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Tcherkez G, Carroll A, Abadie C, Mainguet S, Davanture M, Zivy M. Protein synthesis increases with photosynthesis via the stimulation of translation initiation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 291:110352. [PMID: 31928674 DOI: 10.1016/j.plantsci.2019.110352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/13/2019] [Accepted: 11/21/2019] [Indexed: 05/09/2023]
Abstract
Leaf protein synthesis is an essential process at the heart of plant nitrogen (N) homeostasis and turnover that preferentially takes place in the light, that is, when N and CO2 fixation occur. The carbon allocation to protein synthesis in illuminated leaves generally accounts for ca. 1 % of net photosynthesis. It is likely that protein synthesis activity varies with photosynthetic conditions (CO2/O2 atmosphere composition) since changes in photorespiration and carbon provision should in principle impact on amino acid supply as well as metabolic regulation via leaf sugar content. However, possible changes in protein synthesis and translation activity when gaseous conditions vary are virtually unknown. Here, we address this question using metabolomics, isotopic techniques, phosphoproteomics and polysome quantitation, under different photosynthetic conditions that were varied with atmospheric CO2 and O2 mole fraction, using illuminated Arabidopsis rosettes under controlled gas exchange conditions. We show that carbon allocation to proteins is within 1-2.5 % of net photosynthesis, increases with photosynthesis rate and is unrelated to total amino acid content. In addition, photosynthesis correlates to polysome abundance and phosphorylation of ribosomal proteins and translation initiation factors. Our results demonstrate that translation activity follows photosynthetic activity, showing the considerable impact of metabolism (carboxylation-oxygenation balance) on protein synthesis.
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Affiliation(s)
- Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Sciences, Australian National University, 2601, Canberra, ACT, Australia(1); Institut de Recherche en Horticulture et Semences, INRA, Université d'Angers, 42 rue Georges Morel, 49070, Beaucouzé, France(2).
| | - Adam Carroll
- Joint Mass Spectrometry Facility, Research School of Chemistry, Australian National University, 2601, Canberra, ACT, Australia
| | - Cyril Abadie
- Institut de Recherche en Horticulture et Semences, INRA, Université d'Angers, 42 rue Georges Morel, 49070, Beaucouzé, France(2)
| | - Samuel Mainguet
- Institute of Plant Sciences of Saclay, INRA, University Paris-Sud, CNRS, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
| | - Marlène Davanture
- Plateforme d'Analyse de Protéomique Paris Sud-Ouest (PAPPSO), GQE Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Ferme du Moulon, 91190, Gif-sur-Yvette, France
| | - Michel Zivy
- Plateforme d'Analyse de Protéomique Paris Sud-Ouest (PAPPSO), GQE Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Ferme du Moulon, 91190, Gif-sur-Yvette, France
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2
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Yu L, Fan J, Yan C, Xu C. Starch Deficiency Enhances Lipid Biosynthesis and Turnover in Leaves. PLANT PHYSIOLOGY 2018; 178:118-129. [PMID: 30076222 PMCID: PMC6130009 DOI: 10.1104/pp.18.00539] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/24/2018] [Indexed: 05/18/2023]
Abstract
Starch and lipids represent two major forms of carbon and energy storage in plants and play central roles in diverse cellular processes. However, whether and how starch and lipid metabolic pathways interact to regulate metabolism and growth are poorly understood. Here, we show that lipids can partially compensate for the lack of function of transient starch during normal growth and development in Arabidopsis (Arabidopsis thaliana). Disruption of starch synthesis resulted in a significant increase in fatty acid synthesis via posttranslational regulation of the plastidic acetyl-coenzyme A carboxylase and a concurrent increase in the synthesis and turnover of membrane lipids and triacylglycerol. Genetic analysis showed that blocking fatty acid peroxisomal β-oxidation, the sole pathway for metabolic breakdown of fatty acids in plants, significantly compromised or stunted the growth and development of mutants defective in starch synthesis under long days or short days, respectively. We also found that the combined disruption of starch synthesis and fatty acid turnover resulted in increased accumulation of membrane lipids, triacylglycerol, and soluble sugars and altered fatty acid flux between the two lipid biosynthetic pathways compartmentalized in either the chloroplast or the endoplasmic reticulum. Collectively, our findings provide insight into the role of fatty acid β-oxidation and the regulatory network controlling fatty acid synthesis, and they reveal the mechanistic basis by which starch and lipid metabolic pathways interact and undergo cross talk to modulate carbon allocation, energy homeostasis, and plant growth.
