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Salomón RL, Rodríguez-Calcerrada J, De Roo L, Miranda JC, Bodé S, Boeckx P, Steppe K. Carbon isotope composition of respired CO2 in woody stems and leafy shoots of three tree species along the growing season: physiological drivers for respiratory fractionation. Tree Physiol 2023; 43:1731-1744. [PMID: 37471648 DOI: 10.1093/treephys/tpad091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/10/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
The carbon isotope composition of respired CO2 (δ13CR) and bulk organic matter (δ13CB) of various plant compartments informs about the isotopic fractionation and substrate of respiratory processes, which are crucial to advance the understanding of carbon allocation in plants. Nevertheless, the variation across organs, species and seasons remains poorly understood. Cavity Ring-Down Laser Spectroscopy was applied to measure δ13CR in leafy shoots and woody stems of maple (Acer platanoides L.), oak (Quercus robur L.) and cedar (Thuja occidentalis L.) trees during spring and late summer. Photosynthesis, respiration, growth and non-structural carbohydrates were measured in parallel to evaluate potential drivers for respiratory fractionation. The CO2 respired by maple and oak shoots was 13C-enriched relative to δ13CB during spring, but not late summer or in the stem. In cedar, δ13CR did not vary significantly throughout organs and seasons, with respired CO2 being 13C-depleted relative to δ13CB. Shoot δ13CR was positively related to leaf starch concentration in maple, while stem δ13CR was inversely related to stem growth. These relations were not significant for oak or cedar. The variability in δ13CR suggests (i) different contributions of respiratory pathways between organs and (ii) seasonality in the respiratory substrate and constitutive compounds for wood formation in deciduous species, less apparent in evergreen cedar, whose respiratory metabolism might be less variable.
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Affiliation(s)
- Roberto L Salomón
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Jesús Rodríguez-Calcerrada
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Linus De Roo
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
| | - José Carlos Miranda
- Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Universidad Politécnica de Madrid, Jose Antonio Novais 10, 28040, Madrid, Spain
| | - Samuel Bodé
- Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Isotope Bioscience Laboratory - ISOFYS, Ghent University, Coupure links 653, Gent 9000, Belgium
| | - Pascal Boeckx
- Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Isotope Bioscience Laboratory - ISOFYS, Ghent University, Coupure links 653, Gent 9000, Belgium
| | - Kathy Steppe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Laboratory of Plant Ecology, Ghent University, Coupure links 653, Ghent 9000, Belgium
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Diao H, Wang A, Yuan F, Guan D, Dai G, Wu J. Environmental Effects on Carbon Isotope Discrimination from Assimilation to Respiration in a Coniferous and Broad-Leaved Mixed Forest of Northeast China. Forests 2020; 11:1156. [DOI: 10.3390/f11111156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Carbon (C) isotope discrimination during photosynthetic CO2 assimilation has been extensively studied, but the whole process of fractionation from leaf to soil has been less well investigated. In the present study, we investigated the δ13C signature along the C transfer pathway from air to soil in a coniferous and broad-leaved mixed forest in northeast China and examined the relationship between δ13C of respiratory fluxes (leaf, trunk, soil, and the entire ecosystem) and environmental factors over a full growing season. This study found that the δ13C signal of CO2 from canopy air was strongly imprinted in the organic and respiratory pools throughout C transfer due to the effects of discrimination and isotopic mixing on C assimilation, allocation, and respiration processes. A significant difference in isotopic patterns was found between conifer and broadleaf species in terms of seasonal variations in leaf organic matter. This study also found that δ13C in trunk respiration, compared with that in leaf and soil respiration, was more sensitive to seasonal variations of environmental factors, especially soil temperature and soil moisture. Variation in the δ13C of ecosystem respiration was correlated with air temperature with no time lag and correlated with soil temperature and vapor pressure deficit with a lag time of 10 days, but this correlation was relatively weak, indicating a delayed linkage between above- and belowground processes. The isotopic linkage might be confounded by variations in atmospheric aerodynamic and soil diffusion conditions. These results will help with understanding species differences in isotopic patterns and promoting the incorporation of more influencing factors related to isotopic variation into process-based ecosystem models.
