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Salomón RL, Helm J, Gessler A, Grams TEE, Hilman B, Muhr J, Steppe K, Wittmann C, Hartmann H. The quandary of sources and sinks of CO2 efflux in tree stems-new insights and future directions. TREE PHYSIOLOGY 2024; 44:tpad157. [PMID: 38214910 DOI: 10.1093/treephys/tpad157] [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: 09/15/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024]
Abstract
Stem respiration (RS) substantially contributes to the return of photo assimilated carbon to the atmosphere and, thus, to the tree and ecosystem carbon balance. Stem CO2 efflux (ECO2) is often used as a proxy for RS. However, this metric has often been challenged because of the uncertain origin of CO2 emitted from the stem due to post-respiratory processes. In this Insight, we (i) describe processes affecting the quantification of RS, (ii) review common methodological approaches to quantify and model RS and (iii) develop a research agenda to fill the most relevant knowledge gaps that we identified. Dissolution, transport and accumulation of respired CO2 away from its production site, reassimilation of respired CO2 via stem photosynthesis and the enzyme phosphoenolpyruvate carboxylase, axial CO2 diffusion in the gas phase, shifts in the respiratory substrate and non-respiratory oxygen (O2) consumption are the most relevant processes causing divergence between RS and measured stem gas exchange (ECO2 or O2 influx, IO2). Two common methodological approaches to estimate RS, namely the CO2 mass balance approach and the O2 consumption technique, circumvent some of these processes but have yielded inconsistent results regarding the fate of respired CO2. Stem respiration modelling has recently progressed at the organ and tree levels. However, its implementation in large-scale models, commonly operated from a source-driven perspective, is unlikely to reflect adequate mechanisms. Finally, we propose hypotheses and approaches to advance the knowledge of the stem carbon balance, the role of sap pH on RS, the reassimilation of respired CO2, RS upscaling procedures, large-scale RS modelling and shifts in respiratory metabolism during environmental stress.
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Affiliation(s)
- Roberto L Salomón
- Universidad Politécnica de Madrid (UPM), Departamento de Sistemas y Recursos Naturales, Research Group FORESCENT, Antonio Novais 10, 28040, Madrid, Spain
- Department of Plants and Crops, Laboratory of Plant Ecology, Ghent University, Faculty of Bioscience Engineering, Coupure Links 653, 9000 Ghent, Belgium
| | - Juliane Helm
- Max-Planck-Institute for Biogeochemistry, Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
- Department of Environmental Sciences - Botany, Basel University, Schönbeinstr. 6, Basel CH-4056, Switzerland
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zurcherstrasse 111, 8903 Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zürich, Rämistrasse 101, 8902 Zurich, Switzerland
| | - Thorsten E E Grams
- Technical University of Munich, Ecophysiology of Plants, Land Surface - Atmosphere Interactions, Von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - Boaz Hilman
- Max-Planck-Institute for Biogeochemistry, Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
| | - Jan Muhr
- Department of Forest Botany and Tree Physiology, Laboratory for Radioisotopes, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Kathy Steppe
- Department of Plants and Crops, Laboratory of Plant Ecology, Ghent University, Faculty of Bioscience Engineering, Coupure Links 653, 9000 Ghent, Belgium
| | - Christiane Wittmann
- Faculty of Biology, Botanical Garden, University of Duisburg-Essen, Universitätsstrasse 5, 45117 Essen, Germany
| | - Henrik Hartmann
- Max-Planck-Institute for Biogeochemistry, Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
- Institute for Forest Protection, Julius Kühn Institute Federal Research Centre for Cultivated Plants, Erwin-Baur-Straße 27, 06484 Quedlinburg, Germany
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2
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Schmiege SC, Heskel M, Fan Y, Way DA. It's only natural: Plant respiration in unmanaged systems. PLANT PHYSIOLOGY 2023; 192:710-727. [PMID: 36943293 PMCID: PMC10231469 DOI: 10.1093/plphys/kiad167] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 06/01/2023]
Abstract
Respiration plays a key role in the terrestrial carbon cycle and is a fundamental metabolic process in all plant tissues and cells. We review respiration from the perspective of plants that grow in their natural habitat and how it is influenced by wide-ranging elements at different scales, from metabolic substrate availability to shifts in climate. Decades of field-based measurements have honed our understanding of the biological and environmental controls on leaf, root, stem, and whole-organism respiration. Despite this effort, there remain gaps in our knowledge within and across species and ecosystems, especially in more challenging-to-measure tissues like roots. Recent databases of respiration rates and associated leaf traits from species representing diverse biomes, plant functional types, and regional climates have allowed for a wider-lens view at modeling this important CO2 flux. We also re-analyze published data sets to show that maximum leaf respiration rates (Rmax) in species from around the globe are related both to leaf economic traits and environmental variables (precipitation and air temperature), but that root respiration does not follow the same latitudinal trends previously published for leaf data. We encourage the ecophysiological community to continue to expand their study of plant respiration in tissues that are difficult to measure and at the whole plant and ecosystem levels to address outstanding questions in the field.
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Affiliation(s)
- Stephanie C Schmiege
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biology, Western University, N6A 3K7, London, ON, Canada
| | - Mary Heskel
- Department of Biology, Macalester College, Saint Paul, MN, USA 55105
| | - Yuzhen Fan
- Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Danielle A Way
- Department of Biology, Western University, N6A 3K7, London, ON, Canada
- Research School of Biology, The Australian National University, Acton, ACT, Australia
- Environmental & Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, USA
- Nicholas School of the Environment, Duke University, Durham, NC, USA
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3
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Hillabrand RM, Gordon H, Hynes B, Constabel CP, Landhäusser SM. Populus root salicinoid phenolic glycosides are not mobilized to support metabolism and regrowth under carbon limited conditions. TREE PHYSIOLOGY 2023:tpad020. [PMID: 36809479 DOI: 10.1093/treephys/tpad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Remobilization of carbon storage compounds in trees is crucial for the resilience to disturbances, stress, and the requirements of their perennial lifestyle, all of which can impact photosynthetic carbon gain. Trees contain abundant non-structural carbohydrates (NSC) in the form of starch and sugars for long term carbon storage, yet questions remain about the ability of trees to remobilize non-conventional carbon compounds under stress. Aspens, like other members of the genus Populus, have abundant specialized metabolites called salicinoid phenolic glycosides, which contain a core glucose moiety. In this study, we hypothesized that the glucose-containing salicinoids could be remobilized as an additional carbon source during severe carbon limitation. We made use of genetically modified hybrid aspen (Populus tremula x P. alba) with minimal salicinoid content and compared these to control plants with high salicinoid content during resprouting (suckering) in dark (carbon limited) conditions. As salicinoids are abundant anti-herbivore compounds, identification of such a secondary function for salicinoids may provide insight to the evolutionary pressures that drive their accumulation. Our results show that salicinoid biosynthesis is maintained during carbon limitation and suggests that salicinoids are not remobilized as a carbon source for regenerating shoot tissue. However, we found that salicinoid-producing aspens had reduced resprouting capacity per available root biomass when compared to salicinoid-deficient aspens. Therefore, our work shows that the constitutive salicinoid production in aspens can reduce the capacity for resprouting and survival in carbon limited conditions.