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Affiliation(s)
- Linhui Yu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Jilian Fan
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Chengshi Yan
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Changcheng Xu
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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Quentin AG, Pinkard EA, Ryan MG, Tissue DT, Baggett LS, Adams HD, Maillard P, Marchand J, Landhäusser SM, Lacointe A, Gibon Y, Anderegg WRL, Asao S, Atkin OK, Bonhomme M, Claye C, Chow PS, Clément-Vidal A, Davies NW, Dickman LT, Dumbur R, Ellsworth DS, Falk K, Galiano L, Grünzweig JM, Hartmann H, Hoch G, Hood S, Jones JE, Koike T, Kuhlmann I, Lloret F, Maestro M, Mansfield SD, Martínez-Vilalta J, Maucourt M, McDowell NG, Moing A, Muller B, Nebauer SG, Niinemets Ü, Palacio S, Piper F, Raveh E, Richter A, Rolland G, Rosas T, Saint Joanis B, Sala A, Smith RA, Sterck F, Stinziano JR, Tobias M, Unda F, Watanabe M, Way DA, Weerasinghe LK, Wild B, Wiley E, Woodruff DR. Non-structural carbohydrates in woody plants compared among laboratories. TREE PHYSIOLOGY 2015; 35:1146-1165. [PMID: 26423132 DOI: 10.1093/treephys/tpv073] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 07/09/2015] [Indexed: 06/05/2023]
Abstract
Non-structural carbohydrates (NSC) in plant tissue are frequently quantified to make inferences about plant responses to environmental conditions. Laboratories publishing estimates of NSC of woody plants use many different methods to evaluate NSC. We asked whether NSC estimates in the recent literature could be quantitatively compared among studies. We also asked whether any differences among laboratories were related to the extraction and quantification methods used to determine starch and sugar concentrations. These questions were addressed by sending sub-samples collected from five woody plant tissues, which varied in NSC content and chemical composition, to 29 laboratories. Each laboratory analyzed the samples with their laboratory-specific protocols, based on recent publications, to determine concentrations of soluble sugars, starch and their sum, total NSC. Laboratory estimates differed substantially for all samples. For example, estimates for Eucalyptus globulus leaves (EGL) varied from 23 to 116 (mean = 56) mg g(-1) for soluble sugars, 6-533 (mean = 94) mg g(-1) for starch and 53-649 (mean = 153) mg g(-1) for total NSC. Mixed model analysis of variance showed that much of the variability among laboratories was unrelated to the categories we used for extraction and quantification methods (method category R(2) = 0.05-0.12 for soluble sugars, 0.10-0.33 for starch and 0.01-0.09 for total NSC). For EGL, the difference between the highest and lowest least squares means for categories in the mixed model analysis was 33 mg g(-1) for total NSC, compared with the range of laboratory estimates of 596 mg g(-1). Laboratories were reasonably consistent in their ranks of estimates among tissues for starch (r = 0.41-0.91), but less so for total NSC (r = 0.45-0.84) and soluble sugars (r = 0.11-0.83). Our results show that NSC estimates for woody plant tissues cannot be compared among laboratories. The relative changes in NSC between treatments measured within a laboratory may be comparable within and between laboratories, especially for starch. To obtain comparable NSC estimates, we suggest that users can either adopt the reference method given in this publication, or report estimates for a portion of samples using the reference method, and report estimates for a standard reference material. Researchers interested in NSC estimates should work to identify and adopt standard methods.
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Affiliation(s)
- Audrey G Quentin
- CSIRO Land and Water, Private Bag 12, Hobart, Tasmania 7001, Australia Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | | | - Michael G Ryan
- Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1401, USA USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO 80521, USA
| | - David T Tissue
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - L Scott Baggett
- USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO 80521, USA
| | - Henry D Adams
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Pascale Maillard
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Centre de Nancy, F-54280 Champenoux, France
| | - Jacqueline Marchand
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Plateforme Technique d'Ecologie Fonctionnelle (OC 081) Centre de Nancy, F-54280 Champenoux, France
| | - Simon M Landhäusser
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - André Lacointe
- INRA, UMR 0547 PIAF, F:63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 0547 PIAF, F:6310 Clermont-Ferrand, France
| | - Yves Gibon
- UMR1332, Biologie du Fruit et Pathologie, INRA, Bordeaux University, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France Plateforme Métabolome du Centre de Génomique Fonctionnelle Bordeaux, MetaboHUB, IBVM, Centre INRA, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France
| | - William R L Anderegg
- Princeton Environmental Institute, Princeton University, Princeton NJ 08540, USA
| | - Shinichi Asao
- Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1401, USA
| | - Owen K Atkin
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Marc Bonhomme
- INRA, UMR 0547 PIAF, F:63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 0547 PIAF, F:6310 Clermont-Ferrand, France
| | - Caroline Claye
- Tasmanian Institute of Agriculture, School of Land and Food, Private Bag 98, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Pak S Chow
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | | | - Noel W Davies
- Central Science Laboratory, Private Bag 74, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - L Turin Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Rita Dumbur
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - Kristen Falk
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Lucía Galiano
- Swiss Federal Research Institute WSL, CH-8903 Birmensdorf, Switzerland Institute of Hydrology, Freiburg University, Fahnenbergplatz, D-79098 Freiburg, Germany
| | - José M Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, 07745 Jena, Germany
| | - Günter Hoch
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland
| | - Sharon Hood
- Division of Biological Sciences, University of Montana, Missoula MT-59812, USA
| | - Joanna E Jones
- Tasmanian Institute of Agriculture, School of Land and Food, Private Bag 98, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Takayoshi Koike
- Silviculture and Forest Ecological Studies, Hokkaido University Sapporo, Hokkaido 060-8589, Japan
| | - Iris Kuhlmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, 07745 Jena, Germany
| | - Francisco Lloret
- CREAF, Cerdanyola del Vallès E-08193 Barcelona, Spain Universidad Autònoma Barcelona, Cerdanyola del Vallès E-08193 Barcelona, Spain
| | - Melchor Maestro
- Instituto Pirenaico de Ecología (IPE-CSIC), Av. Nuestra Señora de la Victoria s/n, 22700 Jaca, Huesca, Spain
| | - Shawn D Mansfield
- Department of Wood Science, University of British Columbia, V6T 1Z4 Vancouver, Canada
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès E-08193 Barcelona, Spain Universidad Autònoma Barcelona, Cerdanyola del Vallès E-08193 Barcelona, Spain
| | - Mickael Maucourt