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Vincent-Barbaroux C, Berveiller D, Lelarge-Trouverie C, Maia R, Máguas C, Pereira J, Chaves MM, Damesin C. Carbon-use strategies in stem radial growth of two oak species, one Temperate deciduous and one Mediterranean evergreen: what can be inferred from seasonal variations in the δ13C of the current year ring? Tree Physiol 2019; 39:1329-1341. [PMID: 31100150 DOI: 10.1093/treephys/tpz043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Tree ring synthesis is a key process in wood production; however, little is known of the origin and fate of the carbon involved. We used natural 13C abundance to investigate the carbon-use process for the ring development in a temperate deciduous (Quercus petraea (Matt.) Liebl.) and a Mediterranean evergreen (Quercus ilex L.) oak. The sapwood carbon reserves, phloem sucrose contents, stem respired CO2 efflux and their respective carbon isotope compositions (δ13C) were recorded over 1 year, in the native area of each species. The seasonal δ13C variation of the current year ring was determined in the total ring throughout the seasons, as well as in slices from the fully mature ring after the growth season (intra-ring pattern). Although the budburst dates of the two oaks were similar, the growth of Quercus ilex began 50 days later. Both species exhibited growth cessation during the hot and dry summer but only Q. ilex resumed in the autumn. In the deciduous oak, xylem starch storage showed clear variations during the radial growth. The intra-ring δ13C variations of the two species exhibited similar ranges, but contrasting patterns, with an early increase for Q. petraea. Comparison between δ13C of starch and total ring suggested that Q. petraea (but not Q. ilex) builds its rings using reserves during the first month of growth. Shifts in ring and soluble sugars δ13C suggested an interspecific difference in either the phloem unloading or the use of fresh assimilate inside the ring. A decrease in ring δ13C for both oaks between the end of the radial growth and the winter is attributed to a lignification of ring cell walls after stem increment. This study highlighted the differences in carbon-use during ring growth for evergreen and deciduous oaks, as well as the benefits of exploring the process using natural 13C abundance.
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Affiliation(s)
- Cécile Vincent-Barbaroux
- Laboratoire Biologie des Ligneux et des Grandes Cultures, INRA, Université d'Orléans, USC, Orléans cedex 2, France
- Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal
| | - Daniel Berveiller
- Laboratoire Ecologie Systématique et Evolution, UMR, Université Paris-Sud, CNRS, AgroparisTech, Orsay, France
| | - Caroline Lelarge-Trouverie
- Institute of Plant Sciences Paris-Saclay IPS2, CNRS, INRA, Université Paris-Sud, Université d'Evry, Université Paris-Diderot, Université Paris-Saclay, Bâtiment, Orsay, France
| | - Rodrigo Maia
- Centro de Ecologia, Evolução e Alterações Ambientais (cE3c), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - Cristina Máguas
- Centro de Ecologia, Evolução e Alterações Ambientais (cE3c), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - João Pereira
- Centro de Estudos Florestais Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal
| | - Manuela M Chaves
- Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Claire Damesin
- Laboratoire Ecologie Systématique et Evolution, UMR, Université Paris-Sud, CNRS, AgroparisTech, Orsay, France
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Salomón RL, De Roo L, Bodé S, Boeckx P, Steppe K. Isotope ratio laser spectroscopy to disentangle xylem-transported from locally respired CO2 in stem CO2 efflux. Tree Physiol 2019; 39:819-830. [PMID: 30726992 DOI: 10.1093/treephys/tpy152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 12/18/2018] [Accepted: 01/02/2019] [Indexed: 06/09/2023]
Abstract
Respired CO2 in woody tissues radially diffuses to the atmosphere or it is transported upward with the transpiration stream, making the origin of CO2 in stem CO2 efflux (EA) uncertain, which may confound stem respiration (RS) estimates. An aqueous 13C-enriched solution was infused into stems of Populus tremula L. trees, and real-time measurements of 13C-CO2 and 12C-CO2 in EA were performed via Cavity Ring Down Laser Spectroscopy (CRDS). The contribution of locally respired CO2 (LCO2) and xylem-transported CO2 (TCO2) to EA was estimated from their different isotopic composition. Mean daily values of TCO2/EA ranged from 13% to 38%, evidencing the notable role that xylem CO2 transport plays in the assessment of stem respiration. Mean daily TCO2/EA did not differ between treatments of drought stress and light exclusion of woody tissues, but they showed different TCO2/EA dynamics on a sub-daily time scale. Sub-daily CO2 diffusion patterns were explained by a light-induced axial CO2 gradient ascribed to woody tissue photosynthesis, and the resistance to radial CO2 diffusion determined by bark water content. Here, we demonstrate the outstanding potential of CRDS paired with 13C-CO2 labelling to advance in the understanding of CO2 movement at the plant-atmosphere interface and the respiratory physiology in woody tissues.
