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Pérez-de-Lis G, Richard B, Quilès F, Deveau A, Adikurnia IK, Rathgeber CBK. Multimodal imaging analysis in silver fir reveals coordination in cellulose and lignin deposition. PLANT PHYSIOLOGY 2024; 195:2428-2442. [PMID: 38590143 PMCID: PMC11213250 DOI: 10.1093/plphys/kiae203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/18/2024] [Accepted: 03/18/2024] [Indexed: 04/10/2024]
Abstract
Despite lignin being a key component of wood, the dynamics of tracheid lignification are generally overlooked in xylogenesis studies, which hampers our understanding of environmental drivers and blurs the interpretation of isotopic and anatomical signals stored in tree rings. Here, we analyzed cell wall formation in silver fir (Abies alba Mill.) tracheids to determine if cell wall lignification lags behind secondary wall deposition. For this purpose, we applied a multimodal imaging approach combining transmitted light microscopy (TLM), confocal laser scanning microscopy (CLSM), and confocal Raman microspectroscopy (RMS) on anatomical sections of wood microcores collected in northeast France on 11 dates during the 2010 growing season. Wood autofluorescence after laser excitation at 405 and 488 nm associated with the RMS scattering of lignin and cellulose, respectively, which allowed identification of lignifying cells (cells showing lignified and nonlignified wall fractions at the same time) in CLSM images. The number of lignifying cells in CLSM images mirrored the number of wall-thickening birefringent cells in polarized TLM images, revealing highly synchronized kinetics for wall thickening and lignification (similar timings and durations at the cell level). CLSM images and RMS chemical maps revealed a substantial incorporation of lignin into the wall at early stages of secondary wall deposition. Our results show that most of the cellulose and lignin contained in the cell wall undergo concurrent periods of deposition. This suggests a strong synchronization between cellulose and lignin-related features in conifer tree-ring records, as they originated over highly overlapped time frames.
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Affiliation(s)
- Gonzalo Pérez-de-Lis
- BIOAPLIC, Departamento de Botánica, Universidade de Santiago de Compostela, EPSE, Campus Terra, 27002 Lugo, Spain
- Université de Lorraine, AgroParisTech, INRAE, SILVA, F-54000 Nancy, France
| | - Béatrice Richard
- Université de Lorraine, AgroParisTech, INRAE, SILVA, F-54000 Nancy, France
| | | | - Aurélie Deveau
- Université de Lorraine, INRAE, IAM, F-54000 Nancy, France
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García-Hidalgo M, García-Pedrero Á, Rozas V, Sangüesa-Barreda G, García-Cervigón AI, Resente G, Wilmking M, Olano JM. Tree ring segmentation using UNEt TRansformer neural network on stained microsections for quantitative wood anatomy. FRONTIERS IN PLANT SCIENCE 2024; 14:1327163. [PMID: 38259935 PMCID: PMC10800830 DOI: 10.3389/fpls.2023.1327163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/14/2023] [Indexed: 01/24/2024]
Abstract
Forests are critical in the terrestrial carbon cycle, and the knowledge of their response to ongoing climate change will be crucial for determining future carbon fluxes and climate trajectories. In areas with contrasting seasons, trees form discrete annual rings that can be assigned to calendar years, allowing to extract valuable information about how trees respond to the environment. The anatomical structure of wood provides highly-resolved information about the reaction and adaptation of trees to climate. Quantitative wood anatomy helps to retrieve this information by measuring wood at the cellular level using high-resolution images of wood micro-sections. However, whereas large advances have been made in identifying cellular structures, obtaining meaningful cellular information is still hampered by the correct annual tree ring delimitation on the images. This is a time-consuming task that requires experienced operators to manually delimit ring boundaries. Classic methods of automatic segmentation based on pixel values are being replaced by new approaches using neural networks which are capable of distinguishing structures, even when demarcations require a high level of expertise. Although neural networks have been used for tree ring segmentation on macroscopic images of wood, the complexity of cell patterns in stained microsections of broadleaved species requires adaptive models to accurately accomplish this task. We present an automatic tree ring boundary delineation using neural networks on stained cross-sectional microsection images from beech cores. We trained a UNETR, a combined neural network of UNET and the attention mechanisms of Visual Transformers, to automatically segment annual ring boundaries. Its accuracy was evaluated considering discrepancies with manual segmentation and the consequences of disparity for the goals of quantitative wood anatomy analyses. In most cases (91.8%), automatic segmentation matched or improved manual segmentation, and the rate of vessels assignment to annual rings was similar between the two categories, even when manual segmentation was considered better. The application of convolutional neural networks-based models outperforms human operator segmentations when confronting ring boundary delimitation using specific parameters for quantitative wood anatomy analysis. Current advances on segmentation models may reduce the cost of massive and accurate data collection for quantitative wood anatomy.
