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Rehschuh R, Rehschuh S, Gast A, Jakab AL, Lehmann MM, Saurer M, Gessler A, Ruehr NK. Tree allocation dynamics beyond heat and hot drought stress reveal changes in carbon storage, belowground translocation and growth. THE NEW PHYTOLOGIST 2022; 233:687-704. [PMID: 34668198 DOI: 10.1111/nph.17815] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Heatwaves combined with drought affect tree functioning with as yet undetermined legacy effects on carbon (C) and nitrogen (N) allocation. We continuously monitored shoot and root gas exchange, δ13 CO2 of respiration and stem growth in well-watered and drought-treated Pinus sylvestris (Scots pine) seedlings exposed to increasing daytime temperatures (max. 42°C) and evaporative demand. Following stress release, we used 13 CO2 canopy pulse-labeling, supplemented by soil-applied 15 N, to determine allocation to plant compartments, respiration and soil microbial biomass (SMB) over 2.5 wk. Previously heat-treated seedlings rapidly translocated 13 C along the long-distance transport path, to root respiration (Rroot ; 7.1 h) and SMB (3 d). Furthermore, 13 C accumulated in branch cellulose, suggesting secondary growth enhancement. However, in recovering drought-heat seedlings, the mean residence time of 13 C in needles increased, whereas C translocation to Rroot was delayed (13.8 h) and 13 C incorporated into starch rather than cellulose. Concurrently, we observed stress-induced low N uptake and aboveground allocation. C and N allocation during early recovery were affected by stress type and impact. Although C uptake increased quickly in both treatments, drought-heat in combination reduced the above-belowground coupling and starch accumulated in leaves at the expense of growth. Accordingly, C allocation during recovery depends on phloem translocation capacity.
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Affiliation(s)
- Romy Rehschuh
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, 82467, Germany
| | - Stephanie Rehschuh
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, 82467, Germany
| | - Andreas Gast
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, 82467, Germany
| | - Andrea-Livia Jakab
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, 82467, Germany
| | - Marco M Lehmann
- Swiss Federal Research Institute WSL, Research Unit Forest Dynamics, Birmensdorf, 8903, Switzerland
| | - Matthias Saurer
- Swiss Federal Research Institute WSL, Research Unit Forest Dynamics, Birmensdorf, 8903, Switzerland
| | - Arthur Gessler
- Swiss Federal Research Institute WSL, Research Unit Forest Dynamics, Birmensdorf, 8903, Switzerland
- Department of Environmental System Sciences, ETH Zurich, Zurich, 8092, Switzerland
| | - Nadine K Ruehr
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research - Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen, 82467, Germany
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Withington JM, Goebel M, Bułaj B, Oleksyn J, Reich PB, Eissenstat DM. Remarkable Similarity in Timing of Absorptive Fine-Root Production Across 11 Diverse Temperate Tree Species in a Common Garden. FRONTIERS IN PLANT SCIENCE 2021; 11:623722. [PMID: 33584764 PMCID: PMC7875864 DOI: 10.3389/fpls.2020.623722] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/18/2020] [Indexed: 06/08/2023]
Abstract
Long-term minirhizotron observations of absorptive fine roots provide insights into seasonal patterns of belowground root production and carbon dynamics. Our objective was to compare root dynamics over time across mature individuals of 11 temperate trees species: five evergreen and six deciduous. We analyzed the timing and growth on 1st-and 2nd-order roots in minirhizotron images down to a vertical depth of 35 cm, as well as monthly and total annual length production. Production patterns were related to total annual precipitation of the actual and previous year of root production over 6 years. The main or largest peak of annual fine-root production occurred between June and September for almost all species and years. In most years, when peaks occurred, the timing of peak root production was synchronized across all species. A linear mixed model revealed significant differences in monthly fine-root length production across species in certain years (species x year, P < 0.0001), which was strongly influenced by three tree species. Total annual root production was much higher in 2000-2002, when there was above-average rainfall in the previous year, compared with production in 2005-2007, which followed years of lower-than-average rainfall (2003-2006). Compared to the wetter period all species experienced a decline of at least 75% in annual production in the drier years. Total annual root length production was more strongly associated with previous year's (P < 0.001) compared with the actual year's precipitation (P = 0.003). Remarkably similar timing of monthly absorptive fine-root growth can occur across multiple species of diverse phylogeny and leaf habit in a given year, suggesting a strong influence of extrinsic factors on absorptive fine-root growth. The influence of previous year precipitation on annual absorptive fine-root growth underscores the importance of legacy effects in biological responses and suggests that a growth response of temperate trees to extreme precipitation or drought events can be exacerbated across years.