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Affiliation(s)
- Roberto L Salomón
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Linus De Roo
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Samuel Bodé
- Isotope Bioscience Laboratory - ISOFYS, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Pascal Boeckx
- Isotope Bioscience Laboratory - ISOFYS, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Ghashghaie J, Badeck FW. Opposite carbon isotope discrimination during dark respiration in leaves versus roots - a review. New Phytol 2014; 201:751-769. [PMID: 24251924 DOI: 10.1111/nph.12563] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 09/15/2013] [Indexed: 05/13/2023]
Abstract
In general, leaves are (13) C-depleted compared with all other organs (e.g. roots, stem/trunk and fruits). Different hypotheses are formulated in the literature to explain this difference. One of these states that CO2 respired by leaves in the dark is (13) C-enriched compared with leaf organic matter, while it is (13) C-depleted in the case of root respiration. The opposite respiratory fractionation between leaves and roots was invoked as an explanation for the widespread between-organ isotopic differences. After summarizing the basics of photosynthetic and post-photosynthetic discrimination, we mainly review the recent findings on the isotopic composition of CO2 respired by leaves (autotrophic organs) and roots (heterotrophic organs) compared with respective plant material (i.e. apparent respiratory fractionation) as well as its metabolic origin. The potential impact of such fractionation on the isotopic signal of organic matter (OM) is discussed. Some perspectives for future studies are also proposed .
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Affiliation(s)
- Jaleh Ghashghaie
- Laboratoire d'Ecologie, Systématique et Evolution (ESE), CNRS UMR8079, Bâtiment 362, Université de Paris-Sud (XI), F-91405, Orsay Cedex, France
| | - Franz W Badeck
- Consiglio per la Ricerca e la sperimentazione in Agricoltura, Genomics research centre (CRA - GPG), Via San Protaso, 302, 29017, Fiorenzuola d'Arda (PC), Italy
- Potsdam Institute for Climate Impact Research (PIK), PF 60 12 03, 14412, Potsdam, Germany
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Maunoury-Danger F, Fresneau C, Eglin T, Berveiller D, François C, Lelarge-Trouverie C, Damesin C. Impact of carbohydrate supply on stem growth, wood and respired CO2 delta13C: assessment by experimental girdling. Tree Physiol 2010; 30:818-30. [PMID: 20504776 DOI: 10.1093/treephys/tpq039] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The present study examines the impact of the C source (reserves vs current assimilates) on tree C isotope signals and stem growth, using experimental girdling to stop the supply of C from leaves to stem. Two-year-old sessile oaks (Quercus petraea) were girdled at three different phenological periods during the leafy period: during early wood growth (Girdling Period 1), during late wood growth (Girdling Period 2) and just after growth cessation (Girdling Period 3). The measured variables included stem respiration rates, stem radial increment, delta(13)C of respired CO(2) and contents of starch and water-soluble fraction in stems (below the girdle) and leaves. Girdling stopped growth, even early in the growing season, leading to a decrease in stem CO(2) efflux (CO(2R)). Shift in substrate use from recently fixed carbohydrate to reserves (i.e., starch) induced (13)C enrichment of CO(2) respired by stem. However, change in substrate type was insufficient to explain alone all the observed CO(2R) delta(13)C variations, especially at the period corresponding to large growth rate of control trees. The below-girdle mass balance suggested that, during girdling periods, stem C was invested in metabolic pathways other than respiration and stem growth. After Girdling Period 1, the girdle healed and the effects of girdling on stem respiration were reversed. Stem growth restarted and total radial increment was similar to the control one, indicating that growth can be delayed when a stress event occurs early in the growth period. Concerning tree ring, seasonal shift in substrate use from reserves (i.e., starch) to recently fixed carbohydrate is sufficient to explain the observed (13)C depletion of tree ring during the early wood growth. However, the inter-tree intra-ring delta(13)C variability needs to be resolved in order to improve the interpretation of intra-seasonal ring signals in terms of climatic or ecophysiological information. This study highlighted, via carbohydrate availability effects, the importance of the characterization of stem metabolic pathways for a complete understanding of the delta(13)C signals.
