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Nardini A, Cochard H, Mayr S. Talk is cheap: rediscovering sounds made by plants. TRENDS IN PLANT SCIENCE 2024; 29:662-667. [PMID: 38218649 DOI: 10.1016/j.tplants.2023.11.023] [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: 09/22/2023] [Revised: 11/21/2023] [Accepted: 11/30/2023] [Indexed: 01/15/2024]
Abstract
A recent study and related commentaries have raised new interest in the phenomenon of ultrasonic sound production by plants exposed to stress, especially drought. While recent technological advancements have allowed the demonstration that these sounds can propagate in the air surrounding plants, we remind readers here that research on sound production by plants is more than 100 years old. The mechanisms and patterns of sound emission from plants subjected to different stress factors are also reasonably understood, thanks to the pioneering work of John Milburn and others. By contrast, experimental evidence for a role of these sounds in plant-animal or plant-plant communication remains lacking and, at present, these ideas remain highly speculative.
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Affiliation(s)
- Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy.
| | - Hervé Cochard
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63000, France
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
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2
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Power CC, Normand S, von Arx G, Elberling B, Corcoran D, Krog AB, Bouvin NK, Treier UA, Westergaard-Nielsen A, Liu Y, Prendin AL. No effect of snow on shrub xylem traits: Insights from a snow-manipulation experiment on Disko Island, Greenland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:169896. [PMID: 38185160 DOI: 10.1016/j.scitotenv.2024.169896] [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: 09/21/2023] [Revised: 12/18/2023] [Accepted: 01/02/2024] [Indexed: 01/09/2024]
Abstract
Widespread shrubification across the Arctic has been generally attributed to increasing air temperatures, but responses vary across species and sites. Wood structures related to the plant hydraulic architecture may respond to local environmental conditions and potentially impact shrub growth, but these relationships remain understudied. Using methods of dendroanatomy, we analysed shrub ring width (RW) and xylem anatomical traits of 80 individuals of Salix glauca L. and Betula nana L. at a snow manipulation experiment in Western Greenland. We assessed how their responses differed between treatments (increased versus ambient snow depth) and soil moisture regimes (wet and dry). Despite an increase in snow depth due to snow fences (28-39 %), neither RW nor anatomical traits in either species showed significant responses to this increase. In contrast, irrespective of the snow treatment, the xylem specific hydraulic conductivity (Ks) and earlywood vessel size (LA95) for the study period were larger in S. glauca (p < 0.1, p < 0.01) and B. nana (p < 0.01, p < 0.001) at the wet than the dry site, while both species had larger vessel groups at the dry than the wet site (p < 0.01). RW of B. nana was higher at the wet site (p < 0.01), but no differences were observed for S. glauca. Additionally, B. nana Ks and LA95 showed different trends over the study period, with decreases observed at the dry site (p < 0.001), while for other responses no difference was observed. Our results indicate that, taking into account ontogenetic and allometric trends, hydraulic related xylem traits of both species, along with B. nana growth, were influenced by soil moisture. These findings suggest that soil moisture regime, but not snow cover, may determine xylem responses to future climate change and thus add to the heterogeneity of Arctic shrub dynamics, though more long-term species- and site- specific studies are needed.
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Affiliation(s)
- Candice C Power
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Denmark.
| | - Signe Normand
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Denmark; SustainScapes - Center for Sustainable Landscapes under Global Change, Aarhus University, Denmark
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Bo Elberling
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark; Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Derek Corcoran
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Denmark; SustainScapes - Center for Sustainable Landscapes under Global Change, Aarhus University, Denmark
| | - Amanda B Krog
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Denmark
| | | | - Urs Albert Treier
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Denmark; SustainScapes - Center for Sustainable Landscapes under Global Change, Aarhus University, Denmark
| | - Andreas Westergaard-Nielsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark; Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Yijing Liu
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Angela L Prendin
- Ecoinformatics and Biodiversity, Department of Biology, Aarhus University, Denmark; Department of Land Environment Agriculture and Forestry (TeSAF), University of Padova, Legnaro, Italy
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Charra-Vaskou K, Lintunen A, Améglio T, Badel E, Cochard H, Mayr S, Salmon Y, Suhonen H, van Rooij M, Charrier G. Xylem embolism and bubble formation during freezing suggest complex dynamics of pressure in Betula pendula stems. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5840-5853. [PMID: 37463327 DOI: 10.1093/jxb/erad275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
Freeze-thaw-induced embolism, a key limiting factor for perennial plants results from the formation of gas bubbles during freezing and their expansion during thawing. However, the ice volumetric increase generates local pressures, which can affect the formation of bubbles. To characterize local dynamics of pressure tension and the physical state of the sap during freeze-thaw cycles, we simultaneously used ultrasonic acoustic emission analysis and synchrotron-based high-resolution computed tomography on the diffuse-porous species Betula pendula. Visualization of individual air-filled vessels and the distribution of gas bubbles in frozen xylem were performed.. Ultrasonic emissions occurred after ice formation, together with bubble formation, whereas the development of embolism took place after thawing. The pictures of frozen tissues indicated that the positive pressure induced by the volumetric increase of ice can provoke inward flow from the cell wall toward the lumen of the vessels. We found no evidence that wider vessels within a tissue were more prone to embolism, although the occurrence of gas bubbles in larger conduits would make them prone to earlier embolism. These results highlight the need to monitor local pressure as well as ice and air distribution during xylem freezing to understand the mechanism leading to frost-induced embolism.
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Affiliation(s)
| | - Anna Lintunen
- Institute for Atmospheric and Earth System Research/ Physics, Faculty of Science, University of Helsinki, Finland
- Institute for Atmospheric and Earth System Research/ Forest Science, Faculty of Agriculture and Forestry, University of Helsinki, Finland
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Eric Badel
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Stefan Mayr
- Institute for Botany, University of Innsbruck, Austria
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/ Physics, Faculty of Science, University of Helsinki, Finland
- Institute for Atmospheric and Earth System Research/ Forest Science, Faculty of Agriculture and Forestry, University of Helsinki, Finland
| | | | - Mahaut van Rooij
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Guillaume Charrier
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
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Dai Y, Wang L, Wan X. Maintenance of xylem hydraulic function during winter in the woody bamboo Phyllostachys propinqua McClure. PeerJ 2023; 11:e15979. [PMID: 37719123 PMCID: PMC10504893 DOI: 10.7717/peerj.15979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 08/08/2023] [Indexed: 09/19/2023] Open
Abstract
Background Frost is a common environmental stress for temperate plants. Xylem embolism occurs in many overwintering plants due to freeze-thaw cycles, so coping with freeze-thaw-induced embolisms is essential for the survival of temperate plants. Methods This study was conducted on Phyllostachys propinqua McClure, a woody bamboo species that was grown under natural frost conditions to explore its responses to winter embolisms. From autumn to the following spring, the following measurements were recorded: predawn branch and leaf embolism, branch and leaf relative water content (RWC), root pressure and soil temperature, xylem sap osmotic potential, branch and leaf electrolyte leakage (EL), branch nonstructural carbohydrate (NSC) content and leaf net photosynthetic rate. Results P. propinqua had a mean vessel diameter of 68.95 ±1.27 µm but did not suffer severe winter embolism, peaking around 60% in winter (January), with a distinct reduction in March when root pressure returned. Leaves had a more severe winter embolism, up to 90%. Leaf RWC was much lower in winter, and leaf EL was significantly higher than branch EL in all seasons. Root pressure remained until November when soil temperature reached 9 °C, then appeared again in March when soil temperatures increased from -6 °C (January) to 11 °C. Xylem sap osmotic potential decreased from autumn to winter, reaching a minimum in March, and then increasing again. Soluble sugar (SS) concentration increased throughout the winter, peaked in March, and then decreased. Conclusions These results suggest that (1) there is a hydraulic segmentation between the stem and leaf, which could prevent stem water loss and further embolization in winter; (2) maintenance of root pressure in early winter played an important role in reducing the effect of freeze-thaw cycles on the winter embolism; (3) the physiological process that resulted in a decrease in xylem sap osmotic potential and tissue water content, and an accumulation of SS associated with cold acclimation also aided in reducing the extent of freeze-thaw-induced embolism. All these strategies could be helpful for the maintenance of xylem hydraulic function of this bamboo species during winter.
