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Yu YZ, Liu HT, Yang F, Li L, Schäufele R, Tcherkez G, Schnyder H, Gong XY. δ13C of bulk organic matter and cellulose reveal post-photosynthetic fractionation during ontogeny in C4 grass leaves. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1451-1464. [PMID: 37943576 DOI: 10.1093/jxb/erad445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
The 13C isotope composition (δ13C) of leaf dry matter is a useful tool for physiological and ecological studies. However, how post-photosynthetic fractionation associated with respiration and carbon export influences δ13C remains uncertain. We investigated the effects of post-photosynthetic fractionation on δ13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. With increasing leaf age class, the 12C/13C fractionation of leaf organic matter relative to the δ13C of atmosphere CO2 (ΔDM) increased while that of cellulose (Δcel) was almost constant. The divergence between ΔDM and Δcel increased with leaf age class, with a maximum value of 1.6‰, indicating the accumulation of post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with carbon export of -0.5‰ to -1.0‰. Different ΔDM among leaves, pseudostems, daughter tillers, and roots indicate that post-photosynthetic fractionation happens at the whole-plant level. Compared with ΔDM of old leaves, ΔDM of young leaves and Δcel are more reliable proxies for predicting physiological parameters due to the lower sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes.
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Affiliation(s)
- Yong Zhi Yu
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Henan Agricultural University, Zhengzhou 450046, China
| | - Fang Yang
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Jilin Agricultural University, Changchun 130117, China
| | - Lei Li
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Science, Australian National University, Canberra ACT 0200, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, 42 rue Georges Morel, 49070 Beaucouzé, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
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Ellsworth PZ, Cousins AB. Carbon isotopes and water use efficiency in C4 plants. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:155-61. [PMID: 27155062 DOI: 10.1016/j.pbi.2016.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/07/2016] [Accepted: 04/14/2016] [Indexed: 05/13/2023]
Abstract
Drought is a major agricultural problem worldwide. Therefore, selection for increased water use efficiency (WUE) in food and biofuel crop species will be an important trait in plant breeding programs. The leaf carbon isotopic composition (δ(13)Cleaf) has been suggested to serve as a rapid and effective high throughput phenotyping method for WUE in both C3 and C4 species. This is because WUE, leaf carbon discrimination (Δ(13)Cleaf), and δ(13)Cleaf are correlated through their relationships with intercellular to ambient CO2 partial pressures (Ci/Ca). However, in C4 plants, changing environmental conditions may influence photosynthetic efficiency (bundle-sheath leakiness) and post-photosynthetic fractionation that will potentially alter the relationship between δ(13)Cleaf and Ci/Ca. Here we discuss how these factors influence the relationship between δ(13)Cleaf and WUE, and the potential of using δ(13)Cleaf as a meaningful proxy for WUE.
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Affiliation(s)
| | - Asaph B Cousins
- Washington State University, Pullman, WA 99163, United States.
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Ghashghaie J, Badeck FW, Girardin C, Huignard C, Aydinlis Z, Fonteny C, Priault P, Fresneau C, Lamothe-Sibold M, Streb P, Terwilliger VJ. Changes and their possible causes in δ13C of dark-respired CO2 and its putative bulk and soluble sources during maize ontogeny. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2603-15. [PMID: 26970389 DOI: 10.1093/jxb/erw075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The issues of whether, where, and to what extent carbon isotopic fractionations occur during respiration affect interpretations of plant functions that are important to many disciplines across the natural sciences. Studies of carbon isotopic fractionation during dark respiration in C3 plants have repeatedly shown respired CO2 to be (13)C enriched relative to its bulk leaf sources and (13)C depleted relative to its bulk root sources. Furthermore, two studies showed respired CO2 to become progressively (13)C enriched during leaf ontogeny and (13)C depleted during root ontogeny in C3 legumes. As such data on C4 plants are scarce and contradictory, we investigated apparent respiratory fractionations of carbon and their possible causes in different organs of maize plants during early ontogeny. As in the C3 plants, leaf-respired CO2 was (13)C enriched whereas root-respired CO2 was (13)C depleted relative to their putative sources. In contrast to the findings for C3 plants, however, not only root- but also leaf-respired CO2 became more (13)C depleted during ontogeny. Leaf-respired CO2 was highly (13)C enriched just after light-dark transition but the enrichment rapidly decreased over time in darkness. We conclude that (i) although carbon isotopic fractionations in C4 maize and leguminous C3 crop roots are similar, increasing phosphoenolpyruvate-carboxylase activity during maize ontogeny could have produced the contrast between the progressive (13)C depletion of maize leaf-respired CO2 and (13)C enrichment of C3 leaf-respired CO2 over time, and (ii) in both maize and C3 leaves, highly (13)C enriched leaf-respired CO2 at light-to-dark transition and its rapid decrease during darkness, together with the observed decrease in leaf malate content, may be the result of a transient effect of light-enhanced dark respiration.