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Affiliation(s)
- R M Hillabrand
- Department of Renewable Resources, University of Alberta, 442 ESB, Edmonton, Alberta, T6G 2E3, Canada
| | - H Gordon
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, V8P 5C2, Victoria, British Columbia, Canada
| | - B Hynes
- Department of Renewable Resources, University of Alberta, 442 ESB, Edmonton, Alberta, T6G 2E3, Canada
| | - C P Constabel
- Centre for Forest Biology & Department of Biology, University of Victoria, 3800 Finnerty Road, V8P 5C2, Victoria, British Columbia, Canada
| | - S M Landhäusser
- Department of Renewable Resources, University of Alberta, 442 ESB, Edmonton, Alberta, T6G 2E3, Canada
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4
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Tang Y, Schiestl-Aalto P, Saurer M, Sahlstedt E, Kulmala L, Kolari P, Ryhti K, Salmon Y, Jyske T, Ding Y, Bäck J, Rinne-Garmston KT. Tree organ growth and carbon allocation dynamics impact the magnitude and δ13C signal of stem and soil CO2 fluxes. TREE PHYSIOLOGY 2022; 42:2404-2418. [PMID: 35849053 PMCID: PMC10101690 DOI: 10.1093/treephys/tpac079] [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: 03/11/2022] [Revised: 06/08/2022] [Accepted: 07/02/2022] [Indexed: 05/14/2023]
Abstract
Incomplete knowledge of carbon (C) allocation dynamics in trees hinders accurate modeling and future predictions of tree growth. We studied C allocation dynamics in a mature Pinus sylvestris L. dominated forest with a novel analytical approach, allowing the first comparison of: (i) magnitude and δ13C of shoot, stem and soil CO2 fluxes (Ashoot, Rstem and Rsoil), (ii) concentration and δ13C of compound-specific and/or bulk non-structural carbohydrates (NSCs) in phloem and roots and (iii) growth of stem and fine roots. Results showed a significant effect of phloem NSC concentrations on tracheid growth, and both variables significantly impacted Rstem. Also, concentrations of root NSCs, especially starch, had a significant effect on fine root growth, although no effect of root NSC concentrations or root growth was detected on Rsoil. Time series analysis between δ13C of Ashoot and δ13C of Rstem or δ13C of Rsoil revealed strengthened C allocation to stem or roots under high C demands. Furthermore, we detected a significant correlation between δ13C of Rstem and δ13C of phloem sucrose and glucose, but not for starch or water-soluble carbohydrates. Our results indicate the need to include C allocation dynamics into tree growth models. We recommend using compound-specific concentration and δ13C analysis to reveal C allocation processes that may not be detected by the conventional approach that utilizes bulk organic matter.
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Affiliation(s)
| | - Pauliina Schiestl-Aalto
- Institute for Atmospheric and Earth System Research
(INAR)/Physics, Faculty of Science, University of
Helsinki, P.O. Box 68, FI-00014 Helsinki, Finland
| | - Matthias Saurer
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape
Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Elina Sahlstedt
- Bioeconomy and Environment Unit, Natural Resources Institute
Finland, Latokartanonkaari 9, FI-00790 Helsinki, Finland
| | - Liisa Kulmala
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
- Finnish Meteorological Institute, P.O. Box 503, FI-00101
Helsinki, Finland
| | - Pasi Kolari
- Institute for Atmospheric and Earth System Research
(INAR)/Physics, Faculty of Science, University of
Helsinki, P.O. Box 68, FI-00014 Helsinki, Finland
| | - Kira Ryhti
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
- Institute for Atmospheric and Earth System Research
(INAR)/Physics, Faculty of Science, University of
Helsinki, P.O. Box 68, FI-00014 Helsinki, Finland
| | - Tuula Jyske
- Production Systems Unit, Natural Resources Institute Finland,
Tietotie 2, FI-02150 Espoo, Finland
| | - Yiyang Ding
- Department of Forest Sciences, Faculty of Agriculture and
Forestry, University of Helsinki, P.O. Box 27, FI-00014
Helsinki, Finland
| | - Jaana Bäck
- Institute for Atmospheric and Earth System Research (INAR)/Forest
Sciences, Faculty of Agriculture and Forestry, University
of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland
| | - Katja T Rinne-Garmston
- Bioeconomy and Environment Unit, Natural Resources Institute
Finland, Latokartanonkaari 9, FI-00790 Helsinki, Finland
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5
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Piper FI, Moreno‐Meynard P, Fajardo A. Non‐structural carbohydrates predict survival in saplings of temperate trees under carbon stress. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Frida I. Piper
- Instituto de Ciencias Biológicas (ICB), Universidad de Talca, Campus Lircay 3460000 Talca Chile
- Institute of Ecology and Biodiversity (IEB), Barrio Universitario S/N Concepción Chile
| | - Paulo Moreno‐Meynard
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Moraleda 16 Coyhaique Chile
| | - Alex Fajardo
- Institute of Ecology and Biodiversity (IEB), Barrio Universitario S/N Concepción Chile
- Instituto de Investigación Interdisciplinaria (I3), Universidad de Talca Chile
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6
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Helm J, Hartmann H, Göbel M, Hilman B, Herrera Ramírez D, Muhr J. Low-cost chamber design for simultaneous CO2 and O2 flux measurements between tree stems and the atmosphere. TREE PHYSIOLOGY 2021; 41:1767-1780. [PMID: 33677590 PMCID: PMC8441941 DOI: 10.1093/treephys/tpab022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 02/02/2021] [Indexed: 05/24/2023]
Abstract
Tree stem CO2 efflux is an important component of ecosystem carbon fluxes and has been the focus of many studies. While CO2 efflux can easily be measured, a growing number of studies have shown that it is not identical with actual in situ respiration. Complementing measurements of CO2 flux with simultaneous measurements of O2 flux provides an additional proxy for respiration, and the combination of both fluxes can potentially help getting closer to actual measures of respiratory fluxes. To date, however, the technical challenge to measure relatively small changes in O2 concentration against its high atmospheric background has prevented routine O2 measurements in field applications. Here, we present a new and low-cost field-tested device for autonomous real-time and quasi-continuous long-term measurements of stem respiration by combining CO2 (NDIR-based) and O2 (quenching-based) sensors in a tree stem chamber. Our device operates as a cyclic-closed system and measures changes in both CO2 and O2 concentration within the chamber over time. The device is battery powered with a >1-week power independence, and data acquisition is conveniently achieved by an internal logger. Results from both field and laboratory tests document that our sensors provide reproducible measurements of CO2 and O2 exchange fluxes under varying environmental conditions.