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Affiliation(s)
- Yongxin Dai
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
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Gao Y, Zhang Z, Wang S, Ma N, Wang Y. Transcriptome analysis reveals wax and phytohormone metabolism potentially involved in shooting shrivelling of apple branches overwinter. FUNCTIONAL PLANT BIOLOGY : FPB 2023; 50:540-558. [PMID: 37160284 DOI: 10.1071/fp22283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/27/2023] [Indexed: 05/11/2023]
Abstract
Shoot shrivelling severely threatens growth and development of deciduous trees in the northern hemisphere, and we observed that there was a significant difference in shoot shrivelling rate between different apple varieties in practice. In this study, we investigated the anatomical and physiological characteristics of branches from different germplasm resources combined with an analysis of the transcriptome. Transcriptomes of samples treated in the initial dormancy, deep dormancy and freeze-thaw periods were generated and characterised. In three different periods, 7233 differentially expressed genes (DEGs) were identified including 3538 upregulated genes and 3695 downregulated genes. DEGs related to plant hormone signal transduction, starch and sucrose metabolism, cutin, suberin and wax biosynthesis were significantly enriched. Physiological characterisation showed that dormancy overwinter can induce the accumulation of soluble sugar and starch, shoot shrivelling rate of 'Fuji' was 2.31times that of the 'Delicious'; and the critical water content of 'Delicious' was significantly higher than 'Fuji'. Phytohormone contents and proportions varied irregularly according to the overwintering phase among two varieties. Wax content, morphology and composition also exhibited difference. In conclusion, branch microstructure, phytohormone and wax metabolism all determined the overwintering performance of trees and phytohormones can regulate wax metabolism to ensure normal overwintering of trees.
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Affiliation(s)
- Yanlong Gao
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Zhongxing Zhang
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Shuangcheng Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Naiying Ma
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
| | - Yanxiu Wang
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China
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Carluccio G, Greco D, Sabella E, Vergine M, De Bellis L, Luvisi A. Xylem Embolism and Pathogens: Can the Vessel Anatomy of Woody Plants Contribute to X. fastidiosa Resistance? Pathogens 2023; 12:825. [PMID: 37375515 DOI: 10.3390/pathogens12060825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
The maintenance of an intact water column in the xylem lumen several meters above the ground is essential for woody plant viability. In fact, abiotic and biotic factors can lead to the formation of emboli in the xylem, interrupting sap flow and causing consequences on the health status of the plant. Anyway, the tendency of plants to develop emboli depends on the intrinsic features of the xylem, while the cyto-histological structure of the xylem plays a role in resistance to vascular pathogens, as in the case of the pathogenic bacterium Xylella fastidiosa. Analysis of the scientific literature suggests that on grapevine and olive, some xylem features can determine plant tolerance to vascular pathogens. However, the same trend was not reported in citrus, indicating that X. fastidiosa interactions with host plants differ by species. Unfortunately, studies in this area are still limited, with few explaining inter-cultivar insights. Thus, in a global context seriously threatened by X. fastidiosa, a deeper understanding of the relationship between the physical and mechanical characteristics of the xylem and resistance to stresses can be useful for selecting cultivars that may be more resistant to environmental changes, such as drought and vascular pathogens, as a way to preserve agricultural productions and ecosystems.
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Affiliation(s)
- Giambattista Carluccio
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Davide Greco
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Marzia Vergine
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
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7
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McCulloh KA, Augustine SP, Goke A, Jordan R, Krieg CP, O’Keefe K, Smith DD. At least it is a dry cold: the global distribution of freeze-thaw and drought stress and the traits that may impart poly-tolerance in conifers. TREE PHYSIOLOGY 2023; 43:1-15. [PMID: 36094836 PMCID: PMC9833871 DOI: 10.1093/treephys/tpac102] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/20/2022] [Accepted: 08/30/2022] [Indexed: 05/25/2023]
Abstract
Conifers inhabit some of the most challenging landscapes where multiple abiotic stressors (e.g., aridity, freezing temperatures) often co-occur. Physiological tolerance to multiple stressors ('poly-tolerance') is thought to be rare because exposure to one stress generally limits responses to another through functional trade-offs. However, the capacity to exhibit poly-tolerance may be greater when combined abiotic stressors have similar physiological impacts, such as the disruption of hydraulic function imposed by drought or freezing. Here, we reviewed empirical data in light of theoretical expectations for conifer adaptations to drought and freeze-thaw cycles with particular attention to hydraulic traits of the stem and leaf. Additionally, we examined the commonality and spatial distribution of poly-stress along indices of these combined stressors. We found that locations with the highest values of our poly-stress index (PSi) are characterized by moderate drought and moderate freeze-thaw, and most of the global conifer distribution occupies areas of moderate poly-stress. Among traits examined, we found diverse responses to the stressors. Turgor loss point did not correlate with freeze-thaw or drought stress individually, but did with the PSi, albeit inverse to what was hypothesized. Leaf mass per area was more strongly linked with drought stress than the poly-stress and not at all with freeze-thaw stress. In stems, the water potential causing 50% loss of hydraulic conductivity became more negative with increasing drought stress and poly-stress but did not correlate with freeze-thaw stress. For these traits, we identified a striking lack of coverage for substantial portions of species ranges, particularly at the upper boundaries of their respective PSis, demonstrating a critical gap in our understanding of trait prevalence and plasticity along these stress gradients. Future research should investigate traits that confer tolerance to both freeze-thaw and drought stress in a wide range of species across broad geographic scales.
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Affiliation(s)
| | - Steven P Augustine
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Alex Goke
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Rachel Jordan
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Christopher P Krieg
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Kimberly O’Keefe
- Department of Biological Sciences, Saint Edward’s University, Austin, TX 78704, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
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8
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Taneda H, Ogasa MY, Yazaki K, Funayama-Noguchi S, Miyazawa Y, Mayr S, Maruta E. Impact of freeze-thaw-induced pit aspiration on stem water transport in the subalpine conifer Abies veitchii. PLANT PHYSIOLOGY 2022; 190:1687-1698. [PMID: 35997583 PMCID: PMC9614463 DOI: 10.1093/plphys/kiac388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
During winter, subalpine conifers experience frequent freeze-thaw cycles in stem xylem that may cause embolism and pit aspiration due to increased water volume during the sap to ice transition. This study examined the occurrence and ecological impacts of a combination of freeze-thaw-induced pit aspiration and embolism triggered by natural and artificial stem freezing. In subalpine Veitch's fir (Abies veitchii) trees, the fraction of closed pits and embolized tracheids as well as conductivity losses were measured to examine pit aspiration and its effects. When trees incurred mild drought stress in February and early March, 70%-80% of stem conductivity was lost. Cryo-scanning electron microscopy indicated <20% embolized tracheids but ∼90% closed pits. Severe drought stress in late March caused 96% ± 1.2% (mean ± standard error) loss of stem conductivity, while the fraction of embolized tracheids increased to 64% ± 6.6%, and aspirated pit fraction decreased to 23% ± 5.6%. Experimental freeze-thaw cycles also increased pit aspiration from 7.1% ± 0.89% to 49% ± 10%, and the fraction of closed pits was positively correlated to the percent loss of stem hydraulic conductivity. The results indicated that freezing-induced pit aspiration is an important factor for stem xylem dysfunction under mild drought, and upon severe drought in winter; stem water transport is predominantly inhibited by xylem embolism.
