mv CSIRO Publishing
publisher.none.fl_str_mv CSIRO Publishing
dc.source.none.fl_str_mv Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,811543

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