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Affiliation(s)
- Jennifer M. Withington
- Intercollege Graduate Degree Program in Ecology, Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, United States
- Department of Biology, State University of New York at Oneonta, Oneonta, NY, United States
| | - Marc Goebel
- Intercollege Graduate Degree Program in Ecology, Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, United States
- Department of Natural Resources, Cornell University, Ithaca, NY, United States
| | - Bartosz Bułaj
- Department of Silviculture, Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
| | - Jacek Oleksyn
- Department of Forest Resources, The University of Minnesota, St. Paul, MN, United States
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | - Peter B. Reich
- Department of Forest Resources, The University of Minnesota, St. Paul, MN, United States
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW, Australia
| | - David M. Eissenstat
- Intercollege Graduate Degree Program in Ecology, Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, United States
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Zeng W, Zhang J, Dong L, Wang W, Zeng H. Nonlinear responses of total belowground carbon flux and its components to increased nitrogen availability in temperate forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 715:136954. [PMID: 32041052 DOI: 10.1016/j.scitotenv.2020.136954] [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: 11/05/2019] [Revised: 01/14/2020] [Accepted: 01/25/2020] [Indexed: 06/10/2023]
Abstract
With the increased interest in allocating more carbon (C) belowground for C sequestration, total belowground C flux (TBCF) and its dynamics have become an important research topic. However, it remains uncertain whether TBCF responds nonlinearly to increased nitrogen (N) availability and how its main components (root and ectomycorrhizal (ECM) fungi) contribute to TBCF. We established a four-year N addition experiment with control, low-N, medium-N, and high-N fertilization treatments in a N-limited temperate forest in northern China. We measured TBCF and its three main components including root respiration, ECM fungal respiration, and root production. The involved edaphic and plant factors were also measured. TBCF showed a nonlinear response to the increasing amounts of N addition, accelerated by 10.37% in low-N addition and restrained by 10.29% in high-N addition. Contrasting patterns of the contributions of root respiration and ECM fungal respiration to TBCF implies different strategies of investment in roots and ECM fungi under the different N-availability statuses. The ratio of production and respiration in roots under N addition was nearly 1:2, which indicated that when soil N availability increases, roots prefer to lose C by overflow respiration rather than fix C in new biomass. The low-N addition increased TBCF by directly increasing root respiration and indirectly increasing coarse root biomass. The medium-N addition positively affected TBCF by increasing root respiration but this positive effect was cancelled out by the significantly negative effect of the increased soil total N concentration. The decrease in soil pH was the most effective pathway to decrease TBCF in high-N addition. Because of a large-scale reforestation program for C sink management in recent years, our findings of the nonlinear response of TBCF to different N fertilization treatments could provide insight for predicting belowground C sequestration potential and its response to atmospheric N deposition.
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Affiliation(s)
- Wenjing Zeng
- Department of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Jiangyong Zhang
- Department of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China; Key Laboratory for Urban Habitat Environmental Science and Technology, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Lizheng Dong
- Department of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China
| | - Wei Wang
- Department of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China.
| | - Hui Zeng
- Department of Ecology, College of Urban and Environmental Sciences, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China; Key Laboratory for Urban Habitat Environmental Science and Technology, Peking University Shenzhen Graduate School, Shenzhen, China
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Mannerheim N, Blessing CH, Oren I, Grünzweig JM, Bachofen C, Buchmann N. Carbon allocation to the root system of tropical tree Ceiba pentandra using 13C pulse labelling in an aeroponic facility. TREE PHYSIOLOGY 2020; 40:350-366. [PMID: 31976538 DOI: 10.1093/treephys/tpz142] [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: 01/18/2019] [Revised: 10/28/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Despite the important role of tropical forest ecosystems in the uptake and storage of atmospheric carbon dioxide (CO2), the carbon (C) dynamics of tropical tree species remains poorly understood, especially regarding belowground roots. This study assessed the allocation of newly assimilated C in the fast-growing pioneer tropical tree species Ceiba pentandra (L.), with a special focus on different root categories. During a 5-day pulse-labelling experiment, 9-month-old (~3.5-m-tall) saplings were labelled with 13CO2 in a large-scale aeroponic facility, which allowed tracing the label in bulk biomass and in non-structural carbohydrates (sugars and starch) as well as respiratory CO2 from the canopy to the root system, including both woody and non-woody roots. A combined logistic and exponential model was used to evaluate 13C mean transfer time and mean residence time (MRT) to the root systems. We found 13C in the root phloem as early as 2 h after the labelling, indicating a mean C transfer velocity of 2.4 ± 0.1 m h-1. Five days after pulse labelling, 27% of the tracers taken up by the trees were found in the leaves and 13% were recovered in the woody tissue of the trunk, 6% in the bark and 2% in the root systems, while 52% were lost, most likely by respiration and exudation. Larger amounts of 13C were found in root sugars than in starch, the former also demonstrating shorter MRT than starch. Of all investigated root categories, non-woody white roots (NRW) showed the largest 13C enrichment and peaked in the deepest NRW (2-3.5 m) as early as 24 ± 2 h after labelling. In contrast to coarse woody brown roots, the sink strength of NRW increased with root depth. The findings of this study improve the understanding of C allocation in young tropical trees and provide unique insights into the changing contributions of woody and non-woody roots to C sink strengths with depth.
