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Bozonnet C, Saudreau M, Badel E, Charrier G, Améglio T. On the mechanism for winter stem pressure build-up in walnut trees. TREE PHYSIOLOGY 2024; 44:tpae037. [PMID: 38531772 DOI: 10.1093/treephys/tpae037] [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: 01/04/2024] [Revised: 03/04/2024] [Accepted: 03/19/2024] [Indexed: 03/28/2024]
Abstract
Xylem embolism is a significant factor in tree mortality. Restoration of hydraulic conductivity after massive embolization of the vascular system requires the application of positive pressure to the vessels and/or the creation of new conductive elements. Some species generate positive pressure from the root system to propagate pressure in distal, aboveground organs in spring, whereas other species generate positive pressure locally at the stem level during winter. We provide a mechanistic explanation for winter stem pressure build-up in the walnut tree. We have developed a physical model that accounts for temperature fluctuations and phase transitions. This model is based on the exchange of water and sugars between living cells and vessels. Our computations demonstrate that vessel pressurization can be attributed to the transfer of water between vessels across the parenchyma rays, which is facilitated by a radial imbalance in sugar concentration. The ability to dispose of soluble sugars in living cells, and to transport them between living cells and up to the vessels, is identified as the main drivers of stem pressure build-up in the walnut tree.
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Affiliation(s)
- Cyril Bozonnet
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Marc Saudreau
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Eric Badel
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Guillaume Charrier
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
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Bozonnet C, Saudreau M, Badel E, Améglio T, Charrier G. Freeze dehydration vs supercooling in tree stems: physical and physiological modelling. TREE PHYSIOLOGY 2024; 44:tpad117. [PMID: 37738582 DOI: 10.1093/treephys/tpad117] [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: 06/28/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023]
Abstract
Frost resistance is the major factor affecting the distribution of plant species at high latitude and elevation. The main effects of freeze-thaw cycles are damage to living cells and formation of gas embolism in tree xylem vessels. Lethal intracellular freezing can be prevented in living cells by two mechanisms, such as dehydration and deep supercooling. We developed a multiphysics numerical model coupling water flow, heat transfer and phase change, considering different cell types in plant tissues, to study the dynamics and extent of cell dehydration, xylem pressure changes and stem diameter changes in response to freezing and thawing. Results were validated using experimental data for stem diameter changes of walnut trees (Juglans regia). The effect of cell mechanical properties was found to be negligible as long as the intracellular tension developed during dehydration was sufficiently low compared with the ice-induced cryostatic suction. The model was finally used to explore the coupled effects of relevant physiological parameters (initial water and sugar content) and environmental conditions (air temperature variations) on the dynamics and extent of dehydration. It revealed configurations where cell dehydration could be sufficient to protect cells from intracellular freezing, and situations where supercooling was necessary. This model, freely available with this paper, could easily be extended to explore different anatomical structures, different species and more complex physical processes.
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Affiliation(s)
- Cyril Bozonnet
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Marc Saudreau
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Eric Badel
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Guillaume Charrier
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
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Driller T, Robinson JA, Clearwater M, Holland DJ, van den Berg A, Watson M. Quantitative examination of the anatomy of the juvenile sugar maple xylem. PLoS One 2023; 18:e0292526. [PMID: 37819934 PMCID: PMC10566711 DOI: 10.1371/journal.pone.0292526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 09/22/2023] [Indexed: 10/13/2023] Open
Abstract
New methodologies have enabled viable sap yields from juvenile sugar maple trees. To further improve yields, a better understanding of sap exudation is required. To achieve this, the anatomy of the xylem must first be fully characterised. We examine juvenile maple saplings using light optical microscopy (LOM) and scanning electron microscopy (SEM), looking at sections cut along differing orientations as well as macerations. From this we measure various cell parameters. We find diameter and length of vessel elements to be 28 ± 8 μm and 200 ± 50 μm, for fibre cells 8 ± 3 μm and 400 ± 100 μm, and for ray parenchyma cells 8 ± 2 μm and 50 ± 20 μm. We also examine pitting present on different cell types. On vessel elements we observe elliptical bordered pits connecting to other vessel elements (with major axis of 2.1 ± 0.7 μm and minor 1.3 ± 0.3 μm) and pits connecting to ray parenchyma (with major axis of 4 ± 2 μm and minor 2.0 ± 0.7 μm). We observe two distinct pit sizes on fibres with circular pits 0.7 ± 0.2 μm in diameter and ellipsoidal pits 1.6 ± 0.4 μm by 1.0 ± 0.3 μm. We do not observe distinct pitting patterns on different fibre types. The various cell and pit measurements obtained generally agree with the limited data available for mature trees, with the exception of vessel element and fibre length, both of which were significantly smaller than reported values.