- Plateforme Métabolome du Centre de Génomique Fonctionnelle Bordeaux, MetaboHUB, IBVM, Centre INRA, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France Université Bordeaux, UMR 1332, Biologie du Fruit et Pathologie, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France
| | - Nathan G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Annick Moing
- UMR1332, Biologie du Fruit et Pathologie, INRA, Bordeaux University, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France Plateforme Métabolome du Centre de Génomique Fonctionnelle Bordeaux, MetaboHUB, IBVM, Centre INRA, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France
| | | | - Sergio G Nebauer
- Plant Production Department, Universitat Politécnica de Valéncia, Camino de vera s.n. 46022-Valencia, Spain
| | - Ülo Niinemets
- Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Sara Palacio
- Instituto Pirenaico de Ecología (IPE-CSIC), Av. Nuestra Señora de la Victoria s/n, 22700 Jaca, Huesca, Spain
| | - Frida Piper
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Simpson 471, Coyhaique, Chile
| | - Eran Raveh
- Department of Fruit Trees Sciences, Institute of Plant Sciences, A.R.O., Gilat Research Center, D.N. Negev 85289, Israel
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | | | - Teresa Rosas
- CREAF, Cerdanyola del Vallès E-08193 Barcelona, Spain
| | - Brigitte Saint Joanis
- INRA, UMR 0547 PIAF, F:63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 0547 PIAF, F:6310 Clermont-Ferrand, France
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula MT-59812, USA
| | - Renee A Smith
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, Postbox 47, 6700 AA, Wageningen, the Netherlands
| | - Joseph R Stinziano
- Department of Biology, Western University, 1151 Richmond Street, London, N6A 5B7, ON, Canada
| | - Mari Tobias
- Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Faride Unda
- Department of Wood Science, University of British Columbia, V6T 1Z4 Vancouver, Canada
| | - Makoto Watanabe
- Institute of Agriculture, Tokyo University of Agriculture and Technology Fuchu, Tokyo 183-8509, Japan
| | - Danielle A Way
- Department of Biology, Western University, 1151 Richmond Street, London, N6A 5B7, ON, Canada Nicholas School of the Environment, Duke University, Box 90328, Durham, NC 27708, USA
| | - Lasantha K Weerasinghe
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia Faculty of Agriculture, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Birgit Wild
- Department of Microbiology and Ecosystem Science, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria Department of Earth Sciences, University of Gothenburg, Guldhedsgatan 5A, 40530 Gothenburg, Sweden
| | - Erin Wiley
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - David R Woodruff
- USDA Forest Service, Forestry Sciences Laboratory, Corvallis, OR 97331, USA
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Boex-Fontvieille E, Davanture M, Jossier M, Zivy M, Hodges M, Tcherkez G. Photosynthetic activity influences cellulose biosynthesis and phosphorylation of proteins involved therein in Arabidopsis leaves. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4997-5010. [PMID: 25039072 DOI: 10.1093/jxb/eru268] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cellulose is one of the most important organic compounds in terrestrial ecosystems and represents a major plant structural polymer. However, knowledge of the regulation of cellulose biosynthesis is still rather limited. Recent studies have shown that the phosphorylation of cellulose synthases (CESAs) may represent a key regulatory event in cellulose production. However, the impact of environmental conditions on the carbon flux of cellulose deposition and on phosphorylation levels of CESAs has not been fully elucidated. Here, we took advantage of gas exchange measurements, isotopic techniques, metabolomics, and quantitative phosphoproteomics to investigate the regulation of cellulose production in Arabidopsis rosette leaves in different photosynthetic contexts (different CO2 mole fractions) or upon light/dark transition. We show that the carbon flux to cellulose production increased with photosynthesis, but not proportionally. The phosphorylation level of several phosphopeptides associated with CESA1 and 3, and several enzymes of sugar metabolism was higher in the light and/or increased with photosynthesis. By contrast, a phosphopeptide (Ser126) associated with CESA5 seemed to be more phosphorylated in the dark. Our data suggest that photosynthetic activity affects cellulose deposition through the control of both sucrose metabolism and cellulose synthesis complexes themselves by protein phosphorylation.
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Affiliation(s)
- Edouard Boex-Fontvieille
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris Sud, 91405 Orsay cedex, France
| | - Marlène Davanture
- Plateforme PAPPSO, UMR de Génétique Végétale, Ferme du Moulon, 91190 Gif sur Yvette, France
| | - Mathieu Jossier
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris Sud, 91405 Orsay cedex, France
| | - Michel Zivy
- Plateforme PAPPSO, UMR de Génétique Végétale, Ferme du Moulon, 91190 Gif sur Yvette, France
| | - Michael Hodges
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris Sud, 91405 Orsay cedex, France
| | - Guillaume Tcherkez
- Institut de Biologie des Plantes, CNRS UMR 8618, Saclay Plant Sciences, Université Paris Sud, 91405 Orsay cedex, France Institut Universitaire de France, 103 Boulevard Saint-Michel, 75005 Paris, France
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Kölling K, Müller A, Flütsch P, Zeeman SC. A device for single leaf labelling with CO2 isotopes to study carbon allocation and partitioning in Arabidopsis thaliana. PLANT METHODS 2013; 9:45. [PMID: 24252607 PMCID: PMC4177546 DOI: 10.1186/1746-4811-9-45] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/01/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND Plant biomass consists primarily of carbohydrates derived from photosynthesis. Monitoring the assimilation of carbon via the Calvin-Benson cycle and its subsequent utilisation is fundamental to understanding plant growth. The use of stable and radioactive carbon isotopes, supplied to plants as CO2, allows the measurement of fluxes through the intermediates of primary photosynthetic metabolism, long-distance transport of sugars in the vasculature, and the synthesis of structural and storage components. RESULTS Here we describe the design of a system for supplying isotopically labelled CO2 to single leaves of Arabidopsis thaliana. We demonstrate that the system works well using short pulses of 14CO2 and that it can be used to produce robust qualitative and quantitative data about carbon export from source leaves to the sink tissues, such as the developing leaves and the roots. Time course experiments show the dynamics of carbon partitioning between storage as starch, local production of biomass, and export of carbon to sink tissues. CONCLUSION This isotope labelling method is relatively simple to establish and inexpensive to perform. Our use of 14CO2 helps establish the temporal and spatial allocation of assimilated carbon during plant growth, delivering data complementary to those obtained in recent studies using 13CO2 and MS-based metabolomics techniques. However, we emphasise that this labelling device could also be used effectively in combination with 13CO2 and MS-based techniques.