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Affiliation(s)
- Neringa Mannerheim
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
| | - Carola H Blessing
- Landwirtschaftliches Technologiezentrum Augustenberg, Kutschenweg 20, 76287 Rheinstetten-Forchheim, Germany
| | - Israel Oren
- Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel
| | - José M Grünzweig
- Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 7610001, Israel
| | - Christoph Bachofen
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Universitaetstrasse 2, 8092 Zurich, Switzerland
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Furze ME, Drake JE, Wiesenbauer J, Richter A, Pendall E. Carbon isotopic tracing of sugars throughout whole-trees exposed to climate warming. PLANT, CELL & ENVIRONMENT 2019; 42:3253-3263. [PMID: 31335973 DOI: 10.1111/pce.13625] [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: 02/14/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Trees allocate C from sources to sinks by way of a series of processes involving carbohydrate transport and utilization. Yet these dynamics are not well characterized in trees, and it is unclear how these dynamics will respond to a warmer world. Here, we conducted a warming and pulse-chase experiment on Eucalyptus parramattensis growing in a whole-tree chamber system to test whether warming impacts carbon allocation by increasing the speed of carbohydrate dynamics. We pulse-labelled large (6-m tall) trees with 13 C-CO2 to follow recently fixed C through different organs by using compound-specific isotope analysis of sugars. We then compared concentrations and mean residence times of individual sugars between ambient and warmed (+3°C) treatments. Trees dynamically allocated 13 C-labelled sugars throughout the aboveground-belowground continuum. We did not, however, find a significant treatment effect on C dynamics, as sugar concentrations and mean residence times were not altered by warming. From the canopy to the root system, 13 C enrichment of sugars decreased, and mean residence times increased, reflecting dilution and mixing of recent photoassimilates with older reserves along the transport pathway. Our results suggest that a locally endemic eucalypt was seemingly able to adjust its physiology to warming representative of future temperature predictions for Australia.
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Affiliation(s)
- Morgan E Furze
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138
| | - John E Drake
- Department of Forest and Natural Resources Management, College of Environmental Science and Forestry, State University of New York, Syracuse, New York, 13210
| | - Julia Wiesenbauer
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, 1010, Austria
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, 1010, Austria
| | - Elise Pendall
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, 2751, Australia
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6
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Solly EF, Brunner I, Helmisaari HS, Herzog C, Leppälammi-Kujansuu J, Schöning I, Schrumpf M, Schweingruber FH, Trumbore SE, Hagedorn F. Unravelling the age of fine roots of temperate and boreal forests. Nat Commun 2018; 9:3006. [PMID: 30068916 PMCID: PMC6070616 DOI: 10.1038/s41467-018-05460-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 07/04/2018] [Indexed: 11/30/2022] Open
Abstract
Fine roots support the water and nutrient demands of plants and supply carbon to soils. Quantifying turnover times of fine roots is crucial for modeling soil organic matter dynamics and constraining carbon cycle-climate feedbacks. Here we challenge widely used isotope-based estimates suggesting the turnover of fine roots of trees to be as slow as a decade. By recording annual growth rings of roots from woody plant species, we show that mean chronological ages of fine roots vary from <1 to 12 years in temperate, boreal and sub-arctic forests. Radiocarbon dating reveals the same roots to be constructed from 10 ± 1 year (mean ± 1 SE) older carbon. This dramatic difference provides evidence for a time lag between plant carbon assimilation and production of fine roots, most likely due to internal carbon storage. The high root turnover documented here implies greater carbon inputs into soils than previously thought which has wide-ranging implications for quantifying ecosystem carbon allocation.
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Affiliation(s)
- Emily F Solly
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland.