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Affiliation(s)
- Florence Maunoury-Danger
- Laboratoire Ecologie, Systématique et Evolution, UMR 8079, Université Paris-Sud XI, 91405 Orsay CEDEX, France.
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Ubierna N, Kumar AS, Cernusak LA, Pangle RE, Gag PJ, Marshall JD. Storage and transpiration have negligible effects on delta13C of stem CO2 efflux in large conifer trees. Tree Physiol 2009; 29:1563-1574. [PMID: 19840994 DOI: 10.1093/treephys/tpp089] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Stem respiration rates are often quantified by measuring the CO(2) efflux from stems into chambers. It has been suggested that these measurements underestimate respiration because some of the respired CO(2) can be either retained or transported upwards in the transpiration stream. If the stem CO(2) efflux does not represent all respired CO(2), then the interpretation of its isotopic signal may be compromised as well. The C-isotope composition of the respired CO(2) and the measured efflux could differ due to (i) the release of CO(2) produced elsewhere into the stem and transported upwards in xylem water (soil CO(2) or root respired CO(2)); (ii) the retention or release of CO(2) storage pools within the tree stem and (iii) the removal of CO(2) by the transpiration stream. We investigated the effects of these processes in large conifer trees using two manipulative experiments: a labelling experiment and a crown removal experiment. The labelling experiment used an extreme enrichment of dissolved CO(2) in soil water to assess the C uptake by the roots. In this experiment, we found no contamination of the stem CO(2) pool despite clear evidence that the water itself had been taken up. The crown removal experiment tested for vertical CO(2) flux in xylem water by eliminating transpiration. Here, we found no change in the delta(13)C of stem CO(2) efflux (delta(EA); P > 0.05). We concluded that for these large conifers, sap-flow influenced neither delta(13)C of stem efflux nor that of the stem CO(2) pool. By parameterizing Henry's Law for conditions inside the stem, we estimated the transport flux to represent 1-3% of the stem CO(2) efflux to the atmosphere. Finally, assuming a 2 per thousand difference between delta(13)C of root and stem respiration, we estimated that potential contamination of delta(EA) by root respired CO(2) would be < 0.1 per thousand. Thus, neither the release of soil or root CO(2), nor storage in the stem, nor vertical transport of CO(2) in the xylem sap had any detectable influence on delta(13)C of the CO(2) measured in stem efflux.
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Affiliation(s)
- Nerea Ubierna
- Department of Forest Resources, University of Idaho, Moscow, ID 83844-1133, USA.
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Cernusak LA, Tcherkez G, Keitel C, Cornwell WK, Santiago LS, Knohl A, Barbour MM, Williams DG, Reich PB, Ellsworth DS, Dawson TE, Griffiths HG, Farquhar GD, Wright IJ. Why are non-photosynthetic tissues generally 13C enriched compared with leaves in C 3 plants? Review and synthesis of current hypotheses. Funct Plant Biol 2009; 36:199-213. [PMID: 32688639 DOI: 10.1071/fp08216] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Accepted: 01/18/2009] [Indexed: 05/08/2023]
Abstract
Non-photosynthetic, or heterotrophic, tissues in C3 plants tend to be enriched in 13C compared with the leaves that supply them with photosynthate. This isotopic pattern has been observed for woody stems, roots, seeds and fruits, emerging leaves, and parasitic plants incapable of net CO2 fixation. Unlike in C3 plants, roots of herbaceous C4 plants are generally not 13C-enriched compared with leaves. We review six hypotheses aimed at explaining this isotopic pattern in C3 plants: (1) variation in biochemical composition of heterotrophic tissues compared with leaves; (2) seasonal separation of growth of leaves and heterotrophic tissues, with corresponding variation in photosynthetic discrimination against 13C; (3) differential use of day v. night sucrose between leaves and sink tissues, with day sucrose being relatively 13C-depleted and night sucrose 13C-enriched; (4) isotopic fractionation during dark respiration; (5) carbon fixation by PEP carboxylase; and (6) developmental variation in photosynthetic discrimination against 13C during leaf expansion. Although hypotheses (1) and (2) may contribute to the general pattern, they cannot explain all observations. Some evidence exists in support of hypotheses (3) through to (6), although for hypothesis (6) it is largely circumstantial. Hypothesis (3) provides a promising avenue for future research. Direct tests of these hypotheses should be carried out to provide insight into the mechanisms causing within-plant variation in carbon isotope composition.