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Affiliation(s)
- Katharina Kölling
- Department of Biology, Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, 8092 Zurich, Switzerland
| | - Antonia Müller
- Department of Biology, Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, 8092 Zurich, Switzerland
| | - Patrick Flütsch
- Department of Biology, Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, 8092 Zurich, Switzerland
| | - Samuel C Zeeman
- Department of Biology, Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, 8092 Zurich, Switzerland
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Dirks RC, Singh M, Potter GS, Sobotka LG, Schaefer J. Carbon partitioning in soybean (Glycine max) leaves by combined (11) C and (13) C labeling. THE NEW PHYTOLOGIST 2012; 196:1109-1121. [PMID: 22998467 DOI: 10.1111/j.1469-8137.2012.04333.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 08/09/2012] [Indexed: 05/26/2023]
Abstract
We labeled soybean (Glycine max) leaves with 200 and 600 ppm (13) CO(2) spiked with (11) CO(2) and examined the effects of light intensity and water stress on metabolism by using a combination of direct positron imaging and solid-state (13) C nuclear magnetic resonance (NMR) of the same leaf. We first made 60-min movies of the transport of photosynthetically assimilated (11) C labels. The positron imaging identified zones or patches within which variations in metabolism could be probed later by NMR. At the end of each movie, the labeled leaf was frozen in liquid nitrogen to stop metabolism, the leaf was lyophilized, and solid-state NMR was used either on the whole leaf or on various leaf fragments. The NMR analysis determined total (13) C incorporation into sugars, starch, proteins, and protein precursors. The combination of (11) C and (13) C analytical techniques has led to three major conclusions regarding photosynthetically heterogeneous soybean leaves: transient starch deposition is not the temporary storage of sucrose excluded from a saturated sugar-transport system; peptide synthesis is reduced under high-light, high CO(2) conditions; and all glycine from the photorespiratory pathway is routed to proteins within photosynthetically active zones when the leaf is water stressed and under high-light and low CO(2) conditions.
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Affiliation(s)
- Rebecca C Dirks
- Department of Chemistry, Washington University, St Louis, MO, 63130, USA
| | - Manmilan Singh
- Department of Chemistry, Washington University, St Louis, MO, 63130, USA
| | - Gregory S Potter
- Department of Chemistry, Washington University, St Louis, MO, 63130, USA
| | - Lee G Sobotka
- Department of Chemistry, Washington University, St Louis, MO, 63130, USA
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St Louis, MO, 63130, USA
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7
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Black MZ, Minchin PEH, Gould N, Patterson KJ, Clearwater MJ. Measurement of Bremsstrahlung radiation for in vivo monitoring of 14C tracer distribution between fruit and roots of kiwifruit (Actinidia arguta) cuttings. PLANTA 2012; 236:1327-1337. [PMID: 22729822 DOI: 10.1007/s00425-012-1685-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 05/25/2012] [Indexed: 06/01/2023]
Abstract
In vivo measurements of (14)C tracer distribution have usually involved monitoring the β(-) particles produced as (14)C decays. These particles are only detectable over short distances, limiting the use of this technique to thin plant material. In the present experiments, X-ray detectors were used to monitor the Bremsstrahlung radiation emitted since β(-) particles were absorbed in plant tissues. Bremsstrahlung radiation is detectable through larger tissue depths. The aim of these experiments was to demonstrate the Bremsstrahlung method by monitoring in vivo tracer-labelled photosynthate partitioning in small kiwifruit (Actinidia arguta (Siebold & Zucc.) Planch. ex Miq.) plants in response to root pruning. A source shoot, consisting of four leaves, was pulse labelled with (14)CO(2). Detectors monitored import into a fruit and the root system, and export from a source leaf. Repeat pulse labelling enabled the comparison of pre- and post-treatment observations within an individual plant. Diurnal trends were observed in the distribution of tracer, with leaf export reduced at night. Tracer accumulated in the roots declined after approximately 48 h, which may have resulted from export of (14)C from the roots in carbon skeletons. Cutting off half the roots did not affect tracer distribution to the remaining half. Tracer distribution to the fruit was increased after root pruning, demonstrating the higher competitive strength of the fruit than the roots for carbohydrate supply. Increased partitioning to the fruit following root pruning has also been demonstrated in kiwifruit field trials.
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Affiliation(s)
- Marykate Z Black
- ZESPRI International Limited, 400 Maunganui Road, Mount Maunganui 3149, New Zealand.