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Affiliation(s)
- Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mayumi Y Ogasa
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto, Japan
| | - Kenichi Yazaki
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan
| | - Sachiko Funayama-Noguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | | | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Emiko Maruta
- Department of Biological Sciences, Faculty of Science, Kanagawa University, Yokohama, Japan
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9
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Maruta E, Yazaki K, Ogasa MY, Taneda H. Pit aspiration causes an apparent loss of xylem hydraulic conductivity in a subalpine fir (Abies mariesii Mast.) overwintering at the alpine timberline. TREE PHYSIOLOGY 2022; 42:1228-1238. [PMID: 34962267 DOI: 10.1093/treephys/tpab173] [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: 04/20/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Conifers growing at the alpine timberline are exposed to combinatorial stresses that induce embolism in xylem during winter. We collected branches of Abies mariesii Mast. at the timberline on Mt Norikura of central Japan to evaluate the seasonal changes in the loss of xylem hydraulic conductivity (percent loss of hydraulic conductivity; PLC). Concurrently, we evaluated the distribution of embolized tracheids in native samples via cryo-scanning electron microscopic (cryo-SEM) observation in comparison with the drought-induced embolism samples used for the vulnerability curve. The twigs collected in late winter showed 100 PLC at a water potential of ~-3 MPa, and air-filled tracheids were observed sporadically in the cryo-SEM images. The cryo-SEM images also showed that nearly all pits of the samples from the timberline were aspirated in the xylem with 100 PLC. Conversely, in drought-induced samples used for vulnerability analysis, lower frequency of aspirated pits was observed at similar water potentials and all tracheids in the earlywood of xylem with 100 PLC were filled with air. We hypothesized that pit aspiration is the primary cause of the pronounced winter xylem conductivity loss at the timberline when water potential is near, but still above, the drought-induced vulnerability threshold. Pit aspiration before water loss may be an adaptation to severe winter conditions at timberlines to prevent widespread xylem embolism. The possible causes of pit aspiration are discussed in relation to complex stresses under harsh winter conditions at timberlines.
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Affiliation(s)
- Emiko Maruta
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Kenichi Yazaki
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, 7 Hitsujigaoka, Toyohira, Sapporo, Hokkaido 062-8516, Japan
| | - Mayumi Y Ogasa
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama-choh, Fushimi-ku, Kyoto, Kyoto 612-0855, Japan
| | - Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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10
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Schreel JDM, Brodersen C, De Schryver T, Dierick M, Rubinstein A, Dewettinck K, Boone MN, Van Hoorebeke L, Steppe K. Foliar water uptake does not contribute to embolism repair in beech (Fagus sylvatica L.). ANNALS OF BOTANY 2022; 129:555-566. [PMID: 35141741 PMCID: PMC9007097 DOI: 10.1093/aob/mcac016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/02/2022] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS Foliar water uptake has recently been suggested as a possible mechanism for the restoration of hydraulically dysfunctional xylem vessels. In this paper we used a combination of ecophysiological measurements, X-ray microcomputed tomography and cryo-scanning electron microscopy during a drought treatment to fully evaluate this hypothesis. KEY RESULTS Based on an assessment of these methods in beech (Fagus sylvatica L.) seedlings we were able to (1) confirm an increase in the amount of hydraulically redistributed water absorbed by leaves when the soil water potential decreased, and (2) locate this redistributed water in hydraulically active vessels in the stem. However, (3) no embolism repair was observed irrespective of the organ under investigation (i.e. stem, petiole or leaf) or the intensity of drought. CONCLUSIONS Our data provide evidence for a hydraulic pathway from the leaf surface to the stem xylem following a water potential gradient, but this pathway exists only in functional vessels and does not play a role in embolism repair for beech.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, FL, USA
- For correspondence. E-mail
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, USA
| | - Thomas De Schryver
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Manuel Dierick
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | | | - Koen Dewettinck
- Food Structure & Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Matthieu N Boone
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Luc Van Hoorebeke
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
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11
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Ma J, Niklas KJ, Liu L, Fang Z, Li Y, Shi P. Tree Size Influences Leaf Shape but Does Not Affect the Proportional Relationship Between Leaf Area and the Product of Length and Width. FRONTIERS IN PLANT SCIENCE 2022; 13:850203. [PMID: 35755713 PMCID: PMC9221507 DOI: 10.3389/fpls.2022.850203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 05/23/2022] [Indexed: 05/12/2023]
Abstract
The Montgomery equation predicts leaf area as the product of leaf length and width multiplied by a correction factor. It has been demonstrated to apply to a variety of leaf shapes. However, it is unknown whether tree size (measured as the diameter at breast height) affects leaf shape and size, or whether such variations in leaf shape can invalidate the Montgomery equation in calculating leaf area. Here, we examined 60 individual trees of the alpine oak (Quercus pannosa) in two growth patterns (trees growing from seeds vs. growing from roots), with 30 individuals for each site. Between 100 and 110 leaves from each tree were used to measure leaf dry mass, leaf area, length, and width, and to calculate the ellipticalness index, ratio of area between the two sides of the lamina, and the lamina centroid ratio. We tested whether tree size affects leaf shape, size, and leaf dry mass per unit area, and tested whether the Montgomery equation is valid for calculating leaf area of the leaves from different tree sizes. The diameters at breast height of the trees ranged from 8.6 to 96.4 cm (tree height ranged from 3 to 32 m). The diameter at breast height significantly affected leaf shape, size, and leaf dry mass per unit area. Larger trees had larger and broader leaves with lower leaf dry mass per unit area, and the lamina centroid was closer to the leaf apex than the leaf base. However, the variation in leaf size and shape did not negate the validity of the Montgomery equation. Thus, regardless of tree size, the proportional relationship between leaf area and the product of leaf length and width can be used to calculate the area of the leaves.