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Affiliation(s)
- Jaleh Ghashghaie
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400 Orsay, France
| | - Franz W Badeck
- Genomics Research Centre, Council for Agricultural Research and Economics, 29017 Fiorenzuola d'Arda (PC), Italy
| | - Cyril Girardin
- UMR ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, 78850 Thiverval-Grignon, France
| | - Christophe Huignard
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400 Orsay, France
| | - Zackarie Aydinlis
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400 Orsay, France
| | - Charlotte Fonteny
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400 Orsay, France
| | - Pierrick Priault
- Université de Lorraine, UMR Ecologie et Ecophysiologie Forestière, 54506 Vandoeuvre-lès-Nancy, France INRA, UMR Ecologie et Ecophysiologie Forestière, 54280 Champenoux, France
| | - Chantal Fresneau
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400 Orsay, France
| | - Marlène Lamothe-Sibold
- Institute of Plant Sciences Paris-Saclay, IPS2, CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, 91405 Orsay, France
| | - Peter Streb
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91400 Orsay, France
| | - Valery J Terwilliger
- Department of Geography, 1475 Jayhawk Drive, University of Kansas, Lawrence, KS 66045, USA School of Natural Sciences, 5200 North Lake Road, University of California, CA 95343, USA
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Li L, Wang H, Gago J, Cui H, Qian Z, Kodama N, Ji H, Tian S, Shen D, Chen Y, Sun F, Xia Z, Ye Q, Sun W, Flexas J, Dong H. Harpin Hpa1 Interacts with Aquaporin PIP1;4 to Promote the Substrate Transport and Photosynthesis in Arabidopsis. Sci Rep 2015; 5:17207. [PMID: 26607179 PMCID: PMC4660436 DOI: 10.1038/srep17207] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/27/2015] [Indexed: 12/12/2022] Open
Abstract
Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO2 and H2O. In particular, AtPIP1;4 mediates CO2 transport with a substantial contribute to photosynthesis and further increases this function upon interacting with Hpa1 at the plasma membrane. As a result, leaf photosynthesis rates are increased and the plant growth is enhanced in contrast to the normal process without Hpa1-AtPIP1;4 interaction. Our findings demonstrate the first case that plant sensing of a bacterial harpin protein is connected with photosynthetic physiology to regulate plant growth.
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Affiliation(s)
- Liang Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jorge Gago
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears 07122, Spain
| | - Haiying Cui
- Institute of Grassland Science, Northeast Normal University and National Ministry of Education Key Laboratory of Vegetation Ecology, Changchun 130024, China
| | - Zhengjiang Qian
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Naomi Kodama
- Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, Tsukuba 305-8604, Japan
| | - Hongtao Ji
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Shan Tian
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Dan Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanjuan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Fengli Sun
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhonglan Xia
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Qing Ye
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Wei Sun
- Institute of Grassland Science, Northeast Normal University and National Ministry of Education Key Laboratory of Vegetation Ecology, Changchun 130024, China
| | - Jaume Flexas
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears 07122, Spain
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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Cui H, Wang Y, Jiang Q, Chen S, Ma JY, Sun W. Carbon Isotope Composition of Nighttime Leaf-Respired CO2 in the Agricultural-Pastoral Zone of the Songnen Plain, Northeast China. PLoS One 2015; 10:e0137575. [PMID: 26356083 PMCID: PMC4565631 DOI: 10.1371/journal.pone.0137575] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 08/18/2015] [Indexed: 11/23/2022] Open
Abstract
Variations in the carbon isotope signature of leaf dark-respired CO2 (δ13CR) within a single night is a widely observed phenomenon. However, it is unclear whether there are plant functional type differences with regard to the amplitude of the nighttime variation in δ13CR. These differences, if present, would be important for interpreting the short-term variations in the stable carbon signature of ecosystem respiration and the partitioning of carbon fluxes. To assess the plant functional type differences relating to the magnitude of the nighttime variation in δ13CR and the respiratory apparent fractionation, we measured the δ13CR, the leaf gas exchange, and the δ13C of the respiratory substrates of 22 species present in the agricultural-pastoral zone of the Songnen Plain, northeast China. The species studied were grouped into C3 and C4 plants, trees, grasses, and herbs. A significant nocturnal shift in δ13CR was detected in 20 of the studied species, with the magnitude of the shift ranging from 1‰ to 5.8‰. The magnitude of the nighttime variation in δ13CR was strongly correlated with the daytime cumulative carbon assimilation, which suggests that variation in δ13CR were influenced, to some extent, by changes in the contribution of malate decarboxylation to total respiratory CO2 flux. There were no differences in the magnitude of the nighttime variation in δ13CR between the C3 and C4 plants, as well as among the woody plants, herbs and graminoids. Leaf respired CO2 was enriched in 13C compared to biomass, soluble carbohydrates and lipids; however the magnitude of enrichment differed between 8 pm and 4 am, which were mainly caused by the changes in δ13CR. We also detected the plant functional type differences in respiratory apparent fractionation relative to biomass at 4 am, which suggests that caution should be exercised when using the δ13C of bulk leaf material as a proxy for the δ13C of leaf-respired CO2.