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8
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Donald DG. The Rapid Evaluation of Carbon Uptake and Allocation Using14C as a Means of Grading Selected Clones ofEucalyptus grandis. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/00382167.1988.9628969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Shao M, Zheng H, Hu Y, Liu D, Jang JC, Ma H, Huang H. The GAOLAOZHUANGREN1 gene encodes a putative glycosyltransferase that is critical for normal development and carbohydrate metabolism. PLANT & CELL PHYSIOLOGY 2004; 45:1453-60. [PMID: 15564529 DOI: 10.1093/pcp/pch168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Glycosyltransferases are enzymes that catalyze the attachment of a sugar molecule to specific acceptor molecules. These enzymes have been shown to play important roles in a number of biological processes. Whereas a large number of putative glycosyltransferase genes have been identified by genomic sequencing, the functions of most of these genes are unknown. Here we report the characterization of an Arabidopsis mutant, designated gaolaozhuangren1 (glz1), which is allelic to parvus characterized recently. The glz1 mutant exhibited a reduced plant stature, reduced size of organs in the shoot and dark-green leaves, indicating an important role of GLZ1 gene in normal development. The earliest GLZ1 expression appears at the shoot apical region of 4-d-old seedlings, which coincides with the onset of the glz1 morphological phenotypes. GLZ1 is expressed in a tissue-specific and developmentally regulated manner, predominantly in the stem and silique, and moderately in the flower. GLZ1 expression is strong in the midrib of rosette and cauline leaves; however, its expression was not detectable in the midrib of the cotyledon. Further analyses revealed that carbohydrate composition and distribution were aberrant in the glz1 mutant. These, together with the GLZ1 expression pattern, suggest a requirement for the GLZ1 function in normal sink-source transition during plant development.
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Affiliation(s)
- Minghai Shao
- National Laboratory of Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institute for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
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10
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Baroja-Fernández E, Muñoz FJ, Akazawa T, Pozueta-Romero J. Reappraisal of the currently prevailing model of starch biosynthesis in photosynthetic tissues: a proposal involving the cytosolic production of ADP-glucose by sucrose synthase and occurrence of cyclic turnover of starch in the chloroplast. PLANT & CELL PHYSIOLOGY 2001; 42:1311-1320. [PMID: 11773523 DOI: 10.1093/pcp/pce175] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A vast amount of information has accumulated which supports the view that sucrose and starch are end-products of two segregated, yet highly interconnected, gluconeogenic pathways taking place in the cytosol and chloroplast, respectively. However, several lines of experimental evidences indicate that, essentially identical to the case of heterotrophic tissues, starch formation in the photosynthetic tissues may involve the direct import to the chloroplast of cytosolic hexose (C6) units derived from the sucrose breakdown. This evidence is consistent with the idea that synthesis of a sizable pool of ADP-glucose takes place in the cytosol by means of sucrose synthase whereas, basically in agreement with recent investigations dealing with glycogen biosynthesis in bacteria and animals, chloroplastic phosphoglucomutase and ADP-glucose pyrophosphorylase are most likely playing a role in channelling of glucose units derived from the starch breakdown in the chloroplast, thus making up a regulatory starch turnover cycle. According to this new view, we propose that starch production in the chloroplast is the result of a flexible and dynamic mechanism wherein both catabolic and anabolic reactions take place simultaneously in a highly interactive manner. Starch is seen as an intermediate component of a cyclic gluconeogenic pathway which, in turn, is connected with other metabolic pathways. The possible importance of metabolic turnover as a way to control starch production is exemplified with the recently discovered ADP-glucose pyrophosphatase, an enzyme likely having a dual role in controlling levels of ADP-glucose linked to starch biosynthesis and diverting carbon flow towards other metabolic pathways.
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Affiliation(s)
- E Baroja-Fernández
- Instituto de Agrobiotecnología y Recursos Naturales, Universidad Pública de Navarra/Consejo Superior de Investigaciones Científicas, Ctra. de Mutilva s/n, Mutilva Baja, 31192 Navarra, Spain
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11
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Manipulation of food resources by a gall-forming aphid: the physiology of sink-source interactions. Oecologia 1991; 88:15-21. [PMID: 28312726 DOI: 10.1007/bf00328398] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/1991] [Accepted: 05/08/1991] [Indexed: 10/26/2022]
Abstract
We examined the capacity of the galling aphid, Pemphigus betae, to manipulate the sink-source translocation patterns of its host, narrowleaf cottonwood (Populus angustifolia). A series of 14C-labeling experiments and a biomass allocation experiment showed that P. betae galls functioned as physiologic sinks, drawing in resources from surrounding plant sources. Early gall development was dependent on aphid sinks increasing allocation from storage reserves of the stem, and later development of the progeny within the gall was dependent on resources from the galled leaf blade and from neighboring leaves. Regardless of gall position within a leaf, aphids intercepted 14C exported from the galled leaf (a non-mobilized source). However, only aphid galls at the most basal site of the leaf were strong sinks for 14C fixed in neighboring leaves (a mobilized source). Drawing resources from neighboring leaves represents active herbivore manipulation of normal host transport patterns. Neighboring leaves supplied 29% of the 14C accumulating in aphids in basal galls, while only supplying 7% to aphids in distal galls. This additional resource available to aphids in basal galls can account for the 65% increase in progeny produced in basal galls compared to galls located more distally on the leaf and limited to the galled leaf as a food resource. Developing furits also act as skins and compete with aphid-induced sinks for food supply. Aphid success in producing galls was increased 31% when surrounding female catkins were removed.