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Affiliation(s)
- Jianzhong Ma
- Yunnan Academy of Forestry and Grassland, Kunming, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
| | - Karl J. Niklas
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
| | - Leyi Liu
- College of Landscape Architecture and Horticulture Science, Southwest Forestry University, Kunming, China
| | - Zhendong Fang
- Shangri-la Alpine Botanical Garden, Shangri-la, China
| | - Yirong Li
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
| | - Peijian Shi
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
- *Correspondence: Peijian Shi,
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12
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Lintunen A, Salmon Y, Hölttä T, Suhonen H. Inspection of gas bubbles in frozen Betula pendula xylem with micro‐CT: Conduit size, water status and bark permeability affect bubble characteristics. PHYSIOLOGIA PLANTARUM 2022. [PMCID: PMC9540547 DOI: 10.1111/ppl.13749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bubbles of gas trapped in the xylem during freezing are a major cause of damage for trees growing at high altitudes or latitudes, as the bubbles may cause embolism during thawing. Yet the factors controlling bubble formation upon freeze–thaw cycles remain poorly understood. Especially the size of the bubbles formed in the ice is crucial for winter embolism formation. We used high‐resolution X‐ray microtomography combined with freezing experiments to investigate the size and shape of 68,343 gas bubbles in frozen conduits in branches of Betula pendula. We also studied how conduit size, tree water status (−0.2 MPa vs. −0.6 MPa) and bark permeability to gases (decreased by Vaseline‐coating) affect the gas bubbles characteristics. High‐resolution X‐ray images allowed us to detect gas bubbles down to 1.0 μm in diameter and revealed that not only small spherical gas bubbles but also gaseous volumes of various shapes and sizes were found from the frozen xylem indicating that gas bubbles may have started to grow already during the freezing propagation. Most of the gas bubbles were found in fibers, but the rare gas bubbles found in the vessels were larger than those in the fibers. Bubble volume increased with conduit volume in both fibers and vessels, but conduit size alone could not explain gas bubble volume. Low water potential and restriction of gas escape from the branch seem to cause more, larger, and less spherical bubbles and thus increase the risk of embolism formation. These findings open new research avenues for further studies of winter embolism formation.
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Affiliation(s)
- Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, Faculty of ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Heikki Suhonen
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
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13
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Contribution of Xylem Anatomy to Tree-Ring Width of Two Larch Species in Permafrost and Non-Permafrost Zones of Siberia. FORESTS 2020. [DOI: 10.3390/f11121343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Plants exhibit morphological and anatomical adaptations to cope the environmental constraints of their habitat. How can mechanisms for adapting to contrasting environmental conditions change the patterns of tree rings formation? In this study, we explored differences in climatic conditions of permafrost and non-permafrost zones and assessed their influence on radial growth and wood traits of Larix gmelinii Rupr (Rupr) and Larix sibirica L., respectively. We quantified the contribution of xylem cell anatomy to the tree-ring width variability. Comparison of the anatomical tree-ring parameters over the period 1963–2011 was tested based on non-parametric Mann-Whitney U test. The generalized linear modeling shows the common dependence between TRW and the cell structure characteristics in contrasting environments, which can be defined as non-specific to external conditions. Thus, the relationship between the tree-ring width and the cell production in early- and latewood are assessed as linear, whereas the dependence between the radial cell size in early- and latewood and the tree-ring width becomes significantly non-linear for both habitats. Moreover, contribution of earlywood (EW) and latewood (LW) cells to the variation of TRW (in average 56.8% and 24.4% respectively) was significantly higher than the effect of cell diameters (3.3% (EW) and 17.4% (LW)) for the environments. The results show that different larch species from sites with diverging climatic conditions converge towards similar xylem cell structures and relationships between xylem production and cell traits. The work makes a link between climate and tree-ring structure, and promotes a better understanding the anatomical adaptation of larch species to local environment conditions.
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14
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Yang Y, Sun H, Körner C. Explaining the exceptional 4270 m high elevation limit of an evergreen oak in the south-eastern Himalayas. TREE PHYSIOLOGY 2020; 40:1327-1342. [PMID: 32483630 DOI: 10.1093/treephys/tpaa070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/02/2020] [Indexed: 05/26/2023]
Abstract
Unlike the well-understood alpine treeline, the upper range limits of tree taxa that do not reach the alpine treeline are largely unexplained. In this study, we explored the causes of the exceptionally high elevation (4270 m) occurrence of broad-leaved evergreen oaks (Quercus pannosa) in the south-eastern Himalayas. We assessed the course of freezing resistance of buds and leaves from winter to summer at the upper elevational limit of this oak species. Linked to leaf phenology, we analyzed freezing resistance and assessed minimum crown temperature for the past 65 years. We also examined potential carbon limitation at the range limit of this species. Last season buds and leaves operated at a safety margin of 5.5 and 11 K in mid-winter. Once fully dehardened early in July, last season foliage is damaged at -5.9 and new foliage at -4.6 °C. Bud break is timed for late June to early July when low temperature extremes historically were never below -3.0 °C. The monsoon regime ensures a long remaining season (149 days), thus compensating for the late onset of shoot growth. Compared with a site at 3450 m, specific leaf area is reduced, foliar non-structural carbohydrate concentrations are similar and the δ13C signal is higher, jointly suggesting that carbon limitation is unlikely at the range limit of this species. We also show that these oaks enter the growing season with fully intact (not embolized) xylem. We conclude that the interaction between phenology and freezing tolerance results in safe flushing, while still facilitating shoot maturation before winter. These factors jointly determine the upper range limit of this oak species. Our study illuminates an exceptional case of broad-leaved evergreen tree performance near the treeline, and by exploring a suite of traits, we can underpin the central role of flushing phenology in such a stressful environment.
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Affiliation(s)
- Yang Yang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Lanhei Road 132, Kunming, Yunnan 650204, PR China
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Lanhei Road 132, Kunming, Yunnan 650204, PR China
| | - Christian Körner
- Institute of Botany, University of Basel, Schönbeinstrasse 6, Basel 4056, Switzerland
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15
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Maruta E, Kubota M, Ikeda T. Effects of xylem embolism on the winter survival of Abies veitchii shoots in an upper subalpine region of central Japan. Sci Rep 2020; 10:6594. [PMID: 32313053 PMCID: PMC7171099 DOI: 10.1038/s41598-020-62651-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 03/11/2020] [Indexed: 11/09/2022] Open
Abstract
At high elevations, winter climatic conditions frequently cause excessive drought stress, which can induce embolism in conifer trees. We investigated the formation and repair of winter embolism in subalpine fir (Abies veitchii) growing near the timberline. We found a complete loss in xylem conductivity [100% percent loss of conductivity (PLC)] at the wind-exposed site (W+) and 40% PLC at the wind-protected site (W−). A PLC of 100% was far above the embolism rate expected from the drought-induced vulnerability analysis in the laboratory. At the W+ site, a PLC of 100% was maintained until May; this suddenly decreased to a negligible value in June, whereas the recovery at the W− site started in late winter and proceeded stepwise. The contrast between the two sites may have occurred because of the different underlying mechanisms of winter embolism. If most tracheids in the xylem of 100% PLC are air-filled, it will be difficult to refill quickly. However, embolism caused by pit aspiration could be restored rapidly, because aspirated pits isolate tracheids from each other and prevent the spread of cavitation. Although severe embolism may cause frost damage of needles, it may have a role in holding water within the stem.