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
| | - Ivano Brunner
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Heljä-Sisko Helmisaari
- Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014, Helsinki, Finland
| | - Claude Herzog
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | | | - Ingo Schöning
- Max Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, 07745, Jena, Germany
| | - Marion Schrumpf
- Max Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, 07745, Jena, Germany
| | - Fritz H Schweingruber
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Susan E Trumbore
- Max Planck Institute for Biogeochemistry, Hans Knöll Strasse 10, 07745, Jena, Germany
| | - Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
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Rainer-Lethaus G, Oberhuber W. Phloem Girdling of Norway Spruce Alters Quantity and Quality of Wood Formation in Roots Particularly Under Drought. FRONTIERS IN PLANT SCIENCE 2018; 9:392. [PMID: 29636766 PMCID: PMC5881222 DOI: 10.3389/fpls.2018.00392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 03/12/2018] [Indexed: 05/31/2023]
Abstract
Carbon (C) availability plays an essential role in tree growth and wood formation. We evaluated the hypothesis that a decrease in C availability (i) triggers mobilization of C reserves in the coarse roots of Picea abies to maintain growth and (ii) causes modification of wood structure notably under drought. The 6-year-old saplings were subjected to two levels of soil moisture (watered versus drought conditions) and root C status was manipulated by physically blocking phloem transport in the stem at three girdling dates (GDs). Stem girdling was done before the onset of bud break [day of the year (doy) 77], during vigorous aboveground shoot and radial stem growth (GD doy 138), and after cessation of shoot growth (GD doy 190). The effect of blockage of C transport on root growth, root phenology, and wood anatomical traits [cell lumen diameter (CLD) and cell wall thickness (CWT)] in earlywood (EW) and latewood (LW) was determined. To evaluate changes in belowground C status caused by girdling, non-structural carbohydrates (soluble sugars and starch) in coarse roots were determined at the time of girdling and after the growing season. Although fine root mass significantly decreased in response to blockage of phloem C transport, the phenology of root elongation growth was not affected. Surprisingly, radial root growth and CLD of EW tracheids in coarse roots were strikingly increased in drought-stressed trees, when girdling occurred before bud break or during aboveground stem growth. In watered trees, the growth response to girdling was less distinct, but the CWT of EW significantly increased. Starch reserves in the roots of girdled trees significantly decreased in both soil moisture treatments and at all GDs. We conclude that (i) radial growth and wood development in coarse roots of P. abies saplings are not only dependent on current photosynthates, and (ii) blockage of phloem transport induces physiological changes that outweigh drought effects imposed on root cambial activity and cell differentiation.
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Affiliation(s)
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
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Desalme D, Priault P, Gérant D, Dannoura M, Maillard P, Plain C, Epron D. Seasonal variations drive short-term dynamics and partitioning of recently assimilated carbon in the foliage of adult beech and pine. THE NEW PHYTOLOGIST 2017; 213:140-153. [PMID: 27513732 DOI: 10.1111/nph.14124] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/28/2016] [Indexed: 06/06/2023]
Abstract
13 CO2 pulse-labelling experiments were performed in situ on adult beeches (Fagus sylvatica) and pines (Pinus pinaster) at different phenological stages to study seasonal and interspecific short-term dynamics and partitioning of recently assimilated carbon (C) in leaves. Polar fraction (PF, including soluble sugars, amino acids and organic acids) and starch were purified from foliage sampled during a 10-d chase period. C contents, isotopic compositions and 13 C dynamics parameters were determined in bulk foliage, PF and starch. Decrease in 13 C amount in bulk foliage followed a two-pool exponential model highlighting 13 C partitioning between 'mobile' and 'stable' pools, the relative proportion of the latter being maximal in beech leaves in May. Early in the growing season, new foliage acted as a strong C sink in both species, but although young leaves and needles were already photosynthesizing, the latter were still supplied with previous-year needle photosynthates 2 months after budburst. Mean 13 C residence times (MRT) were minimal in summer, indicating fast photosynthate export to supply perennial organ growth in both species. In late summer, MRT differed between senescing beech leaves and overwintering pine needles. Seasonal variations of 13 C partitioning and dynamics in field-grown tree foliage are closely linked to phenological differences between deciduous and evergreen trees.