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12
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Dancer J, Hatzfeld WD, Stitt M. Cytosolic cycles regulate the turnover of sucrose in heterotrophic cell-suspension cultures of Chenopodium rubrum L. PLANTA 1990; 182:223-231. [PMID: 24197100 DOI: 10.1007/bf00197115] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/18/1990] [Indexed: 06/02/2023]
Abstract
We have investigated whether sucrose accumulation in heterotrophic cell-suspension cultures of Chenopodium rubrum L. is regulated by a cycle in which sucrose is simultaneously synthesised and degraded. Net sucrose accumulation was measured by monitoring the sucrose content, unidirectional synthesis was monitored by supplying pulses of [(14)C] glucose, and unidirectional degradation was estimated from the difference between unidirectional synthesis and net accumulation. When 50 mM glucose was supplied to carbohydrate-depleted cells there was a rapid net accumulation of sucrose, which stopped after 24 h. The incorporation of (14)C into sucrose was similar to the initial rate of net sucrose accumulation, but rapid (14)C incorporation continued after the cells had stopped accumulating sucrose. A method was developed to rapidly separate sucrose-phosphate synthase (SPS) from uridine-diphosphate-hydrolysing activities which interfered with the assay. The cells contained enough SPS activity to catalyse the observed rate of sucrose synthesis. SPS activity increased in cells which had stopped accumulating sucrose, and the enzyme became less sensitive to inhibition by inorganic phosphate. Sucrose synthase and alkaline invertase activity were four- and twofold higher than SPS activity, and both degradative enzymes increased in cells which had stopped accumulating sucrose. Sucrose synthase is strongly modulated by the concentration of sucrose and by competitive feedback regulation by fructose in these cells. It is concluded that sucrose accumulation ceases in these cells because the rate of degradation of sucrose increases until it matches the rate of synthesis. It is discussed how this cycle is regulated, and how it may interact with the substrate cycle between triose-phosphates and hexose-phosphates (Hatzfeld and Stitt, 1990, Planta 180, 198-204). These cycles allow sucrose turnover to respond in a highly sensitive manner to small changes in the balance between the supply of sucrose and the demand for carbon for respiration and biosynthesis in the cell.
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Affiliation(s)
- J Dancer
- Lehrstuhl für Pflanzenphysiologie, Universität Bayreuth, D-8580, Bayreuth, Germany
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13
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Fellows RJ, Patterson RP, Raper CD, Harris D. Nodule activity and allocation of photosynthate of soybean during recovery from water stress. PLANT PHYSIOLOGY 1987; 84:456-60. [PMID: 11539766 PMCID: PMC1056602 DOI: 10.1104/pp.84.2.456] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nodulated soybean plants (Glycine max [L.] Merr. cv Ransom) in a growth-chamber study were subjected to a leaf water potential (psi w) of -2.0 megapascal during vegetative growth. Changes in nonstructural carbohydrate contents of leaves, stems, roots, and nodules, allocation of dry matter among plant parts, in situ specific nodule activity, and in situ canopy apparent photosynthetic rate were measured in stressed and nonstressed plants during a 7-day period following rewatering. Leaf and nodule psi w also were determined. At the time of maximum stress, concentration of nonstructural carbohydrates had declined in leaves of stressed, relative to nonstressed, plants, and the concentration of nonstructural carbohydrates had increased in stems, roots, and nodules. Sucrose concentrations in roots and nodules of stressed plants were 1.5 and 3 times greater, respectively, than those of nonstressed plants. Within 12 hours after rewatering, leaf and nodule psi w of stressed plants had returned to values of nonstressed plants. Canopy apparent photosynthesis and specific nodule activity of stressed plants recovered to levels for nonstressed plants within 2 days after rewatering. The elevated sucrose concentrations in roots and nodules of stressed plants also declined rapidly upon rehydration. The increase in sucrose concentration in nodules, as well as the increase of carbohydrates in roots and stems, during water stress and the rapid disappearance upon rewatering indicates that inhibition of carbohydrate utilization within the nodule may be associated with loss of nodule activity. Availability of carbohydrates within the nodules and from photosynthetic activity following rehydration of nodules may mediate the rate of recovery of N2-fixation activity.
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Affiliation(s)
- R J Fellows
- Battelle-Northwest, Richland, Washington 99352, USA
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14
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Kagawa T, Wong JH. Allocation and Turnover of Photosynthetically Assimilated CO(2) in Leaves of Glycine max L. Clark. PLANT PHYSIOLOGY 1985; 77:266-74. [PMID: 16664040 PMCID: PMC1064501 DOI: 10.1104/pp.77.2.266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The allocation and turnover of photosynthetically assimilated (14)CO(2) in lipid and protein fractions of soybean (Glycine max L. Clark) leaves and stem materials was measured. In whole plant labeling experiments, allocation of photosynthate from a pulse of (14)CO(2) into polymeric compounds was: 25% to proteins in 4 days, 20% to metabolically inert cell wall products in 1 to 2 days, 10% to lipids in 4 days, and 4% to starch in 1 day. The amount of (14)C labeled photosynthate that an actively growing leaf (leaf 4) used for its own lipid synthesis immediately following pulse labeling was about 25%. The (14)C of labeled proteins turned over with half-lives of 3.8, 3.3, and 4.1 days in leaves 1, 2, and 3, respectively; and turnover of (14)C in total shoot protein proceeded with a half-life of 5.2 days. Three kinetic (14)C turnover patterns were observed in lipids: a rapid turnover fraction (within a day), an intermediate fraction (half-life about 5 days), and a slow turnover fraction. These results are discussed in terms of previously published accounts of translocation, carbon budgets, carbon use, and turnover in starch, lipid, protein, and cell wall materials of various plants including soybeans.
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Affiliation(s)
- T Kagawa
- Biochemistry Department, University of Missouri-Columbia, Columbia, Missouri 65211
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15
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Fox TC, Geiger DR. Effects of decreased net carbon exchange on carbohydrate metabolism in sugar beet source leaves. PLANT PHYSIOLOGY 1984; 76:763-8. [PMID: 16663921 PMCID: PMC1064370 DOI: 10.1104/pp.76.3.763] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The relationship between CO(2) concentration and starch synthesis and degradation was studied by measuring leaf starch content and disappearance of (14)C-starch. At a concentration of 340 microliters CO(2) per liter, starch accumulated without degradation of previously synthesized starch. Degradation of starch began when CO(2) concentration was lowered, but its synthesis continued. At 120 microliters CO(2) per liter rates of synthesis and degradation were equal. Even at the CO(2) compensation point, synthesis of starch continued. Concomitant starch synthesis and mobilization supported export from the leaf. Changes in starch metabolism that occur when photosynthesis is CO(2)-limited provide a means to study regulation of starch metabolism and carbon allocation in translocating leaves.