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Affiliation(s)
- Emiko Maruta
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8520, Japan. .,Department of Biological Science, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan.
| | - Mitsumasa Kubota
- Department of Bioresource Science, Faculty of Agriculture, Shizuoka University, 836 Oya, Surugaku, Shizuoka, 422-8529, Japan.,Daitou Techuno Green Inc., 1-2-3 Haramachida, Machida, Tokyo, 194-0013, Japan
| | - Takefumi Ikeda
- Department of Forest Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamohangi-cho, Sakyo-ku, Kyoto, 606-8522, Japan
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16
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He P, Gleason SM, Wright IJ, Weng E, Liu H, Zhu S, Lu M, Luo Q, Li R, Wu G, Yan E, Song Y, Mi X, Hao G, Reich PB, Wang Y, Ellsworth DS, Ye Q. Growing-season temperature and precipitation are independent drivers of global variation in xylem hydraulic conductivity. GLOBAL CHANGE BIOLOGY 2020; 26:1833-1841. [PMID: 31749261 DOI: 10.1111/gcb.14929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Stem xylem-specific hydraulic conductivity (KS ) represents the potential for plant water transport normalized by xylem cross section, length, and driving force. Variation in KS has implications for plant transpiration and photosynthesis, growth and survival, and also the geographic distribution of species. Clarifying the global-scale patterns of KS and its major drivers is needed to achieve a better understanding of how plants adapt to different environmental conditions, particularly under climate change scenarios. Here, we compiled a xylem hydraulics dataset with 1,186 species-at-site combinations (975 woody species representing 146 families, from 199 sites worldwide), and investigated how KS varied with climatic variables, plant functional types, and biomes. Growing-season temperature and growing-season precipitation drove global variation in KS independently. Both the mean and the variation in KS were highest in the warm and wet tropical regions, and lower in cold and dry regions, such as tundra and desert biomes. Our results suggest that future warming and redistribution of seasonal precipitation may have a significant impact on species functional diversity, and is likely to be particularly important in regions becoming warmer or drier, such as high latitudes. This highlights an important role for KS in predicting shifts in community composition in the face of climate change.
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Affiliation(s)
- Pengcheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Sean M Gleason
- USDA-ARS Water Management and Systems Research Unit, Fort Collins, CO, USA
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ensheng Weng
- Center for Climate Systems Research, Columbia University, New York, NY, USA
| | - Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Mingzhen Lu
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Qi Luo
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Ronghua Li
- Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou, China
| | - Guilin Wu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Enrong Yan
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yanjun Song
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xiangcheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Guangyou Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Yingping Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- CSIRO Oceans and Atmosphere, Aspendale, Vic., Australia
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
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17
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Lintunen A, Losso A, Aalto J, Chan T, Hölttä T, Mayr S. Propagating ice front induces gas bursts and ultrasonic acoustic emissions from freezing xylem. TREE PHYSIOLOGY 2020; 40:170-182. [PMID: 31860711 DOI: 10.1093/treephys/tpz123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Ice formation and propagation in the xylem of plants is a complex process. During freezing of xylem sap, gases dissolved in liquid sap are forced out of the ice lattice due to their low solubility in ice, and supersaturation of xylem sap as well as low water potential (Ѱ) are induced at the ice-liquid interface. Supersaturation of gases near the ice front may lead to bubble formation and potentially to cavitation and/or to burst of gases driven out from the branch. In this study, we investigated the origin and dynamics of freezing-related gas bursts and ultrasonic acoustic emissions (AEs), which are suggested to indicate cavitation. Picea abies (L.) H. Karst. and Salix caprea L. branch segments were exposed to frost cycles in a temperature test chamber, and CO2 efflux (indicating gas bursts) and AEs were recorded. On freezing, two-thirds of the observed gas bursts originated from the xylem and only one-third from the bark. Simultaneously with gas bursts, AEs were detected. Branch Ѱ affected both gas bursts and AEs, with high gas burst in saturated and dry samples but relevant AEs only in the latter. Repeated frost cycles led to decreasing gas burst volumes and AE activity. Experiments revealed that the expanding ice front in freezing xylem was responsible for observed gas bursts and AEs, and that branch Ѱ influenced both processes. Results also indicated that gas bursts and cavitation are independently induced by ice formation, though both may be relevant for bubble dynamics during freezing.
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Affiliation(s)
- Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00014, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, Helsinki FI-00014, Finland
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestrasse 15, Innsbruck A-6020, Austria
| | - Juho Aalto
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00014, Finland
| | - Tommy Chan
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00014, Finland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, Helsinki FI-00014, Finland
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestrasse 15, Innsbruck A-6020, Austria
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18
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Dai Y, Wang L, Wan X. Frost fatigue and its spring recovery of xylem conduits in ring-porous, diffuse-porous, and coniferous species in situ. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 146:177-186. [PMID: 31756604 DOI: 10.1016/j.plaphy.2019.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Frost-induced embolism and frost fatigue are two major aspects of frost damage to xylem water transport in trees. In this study, three species of each ring-porous, diffuse-porous, and coniferous trees growing in situ were used to explore their differences in winter embolism and frost fatigue. Changes in predawn water potential, predawn native embolism, maximal specific conductivity (Kmax), and cavitation resistance (P50, xylem water potential at 50% loss of conductivity) of current-year branches were measured from autumn to spring. Maximum native embolism of late winter was near 100% for ring-porous species, approximately 80% for diffuse-porous species, and below 50% for conifers. In early spring, there was no significant reduction of native embolism until formation of new vessels in ring-porous trees, while diffuse-porous trees and conifers exhibited a reduction in native embolism before development of new xylem. There was a significant decrease in P50 of ring- and diffuse-porous species over winter; however, in May P50 was markedly reduced along with formation of new vessels. Kmax of ring- and diffuse-porous species significantly decreased from autumn to late winter. The results revealed that vulnerability to cavitation and frost fatigue was related to conduit diameter. The strategies for coping with winter embolism differed among the three wood types: in ring-porous species there was no active embolism refilling; in diffuse-porous species there was refilling associated with positive xylem pressure; and in conifers there was refilling without positive xylem pressure. New vessels could completely restore stem hydraulic conductivity but only partially restore xylem cavitation resistance in spring.
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Affiliation(s)
- Yongxin Dai
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, PR China; College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, PR China.
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19
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Ogasa MY, Yazaki K, Utsumi Y, Miki NH, Fukuda K. Short-time xylem tension relaxation prevents vessel refilling and alleviates cryo-fixation artifacts in diffuse-porous Carpinus tschonoskii and Cercidiphyllum japonicum. TREE PHYSIOLOGY 2019; 39:1685-1695. [PMID: 31222295 DOI: 10.1093/treephys/tpz072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/27/2019] [Accepted: 06/12/2019] [Indexed: 06/09/2023]
Abstract
Xylem tension relaxation is an important procedure that closely resembles the in vivo xylem water distribution when measuring conductivity or observing water distribution of plant tissue samples by cryo-scanning electron microscopy (cryo-SEM). Recent studies have shown that partial xylem embolism occurs when samples under tension are cut under water and that gas-filled vessels are refilled during tension relaxation. Furthermore, the frequency of gas-filled vessels has been reported to increase in samples without tension relaxation before cryo-fixation by liquid nitrogen, particularly in samples with significant tension. Here, we examined the effect of tension relaxation on these artifacts in Carpinus tschonoskii and Cercidiphyllum japonicum using magnetic resonance imaging. We observed that xylem embolism rarely occurs in bench-dried samples cut under water. In both species, a small portion of the xylem was refilled within ~1 h after tension relaxation. Cryo-SEM observations revealed that short-time (<1 h) xylem tension relaxation decreases the frequency of gas-filled vessels in samples frozen after xylem tension relaxation regardless of the water potential compared with that in samples frozen without rehydration in both species. Therefore, short-time tension relaxation is necessary to retain xylem water distribution during sample preparation against artifacts.