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Affiliation(s)
- Dorine Desalme
- Ecologie et Ecophysiologie Forestières, Université de Lorraine, INRA, UMR 1137, Vandoeuvre-lès-Nancy F-54500, France
| | - Pierrick Priault
- Ecologie et Ecophysiologie Forestières, Université de Lorraine, INRA, UMR 1137, Vandoeuvre-lès-Nancy F-54500, France
| | - Dominique Gérant
- Ecologie et Ecophysiologie Forestières, Université de Lorraine, INRA, UMR 1137, Vandoeuvre-lès-Nancy F-54500, France
| | - Masako Dannoura
- INRA, UMR 1263, F-33883 Villenave d'Ornon, France
- Laboratory of Forest Utilization, Kyoto University, Kyoto 606-8502, Japan
| | - Pascale Maillard
- Ecologie et Ecophysiologie Forestières, Université de Lorraine, INRA, UMR 1137, Vandoeuvre-lès-Nancy F-54500, France
| | - Caroline Plain
- Ecologie et Ecophysiologie Forestières, Université de Lorraine, INRA, UMR 1137, Vandoeuvre-lès-Nancy F-54500, France
| | - Daniel Epron
- Ecologie et Ecophysiologie Forestières, Université de Lorraine, INRA, UMR 1137, Vandoeuvre-lès-Nancy F-54500, France
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Carbon Allocation into Different Fine-Root Classes of Young Abies alba Trees Is Affected More by Phenology than by Simulated Browsing. PLoS One 2016; 11:e0154687. [PMID: 27123860 PMCID: PMC4849635 DOI: 10.1371/journal.pone.0154687] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/18/2016] [Indexed: 12/02/2022] Open
Abstract
Abies alba (European silver fir) was used to investigate possible effects of simulated browsing on C allocation belowground by 13CO2 pulse-labelling at spring, summer or autumn, and by harvesting the trees at the same time point of the labelling or at a later season for biomass and for 13C-allocation into the fine-root system. Before budburst in spring, the leader shoots and 50% of all lateral shoots of half of the investigated 5-year old Abies alba saplings were clipped to simulate browsing. At harvest, different fine-root classes were separated, and starch as an important storage compartment was analysed for concentrations. The phenology had a strong effect on the allocation of the 13C-label from shoots to roots. In spring, shoots did not supply the fine-roots with high amounts of the 13C-label, because the fine-roots contained less than 1% of the applied 13C. In summer and autumn, however, shoots allocated relatively high amounts of the 13C-label to the fine roots. The incorporation of the 13C-label as structural C or as starch into the roots is strongly dependent on the root type and the root diameter. In newly formed fine roots, 3–5% of the applied 13C was incorporated, whereas 1–3% in the ≤0.5 mm root class and 1–1.5% in the >0.5–1.0 mm root class were recorded. Highest 13C-enrichment in the starch was recorded in the newly formed fine roots in autumn. The clipping treatment had a significant positive effect on the amount of allocated 13C-label to the fine roots after the spring labelling, with high relative 13C-contents observed in the ≤0.5 mm and the >0.5–1.0 mm fine-root classes of clipped trees. No effects of the clipping were observed after summer and autumn labelling in the 13C-allocation patterns. Overall, our data imply that the season of C assimilation and, thus, the phenology of trees is the main determinant of the C allocation from shoots to roots and is clearly more important than browsing.
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Wegener F, Beyschlag W, Werner C. High intraspecific ability to adjust both carbon uptake and allocation under light and nutrient reduction in Halimium halimifolium L. FRONTIERS IN PLANT SCIENCE 2015; 6:609. [PMID: 26300906 PMCID: PMC4528176 DOI: 10.3389/fpls.2015.00609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/23/2015] [Indexed: 05/28/2023]
Abstract
The allocation of recently assimilated carbon (C) by plants depends on developmental stage and on environmental factors, but the underlying mechanisms are still a matter of debate. In the present study, we investigated the regulation of C uptake and allocation and their adjustments during plant growth. We induced different allocation strategies in the Mediterranean shrub Halimium halimifolium L. by a reduction of light (Low L treatment) and nutrient availability (Low N treatment) and analyzed allocation parameters as well as morphological and physiological traits for 15 months. Further, we conducted a (13)CO2 pulse-labeling and followed the way of recently assimilated carbon to eight different tissue classes and respiration for 13 days. The plant responses were remarkably distinct in our study, with mainly morphological/physiological adaptions in case of light reduction and adjustment of C allocation in case of nutrient reduction. The transport of recently assimilated C to the root system was enhanced in amount (c. 200%) and velocity under nutrient limited conditions compared to control plants. Despite the 57% light reduction the total biomass production was not affected in the Low L treatment. The plants probably compensated light reduction by an improvement of their ability to fix C. Thus, our results support the concept that photosynthesis is, at least in a medium term perspective, influenced by the C demand of the plant and not exclusively by environmental factors. Finally, our results indicate that growing heterotrophic tissues strongly reduce the C reflux from storage and structural C pools and therefore enhance the fraction of recent assimilates allocated to respiration. We propose that this interruption of the C reflux from storage and structural C pools could be a regulation mechanism for C translocation in plants.