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Affiliation(s)
| | - Henrik Hartmann
- Max-Planck-Institute for Biogeochemistry, Department of Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
| | - Martin Göbel
- Max-Planck-Institute for Biogeochemistry, Department of Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
| | - Boaz Hilman
- Max-Planck-Institute for Biogeochemistry, Department of Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
| | - David Herrera Ramírez
- Max-Planck-Institute for Biogeochemistry, Department of Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
| | - Jan Muhr
- Max-Planck-Institute for Biogeochemistry, Department of Biogeochemical Processes, Hans-Knöll-Str. 10, 07743 Jena, Germany
- Georg-August University Göttingen, Department of Bioclimatology, Büsgenweg 2, 37077 Göttingen, Germany
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7
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Schoonmaker AL, Hillabrand RM, Lieffers VJ, Chow PS, Landhäusser SM. Seasonal dynamics of non-structural carbon pools and their relationship to growth in two boreal conifer tree species. TREE PHYSIOLOGY 2021; 41:1563-1582. [PMID: 33554258 DOI: 10.1093/treephys/tpab013] [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: 06/27/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
In an attempt to comprehensively study the dynamics of non-structural carbon compounds (NCCs), we measured the seasonal changes of soluble sugars, starch, lipids and sugar alcohols in the leaves, branches, stem and roots of the fast-growing Pinus contorta (Loudon) (pine) and slow-growing Picea glauca (Moench) Voss (spruce) trees growing in a boreal climate. In addition to measuring the seasonal concentrations of these compounds, the relative contribution of these compounds to the total NCC pool within the organs of trees (~8 m tall) was estimated and compared across different phenological and growth stages. Both species showed large seasonal shifts from starch to sugars from spring to fall in nearly all organs and tissues; most likely an adaptation to the cold winters. For both species, the total fluctuation of sugar + starch across the year (i.e., the difference between the minimum and maximum observed across collection times) was estimated to be between 1.6 and 1.8 kg for all NCCs. The fluctuation, however, was 1.40 times greater than the minimum reserves in pine, while only 0.72 times the minimum reserves in spruce. By tissue type, NCC fluctuations were greatest in the roots of both species. Roots showed a large build-up of reserves in late spring, but these reserves were depleted over summer and fall. Storage reserves in needles and branches declined over the summer, and this decline may be linked to the sink strength of the stem during diameter growth. Some notable highlights of this holistic study: a late winter build-up of sugars in the stem xylem of both species, but especially spruce; and an increase in sugar alcohols in the bark of spruce in very late winter, which could indicate mobilization to support early growth in spring and high lipid reserves in the bark of pine, which appeared not to be impacted by seasonal changes between summer and winter. Collectively, these observations point toward a more conservative NCC reserve strategy in spruce compared with pine, which is consistent with its stress tolerance and greater longevity.
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Affiliation(s)
- A L Schoonmaker
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
- Centre for Boreal Research, Northern Alberta Institute of Technology, 8102 99 avenue, Peace River, AB T8S1R2, Canada
| | - R M Hillabrand
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
| | - V J Lieffers
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
| | - P S Chow
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
| | - S M Landhäusser
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
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8
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Hilman B, Muhr J, Helm J, Kuhlmann I, Schulze ED, Trumbore S. The size and the age of the metabolically active carbon in tree roots. PLANT, CELL & ENVIRONMENT 2021; 44:2522-2535. [PMID: 34096615 DOI: 10.1111/pce.14124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
Little is known about the sources and age of C respired by tree roots. Previous research in stems identified two functional pools of non-structural carbohydrates (NSC): an "active" pool supplied directly from canopy photo-assimilates supporting metabolism and a "stored" pool used when fresh C supplies are limited. We compared the C isotope composition of water-soluble NSC and respired CO2 for aspen roots (Populus tremula hybrids) cut off from fresh C supply after stem-girdling or prolonged incubation of excised roots. We used bomb radiocarbon to estimate the time elapsed since C fixation for respired CO2 , water-soluble NSC and structural α-cellulose. While freshly excised roots (mostly <2.9 mm in diameter) respired CO2 fixed <1 year previously, the age increased to 1.6-2.9 year within a week after root excision. Freshly excised roots from trees girdled ~3 months ago had respiration rates and NSC stocks similar to un-girdled trees but respired older C (~1.2 year). We estimate that over 3 months NSC in girdled roots must be replaced 5-7 times by reserves remobilized from root-external sources. Using a mixing model and observed correlations between Δ14 C of water-soluble C and α-cellulose, we estimate ~30% of C is "active" (~5 mg C g-1 ).
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Affiliation(s)
- Boaz Hilman
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Jan Muhr
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
- Department of Bioclimatology, Georg-August University Göttingen, Göttingen, Germany
| | - Juliane Helm
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Iris Kuhlmann
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Ernst-Detlef Schulze
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
| | - Susan Trumbore
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Jena, Germany
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9
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Rodríguez-Calcerrada J, Rodrigues AM, António C, Perdiguero P, Pita P, Collada C, Li M, Gil L. Stem metabolism under drought stress - a paradox of increasing respiratory substrates and decreasing respiratory rates. PHYSIOLOGIA PLANTARUM 2021; 172:391-404. [PMID: 32671841 DOI: 10.1111/ppl.13145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
Metabolic changes underpinning drought-induced variations in stem respiration (Rs ) are unknown. We measured Rs rates and metabolite and gene expression profiles in Ulmus minor Mill. and Quercus ilex L. seedlings subjected to increasing levels of drought stress to better understand how carbon, nitrogen and energy metabolism interact during drought. In both species, only plants showing extreme stress symptoms - i.e. negligible rates of leaf stomatal conductance and photosynthesis, and high stem dehydration (30-50% of maximum water storage) and contraction (50-150 μm week-1 ) - exhibited lower Rs rates than well-watered plants. Abundance of low-molecular weight sugars (e.g. glucose and fructose) and sugar alcohols (e.g. mannitol) increased with drought, at more moderate stress and to a higher extent in Q. ilex than U. minor. Abundance of amino acids increased at more severe stress, more abruptly, and to a higher extent in U. minor, coinciding with leaf senescence, which did not occur in Q. ilex. Organic acids changed less in response to drought: threonate and glycerate increased, and citrate decreased although slightly in both species. Transcripts of genes coding for enzymes of the Krebs cycle decreased in Q. ilex and increased in U. minor in conditions of extreme drought stress. The maintenance of Rs under severe growth and photosynthetic restrictions reveals the importance of stem mitochondrial activity in drought acclimation. The eventual decline in Rs diverts carbon substrates from entering the Krebs cycle that may help to cope with osmotic and oxidative stress during severe drought and to recover hydraulic functionality afterwards.