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Affiliation(s)
- T C Fox
- Department of Biology, University of Dayton, Dayton, Ohio 45469
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16
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Kruger NJ, Bulpin PV, Ap Rees T. The extent of starch degradation in the light in pea leaves. PLANTA 1983; 157:271-273. [PMID: 24264158 DOI: 10.1007/bf00405193] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/1982] [Accepted: 11/16/1982] [Indexed: 06/02/2023]
Abstract
When 16-d-old plants of Pisum sativum, grown in a 12-h photoperiod, were transferred to continuous illumination, the starch content of the leaves rose steadily for 20 h but then declined appreciably. Plants of the same age, grown in an 18-h photoperiod, were, after 9 h light, exposed to (14)CO2 in the light for 15 min, and then transferred to (12)CO2 in the light or dark for up to 4.25 h. In (12)CO2 in the dark there was a marked decline in the amount and labelling of starch in the leaves. In the light in (12)CO2 the amount of starch in the leaves increased steadily but no change in its radioactivity could be detected. Thus, although pea leaves can degrade starch in the light, extensive degradation does not necessarily accompany starch synthesis.
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Affiliation(s)
- N J Kruger
- Botany School, University of Cambridge, Downing Street, CB2 3EA, Cambridge, UK
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17
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Vogelmann TC, Larson PR, Dickson RE. Translocation pathways in the petioles and stem between source and sink leaves of Populus deltoides Bartr. ex Marsh. PLANTA 1982; 156:345-358. [PMID: 24272580 DOI: 10.1007/bf00397473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/1982] [Accepted: 08/24/1982] [Indexed: 06/02/2023]
Abstract
Microautoradiography was used to follow the translocation pathways of (14)C-labeled photosynthate from mature source leaves, through the stem, to immature sink leaves three nodes above. Translocation occurred in specific bundles of the midveins and petioles of both the source and sink leaves and in the interjacent internodes. When each of six major veins in the lamina of an exporting leaf was independently spot-fed (14)CO2, label was exported through specific bundles in the petiole associated with that vein. When the whole lamina of a mature source leaf was fed (14)CO2, export occurred through all bundles of the lamina, but acropetal export in the stem was confined to bundles serving certain immature sink leaves. Cross-transfer occurred within the stem via phloem bridges. Leaves approaching maturity translocated photosynthate bidirectionally in adjacent subsidiary bundles of the petiole. That is, petiolar bundles serving the lamina apex were exporting unlabeled photosynthate while those serving the lamina base were simultaneously importing labeled photosynthate. The petioles and midveins of maturing leaves were strong sinks for photosynthate, which was diverted from the export front to differentiating structural tissues. The data support the idea of bidirectional transport in adjacent bundles of the petiole and possibly in adjacent sieve tubes within an individual bundle.
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Affiliation(s)
- T C Vogelmann
- North Central Forest Experiment Station, U.S. Department of Agriculture, Forest Service, Box 898, 54501, Rhinelander, WI, USA
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18
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Vogelmann TC, Dickson RE. Microautoradiography of water-soluble compounds in plant tissue after freeze-drying and pressure infiltration with epoxy resin. PLANT PHYSIOLOGY 1982; 70:606-9. [PMID: 16662542 PMCID: PMC1067196 DOI: 10.1104/pp.70.2.606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
It is difficult to retain and localize radioactive, water-soluble compounds within plant cells. Existing techniques retain water-soluble compounds with varying rates of efficiency and are limited to processing only a few samples at one time. We developed a modified pressure infiltration technique for the preparation of microautoradiographs of (14)C-labeled, water-soluble compounds in plant tissue. Samples from cottonwood (Populus deltoides Bartr. ex Marsh.) labeled with (14)C were excised, quick frozen in liquid N(2), freeze-dried at -50 degrees C, and pressure-infiltrated with epoxy resin without intermediate solvents or prolonged incubation times. The technique facilitates the mass processing of samples for microautoradiography, gives good cellular retention of labeled water-soluble compounds, and is highly reproducible.
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Affiliation(s)
- T C Vogelmann
- United States Department of Agriculture, Rhinelander, Wisconsin 54501
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19
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Simultaneous synthesis and degradation of starch in spinach chloroplasts in the light. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1981. [DOI: 10.1016/0005-2728(81)90179-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Dickson RE, Larson PR. (14)C fixation, metabolic labeling patterns, and translocation profiles during leaf development in Populus deltoides. PLANTA 1981; 152:461-470. [PMID: 24301121 DOI: 10.1007/bf00385364] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/1980] [Accepted: 05/12/1981] [Indexed: 06/02/2023]
Abstract
The incorporation of photosynthetically fixed (14)CO2 and the distribution of (14)C among the main chemical constituents of laminae and petioles were examined in cottonwood (Populus deltoides Bartr. ex Marsh.) leaves ranging in age from Leaf Plastochron Index (LPI) 3 (about one-quarter to one-third expanded) to LPI 30 (beginning of senescence). In addition, carbon flow among chemical fractions and translocation from leaves of LPI 7 and 14 were examined periodically up to 24 h after labeling. Specific activity of (14)C (on dry-weight basis) increased in developing laminae to full leaf expansion, decreased in the mature leaves to LPI 16, then remained constant to LPI 30. In developing leaves (LPI 3-5), after 2 h, most of the (14)C was found in protein, pigments, lipids, and other structural and metabolic components necessary for cell development; only 28% was in the sugar fraction of the lamina. In fully expanded leaves (LPI 6-8), after 2 h, the sugar fraction contained 50-60% and about 90% of fixed (14)C in the lamina and the petiole, respectively. In a pulsechase "kinetic series" with recently mature leaves, 60% of the (14)C was found in the sugar fraction after 15 min of (14)CO2 fixation. Over the 24-h translocation period, (14)C decreased in sugars to 23% and increased in the combined residue fraction (protein, starch, and structural carbohydrates) to about 60% of the total activity left in the lamina. Within 24 h after labeling, the turnover of (14)C-organic acids,-sugar, and-amino acids (either metabolzed or translocated from the leaf) was 30, 70 and 80%, respectively, of that initially incorporated into these fractions by a leaf at LPI 7 (turnover was 55% of (14)C-organic acids, 80% of (14)C-sugar, and 95% of (14)C-amino acids at LPI 14). Anatomical maturity in cottonwood leaves is closely correlated with physiological maturity and with production of translocatable sugar.