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Affiliation(s)
- Frederik Wegener
- Ecosystem Physiology, University of FreiburgFreiburg, Germany
- AgroEcosystem Research, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of BayreuthBayreuth, Germany
| | - Wolfram Beyschlag
- Experimental and Systems Ecology, University of BielefeldBielefeld, Germany
| | - Christiane Werner
- Ecosystem Physiology, University of FreiburgFreiburg, Germany
- AgroEcosystem Research, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of BayreuthBayreuth, Germany
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11
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Blessing CH, Werner RA, Siegwolf R, Buchmann N. Allocation dynamics of recently fixed carbon in beech saplings in response to increased temperatures and drought. TREE PHYSIOLOGY 2015; 35:585-98. [PMID: 25877767 DOI: 10.1093/treephys/tpv024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 03/08/2015] [Indexed: 05/05/2023]
Abstract
The response of carbon allocation to drought has often been studied in terms of short-term transport velocity of recently fixed carbon from leaves to roots and root respiration. However, its dynamic response to other environmental conditions, e.g., to changes in temperature, is less clear. Here, we investigated the effects of drought, increased temperatures and their combination on transport velocity as well as on distribution of recent photoassimilates for different compounds, such as sugars, starch, organic acids and amino acids. We used a (13)CO(2) pulse-labelling approach and studied the recovery of (13)C in different plant tissues and compounds of beech saplings (Fagus sylvatica L.) during a 9-day chase period. Neither total dry biomass nor dry weights of leaves or roots were affected by drought or increased temperatures. Generally, the fast transfer of recently fixed assimilates from leaves to roots took about 1 day, while (13)C enrichment in soil CO(2) efflux peaked only 2 days after labelling. Increased temperatures prolonged mean transfer times of recent photoassimilates from the leaves to the roots, probably caused by enhanced intermediate storage alongside basipetal transfer, clearly impacting short-term carbon allocation. This temperature effect was seen in the delayed peak in (13)C excess of root sugars, decoupling the roots from the leaves in the short term. On average, ∼40% of the (13)C label initially present in the plant was recovered in the roots (over all treatment combinations), providing strong evidence for preferred carbon allocation into the roots at the end of the growing season. Root starch was the principal compound for long-term storage of carbon, whereas leaf (transitory) starch was remobilized again after some days, exhibiting the longest mean residence times under dry and warm conditions. These observation clearly point to different functionalities of the same compound (i.e., starch) in different plant tissues and the crucial role of roots for long-term carbon storage.
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Affiliation(s)
- Carola H Blessing
- Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8048 Zurich, Switzerland
| | - Roland A Werner
- Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8048 Zurich, Switzerland
| | - Rolf Siegwolf
- Paul Scherrer Institute (PSI), Laboratory of Atmospheric Chemistry, CH-5232 Villigen PSI, Switzerland
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Universitätstrasse 2, 8048 Zurich, Switzerland
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Herzog C, Steffen J, Graf Pannatier E, Hajdas I, Brunner I. Nine years of irrigation cause vegetation and fine root shifts in a water-limited pine forest. PLoS One 2014; 9:e96321. [PMID: 24802642 PMCID: PMC4011741 DOI: 10.1371/journal.pone.0096321] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/05/2014] [Indexed: 11/19/2022] Open
Abstract
Scots pines (Pinus sylvestris L.) in the inner-Alpine dry valleys of Switzerland have suffered from increased mortality during the past decades, which has been caused by longer and more frequent dry periods. In addition, a proceeding replacement of Scots pines by pubescent oaks (Quercus pubescens Willd.) has been observed. In 2003, an irrigation experiment was performed to track changes by reducing drought pressure on the natural pine forest. After nine years of irrigation, we observed major adaptations in the vegetation and shifts in Scots pine fine root abundance and structure. Irrigation permitted new plant species to assemble and promote canopy closure with a subsequent loss of herb and moss coverage. Fine root dry weight increased under irrigation and fine roots had a tendency to elongate. Structural composition of fine roots remained unaffected by irrigation, expressing preserved proportions of cellulose, lignin and phenolic substances. A shift to a more negative δ13C signal in the fine root C indicates an increased photosynthetic activity in irrigated pine trees. Using radiocarbon (14C) measurement, a reduced mean age of the fine roots in irrigated plots was revealed. The reason for this is either an increase in newly produced fine roots, supported by the increase in fine root biomass, or a reduced lifespan of fine roots which corresponds to an enhanced turnover rate. Overall, the responses belowground to irrigation are less conspicuous than the more rapid adaptations aboveground. Lagged and conservative adaptations of tree roots with decadal lifespans are challenging to detect, hence demanding for long-term surveys. Investigations concerning fine root turnover rate and degradation processes under a changing climate are crucial for a complete understanding of C cycling.