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Affiliation(s)
- Lucas A Cernusak
- Charles Darwin University, School of Environmental and Life Sciences, Darwin, NT 0909, Australia
| | - Guillaume Tcherkez
- Plateforme Métabolisme-Metabolome IFR87, Batiment 630, IBP CNRS UMR8618, Université Paris-Sud XI, 91405 Orsay cedex, France
| | - Claudia Keitel
- Environmental Biology Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - William K Cornwell
- Biodiversity Research Group, University of British Colombia, Vancouver, BC V6T 1Z4, Canada
| | - Louis S Santiago
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, CA 92521, USA
| | - Alexander Knohl
- Institute of Plant Sciences, ETH Zurich, Zurich 8092, Switzerland
| | | | - David G Williams
- Department of Renewable Resources, University of Wyoming, Laramie, WY 82071, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St Paul, MN 55108, USA
| | - David S Ellsworth
- Center for Plant and Food Sciences, University of Western Sydney, Penrith, NSW 1797, Australia
| | - Todd E Dawson
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Howard G Griffiths
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - Graham D Farquhar
- Environmental Biology Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 2601, Australia
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Kodama N, Barnard RL, Salmon Y, Weston C, Ferrio JP, Holst J, Werner RA, Saurer M, Rennenberg H, Buchmann N, Gessler A. Temporal dynamics of the carbon isotope composition in a Pinus sylvestris stand: from newly assimilated organic carbon to respired carbon dioxide. Oecologia 2008; 156:737-50. [DOI: 10.1007/s00442-008-1030-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Accepted: 03/14/2008] [Indexed: 11/25/2022]
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Gessler A, Keitel C, Kodama N, Weston C, Winters AJ, Keith H, Grice K, Leuning R, Farquhar GD. δ 13C of organic matter transported from the leaves to the roots in Eucalyptus delegatensis: short-term variations and relation to respired CO 2. Funct Plant Biol 2007; 34:692-706. [PMID: 32689397 DOI: 10.1071/fp07064] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Accepted: 05/31/2007] [Indexed: 06/11/2023]
Abstract
Post-photosynthetic carbon isotope fractionation might alter the isotopic signal imprinted on organic matter (OM) during primary carbon fixation by Rubisco. To characterise the influence of post-photosynthetic processes, we investigated the effect of starch storage and remobilisation on the stable carbon isotope signature (δ13C) of different carbon pools in the Eucalyptus delegatensis R. T. Baker leaf and the potential carbon isotope fractionation associated with phloem transport and respiration. Twig phloem exudate and leaf water-soluble OM showed diel variations in δ13C of up to 2.5 and 2‰, respectively, with 13C enrichment during the night and depletion during the day. Damped diel variation was also evident in bulk lipids of the leaf and in the leaf wax fraction. δ13C of nocturnal phloem exudate OM corresponded with the δ13C of carbon released from starch. There was no change in δ13C of phloem carbon along the trunk. CO2 emitted from trunks and roots was 13C enriched compared with the potential organic substrate, and depleted compared with soil-emitted CO2. The results are consistent with transitory starch accumulation and remobilisation governing the diel rhythm of δ13C in phloem-transported OM and fragmentation fractionation occurring during respiration. When using δ13C of OM or CO2 for assessing ecosystem processes or plant reactions towards environmental constraints, post-photosynthetic discrimination should be considered.