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Affiliation(s)
- R E Dickson
- U.S. Department of Agriculture, Forest Service, Forestry Sciences Laboratory, North Central Forest Experiment Station, 54501, Rhinelander, WI, USA
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21
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22
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Giaquinta R. Source and sink leaf metabolism in relation to Phloem translocation: carbon partitioning and enzymology. PLANT PHYSIOLOGY 1978; 61:380-5. [PMID: 16660297 PMCID: PMC1091872 DOI: 10.1104/pp.61.3.380] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The import-export transition in sugar beet leaves (Beta vulgaris) occurred at 40 to 50% leaf expansion and was characterized by loss in assimilate import and increase in photosynthesis. The metabolism and partitioning of assimilated and translocated C were determined during leaf development and related to the translocation status of the leaf. The import stage was characterized by C derived from either (14)C-translocate or (14)C-photosynthate being incorporated into protein and structural carbohydrates. Marked changes in the C partitioning were temporally correlated with the import-export conversion. Exporting leaves did not hydrolyze accumulated sucrose and the C derived from CO(2) fixation was preferentially incorporated into sucrose. Both source and sink leaves contained similar levels of acid invertase and sucrose synthetase activities (sucrose hydrolysis) while sucrose phosphate synthetase (sucrose synthesis) was detected only in exporting leaves. The results are discussed in terms of intracellular compartmentation of sucrose and sucrose-metabolizing enzymes in source and sink leaves.
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Affiliation(s)
- R Giaquinta
- Central Research and Development Department, Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19898
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23
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Larson PR. Phyllotactic transitions in the vascular system of Populus deltoides bartr. as determined by (14)C labeling. PLANTA 1977; 134:241-249. [PMID: 24419777 DOI: 10.1007/bf00384188] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/1976] [Accepted: 12/14/1976] [Indexed: 06/03/2023]
Abstract
Populus deltoides seedlings progress through 2/5, 3/8, and 5/13 orders of phyllotaxis in attaining Plastochron Index 16 (PI 16). The manner in which the vascular system was reoriented during these phyllotactic transitions was determined by anatomical analysis of serial microsections, whereas the positions of the transitions were determined by (14)C labeling. The midvein at the tip of leaves representing plants of different PI and leaves of different Leaf Plastochron Index (LPI) was fed (14)CO2 photosynthetically, and primordia LPI 0 through LPI-9 were dissected from the buds and analyzed for (14)C. By combining the labeling data with the anatomical observations it was possible to reconstruct the vascular system of a plant of PI 16 and to locate the phyllotactic transitions. Both the anatomical and the labeling data showed a high degree of reproducibility among plants suggesting that the phyllotactic pattern to which the vascular system conforms may be programmed in the plant and transmitted acropetally through the developing leaves and procambial strands. The origin of new primordia and the concepts of orthostichy, ontogenetic helix, and Fibonacci sequence are discussed as they apply to the vascular system of P. deltoides.
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Affiliation(s)
- P R Larson
- North Central Forest Experiment Station, U.S. Department of Agriculture, Forest Service, Box 898, 54501, Rhinelander, WI, USA
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24
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Isebrands JG, Dickson RE, Larson PR. Translocation and incorporation of (14)C into the petiole from different regions within developing cottonwood leaves. PLANTA 1976; 128:185-193. [PMID: 24430745 DOI: 10.1007/bf00393227] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/1975] [Accepted: 06/27/1975] [Indexed: 06/03/2023]
Abstract
The ability of a developing cottonwood (Populus deltoides Bartr.) leaf to export (14)C-labeled assimilates begins at the lamina tip and progresses basipetally with increasing LPI. This progression indicates that portions of leaves function quasi-independently in their ability to export (14)C-photosynthate. Although most of the exported radioactivity was recovered in the petiole as water-80% alcohol-soluble compounds, there was also substantial incorporation into the chloroform and insoluble fractions. This observation indicates that assimilates translocated from the lamina are used in structural development of the petiole. Freeze substitution and epoxy embedding were used to prepare microautoradiographs for localization of water-soluble compounds. Radioactivity was found in all cell types within specific subsidiary bundles of the petiole. However, radioactive assimilates appeared to move from the translocation pathway in the phloem toward active sinks in the walls of the expanding metaxylem cells. Translocation in the mature xylem vessels was not observed.
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Affiliation(s)
- J G Isebrands
- North Central Forest Experiment Station, U.S. Department of Agriculture, Forest Service, 54501, Rhinelander, Wisconsin, USA
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