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Affiliation(s)
- Jesús Rodríguez-Calcerrada
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Ana M Rodrigues
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, 2780-157, Portugal
| | - Carla António
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, 2780-157, Portugal
| | - Pedro Perdiguero
- Animal Health Research Center, National Institute for Agriculture and Food Research and Technology (CISA-INIA), Valdeolmos, Madrid, 28130, Spain
| | - Pilar Pita
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Carmen Collada
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Meng Li
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
| | - Luis Gil
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid, 28040, Spain
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10
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Herrera-Ramírez D, Sierra CA, Römermann C, Muhr J, Trumbore S, Silvério D, Brando PM, Hartmann H. Starch and lipid storage strategies in tropical trees relate to growth and mortality. THE NEW PHYTOLOGIST 2021; 230:139-154. [PMID: 33507548 DOI: 10.1111/nph.17239] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
Non-structural carbon (NSC) storage (i.e. starch, soluble sugras and lipids) in tree stems play important roles in metabolism and growth. Their spatial distribution in wood may explain species-specific differences in carbon storage dynamics, growth and survival. However, quantitative information on the spatial distribution of starch and lipids in wood is sparse due to methodological limitations. Here we assessed differences in wood NSC and lipid storage between tropical tree species with different growth and mortality rates and contrasting functional types. We measured starch and soluble sugars in wood cores up to 4 cm deep into the stem using standard chemical quantification methods and histological slices stained with Lugol's iodine. We also detected neutral lipids using histological slices stained with Oil-Red-O. The histological method allowed us to group individuals into two categories according to their starch storage strategy: fiber-storing trees and parenchyma-storing trees. The first group had a bigger starch pool, slower growth and lower mortality rates than the second group. Lipid storage was found in wood parenchyma in five species and was related to low mortality rates. The quantification of the spatial distribution of starch and lipids in wood improves our understanding of NSC dynamics in trees and reveals additional dimensions of tree growth and survival strategies.
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Affiliation(s)
| | - Carlos A Sierra
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str 10, Jena, 07745, Germany
| | - Christine Römermann
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, D-04103, Germany
- Department of Bioclimatology, Georg August University Göttingen, Büsgenweg 2, Göttingen, 37077, Germany
| | - Jan Muhr
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str 10, Jena, 07745, Germany
- Institute of Ecology and Evolution, Friedrich Schiller University Jena, Philosophenweg 16, Jena, 07743, Germany
| | - Susan Trumbore
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str 10, Jena, 07745, Germany
| | - Divino Silvério
- Department of Biology, Universidade Federal Rural da Amazônia - UFRA, Capitão Poço, Pará, 68650-000, Brazil
| | - Paulo M Brando
- Department of Earth System Science, University of California, Irvine, CA, 92697, USA
- Instituto de Pesquisa Ambiental da Amazônia, Brasília, DF, 70863-520, Brazil
- Woodwell Climate Research Center, Falmouth, MA, 02540, USA
| | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str 10, Jena, 07745, Germany
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Wiley E, King CM, Landhäusser SM. Identifying the relevant carbohydrate storage pools available for remobilization in aspen roots. TREE PHYSIOLOGY 2019; 39:1109-1120. [PMID: 31094427 DOI: 10.1093/treephys/tpz051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/27/2019] [Accepted: 04/23/2019] [Indexed: 05/17/2023]
Abstract
Nonstructural carbohydrate (NSC) remobilization remains poorly understood in trees. In particular, it remains unclear (i) which tissues (e.g., living bark or xylem) and compounds (sugars or starch) in woody plants are the main sources of remobilized carbon, (ii) to what extent these NSC pools can be depleted and (iii) whether initial NSC mass or concentration is a better predictor of regrowth potential following disturbance. To address these questions, we collected root segments from a large mature trembling aspen stand; we then allowed them to resprout (sucker) in the dark and remobilize NSC until all sprouts had died. We found that initial starch mass, not concentration, was the best predictor of subsequent sprout mass. In total, more NSC mass (~4×) was remobilized from the living inner bark than the xylem of the roots. After resprouting, root starch was generally depleted to <0.6% w/w in both tissues. In contrast, a large portion of sugars appear unavailable for remobilization: sugar concentrations were only reduced to 12% w/w in the bark and 2% in the xylem. These findings suggest that in order to test whether plant processes like resprouting are limited by storage we need to (i) measure storage in the living bark, not just the xylem, (ii) consider storage pool size-not just concentration-and (iii) carefully determine which compounds are actually components of the storage pool.
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Affiliation(s)
- Erin Wiley
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
| | - Carolyn M King
- Department of Renewable Resources, University of Alberta, Edmonton, Canada
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12
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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 PHYSIOLOGY 2019; 39:819-830. [PMID: 30726992 DOI: 10.1093/treephys/tpy152] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [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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13
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Huang J, Hammerbacher A, Weinhold A, Reichelt M, Gleixner G, Behrendt T, van Dam NM, Sala A, Gershenzon J, Trumbore S, Hartmann H. Eyes on the future - evidence for trade-offs between growth, storage and defense in Norway spruce. THE NEW PHYTOLOGIST 2019; 222:144-158. [PMID: 30289558 DOI: 10.1111/nph.15522] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/28/2018] [Indexed: 05/20/2023]
Abstract
Carbon (C) allocation plays a central role in tree responses to environmental changes. Yet, fundamental questions remain about how trees allocate C to different sinks, for example, growth vs storage and defense. In order to elucidate allocation priorities, we manipulated the whole-tree C balance by modifying atmospheric CO2 concentrations [CO2 ] to create two distinct gradients of declining C availability, and compared how C was allocated among fluxes (respiration and volatile monoterpenes) and biomass C pools (total biomass, nonstructural carbohydrates (NSC) and secondary metabolites (SM)) in well-watered Norway spruce (Picea abies) saplings. Continuous isotope labelling was used to trace the fate of newly-assimilated C. Reducing [CO2 ] to 120 ppm caused an aboveground C compensation point (i.e. net C balance was zero) and resulted in decreases in growth and respiration. By contrast, soluble sugars and SM remained relatively constant in aboveground young organs and were partially maintained with a constant allocation of newly-assimilated C, even at expense of root death from C exhaustion. We conclude that spruce trees have a conservative allocation strategy under source limitation: growth and respiration can be downregulated to maintain 'operational' concentrations of NSC while investing newly-assimilated C into future survival by producing SM.