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Affiliation(s)
- Claude Herzog
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Swiss Federal Institute of Technology Zürich ETH, Zurich, Switzerland
| | - Jan Steffen
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | | | - Irka Hajdas
- Swiss Federal Institute of Technology Zürich ETH, Zurich, Switzerland
| | - Ivano Brunner
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
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Mildner M, Bader MKF, Leuzinger S, Siegwolf RTW, Körner C. Long-term 13C labeling provides evidence for temporal and spatial carbon allocation patterns in mature Picea abies. Oecologia 2014; 175:747-62. [DOI: 10.1007/s00442-014-2935-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 03/15/2014] [Indexed: 10/25/2022]
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14
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Streit K, Rinne KT, Hagedorn F, Dawes MA, Saurer M, Hoch G, Werner RA, Buchmann N, Siegwolf RTW. Tracing fresh assimilates through Larix decidua exposed to elevated CO₂ and soil warming at the alpine treeline using compound-specific stable isotope analysis. THE NEW PHYTOLOGIST 2013; 197:838-849. [PMID: 23252478 DOI: 10.1111/nph.12074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 10/29/2012] [Indexed: 06/01/2023]
Abstract
How will carbon source-sink relations of 35-yr-old larch trees (Larix decidua) at the alpine treeline respond to changes in atmospheric CO(2) and climate? We evaluated the effects of previously elevated CO(2) concentrations (9 yr, 580 ppm, ended the previous season) and ongoing soil warming (4 yr, + 4°C). Larch branches were pulse labeled (50 at% (13)CO(2)) in July 2010 to trace fresh assimilates through tissues (buds, needles, bark and wood) and non-structural carbon compounds (NCC; starch, lipids, individual sugars) using compound-specific isotope analysis. Nine years of elevated CO(2) did not lead to increased NCC concentrations, nor did soil warming increase NCC transfer velocities. By contrast, we found slower transfer velocities and higher NCC concentrations than reported in the literature for lowland larch. As a result of low dilution with older carbon, sucrose and glucose showed the highest maximum (13)C labels, whereas labels were lower for starch, lipids and pinitol. Label residence times in needles were shorter for sucrose and starch (c. 2 d) than for glucose (c. 6 d). Although our treatments showed no persistent effect on larch carbon relations, low temperature at high altitudes clearly induced a limitation of sink activities (growth, respiration, root exudation), expressed in slower carbon transfer and higher NCC concentrations.
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Affiliation(s)
- Kathrin Streit
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland
| | - Katja T Rinne
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland
| | - Frank Hagedorn
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Melissa A Dawes
- Mountain Ecosystems, WSL Institute for Snow and Avalanche Research (SLF), Flüelastrasse 11, CH-7260, Davos Dorf, Switzerland
| | - Matthias Saurer
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland
| | - Günter Hoch
- Institute of Botany, University of Basel, Schönbeinstrasse 6, CH-4056, Basel, Switzerland
| | - Roland A Werner
- Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, CH-8092, Zurich, Switzerland
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, CH-8092, Zurich, Switzerland
| | - Rolf T W Siegwolf
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI), CH-5232, Villigen, Switzerland
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15
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Churchland C, Weatherall A, Briones MJI, Grayston SJ. Stable-isotope labeling and probing of recent photosynthates into respired CO2, soil microbes and soil mesofauna using a xylem and phloem stem-injection technique on Sitka spruce (Picea sitchensis). RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:2493-2501. [PMID: 23008066 DOI: 10.1002/rcm.6368] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
RATIONALE Here we report on the successful application of a novel stem-injection stable-isotope-labeling and probing technique in mature trees to trace the spatial and temporal distribution of rhizosphere carbon belowground. METHODS Three 22-year-old Sitka spruce trees were injected with 6.66 g of (13)C-labeled aspartic acid. Over the succeeding 30 days, soil CO(2) efflux, phospholipid fatty-acid (PLFA) microbial biomarkers and soil invertebrates (mites, collembolans and enchytraeids) were analyzed along a 50 m transect from each tree to determine the temporal and spatial patterns in the translocation of recently fixed photosynthates belowground. RESULTS Soil δ(13)CO(2) values peaked 13-23 days after injection, up to 5 m from the base of the injected tree and was, on average, 3.5‰ enriched in (13)C relative to the baseline. Fungal PLFA biomarkers peaked 2-4 days after stem-injection, up to 20 m from the base of the injected tree and were (13)C-enriched by up to 50‰. Significant (13)C enrichment in mites and enchytraeids occurred 4-6 days after injection (by, on average, 1.5‰). CONCLUSIONS Stem injection of large trees with (13)C-enriched compounds is a successful tool to trace C-translocation belowground. In particular, the significant (13)C enrichment of CO(2) and enchytraeids near the base of the tree and the significant (13)C enrichment of PLFAs up to 20 m away indicate that mature Sitka spruce (Picea sitchensis) have the capacity to support soil communities over large distances.