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Affiliation(s)
- Mayumi Y Ogasa
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Tsukuba, Japan
- Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama, Fushimi-ku, Kyoto, Kyoto, Japan
| | - Kenichi Yazaki
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Tsukuba, Japan
| | | | - Naoko H Miki
- Department of Environmental Ecology, Graduate School of Environmental and Life Science, Okayama University, 1-1-1 Tsushimanaka, Kita-ku, Okayama, Japan
| | - Kenji Fukuda
- Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- Department of Forest Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
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20
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Prendin AL, Mayr S, Beikircher B, von Arx G, Petit G. Xylem anatomical adjustments prioritize hydraulic efficiency over safety as Norway spruce trees grow taller. TREE PHYSIOLOGY 2018; 38:1088-1097. [PMID: 29920598 DOI: 10.1093/treephys/tpy065] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 05/16/2018] [Indexed: 05/23/2023]
Abstract
As a tree grows taller, the increase in gravitational pressure and path length resistance results in lower water potentials at a given flow rate and higher carbon construction costs to transport a given amount of water to the leaves. We investigated how hydraulic safety and efficiency are coordinated under the constraints of higher cavitation risks and higher carbon construction costs with increasing tree height. We combined measurements of xylem tracheid anatomical traits with the vulnerability to drought-induced embolism and hydraulic conductivity of the apical shoots of 2- to 37-m tall Picea abies trees growing at two sites in the Dolomites (Italian Eastern Alps). We found that the theoretical hydraulic conductivity of the apical shoots increased with tree height at both sites (P < 0.001) as a result of an increase in either total tracheid number or mean hydraulic diameter. The xylem water potential inducing 50% loss of apical conductance significantly increased from small (-4.45 ± 0.20 MPa) to tall trees (-3.65 ± 0.03 MPa) (P = 0.007). The more conductive xylem at the treetop of taller trees allows the full compensation for the height-related hydraulic constraints and minimizes the additional carbon costs of transporting water over a longer path length. The corresponding increase in vulnerability to cavitation shows that hydraulic efficiency is prioritized over safety during height growth.
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Affiliation(s)
- Angela Luisa Prendin
- Department TeSAF-Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, viale dell'Università 16, Legnaro (PD), Italy
| | - Stefan Mayr
- Institut für Botanik, Universität Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Barbara Beikircher
- Institut für Botanik, Universität Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, Switzerland
- Climatic Change and Climate Impacts, Institute for Environmental Sciences, 66 Boulevard Carl-Vogt, Geneva, Switzerland
| | - Giai Petit
- Department TeSAF-Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, viale dell'Università 16, Legnaro (PD), Italy
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21
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Lintunen A, Mayr S, Salmon Y, Cochard H, Hölttä T. Drivers of apoplastic freezing in gymnosperm and angiosperm branches. Ecol Evol 2018; 8:333-343. [PMID: 29321875 PMCID: PMC5756836 DOI: 10.1002/ece3.3665] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/11/2022] Open
Abstract
It is not well understood what determines the degree of supercooling of apoplastic sap in trees, although it determines the number and duration of annual freeze-thaw cycles in a given environment. We studied the linkage between apoplastic ice nucleation temperature, tree water status, and conduit size. We used branches of 10 gymnosperms and 16 angiosperms collected from an arboretum in Helsinki (Finland) in winter and spring. Branches with lower relative water content froze at lower temperatures, and branch water content was lower in winter than in spring. A bench drying experiment with Picea abies confirmed that decreasing branch water potential decreases apoplastic ice nucleation temperature. The studied angiosperms froze on average 2.0 and 1.8°C closer to zero Celsius than the studied gymnosperms during winter and spring, respectively. This was caused by higher relative water content in angiosperms; when branches were saturated with water, apoplastic ice nucleation temperature of gymnosperms increased to slightly higher temperature than that of angiosperms. Apoplastic ice nucleation temperature in sampled branches was positively correlated with xylem conduit diameter as shown before, but saturating the branches removed the correlation. Decrease in ice nucleation temperature decreased the duration of freezing, which could have an effect on winter embolism formation via the time available for gas escape during ice propagation. The apoplastic ice nucleation temperature varied not only between branches but also within a branch between consecutive freeze-thaw cycles demonstrating the stochastic nature of ice nucleation.
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Affiliation(s)
- Anna Lintunen
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Stefan Mayr
- Institute of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Yann Salmon
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Hervé Cochard
- University of Clermont‐AuvergneClermont‐FerrandFrance
| | - Teemu Hölttä
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
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22
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Beikircher B, Mayr S. Annual patterns of xylem embolism in high-yield apple cultivars. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:587-596. [PMID: 32480590 DOI: 10.1071/fp16048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 02/20/2017] [Indexed: 05/26/2023]
Abstract
Temperate angiosperm species show pronounced annual patterns in xylem embolism. In this study, we investigated whether high-yield cultivars of Malus domestica Borkh. growing under optimised soil water conditions follow similar patterns to wild-type plants, and evaluated crucial factors for the formation of winter embolism and the subsequent restoration of the hydraulic system in spring. In five different cultivars growing at three different sites, various hydraulic and microclimatic parameters were monitored over three successive years. In all cultivars on all sites and in all years, the percentage loss of hydraulic conductivity (PLC) increased in autumn with freeze-thaw events and accumulated over winter. Maximum values were reached in late winter and differed significantly among cultivars. In spring, the hydraulic system was restored and PLC remained negligible during summer. Embolism formation in autumn was significantly correlated with the occurrence of freeze-thaw events, whereas further conductivity losses over winter were related to winter desiccation and influenced by climatic and cultivar-specific parameters. Restoration of the hydraulic system in spring was strongly linked to a decrease in the starch content of wood and buds, and soil temperature. Despite high soil water availability, hydraulic recovery took several weeks and was not completed before bud break. Spring is thus a critical phase for temperate angiosperms, especially for high-yield cultivars with risky hydraulic strategies.
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Affiliation(s)
- Barbara Beikircher
- University of Innsbruck, Institute of Botany, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - Stefan Mayr
- University of Innsbruck, Institute of Botany, Sternwartestrasse 15, 6020 Innsbruck, Austria
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23
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Charrier G, Nolf M, Leitinger G, Charra-Vaskou K, Losso A, Tappeiner U, Améglio T, Mayr S. Monitoring of Freezing Dynamics in Trees: A Simple Phase Shift Causes Complexity. PLANT PHYSIOLOGY 2017; 173:2196-2207. [PMID: 28242655 PMCID: PMC5373037 DOI: 10.1104/pp.16.01815] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/20/2017] [Indexed: 05/10/2023]
Abstract
During winter, trees have to cope with harsh conditions, including extreme freeze-thaw stress. This study focused on ice nucleation and propagation, related water shifts and xylem cavitation, as well as cell damage and was based on in situ monitoring of xylem (thermocouples) and surface temperatures (infrared imaging), ultrasonic emissions, and dendrometer analysis. Field experiments during late winter on Picea abies growing at the alpine timberline revealed three distinct freezing patterns: (1) from the top of the tree toward the base, (2) from thin branches toward the main stem's top and base, and (3) from the base toward the top. Infrared imaging showed freezing within branches from their base toward distal parts. Such complex freezing causes dynamic and heterogenous patterns in water potential and probably in cavitation. This study highlights the interaction between environmental conditions upon freezing and thawing and demonstrates the enormous complexity of freezing processes in trees. Diameter shrinkage, which indicated water fluxes within the stem, and acoustic emission analysis, which indicated cavitation events near the ice front upon freezing, were both related to minimum temperature and, upon thawing, related to vapor pressure deficit and soil temperature. These complex patterns, emphasizing the common mechanisms between frost and drought stress, shed new light on winter tree physiology.