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Affiliation(s)
- Tenaya Driller
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - James A. Robinson
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Mike Clearwater
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Daniel J. Holland
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Abby van den Berg
- Proctor Maple Research Center, University of Vermont, Underhill, Vermont, United States of America
| | - Matthew Watson
- Biomolecular Interaction Centre & Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
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Velander TB, Joyce MJ, Kujawa AM, Sanders RL, Keenlance PW, Moen RA. A dynamic thermal model for predicting internal temperature of tree cavities and nest boxes. Ecol Modell 2023. [DOI: 10.1016/j.ecolmodel.2023.110302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Robinson JA, Rennie M, Clearwater M, Holland DJ, van den Berg AK, Watson M. Examination of embolisms in maple and birch saplings utilising microCT. Micron 2023; 168:103438. [PMID: 36889230 DOI: 10.1016/j.micron.2023.103438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
We demonstrate the application of synchrotron x-ray microtomography (microCT) to non-invasively examine the internal structure of a maple and birch sapling. We show that, through the use of standard image analysis techniques, embolised vessels can be extracted from reconstructed slices of the stem. By combining these thresholded images with connectivity analysis, we map out the embolisms within the sapling in three dimensions and evaluate the size distribution, showing that large embolisms over 0.005 mm3 in volume compose the majority of the saplings' total embolised volume. Finally we evaluate the radial distribution of embolisms, showing that in maple fewer embolisms are present towards the cambium, while birch has a more uniform distribution.
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Affiliation(s)
- James A Robinson
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand.
| | - Matt Rennie
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
| | - Mike Clearwater
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Daniel J Holland
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
| | - Abby K van den Berg
- Proctor Maple Research Center, University of Vermont, Underhill, VT, United States
| | - Matthew Watson
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
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Kurokawa SYS, Weiss G, Lapointe D, Delagrange S, Rossi S. Daily timings of sap production in sugar maple in Quebec, Canada. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023; 67:211-218. [PMID: 36318316 DOI: 10.1007/s00484-022-02399-8] [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: 05/23/2022] [Revised: 10/13/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
Global warming is affecting plant phenology, with potential consequences on the dynamics of growth reactivation of sugar maple and the timings of maple syrup production. In this study, we assess the temperatures inducing the daily reactivation or cessation of sap production. We selected 19 sugarbushes across Quebec, Canada, using a tapping method associated with the tubing system, we recorded the daily timings of onset and ending of sap production during winter and spring 2018, and we associated the hourly temperatures at each site. Sap production occurred from mid-February to the end of April, starting on average between 10 and 11 AM, and ending from 6 to 8 PM. We observed a seasonal pattern in the onset and ending of sap production during spring, with the onset showing a greater change than the ending. Onset and ending of sap production occurred mostly under temperatures ranging between -2 and 2 °C. The production of sap in maple is closely related to circadian freeze-thaw cycles and occurs under nighttime and daytime temperatures fluctuating below and above 0 °C. The daily lengthening of the duration of sap production mirrors the changes in the timings of freeze and thaw events and can be explained by the physical properties of the water and the physiological processes occurring during growth reactivation. The ongoing warming will result in earlier and warmer springs, which may anticipate the cycles of freeze and thaw and advance sap production in sugar maple.
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Affiliation(s)
- Sara Yumi Sassamoto Kurokawa
- Laboratoire sur les écosystèmes terrestres boréaux (EcoTer), Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, G7H 2B1, Canada.
| | - Gabriel Weiss
- Ministère de L'Agriculture, des Pêcheries et de L'Alimentation, Direction Régionale de L'Estrie, Lac-Mégantic, QC, G6B 1H6, Canada
| | - David Lapointe
- Ministère de L'Agriculture, des Pêcheries et de L'Alimentation, Direction Régionale du Centre-du-Québec, Québec, QC, Canada
| | - Sylvain Delagrange
- Department of Natural Sciences, Université du Québec en Outaouais (UQO), 58 Main Street, Ripon, QC, J0V 1W0, Canada
| | - Sergio Rossi
- Laboratoire sur les écosystèmes terrestres boréaux (EcoTer), Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC, G7H 2B1, Canada
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Schenk HJ, Jansen S, Hölttä T. Positive pressure in xylem and its role in hydraulic function. THE NEW PHYTOLOGIST 2021; 230:27-45. [PMID: 33206999 DOI: 10.1111/nph.17085] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 10/13/2020] [Indexed: 05/29/2023]
Abstract
Although transpiration-driven transport of xylem sap is well known to operate under absolute negative pressure, many terrestrial, vascular plants show positive xylem pressure above atmospheric pressure on a seasonal or daily basis, or during early developmental stages. The actual location and mechanisms behind positive xylem pressure remain largely unknown, both in plants that show seasonal xylem pressure before leaf flushing, and those that show a diurnal periodicity of bleeding and guttation. Available evidence shows that positive xylem pressure can be driven based on purely physical forces, osmotic exudation into xylem conduits, or hydraulic pressure in parenchyma cells associated with conduits. The latter two mechanisms may not be mutually exclusive and can be understood based on a similar modelling scenario. Given the renewed interest in positive xylem pressure, this review aims to provide a constructive way forward by discussing similarities and differences of mechanistic models, evaluating available evidence for hydraulic functions, such as rehydration of tissues, refilling of water stores, and embolism repair under positive pressure, and providing recommendations for future research, including methods that avoid or minimise cutting artefacts.
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, PO Box 6850, Fullerton, CA, 92834, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
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