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Affiliation(s)
- Haiying Cui
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, P. R. China, 130024
| | - Yunbo Wang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, P. R. China, 130024
| | - Qi Jiang
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, P. R. China, 130024
| | - Shiping Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, P. R. China, 100093
| | - Jian-Ying Ma
- Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, P. R. China, 830011
| | - Wei Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, Jilin Province, P. R. China, 130024
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Wegener F, Beyschlag W, Werner C. Dynamic carbon allocation into source and sink tissues determine within-plant differences in carbon isotope ratios. FUNCTIONAL PLANT BIOLOGY : FPB 2015; 42:620-629. [PMID: 32480706 DOI: 10.1071/fp14152] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 03/10/2015] [Indexed: 05/28/2023]
Abstract
Organs of C3 plants differ in their C isotopic signature (δ13C). In general, leaves are 13C-depleted relative to other organs. To investigate the development of spatial δ13C patterns, we induced different C allocation strategies by reducing light and nutrient availability for 12 months in the Mediterranean shrub Halimium halimifolium L. We measured morphological and physiological traits and the spatial δ13C variation among seven tissue classes during the experiment. A reduction of light (Low-L treatment) increased aboveground C allocation, plant height and specific leaf area. Reduced nutrient availability (Low-N treatment) enhanced C allocation into fine roots and reduced the spatial δ13C variation. In contrast, control and Low-L plants with high C allocation in new leaves showed a high δ13C variation within the plant (up to 2.5‰). The spatial δ13C variation was significantly correlated with the proportion of second-generation leaves from whole-plant biomass (R2=0.46). According to our results, isotope fractionation in dark respiration can influence the C isotope composition of plant tissues but cannot explain the entire spatial pattern seen. Our study indicates a foliar depletion in 13C during leaf development combined with export of relatively 13C-enriched C by mature source leaves as an important reason for the observed spatial δ13C pattern.