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Affiliation(s)
| | - Ángel García-Pedrero
- Department of Computer Architecture and Technology, Universidad Politécnica de Madrid, Madrid, Spain
- Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain
| | - Vicente Rozas
- iuFOR, EiFAB, Universidad de Valladolid, Soria, Spain
| | | | | | - Giulia Resente
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
- Department DISAFA, University of Torino, Torino, Italy
| | - Martin Wilmking
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
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Unterholzner L, Castagneri D, Cerrato R, Știrbu MI, Roibu CC, Carrer M. Climate response of a glacial relict conifer across its distribution range is invariant in space but not in time. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167512. [PMID: 37813259 DOI: 10.1016/j.scitotenv.2023.167512] [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: 07/25/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/11/2023]
Abstract
Climate change impacts on forest trees will be particularly severe for relict species endemic to the subalpine forest, such as Pinus cembra in the Alps and Carpathians. Most current knowledge about the response of this species to climate comes from tree-ring width analysis. However, this approach cannot perform in-depth and highly time-resolved analysis on the climate influence on specific growth processes and xylem functions. We analyzed xylem anatomical traits from six sites covering most of the longitudinal range of this species. Associations between climate and cell number, lumen area and cell wall thickness were computed for the 1920-2010 period using climate records aligned to degree-day temperature sum thresholds. The anatomical chronologies were clearly distinct between the Alps and Carpathians. However, climate responses were similar for all sites, suggesting common species-specific response mechanisms. Temperature showed a positive correlation with both cell number and cell wall thickness. Cell lumen size exhibited an early positive association, followed by strong negative association with temperature and a positive one with precipitation. This highlights that the cell enlargement process was negatively related to high temperature at high elevation, where meristematic processes are rather supposed to be constrained by low temperatures. Therefore, long-term climate warming can have negative consequences on the xylem potential to transport water at all investigated sites. Moreover, in the last 30 years, we observed a slight anticipation of some responses and a decrease in climate sensitivity of some xylem parameters. Our findings provide evidence of temporally unstable but spatially consistent climate response of Pinus cembra from the Alps to the Carpathians. The low diversity in xylem phenotypic responses to climate suggests that future warming could extensively and evenly affect the species throughout its entire distribution.
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Affiliation(s)
- Lucrezia Unterholzner
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, via dell'Università 16, 35020 Legnaro, Italy; Chair of Forest Growth and Woody Biomass Production, Technische Universität Dresden, Pienner Straße 8, 01737 Tharandt, Germany
| | - Daniele Castagneri
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, via dell'Università 16, 35020 Legnaro, Italy.
| | - Riccardo Cerrato
- Department of Earth Sciences (DST), University of Pisa, via S. Maria 53, 56124 Pisa, Italy
| | - Marian-Ionuț Știrbu
- Forest Biometrics Laboratory, Faculty of Forestry, "Ștefan cel Mare" University of Suceava, Universității street, no. 13, 720229 Suceava, Romania
| | - Cătălin-Constantin Roibu
- Forest Biometrics Laboratory, Faculty of Forestry, "Ștefan cel Mare" University of Suceava, Universității street, no. 13, 720229 Suceava, Romania
| | - Marco Carrer
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, via dell'Università 16, 35020 Legnaro, Italy
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Martínez-Sancho E, Cernusak LA, Fonti P, Gregori A, Ullrich B, Pannatier EG, Gessler A, Lehmann MM, Saurer M, Treydte K. Unenriched xylem water contribution during cellulose synthesis influenced by atmospheric demand governs the intra-annual tree-ring δ 18 O signature. THE NEW PHYTOLOGIST 2023; 240:1743-1757. [PMID: 37753542 DOI: 10.1111/nph.19278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023]
Abstract
The oxygen isotope composition (δ18 O) of tree-ring cellulose is used to evaluate tree physiological responses to climate, but their interpretation is still limited due to the complexity of the isotope fractionation pathways. We assessed the relative contribution of seasonal needle and xylem water δ18 O variations to the intra-annual tree-ring cellulose δ18 O signature of larch trees at two sites with contrasting soil water availability in the Swiss Alps. We combined biweekly δ18 O measurements of soil water, needle water, and twig xylem water with intra-annual δ18 O measurements of tree-ring cellulose, xylogenesis analysis, and mechanistic and structural equation modeling. Intra-annual cellulose δ18 O values resembled source water δ18 O mean levels better than needle water δ18 O. Large parts of the rings were formed under high proportional exchange with unenriched xylem water (pex ). Maximum pex values were achieved in August and imprinted on sections at 50-75% of the ring. High pex values were associated with periods of high atmospheric evaporative demand (VPD). While VPD governed needle water δ18 O variability, we estimated a limited Péclet effect at both sites. Due to a variable pex , source water has a strong influence over large parts of the intra-annual tree-ring cellulose δ18 O variations, potentially masking signals coming from needle-level processes.