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Affiliation(s)
- Jianbei Huang
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Almuth Hammerbacher
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany
- Department of Zoology and Entomology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, 0028, Pretoria, South Africa
| | - Alexander Weinhold
- German Centre for Integrative Biodiversity Research, Deutscher Platz 5e, 04103, Leipzig, Germany
| | - Michael Reichelt
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany
| | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Thomas Behrendt
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Nicole M van Dam
- German Centre for Integrative Biodiversity Research, Deutscher Platz 5e, 04103, Leipzig, Germany
- Institute of Biodiversity, Friedrich Schiller University, Dornburger-Str. 159, 07743, Jena, Germany
| | - Anna Sala
- Division of Biological Sciences, The University of Montana, Missoula, MT, 59812, USA
| | - Jonathan Gershenzon
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany
| | - Susan Trumbore
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
| | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll-Str. 10, 07745, Jena, Germany
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14
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Landhäusser SM, Chow PS, Dickman LT, Furze ME, Kuhlman I, Schmid S, Wiesenbauer J, Wild B, Gleixner G, Hartmann H, Hoch G, McDowell NG, Richardson AD, Richter A, Adams HD. Standardized protocols and procedures can precisely and accurately quantify non-structural carbohydrates. TREE PHYSIOLOGY 2018; 38:1764-1778. [PMID: 30376128 PMCID: PMC6301340 DOI: 10.1093/treephys/tpy118] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 10/02/2018] [Indexed: 05/08/2023]
Abstract
Non-structural carbohydrates (NSCs), the stored products of photosynthesis, building blocks for growth and fuel for respiration, are central to plant metabolism, but their measurement is challenging. Differences in methods and procedures among laboratories can cause results to vary widely, limiting our ability to integrate and generalize patterns in plant carbon balance among studies. A recent assessment found that NSC concentrations measured for a common set of samples can vary by an order of magnitude, but sources for this variability were unclear. We measured a common set of nine plant material types, and two synthetic samples with known NSC concentrations, using a common protocol for sugar extraction and starch digestion, and three different sugar quantification methods (ion chromatography, enzyme, acid) in six laboratories. We also tested how sample handling, extraction solvent and centralizing parts of the procedure in one laboratory affected results. Non-structural carbohydrate concentrations measured for synthetic samples were within about 11.5% of known values for all three methods. However, differences among quantification methods were the largest source of variation in NSC measurements for natural plant samples because the three methods quantify different NSCs. The enzyme method quantified only glucose, fructose and sucrose, with ion chromatography we additionally quantified galactose, while the acid method quantified a large range of mono- and oligosaccharides. For some natural samples, sugars quantified with the acid method were two to five times higher than with other methods, demonstrating that trees allocate carbon to a range of sugar molecules. Sample handling had little effect on measurements, while ethanol sugar extraction improved accuracy over water extraction. Our results demonstrate that reasonable accuracy of NSC measurements can be achieved when different methods are used, as long as protocols are robust and standardized. Thus, we provide detailed protocols for the extraction, digestion and quantification of NSCs in plant samples, which should improve the comparability of NSC measurements among laboratories.
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Affiliation(s)
- Simon M Landhäusser
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
- Corresponding author ()
| | - Pak S Chow
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - L Turin Dickman
- Los Alamos National Laboratory, Earth and Environmental Sciences, Los Alamos, NM, USA
| | - Morgan E Furze
- Harvard University, Department of Organismic and Evolutionary Biology, 26 Oxford Street, Cambridge, MA, USA
| | - Iris Kuhlman
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, Jena, Germany
| | - Sandra Schmid
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel, Switzerland
| | - Julia Wiesenbauer
- University of Vienna, Department of Microbiology and Ecosystem Science, Althanstraße 14, Vienna, Austria
| | - Birgit Wild
- Stockholm University, Department of Environmental Science and Analytical Chemistry, Stockholm, Sweden
- University of Gothenburg, Department of Earth Sciences, Guldhedsgatan 5 A, Gothenburg, Sweden
| | - Gerd Gleixner
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, Jena, Germany
| | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, Jena, Germany
| | - Günter Hoch
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel, Switzerland
| | | | - Andrew D Richardson
- Harvard University, Department of Organismic and Evolutionary Biology, 26 Oxford Street, Cambridge, MA, USA
- Northern Arizona University, Center for Ecosystem Science and Society and School of Informatics, Computing and Cyber Systems, Flagstaff, AZ, USA
| | - Andreas Richter
- University of Vienna, Department of Microbiology and Ecosystem Science, Althanstraße 14, Vienna, Austria
| | - Henry D Adams
- Oklahoma State University, Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Stillwater, OK, USA
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15
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Hartmann H, Moura CF, Anderegg WRL, Ruehr NK, Salmon Y, Allen CD, Arndt SK, Breshears DD, Davi H, Galbraith D, Ruthrof KX, Wunder J, Adams HD, Bloemen J, Cailleret M, Cobb R, Gessler A, Grams TEE, Jansen S, Kautz M, Lloret F, O'Brien M. Research frontiers for improving our understanding of drought-induced tree and forest mortality. THE NEW PHYTOLOGIST 2018; 218:15-28. [PMID: 29488280 DOI: 10.1111/nph.15048] [Citation(s) in RCA: 158] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 01/08/2018] [Indexed: 05/20/2023]
Abstract
Accumulating evidence highlights increased mortality risks for trees during severe drought, particularly under warmer temperatures and increasing vapour pressure deficit (VPD). Resulting forest die-off events have severe consequences for ecosystem services, biophysical and biogeochemical land-atmosphere processes. Despite advances in monitoring, modelling and experimental studies of the causes and consequences of tree death from individual tree to ecosystem and global scale, a general mechanistic understanding and realistic predictions of drought mortality under future climate conditions are still lacking. We update a global tree mortality map and present a roadmap to a more holistic understanding of forest mortality across scales. We highlight priority research frontiers that promote: (1) new avenues for research on key tree ecophysiological responses to drought; (2) scaling from the tree/plot level to the ecosystem and region; (3) improvements of mortality risk predictions based on both empirical and mechanistic insights; and (4) a global monitoring network of forest mortality. In light of recent and anticipated large forest die-off events such a research agenda is timely and needed to achieve scientific understanding for realistic predictions of drought-induced tree mortality. The implementation of a sustainable network will require support by stakeholders and political authorities at the international level.