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Affiliation(s)
- Arthur Gessler
- Environmental Biology Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 0200, Australia
| | - Claudia Keitel
- Environmental Biology Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 0200, Australia
| | - Naomi Kodama
- Chair of Tree Physiology, University of Freiburg, Georges-Köhler Allee 53/54, 79085 Freiburg, Germany
| | - Christopher Weston
- School of Forest and Ecosystem Science, University of Melbourne, Water Street, Creswick, Vic. 3363, Australia
| | - Anthony J Winters
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Heather Keith
- CSIRO Climate Program, PO Box 3023, Canberra, ACT 2601, Australia
| | - Kliti Grice
- Stable Isotope and Molecular Biogeochemistry Group, Centre for Applied Organic Geochemistry, The Institute for Geoscience Research Department of Applied Chemistry, Curtin University of Technology, Perth, WA 6845, Australia
| | - Ray Leuning
- CSIRO Marine and Atmospheric Research, GPO Box 3023, Canberra, ACT 2601, Australia
| | - Graham D Farquhar
- Environmental Biology Group, Research School of Biological Sciences, Australian National University, Canberra, ACT 0200, Australia
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Maunoury F, Berveiller D, Lelarge C, Pontailler JY, Vanbostal L, Damesin C. Seasonal, daily and diurnal variations in the stable carbon isotope composition of carbon dioxide respired by tree trunks in a deciduous oak forest. Oecologia 2006; 151:268-79. [PMID: 17115189 DOI: 10.1007/s00442-006-0592-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Accepted: 10/12/2006] [Indexed: 10/23/2022]
Abstract
The stable C isotope composition (delta13C) of CO2 respired by trunks was examined in a mature temperate deciduous oak forest (Quercus petraea). Month-to-month, day-to-day and diurnal, measurements were made to determine the range of variations at different temporal scales. Trunk growth and respiration rates were assessed. Phloem tissue was sampled and was analysed for total organic matter and soluble sugar 13C composition. The CO2 respired by trunk was always enriched in 13C relative to the total organic matter, sometimes by as much as 5 per thousand. The delta13C of respired CO2 exhibited a large seasonal variation (3.3 per thousand), with a relative maximum at the beginning of the growth period. The lowest values occurred in summer when the respiration rates were maximal. After the cessation of radial trunk growth, the respired CO2 delta13C values showed a progressive increase, which was linked to a parallel increase in soluble sugar content in the phloem tissue (R=0.95; P<0.01). At the same time, the respiration rates declined. This limited use of the substrate pool might allow the discrimination during respiration to be more strongly expressed. The late-season increase in CO2 delta13C might also be linked to a shift from recently assimilated C to reserves. At the seasonal scale, CO2 delta13C was negatively correlated with air temperature (R=-0.80; P<0.01). The diurnal variation sometimes reached 3 per thousand, but the range and the pattern depended on the period within the growing season. Contrary to expectations, diurnal variations were maximal in winter and spring when the leaves were missing or not totally functional. By contrast to the seasonal scale, these diurnal variations were not related to air temperature or sugar content. Our study shows that seasonal and diurnal variations of respired 13C exhibited a similar large range but were probably explained by different mechanisms.
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Affiliation(s)
- Florence Maunoury
- Laboratoire d'Ecologie, Systématique et Evolution (ESE), Université Paris XI, CNRS UMR 8079, Bâtiment 362, 91405, Orsay Cedex, France.
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Nogués S, Damesin C, Tcherkez G, Maunoury F, Cornic G, Ghashghaie J. (13)C/(12)C isotope labelling to study leaf carbon respiration and allocation in twigs of field-grown beech trees. Rapid Commun Mass Spectrom 2006; 20:219-26. [PMID: 16345109 DOI: 10.1002/rcm.2297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In situ (13)C/(12)C isotopic labelling was conducted in field-grown beech (Fagus sylvatica) twigs to study carbon respiration and allocation. This was achieved with a portable gas-exchange open system coupled to an external chamber. This method allowed us to subject leafy twigs to CO(2) with a constant carbon isotope composition (delta(13)C of -51.2 per thousand) in an open system in the field. The labelling was done during the whole light period at two different dates (in June 2002 and October 2003). The delta(13)C values of respiratory metabolites and CO(2) that is subsequently respired during the night were measured. It was found that night-respired CO(2) is not completely labelled (only ca. 58% and 27% of new carbon is found in respired CO(2) immediately after the labelling in June 2002 and October 2003, respectively) and the labelling level progressively disappeared during the next day. It is concluded that the carbon respired by beech leaves after illumination was supplied by a mixture of carbon sources in which current carbohydrates were not the only contributors. In addition, as has been found in herbaceous plants, isotopic data before labelling showed that carbon isotope discrimination favoring the (13)C isotope occurred during the night respiration of beech leaves.
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Affiliation(s)
- Salvador Nogués
- Laboratoire d'Ecologie Systématique et Evolution, Unité Mixte de Recherche 8079, Université de Paris XI, Bâtiment 362, 91405 Orsay, France.
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Current literature in mass spectrometry. J Mass Spectrom 2005; 40:973-84. [PMID: 16034836 DOI: 10.1002/jms.808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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