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Affiliation(s)
- Guillaume Charrier
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.);
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.);
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.);
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.);
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Markus Nolf
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Georg Leitinger
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Katline Charra-Vaskou
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Adriano Losso
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Ulrike Tappeiner
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Thierry Améglio
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Stefan Mayr
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
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24
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Sperling O, Secchi F, Godfrey J, Zwieniecki MA. Acclimation of Pistacia integerrima trees to frost in semi-arid environments depends on autumn's drought. PLANTA 2017; 245:671-679. [PMID: 27995314 DOI: 10.1007/s00425-016-2629-9] [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: 09/11/2016] [Accepted: 11/28/2016] [Indexed: 06/06/2023]
Abstract
Main conclusion Cold acclimation is revealed through induced stem respiration during pre-winter frost of native Pistacia integerrima trees in continental semi-arid environments. Semi-arid environments challenge vegetation by simultaneous abiotic stresses. In this study, we examine the combined effects of water stress and frost on the physiology of Pistacia integerrima stems. This species is native to semi-arid environments where drought and frost frequently co-occur. We quantified carbohydrates and proline in P. integerrima stems responding to frost and experiencing water potentials between -0.2 and -1.8 MPa. We report that dehydrated trees (i.e., Ψstem <=-1 MPa) had more soluble sugars and proline than the well-watered trees (-0.2 MPa). The dehydrated trees also froze at lower temperatures and were less damaged by freezing. Interestingly, we observed a significant increase in stem CO2 efflux at near-freezing temperatures that could be linked to frost protection. This novel finding challenges current paradigm of plant respiration-kinetics which predicts, according to Arrhenius equation, lower respiration rates during frost. Our results support the notion that drought and frost are analogous stresses that can independently activate corresponding physiological processes in trees and amplify protection. This inevitable stress response 'collaboration' may be the key to understanding how non-dormant perennial plants survive the highly variable weather patterns of early winters in semi-arid environments.
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Affiliation(s)
- Or Sperling
- Department of Plant Sciences, UC Davis, Davis, CA, 95616, USA.
| | - Francesca Secchi
- Department of Agricultural, Forest and Food Sciences (DISAFA), University of Torino, Largo Paolo Braccini 2, 10095, Grugliasco (TO), Italy
| | - Jessie Godfrey
- Department of Plant Sciences, UC Davis, Davis, CA, 95616, USA
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25
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Umebayashi T, Utsumi Y, Koga S, Murata I, Fukuda K. Differences in drought- and freeze-induced embolisms in deciduous ring-porous plant species in Japan. PLANTA 2016; 244:753-760. [PMID: 27376942 DOI: 10.1007/s00425-016-2564-9] [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: 04/28/2016] [Accepted: 06/22/2016] [Indexed: 06/06/2023]
Abstract
Deciduous ring-porous species in Japan shed all of their leaves under severe water stress before large vessels in earlywood are embolized, and embolization take place during winter. Water in deciduous ring-porous species is mainly conducted upward via large earlywood vessels of the current year. Water columns in large vessels are vulnerable to drought-induced and freeze stress-induced embolisms. Although a vulnerability curve can be created to estimate the hydraulic capacity of plants, it remains unclear why the loss of conductivity in potted plants of ring-porous species does not reach 100 % under severe drought stress. In this study, two deciduous ring-porous species in Japan (Kalopanax septemlobus and Toxicodendron trichocarpum) were used to explain the species-specific pattern in the water-conducting pathway of the stem. We monitored and visualized the spatial distribution of xylem embolisms in the stem of K. septemlobus saplings under drought stress and freeze stress using compact magnetic resonance imaging and cryo-scanning microscopy. In addition, we evaluated the water ascent in the stems of both species using a dye uptake method. Although embolisms of large vessels were observed under drought stress and in winter, all leaves were dropped to avoid fatal water loss after embolization of some large vessels. In contrast, all large vessels were embolized in winter. Larger-diameter vessels of latewood in T. trichocarpum tended to function in trees growing in the warm temperate zone. Thus, our results suggest that the unclear curve may be derived from a discrepancy between leaf water potential and actual water potential in the xylem under severe drought stress. The frequency of xylem embolisms in deciduous ring-porous species in Japan mainly depends on the number of freeze-thaw cycles.
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Affiliation(s)
- Toshihiro Umebayashi
- Laboratory of Evaluation of Natural Environment, Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
| | | | - Shinya Koga
- Kasuya Research Forest, Kyushu University, Sasaguri, Japan
| | - Ikue Murata
- Kasuya Research Forest, Kyushu University, Sasaguri, Japan
| | - Kenji Fukuda
- Laboratory of Evaluation of Natural Environment, Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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26
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Beikircher B, Mittmann C, Mayr S. Prolonged Soil Frost Affects Hydraulics and Phenology of Apple Trees. FRONTIERS IN PLANT SCIENCE 2016; 7:867. [PMID: 27379146 PMCID: PMC4913089 DOI: 10.3389/fpls.2016.00867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 06/02/2016] [Indexed: 05/24/2023]
Abstract
Restoration of an adequate water supply in spring is a prerequisite for survival of angiosperm trees in temperate regions. Trees must re-establish access to soil water and recover xylem functionality. We thus hypothesized that prolonged soil frost impairs recovery and affects hydraulics and phenology of Malus domestica var. 'Golden Delicious.' To test this hypothesis, over two consecutive winters the soil around some trees was insulated to prolong soil frosting, From mid-winter to early summer, the level of native embolism, the water and starch contents of wood, bark and buds were quantified at regular intervals and findings correlated with various phenological parameters, xylogenesis and fine root growth. The findings confirm that prolonged soil frost affects tree hydraulics and phenology but the severity of the effect depends on the climatic conditions. In both study years, percentage loss of hydraulic conductivity (PLC) decreased from about 70% at the end of winter to about 10% in May. Thereby, xylem refilling strongly coincided with a decrease of starch in wood and bark. Also treated trees were able to restore their hydraulic system by May but, in the warm spring of 2012, xylem refilling, the increases in water content and starch depolymerization were delayed. In contrast, in the cold spring of 2013 only small differences between control and treated trees were observed. Prolongation of soil frost also led to a delay in phenology, xylogenesis, and fine root growth. We conclude that reduced water uptake from frozen or cold soils impairs refilling and thus negatively impacts tree hydraulics and growth of apple trees in spring. Under unfavorable circumstances, this may cause severe winter damage or even dieback.
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27
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Charra-Vaskou K, Badel E, Charrier G, Ponomarenko A, Bonhomme M, Foucat L, Mayr S, Améglio T. Cavitation and water fluxes driven by ice water potential in Juglans regia during freeze-thaw cycles. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:739-50. [PMID: 26585223 PMCID: PMC4737071 DOI: 10.1093/jxb/erv486] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Freeze-thaw cycles induce major hydraulic changes due to liquid-to-ice transition within tree stems. The very low water potential at the ice-liquid interface is crucial as it may cause lysis of living cells as well as water fluxes and embolism in sap conduits, which impacts whole tree-water relations. We investigated water fluxes induced by ice formation during freeze-thaw cycles in Juglans regia L. stems using four non-invasive and complementary approaches: a microdendrometer, magnetic resonance imaging, X-ray microtomography, and ultrasonic acoustic emissions analysis. When the temperature dropped, ice nucleation occurred, probably in the cambium or pith areas, inducing high water potential gradients within the stem. The water was therefore redistributed within the stem toward the ice front. We could thus observe dehydration of the bark's living cells leading to drastic shrinkage of this tissue, as well as high tension within wood conduits reaching the cavitation threshold in sap vessels. Ultrasonic emissions, which were strictly emitted only during freezing, indicated cavitation events (i.e. bubble formation) following ice formation in the xylem sap. However, embolism formation (i.e. bubble expansion) in stems was observed only on thawing via X-ray microtomography for the first time on the same sample. Ultrasonic emissions were detected during freezing and were not directly related to embolism formation. These results provide new insights into the complex process and dynamics of water movements and ice formation during freeze-thaw cycles in tree stems.
