Respiratory Effects on the Carbon IsotopeDiscrimination Near the Compensation Point

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dc.contributor.authorBarbour, Margaret M
dc.contributor.authorRyazanova, Svetlana
dc.contributor.authorTcherkez, Guillaume
dc.contributor.editorGuillaume Tcherkez
dc.contributor.editorJaleh Ghashghaie
dc.date.accessioned2019-09-18T01:23:38Z
dc.date.issued2017
dc.date.updated2019-04-14T08:36:24Z
dc.description.abstractThe carbon isotope discrimination associated with net photosynthesis (Δobs) when photosynthetic rates are low, such as approaching the light and CO2 compensation points, has rarely been measured but may contain useful information on day respiration (Rd). In fact, at low assimilation rates, the relative importance of respiratory CO2 release is larger and its isotopic signal can be captured. In this chapter, we describe the measurement of Δobs in cocklebur, spinach and magnolia leaves at very low irradiance and CO2 concentration. The carbon isotope fractionation associated with day respiration appears to be similar when approaching the light and CO2 compensation points, and not strongly affected by oxygen concentration. Under the experimental conditions imposed, the apparent fractionation associated with day respiration was found to be −100‰ for cocklebur and spinach, and −62‰ for magnolia. These strongly negative values were due to the use of 13C-depleted CO2 during gas exchange measurements and the use of respiratory carbon fixed prior to gas exchange measurements. Theoretical considerations allowed estimation of the proportion of newly-fixed carbon as a respiratory substrate, which was found to be zero for all species when a single respiratory source is assumed. When two respiratory sources are assumed (with a respiratory pool in photosynthesizing cells and a photosynthetically disconnected pool in heterotrophic, non-photosynthesizing cells), the heterotrophic component dominated day respiration in cocklebur and magnolia leaves, with newly-fixed carbon contributing little to total efflux in magnolia, but representing about one half in cocklebur. In contrast, respiration from photosynthesizing cells dominated Rd in spinach leaves, but newly-fixed carbon formed just 11% of the respiratory substrate. Therefore, day respiration appears to be mostly fed by “old” carbon sources, and this can lead to a considerable isotopic difference between net fixed CO2 and CO2 liberated by day respiration at the same moment.en_AU
dc.format.mimetypeapplication/pdfen_AU
dc.identifier.isbn978-3-319-68701-8en_AU
dc.identifier.issn1572-0233en_AU
dc.identifier.urihttp://hdl.handle.net/1885/170544
dc.language.isoen_AUen_AU
dc.publisherSpringer International Publishing AGen_AU
dc.relation.ispartofPlant Respiration: Metabolic Fluxes and Carbon Balanceen_AU
dc.rights© Springer International Publishing AG 2017en_AU
dc.titleRespiratory Effects on the Carbon IsotopeDiscrimination Near the Compensation Pointen_AU
dc.typeBook chapteren_AU
local.bibliographicCitation.lastpage160en_AU
local.bibliographicCitation.placeofpublicationSwitzerland
local.bibliographicCitation.startpage143en_AU
local.contributor.affiliationBarbour, Margaret M , University of Sydneyen_AU
local.contributor.affiliationRyazanova, Svetlana, University of Sydneyen_AU
local.contributor.affiliationTcherkez, Guillaume, College of Science, ANUen_AU
local.contributor.authoremailu4641357@anu.edu.auen_AU
local.contributor.authoruidTcherkez, Guillaume, u4641357en_AU
local.description.embargo2037-12-31
local.description.notesImported from ARIESen_AU
local.description.refereedYes
local.identifier.absfor060705 - Plant Physiologyen_AU
local.identifier.absseo829999 - Plant Production and Plant Primary Products not elsewhere classifieden_AU
local.identifier.absseo970106 - Expanding Knowledge in the Biological Sciencesen_AU
local.identifier.ariespublicationu9511635xPUB1864en_AU
local.identifier.doi10.1007/978-3-319-68703-2_7en_AU
local.identifier.uidSubmittedByu9511635en_AU
local.publisher.urlhttps://link.springer.comen_AU
local.type.statusPublished Versionen_AU

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