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Affiliation(s)
- Henrik Hartmann
- Max-Planck Institute for Biogeochemistry, Hans Knöll Str. 10, 07745, Jena, Germany
| | - Catarina F Moura
- Max-Planck Institute for Biogeochemistry, Hans Knöll Str. 10, 07745, Jena, Germany
- Faculty of Sciences and Technology, NOVA University of Lisbon, Campus da Caparica, 2829-516, Caparica, Portugal
- Centre for Functional Ecology, Department of Life Sciences, Universilty of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | | | - Nadine K Ruehr
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Kreuzeckbahnstr. 19, 82467, Garmisch-Partenkirchen, Germany
| | - Yann Salmon
- School of Geosciences, University of Edinburgh, Crew Building, The Kings Buildings, Alexander Crum Brown Road, Edinburgh, EH9 3FF, UK
- Faculty of Science, Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, PO Box 68, Gustaf Hällströmin katu 2b, 00014, Helsinki, Finland
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, Latokartanonkaari 7, PO Box 27, 00014, Helsinki, Finland
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Centre, New Mexico Landscapes Field Station, Los Alamos, NM, 87544, USA
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, The University of Melbourne, 500 Yarra Boulevard, Richmond, 3121, Vic., Australia
| | - David D Breshears
- School of Natural Resources and the Environment and Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Hendrik Davi
- INRA, URFM Ecologie des Forest Méditerranéennes, Domaine Saint Paul, Site Agroparc, 84914, Avignon Cedex 9, France
| | - David Galbraith
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
| | - Katinka X Ruthrof
- School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA, 6150, Australia
- Botanic Gardens and Parks Authority, Fraser Avenue, Kings Park, WA, 6005, Australia
| | - Jan Wunder
- Insubric Ecosystems Research Group, Community Ecology, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, a Ramèl 18, CH-6593, Cadenazzo, Switzerland
- Tree-Ring Laboratory, School of Environment, University of Auckland, Auckland, 1142, New Zealand
| | - Henry D Adams
- Department of Plant Biology, Ecology, and Evolution, 301 Physical Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Jasper Bloemen
- Institute of Ecology, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
- Department of Biology, University of Antwerp, 2610, Wilrijk, Belgium
| | - Maxime Cailleret
- Forest Ecology, Department of Environmental Sciences, ETH Zürich. ETH-Zentrum, CHN G77, Universitätstrasse 16, CH-8092, Zürich, Switzerland
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Richard Cobb
- Department of Natural Resources and Environmental Science, California Polytechnic State University, San Luis Obispo, CA, 93407, USA
| | - Arthur Gessler
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Thorsten E E Grams
- Ecophysiology of Plants, Technical University of Munich, Von-Carlowitz-Platz 2, 85354, Freising, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Markus Kautz
- Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology (KIT), Kreuzeckbahnstr. 19, 82467, Garmisch-Partenkirchen, Germany
| | - Francisco Lloret
- CREAF - Centre for Ecological Research and Applied Forestry, Cerdanyola del Vallès, Barcelona, Spain
- Unitat d'Ecologia, Department of Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma Barcelona, Edifici C, Campus UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Michael O'Brien
- Estación Experimental de Zonas Áridas, Consejo Superior de Investigaciones Científicas, Carretera de Sacramento s/n, E-04120 La Cañada, Almería, Spain
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16
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Weber R, Schwendener A, Schmid S, Lambert S, Wiley E, Landhäusser SM, Hartmann H, Hoch G. Living on next to nothing: tree seedlings can survive weeks with very low carbohydrate concentrations. THE NEW PHYTOLOGIST 2018; 218:107-118. [PMID: 29424009 DOI: 10.1111/nph.14987] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/07/2017] [Indexed: 06/08/2023]
Abstract
The usage of nonstructural carbohydrates (NSCs) to indicate carbon (C) limitation in trees requires knowledge of the minimum tissue NSC concentrations at lethal C starvation, and the NSC dynamics during and after severe C limitation. We completely darkened and subsequently released seedlings of two deciduous and two evergreen temperate tree species for varying periods. NSCs were measured in all major organs, allowing assessment of whole-seedling NSC balances. NSCs decreased fast in darkness, but seedlings survived species-specific whole-seedling starch concentrations as low as 0.4-0.8% per dry matter (DM), and sugar (sucrose, glucose and fructose) concentrations as low as 0.5-2.0% DM. After re-illumination, the refilling of NSC pools began within 3 wk, while the resumption of growth was delayed or restricted. All seedlings had died after 12 wk of darkness, and starch and sugar concentrations in most tissues were lower than 1% DM. We conclude that under the applied conditions, tree seedlings can survive several weeks with very low NSC reserves probably also using alternative C sources like lipids, proteins or hemicelluloses; lethal C starvation cannot be assumed, if NSC concentrations are higher than the minimum concentrations found in surviving seedlings; and NSC reformation after re-illumination occurs preferentially over growth.