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Affiliation(s)
- Frederik Wegener
- AgroEcosystem Research, BAYCEER, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Wolfram Beyschlag
- Experimental and Systems Ecology, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - Christiane Werner
- AgroEcosystem Research, BAYCEER, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
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Zhou Y, Stuart-Williams H, Grice K, Kayler ZE, Zavadlav S, Vogts A, Rommerskirchen F, Farquhar GD, Gessler A. Allocate carbon for a reason: priorities are reflected in the ¹³C/¹²C ratios of plant lipids synthesized via three independent biosynthetic pathways. PHYTOCHEMISTRY 2015; 111:14-20. [PMID: 25576502 DOI: 10.1016/j.phytochem.2014.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 11/27/2014] [Accepted: 12/03/2014] [Indexed: 06/04/2023]
Abstract
It has long been theorized that carbon allocation, in addition to the carbon source and to kinetic isotopic effects associated with a particular lipid biosynthetic pathway, plays an important role in shaping the carbon isotopic composition ((13)C/(12)C) of lipids (Park and Epstein, 1961). If the latter two factors are properly constrained, valuable information about carbon allocation during lipid biosynthesis can be obtained from carbon isotope measurements. Published work of Chikaraishi et al. (2004) showed that leaf lipids isotopic shifts from bulk leaf tissue Δδ(13)C(bk-lp) (defined as δ(13)C(bulkleaftissue)-δ(13)C(lipid)) are pathway dependent: the acetogenic (ACT) pathway synthesizing fatty lipids has the largest isotopic shift, the mevalonic acid (MVA) pathway synthesizing sterols the lowest and the phytol synthesizing 1-deoxy-D-xylulose 5-phosphate (DXP) pathway gives intermediate values. The differences in Δδ(13)C(bk-lp) between C3 and C4 plants Δδ(13)C(bk-lp,C4-C3) are also pathway-dependent: Δδ(13)C(ACT)(bk-lp,C4-C3) > Δδ(13)C(DXP(bk-lp,C4-C3) > Δδ(13)C(MVA)(bk-lp,C4-C3). These pathway-dependent differences have been interpreted as resulting from kinetic isotopic effect differences of key but unspecified biochemical reactions involved in lipids biosynthesis between C3 and C4 plants. After quantitatively considering isotopic shifts caused by (dark) respiration, export-of-carbon (to sink tissues) and photorespiration, we propose that the pathway-specific differences Δδ(13)C(bk-lp,C4-C3) can be successfully explained by C4-C3 carbon allocation (flux) differences with greatest flux into the ACT pathway and lowest into the MVA pathways (when flux is higher, isotopic shift relative to source is smaller). Highest carbon allocation to the ACT pathway appears to be tied to the most stringent role of water-loss-minimization by leaf waxes (composed mainly of fatty lipids) while the lowest carbon allocation to the MVA pathway can be largely explained by the fact that sterols act as regulatory hormones and membrane fluidity modulators in rather low concentrations.
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Affiliation(s)
- Youping Zhou
- Institute for Landscape Biogeochemistry, ZALF, Germany; Department of Chemistry, Curtin University, Perth, Australia; SKLLQG, Chinese Academy of Sciences, Xi'an, China; Leibniz Institute for Freshwater Ecology & Inland Fisheries, Germany.
| | | | - Kliti Grice
- Department of Chemistry, Curtin University, Perth, Australia
| | | | | | - Angela Vogts
- Leibniz-Institut für Ostseeforschung, Rostock, Germany
| | | | | | - Arthur Gessler
- Institute for Landscape Biogeochemistry, ZALF, Germany; Swiss Federal Institute WSL, Birmensdorf, Switzerland
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Ghashghaie J, Badeck FW. Opposite carbon isotope discrimination during dark respiration in leaves versus roots - a review. THE NEW PHYTOLOGIST 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] [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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9
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Tucker CL, Bell J, Pendall E, Ogle K. Does declining carbon-use efficiency explain thermal acclimation of soil respiration with warming? GLOBAL CHANGE BIOLOGY 2013; 19:252-63. [PMID: 23504736 DOI: 10.1111/gcb.12036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 08/11/2012] [Accepted: 09/08/2012] [Indexed: 05/16/2023]
Abstract
Enhanced soil respiration in response to global warming may substantially increase atmospheric CO2 concentrations above the anthropogenic contribution, depending on the mechanisms underlying the temperature sensitivity of soil respiration. Here, we compared short-term and seasonal responses of soil respiration to a shifting thermal environment and variable substrate availability via laboratory incubations. To analyze the data from incubations, we implemented a novel process-based model of soil respiration in a hierarchical Bayesian framework. Our process model combined a Michaelis-Menten-type equation of substrate availability and microbial biomass with an Arrhenius-type nonlinear temperature response function. We tested the competing hypotheses that apparent thermal acclimation of soil respiration can be explained by depletion of labile substrates in warmed soils, or that physiological acclimation reduces respiration rates. We demonstrated that short-term apparent acclimation can be induced by substrate depletion, but that decreasing microbial biomass carbon (MBC) is also important, and lower MBC at warmer temperatures is likely due to decreased carbon-use efficiency (CUE). Observed seasonal acclimation of soil respiration was associated with higher CUE and lower basal respiration for summer- vs. winter-collected soils. Whether the observed short-term decrease in CUE or the seasonal acclimation of CUE with increased temperatures dominates the response to long-term warming will have important consequences for soil organic carbon storage.
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Affiliation(s)
- Colin L Tucker
- Department of Botany, University of Wyoming, 3165, 1000 E. University Avenue, Laramie, WY, 82071, USA.
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