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Affiliation(s)
- Elisabet Martínez-Sancho
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
- Department of Biological Evolution, Ecology and Environmental Sciences, University of Barcelona, Diagonal 643, Barcelona, 08028, Spain
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, QLD, 4878, Australia
| | - Patrick Fonti
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Alessandro Gregori
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Bastian Ullrich
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Elisabeth Graf Pannatier
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Arthur Gessler
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Marco M Lehmann
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Matthias Saurer
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
| | - Kerstin Treydte
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, 8903, Switzerland
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Saurer M, Sahlstedt E, Rinne-Garmston KT, Lehmann MM, Oettli M, Gessler A, Treydte K. Progress in high-resolution isotope-ratio analysis of tree rings using laser ablation. TREE PHYSIOLOGY 2023; 43:694-705. [PMID: 36519757 DOI: 10.1093/treephys/tpac141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/29/2022] [Accepted: 12/11/2022] [Indexed: 05/13/2023]
Abstract
Stable isotope ratio analysis of tree rings has been widely and successfully applied in recent decades for climatic and environmental reconstructions. These studies were mostly conducted at an annual resolution, considering one measurement per tree ring, often focusing on latewood. However, much more information could be retrieved with high-resolution intra-annual isotope studies, based on the fact that the wood cells and the corresponding organic matter are continuously laid down during the growing season. Such studies are still relatively rare, but have a unique potential for reconstructing seasonal climate variations or short-term changes in physiological plant properties, like water-use efficiency. The reason for this research gap is mostly technical, as on the one hand sub-annual, manual splitting of rings is very tedious, while on the other hand automated laser ablation for high-resolution analyses is not yet well established and available. Here, we give an update on the current status of laser ablation research for analysis of the carbon isotope ratio (δ13C) of wood, describe an easy-to-use laser ablation system, its operation and discuss practical issues related to tree core preparation, including cellulose extraction. The results show that routine analysis with up to 100 laser shot-derived δ13C-values daily and good precision and accuracy (ca. 0.1‰) comparable to conventional combustion in an elemental analyzer are possible. Measurements on resin-extracted wood is recommended as most efficient, but laser ablation is also possible on cellulose extracted wood pieces. Considering the straightforward sample preparation, the technique is therefore ripe for wide-spread application. With this work, we hope to stimulate future progress in the promising field of high-resolution environmental reconstruction using laser ablation.
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Affiliation(s)
- Matthias Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
| | - Elina Sahlstedt
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, Helsinki 00790, Finland
| | - Katja T Rinne-Garmston
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, Helsinki 00790, Finland
| | - Marco M Lehmann
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
| | - Manuela Oettli
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetstrasse 16, Zurich 8092, Switzerland
| | - Kerstin Treydte
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf 8903, Switzerland
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Schönbeck LC, Santiago LS. Time will tell: towards high-resolution temporal tree-ring isotope analyses. TREE PHYSIOLOGY 2022; 42:2401-2403. [PMID: 36222495 DOI: 10.1093/treephys/tpac121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Affiliation(s)
- Leonie C Schönbeck
- Department of Botany & Plant Sciences, 2150 Batchelor Hall, University of California, Riverside, CA 92521, USA
| | - Louis S Santiago
- Department of Botany & Plant Sciences, 2150 Batchelor Hall, University of California, Riverside, CA 92521, USA
- Smithsonian Tropical Research Institute, Balboa, Ancón, Panamá, Republic of Panamá
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Martínez‐Sancho E, Treydte K, Lehmann MM, Rigling A, Fonti P. Drought impacts on tree carbon sequestration and water use - evidence from intra-annual tree-ring characteristics. THE NEW PHYTOLOGIST 2022; 236:58-70. [PMID: 35576102 PMCID: PMC9542003 DOI: 10.1111/nph.18224] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/04/2022] [Indexed: 05/22/2023]
Abstract
The impact of climate extremes on forest ecosystems is poorly understood but important for predicting carbon and water cycle feedbacks to climate. Some knowledge gaps still remain regarding how drought-related adjustments in intra-annual tree-ring characteristics directly impact tree carbon and water use. In this study we quantified the impact of an extreme summer drought on the water-use efficiency and carbon sequestration of four mature Norway spruce trees. We used detailed observations of wood formation (xylogenesis) and intra-annual tree-ring properties (quantitative wood anatomy and stable carbon isotopes) combined with physiological water-stress monitoring. During 41 d of tree water deficit, we observed an enrichment in 13 C but a reduction in cell enlargement and wall-thickening processes, which impacted the anatomical characteristics. These adjustments diminished carbon sequestration by 67% despite an 11% increase in water-use efficiency during drought. However, with the resumption of a positive hydric state in the stem, we observed a fast recovery of cell formation rates based on the accumulated assimilates produced during drought. Our findings enhance our understanding of carbon and water fluxes between the atmosphere and forest ecosystems, providing observational evidence on the tree intra-annual carbon sequestration and water-use efficiency dynamics to improve future generations of vegetation models.
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Affiliation(s)
- Elisabet Martínez‐Sancho
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
| | - Kerstin Treydte
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
| | - Marco M. Lehmann
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
| | - Andreas Rigling
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsSwiss Federal Institute of Technology ETHUniversitaetsstrasse 168092ZurichSwitzerland
| | - Patrick Fonti
- Research Unit Forest DynamicsSwiss Federal Institute for Forest Snow and Landscape Research WSLZürcherstrasse 1118903BirmensdorfSwitzerland
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