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Affiliation(s)
- Raphael Weber
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel, 4056, Switzerland
| | - Andrea Schwendener
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel, 4056, Switzerland
| | - Sandra Schmid
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel, 4056, Switzerland
| | - Savoyane Lambert
- Max-Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, Jena, 07745, Germany
| | - Erin Wiley
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Simon M Landhäusser
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Henrik Hartmann
- Max-Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, Jena, 07745, Germany
| | - Günter Hoch
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, Basel, 4056, Switzerland
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17
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Rodríguez-Calcerrada J, Rodrigues AM, Perdiguero P, António C, Atkin OK, Li M, Collada C, Gil L. A molecular approach to drought-induced reduction in leaf CO 2 exchange in drought-resistant Quercus ilex. PHYSIOLOGIA PLANTARUM 2018; 162:394-408. [PMID: 28984911 DOI: 10.1111/ppl.12649] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/20/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
Drought-induced reduction of leaf gas exchange entails a complex regulation of the plant leaf metabolism. We used a combined molecular and physiological approach to understand leaf photosynthetic and respiratory responses of 2-year-old Quercus ilex seedlings to drought. Mild drought stress resulted in glucose accumulation while net photosynthetic CO2 uptake (Pn ) remained unchanged, suggesting a role of glucose in stress signaling and/or osmoregulation. Simple sugars and sugar alcohols increased throughout moderate-to-very severe drought stress conditions, in parallel to a progressive decline in Pn and the quantum efficiency of photosystem II; by contrast, minor changes occurred in respiration rates until drought stress was very severe. At very severe drought stress, 2-oxoglutarate dehydrogenase complex gene expression significantly decreased, and the abundance of most amino acids dramatically increased, especially that of proline and γ-aminobutyric acid (GABA) suggesting enhanced protection against oxidative damage and a reorganization of the tricarboxylic cycle acid cycle via the GABA shunt. Altogether, our results point to Q. ilex drought tolerance being linked to signaling and osmoregulation by hexoses during early stages of drought stress, and enhanced protection against oxidative damage by polyols and amino acids under severe drought stress.
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Affiliation(s)
- Jesús Rodríguez-Calcerrada
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
| | - Ana M Rodrigues
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Pedro Perdiguero
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
- Forest Biotech Laboratory, Instituto de Biologia Experimental e Tecnológica, iBET, 2781-901 Oeiras, Portugal
| | - Carla António
- Plant Metabolomics Laboratory, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, 2601, Australia
| | - Meng Li
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
| | - Carmen Collada
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
| | - Luis Gil
- Forest History, Physiology and Genetics Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid 28040, Spain
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18
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Abiotic Stresses Shift Belowground Populus-Associated Bacteria Toward a Core Stress Microbiome. mSystems 2018; 3:mSystems00070-17. [PMID: 29404422 PMCID: PMC5781258 DOI: 10.1128/msystems.00070-17] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 12/20/2017] [Indexed: 12/24/2022] Open
Abstract
The identification of a common “stress microbiome” indicates tightly controlled relationships between the plant host and bacterial associates and a conserved structure in bacterial communities associated with poplar trees under different growth conditions. The ability of the microbiome to buffer the plant from extreme environmental conditions coupled with the conserved stress microbiome observed in this study suggests an opportunity for future efforts aimed at predictably modulating the microbiome to optimize plant growth. Adverse growth conditions can lead to decreased plant growth, productivity, and survival, resulting in poor yields or failure of crops and biofeedstocks. In some cases, the microbial community associated with plants has been shown to alleviate plant stress and increase plant growth under suboptimal growing conditions. A systematic understanding of how the microbial community changes under these conditions is required to understand the contribution of the microbiome to water utilization, nutrient uptake, and ultimately yield. Using a microbiome inoculation strategy, we studied how the belowground microbiome of Populus deltoides changes in response to diverse environmental conditions, including water limitation, light limitation (shading), and metal toxicity. While plant responses to treatments in terms of growth, photosynthesis, gene expression and metabolite profiles were varied, we identified a core set of bacterial genera that change in abundance in response to host stress. The results of this study indicate substantial structure in the plant microbiome community and identify potential drivers of the phytobiome response to stress. IMPORTANCE The identification of a common “stress microbiome” indicates tightly controlled relationships between the plant host and bacterial associates and a conserved structure in bacterial communities associated with poplar trees under different growth conditions. The ability of the microbiome to buffer the plant from extreme environmental conditions coupled with the conserved stress microbiome observed in this study suggests an opportunity for future efforts aimed at predictably modulating the microbiome to optimize plant growth.
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19
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Karst J, Gaster J, Wiley E, Landhäusser SM. Stress differentially causes roots of tree seedlings to exude carbon. TREE PHYSIOLOGY 2017; 37:154-164. [PMID: 27744381 DOI: 10.1093/treephys/tpw090] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 08/04/2016] [Indexed: 05/29/2023]
Abstract
How carbon (C) flows through plants into soils is poorly understood. Carbon exuded comes from a pool of non-structural carbohydrates (NSC) in roots. Simple models of diffusion across concentration gradients indicate that the more C in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by plants. Thus, stress type may influence exudation independent of NSC. We tested this hypothesis by examining the relationship between NSC in fine roots and exudation of organic C in aspen (Populus tremuloides Michx.) seedlings after exposure to shade, cold soils and drought in a controlled environment. Fine root concentrations of NSC varied by treatment. Mass-specific C exudation increased with increasing fine root sugar concentration in all treatments, but stress type affected exudation independently of sugar concentration. Seedlings exposed to cold soils exuded the most C on a per mass basis. Through 13C labeling, we also found that stressed seedlings allocated relatively more new C to exudates than roots compared with unstressed seedlings. Stress affects exudation of C via mechanisms other than changes in root carbohydrate availability.
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Affiliation(s)
- Justine Karst
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Jacob Gaster
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Erin Wiley
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
| | - Simon M Landhäusser
- Department of Renewable Resources, University of Alberta , 442 Earth Sciences Building, Edmonton, Alberta, CanadaT6G 2E3
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20
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Hilman B, Angert A. Measuring the ratio of CO2 efflux to O2 influx in tree stem respiration. TREE PHYSIOLOGY 2016; 36:1422-1431. [PMID: 27417515 DOI: 10.1093/treephys/tpw057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 06/09/2016] [Indexed: 06/06/2023]
Abstract
In recent studies, the ratio of tree stem CO2 efflux to O2 influx has been defined as the apparent respiratory quotient (ARQ). The metabolism of carbohydrates, the putative respiratory substrate in trees, is expected to yield an ARQ of 1.0. However, previous studies have reported ARQ values ranging between 0.23 and 0.90. These interesting results may indicate internal transport of respired CO2 within stems; yet no simple field applicable methods for ARQ measurement have been available. Here, we report on the assembly of a closed circulating system called 'Hampadah', which uses CO2 and O2 analyzers to measure air samples from stem chambers. We tested the performance of the Hampadah with samples from 36 trees (Tetragastris panamensis (Engl.) Kuntze). Additionally, we showed the feasibility of measuring ARQ directly from stem chambers, using portable CO2 and O2 sensors, in both discrete and continuous modes of operation. The Hampadah measurement proved to be consistent with CO2 gas standards (R2 = 0.999) and with O2 determined by O2/Ar measurements with a mass spectrometer (R2 = 0.998). The Hampadah gave highly reproducible results for ARQ determination of field samples (±0.01 for duplicates). The portable sensors measurement showed good correlation with the Hampadah in measuring CO2, O2 and ARQ (n = 5, R2 = 0.97, 0.98 and 0.91, respectively). We have demonstrated here that the Hampadah and the sensors' methods enable accurate ARQ measurements for both laboratory and field research.