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Affiliation(s)
- Carolyn Churchland
- Belowground Ecosystem Group, Department of Forest Sciences, University of British Columbia, Vancouver, B.C., Canada.
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Keel SG, Campbell CD, Högberg MN, Richter A, Wild B, Zhou X, Hurry V, Linder S, Näsholm T, Högberg P. Allocation of carbon to fine root compounds and their residence times in a boreal forest depend on root size class and season. THE NEW PHYTOLOGIST 2012; 194:972-981. [PMID: 22452424 DOI: 10.1111/j.1469-8137.2012.04120.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fine roots play a key role in the forest carbon balance, but their carbon dynamics remain largely unknown. We pulse labelled 50 m(2) patches of young boreal forest by exposure to (13)CO(2) in early and late summer. Labelled photosynthates were traced into carbon compounds of < 1 and 1-3 mm diameter roots (fine roots), and into bulk tissue of these and first-order roots (root tips). Root tips were the most strongly labelled size class. Carbon allocation to all size classes was higher in late than in early summer; mean residence times (MRTs) in starch increased from 4 to 11 months. In structural compounds, MRTs were 0.8 yr in tips and 1.8 yr in fine roots. The MRT of carbon in sugars was in the range of days. Functional differences within the fine root population were indicated by carbon allocation patterns and residence times. Pronounced allocation of recent carbon and higher turnover rates in tips are associated with their role in nutrient and water acquisition. In fine roots, longer MRTs but high allocation to sugars and starch reflect their role in structural support and storage. Accounting for heterogeneity in carbon residence times will improve and most probably reduce the estimates of fine root production.
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Affiliation(s)
- Sonja G Keel
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
- Present address: Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Catherine D Campbell
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Mona N Högberg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
| | - Andreas Richter
- Department of Terrestrial Ecosystem Research, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, AT-1090 Vienna, Austria
| | - Birgit Wild
- Department of Terrestrial Ecosystem Research, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, AT-1090 Vienna, Austria
| | - Xuhui Zhou
- Research Institute for the Changing Global Environment, Fudan University, Shanghai 200433 China
- Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA
| | - Vaughan Hurry
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Sune Linder
- Southern Swedish Forest Research Centre, SLU, PO Box 49, SE-230 53 Alnarp, Sweden
| | - Torgny Näsholm
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
| | - Peter Högberg
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), SE-901 83 Umeå, Sweden
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Epron D, Bahn M, Derrien D, Lattanzi FA, Pumpanen J, Gessler A, Högberg P, Maillard P, Dannoura M, Gérant D, Buchmann N. Pulse-labelling trees to study carbon allocation dynamics: a review of methods, current knowledge and future prospects. TREE PHYSIOLOGY 2012; 32:776-98. [PMID: 22700544 DOI: 10.1093/treephys/tps057] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pulse-labelling of trees with stable or radioactive carbon (C) isotopes offers the unique opportunity to trace the fate of labelled CO(2) into the tree and its release to the soil and the atmosphere. Thus, pulse-labelling enables the quantification of C partitioning in forests and the assessment of the role of partitioning in tree growth, resource acquisition and C sequestration. However, this is associated with challenges as regards the choice of a tracer, the methods of tracing labelled C in tree and soil compartments and the quantitative analysis of C dynamics. Based on data from 47 studies, the rate of transfer differs between broadleaved and coniferous species and decreases as temperature and soil water content decrease. Labelled C is rapidly transferred belowground-within a few days or less-and this transfer is slowed down by drought. Half-lives of labelled C in phloem sap (transfer pool) and in mature leaves (source organs) are short, while those of sink organs (growing tissues, seasonal storage) are longer. (13)C measurements in respiratory efflux at high temporal resolution provide the best estimate of the mean residence times of C in respiratory substrate pools, and the best basis for compartmental modelling. Seasonal C dynamics and allocation patterns indicate that sink strength variations are important drivers for C fluxes. We propose a conceptual model for temperate and boreal trees, which considers the use of recently assimilated C versus stored C. We recommend best practices for designing and analysing pulse-labelling experiments, and identify several topics which we consider of prime importance for future research on C allocation in trees: (i) whole-tree C source-sink relations, (ii) C allocation to secondary metabolism, (iii) responses to environmental change, (iv) effects of seasonality versus phenology in and across biomes, and (v) carbon-nitrogen interactions. Substantial progress is expected from emerging technologies, but the largest challenge remains to carry out in situ whole-tree labelling experiments on mature trees to improve our understanding of the environmental and physiological controls on C allocation.
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Affiliation(s)
- Daniel Epron
- Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre-les-Nancy, France.
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