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Affiliation(s)
- Boaz Hilman
- The Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Alon Angert
- The Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Piper FI, Fajardo A. Carbon dynamics of Acer pseudoplatanus seedlings under drought and complete darkness. TREE PHYSIOLOGY 2016; 36:1400-1408. [PMID: 27539732 DOI: 10.1093/treephys/tpw063] [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] [Received: 03/29/2016] [Accepted: 06/18/2016] [Indexed: 06/06/2023]
Abstract
Carbon (C) storage is considered a key component to plant survival under drought and shade, although the combined effects of these factors on survival remain poorly understood. We investigated how drought and shade alter the C dynamics and survival of tree seedlings, and whether drought limits the access to or usage of stored C. We experimentally applied two levels of soil humidity (well-watered versus drought, the latter induced by dry-down) and light availability (light versus complete darkness) on 1-year-old seedlings of Acer pseudoplatanus L. for 3 months. We quantified the survival, biomass, growth rate and non-structural carbohydrates (NSC) of seedlings at their time of death or at the end of the experiment for those that survived. We found that the soil dried out faster when drought was combined with light than when it was combined with complete darkness. Seedlings subjected to both drought and light showed reduced growth and reached 100% mortality earlier than any other treatment, with the highest NSC concentrations at the time of death. Seedlings exposed to both drought and complete darkness died significantly earlier than seedlings exposed to complete darkness only, but had similar NSC concentrations at time of their death, suggesting that drought accelerated the use of stored C under complete darkness. Complete darkness significantly reduced seedling growth and whole-plant NSC concentrations regardless of soil humidity, while root NSC concentrations were significantly more reduced when complete darkness was combined with drought conditions. Thus, the C dynamics in A. pseudoplatanus seedlings under complete darkness was not hindered by drought, i.e., the access and use of stored C was not limited by drought. The contrasting growth and C storage responses driven by drought under light versus complete darkness are consistent with a key role of the drought progression in the C dynamics of trees.
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Affiliation(s)
- Frida I Piper
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Almirante Simpson 471, 5951822 Coyhaique, Chile
- Instituto Milenio de Ecología y Biodiversidad (IEB), 7800003 Santiago, Chile
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Almirante Simpson 471, 5951822 Coyhaique, Chile
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Garcia-Forner N, Sala A, Biel C, Savé R, Martínez-Vilalta J. Individual traits as determinants of time to death under extreme drought in Pinus sylvestris L. TREE PHYSIOLOGY 2016; 36:1196-1209. [PMID: 27217530 DOI: 10.1093/treephys/tpw040] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 04/11/2016] [Indexed: 06/05/2023]
Abstract
Plants exhibit a variety of drought responses involving multiple interacting traits and processes, which makes predictions of drought survival challenging. Careful evaluation of responses within species, where individuals share broadly similar drought resistance strategies, can provide insight into the relative importance of different traits and processes. We subjected Pinus sylvestris L. saplings to extreme drought (no watering) leading to death in a greenhouse to (i) determine the relative effect of predisposing factors and responses to drought on survival time, (ii) identify and rank the importance of key predictors of time to death and (iii) compare individual characteristics of dead and surviving trees sampled concurrently. Time until death varied over 3 months among individual trees (from 29 to 147 days). Survival time was best predicted (higher explained variance and impact on the median survival time) by variables related to carbon uptake and carbon/water economy before and during drought. Trees with higher concentrations of monosaccharides before the beginning of the drought treatment and with higher assimilation rates prior to and during the treatment survived longer (median survival time increased 25-70 days), even at the expense of higher water loss. Dead trees exhibited less than half the amount of nonstructural carbohydrates (NSCs) in branches, stem and relative to surviving trees sampled concurrently. Overall, our results indicate that the maintenance of carbon assimilation to prevent acute depletion of NSC content above some critical level appears to be the main factor explaining survival time of P. sylvestris trees under extreme drought.
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Affiliation(s)
- Núria Garcia-Forner
- CREAF, Cerdanyola del Vallès 08193, Spain
- Univ. Autònoma Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Anna Sala
- Division of Biological Sciences, The University of Montana, Missoula, MT 59812, USA
| | - Carme Biel
- Environmental Horticulture, IRTA, Caldes de Montbui 08140, Spain
| | - Robert Savé
- Environmental Horticulture, IRTA, Caldes de Montbui 08140, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès 08193, Spain
- Univ. Autònoma Barcelona, Cerdanyola del Vallès 08193, Spain
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Hartmann H, Trumbore S. Understanding the roles of nonstructural carbohydrates in forest trees - from what we can measure to what we want to know. THE NEW PHYTOLOGIST 2016; 211:386-403. [PMID: 27061438 DOI: 10.1111/nph.13955] [Citation(s) in RCA: 265] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/01/2016] [Indexed: 05/17/2023]
Abstract
Contents 386 I. 386 II. 388 III. 392 IV. 392 V. 396 VI. 399 399 References 399 SUMMARY: Carbohydrates provide the building blocks for plant structures as well as versatile resources for metabolic processes. The nonstructural carbohydrates (NSC), mainly sugars and starch, fulfil distinct functional roles, including transport, energy metabolism and osmoregulation, and provide substrates for the synthesis of defence compounds or exchange with symbionts involved in nutrient acquisition or defence. At the whole-plant level, NSC storage buffers the asynchrony of supply and demand on diel, seasonal or decadal temporal scales and across plant organs. Despite its central role in plant function and in stand-level carbon cycling, our understanding of storage dynamics, its controls and response to environmental stresses is very limited, even after a century of research. This reflects the fact that often storage is defined by what we can measure, that is, NSC concentrations, and the interpretation of these as a proxy for a single function, storage, rather than the outcome of a range of NSC source and sink functions. New isotopic tools allow direct quantification of timescales involved in NSC dynamics, and show that NSC-C fixed years to decades previously is used to support tree functions. Here we review recent advances, with emphasis on the context of the interactions between NSC, drought and tree mortality.
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Affiliation(s)
- Henrik Hartmann
- Max-Planck Institute for Biogeochemistry, Hans Knöll Str. 10, 07745, Jena, Germany
| | - Susan Trumbore
- Max-Planck Institute for Biogeochemistry, Hans Knöll Str. 10, 07745, Jena, Germany
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