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Affiliation(s)
- Katline Charra-Vaskou
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | - Eric Badel
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | - Guillaume Charrier
- Department of Botany, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Alexandre Ponomarenko
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | - Marc Bonhomme
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
| | | | - Stefan Mayr
- Department of Botany, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Thierry Améglio
- INRA, UMR PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Blaise Pascal University, UMR PIAF, F-63100 Clermont-Ferrand, France
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28
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Gleason SM, Westoby M, Jansen S, Choat B, Hacke UG, Pratt RB, Bhaskar R, Brodribb TJ, Bucci SJ, Cao KF, Cochard H, Delzon S, Domec JC, Fan ZX, Feild TS, Jacobsen AL, Johnson DM, Lens F, Maherali H, Martínez-Vilalta J, Mayr S, McCulloh KA, Mencuccini M, Mitchell PJ, Morris H, Nardini A, Pittermann J, Plavcová L, Schreiber SG, Sperry JS, Wright IJ, Zanne AE. Weak tradeoff between xylem safety and xylem-specific hydraulic efficiency across the world's woody plant species. THE NEW PHYTOLOGIST 2016; 209:123-36. [PMID: 26378984 DOI: 10.1111/nph.13646] [Citation(s) in RCA: 283] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/13/2015] [Indexed: 05/18/2023]
Abstract
The evolution of lignified xylem allowed for the efficient transport of water under tension, but also exposed the vascular network to the risk of gas emboli and the spread of gas between xylem conduits, thus impeding sap transport to the leaves. A well-known hypothesis proposes that the safety of xylem (its ability to resist embolism formation and spread) should trade off against xylem efficiency (its capacity to transport water). We tested this safety-efficiency hypothesis in branch xylem across 335 angiosperm and 89 gymnosperm species. Safety was considered at three levels: the xylem water potentials where 12%, 50% and 88% of maximal conductivity are lost. Although correlations between safety and efficiency were weak (r(2) < 0.086), no species had high efficiency and high safety, supporting the idea for a safety-efficiency tradeoff. However, many species had low efficiency and low safety. Species with low efficiency and low safety were weakly associated (r(2) < 0.02 in most cases) with higher wood density, lower leaf- to sapwood-area and shorter stature. There appears to be no persuasive explanation for the considerable number of species with both low efficiency and low safety. These species represent a real challenge for understanding the evolution of xylem.
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Affiliation(s)
- Sean M Gleason
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
- USDA-ARS, Water Management Research, 2150 Center Ave, Build D, Suite 320, Fort Collins, CO, 80526, USA
| | - Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3, Canada
| | - Robert B Pratt
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Radika Bhaskar
- Department of Biology, Haverford College, 370 Lancaster Avenue, Haverford, PA, 19041, USA
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Sandra J Bucci
- Grupo de Estudios Biofísicos y Eco-fisiológicos (GEBEF), Universidad Nacional de la Patagonia San Juan Bosco, 9000, Comodoro Rivadavia, Argentina
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, and College of Forestry, Guangxi University, Daxuedonglu 100, Nanning, Guangxi, 530004, China
| | - Hervé Cochard
- INRA, UMR547 PIAF, F-63100, Clermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, F-63000, Clermont-Ferrand, France
| | - Sylvain Delzon
- INRA, University of Bordeaux, UMR BIOGECO, F-33450, Talence, France
| | - Jean-Christophe Domec
- Bordeaux Sciences AGRO, UMR1391 ISPA INRA, 1 Cours du général de Gaulle, 33175, Gradignan Cedex, France
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Ze-Xin Fan
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Taylor S Feild
- School of Marine and Tropical Biology, James Cook University, Townsville, Qld, 4811, Australia
| | - Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, CA, 93311, USA
| | - Daniel M Johnson
- Department of Forest, Rangeland and Fire Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, PO Box 9517, 2300RA, Leiden, the Netherlands
| | - Hafiz Maherali
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G2W1, Canada
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, E-08193, Barcelona, Spain
- ICREA at CREAF, Cerdanyola del Vallès, E-08193, Barcelona, Spain
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestr. 15, 6020, Innsbruck, Austria
| | | | - Maurizio Mencuccini
- ICREA at CREAF, Cerdanyola del Vallès, E-08193, Barcelona, Spain
- School of GeoSciences, University of Edinburgh, Crew Building, West Mains Road, Edinburgh, EH9 3FF, UK
| | | | - Hugh Morris
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Andrea Nardini
- Dipartimento Scienze della Vita, Università Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
| | - Lenka Plavcová
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3, Canada
| | - Stefan G Schreiber
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3, Canada
| | - John S Sperry
- Department of Biology, University of Utah, 257S 1400E, Salt Lake City, UT, 84112, USA
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Amy E Zanne
- Department of Biological Sciences, George Washington University, Science and Engineering Hall, 800 22nd Street NW, Suite 6000, Washington, DC, 20052, USA
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Nolf M, Beikircher B, Rosner S, Nolf A, Mayr S. Xylem cavitation resistance can be estimated based on time-dependent rate of acoustic emissions. THE NEW PHYTOLOGIST 2015; 208:625-32. [PMID: 26010417 PMCID: PMC4744691 DOI: 10.1111/nph.13476] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 04/22/2015] [Indexed: 05/05/2023]
Abstract
Acoustic emission (AE) analysis allows nondestructive monitoring of embolism formation in plant xylem, but signal interpretation and agreement of acoustically measured hydraulic vulnerability with reference hydraulic techniques remain under debate. We compared the hydraulic vulnerability of 16 species and three crop tree cultivars using hydraulic flow measurements and acoustic emission monitoring, proposing the use of time-dependent AE rates as a novel parameter for AE analysis. There was a linear correlation between the water potential (Ψ) at 50% loss of hydraulic conductivity (P50 ) and the Ψ at maximum AE activity (Pmaxrate ), where species with lower P50 also had lower Pmaxrate (P < 0.001, R(2) = 0.76). Using AE rates instead of cumulative counts for AE analysis allows more efficient estimation of P50 , while excluding problematic AE at late stages of dehydration.
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Affiliation(s)
- Markus Nolf
- Institute of BotanyUniversity of InnsbruckSternwartestr. 15Innsbruck6020Austria
- Hawkesbury Institute for the EnvironmentUniversity of Western SydneyRichmondNSW2753Australia
| | - Barbara Beikircher
- Institute of BotanyUniversity of InnsbruckSternwartestr. 15Innsbruck6020Austria
| | - Sabine Rosner
- Institute of BotanyBOKU ViennaGregor Mendel Str. 33Vienna1180Austria
| | - Anton Nolf
- Institute for Experimental PhysicsUniversity of InnsbruckTechnikerstr. 25Innsbruck6020Austria
| | - Stefan Mayr
- Institute of BotanyUniversity of InnsbruckSternwartestr. 15Innsbruck6020Austria
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Zwieniecki MA, Secchi F. Threats to xylem hydraulic function of trees under 'new climate normal' conditions. PLANT, CELL & ENVIRONMENT 2015; 38:1713-24. [PMID: 25039674 DOI: 10.1111/pce.12412] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/02/2014] [Accepted: 07/06/2014] [Indexed: 05/23/2023]
Abstract
Climate models predict increases in frequency and intensity of extreme environmental conditions, such as changes to minimum and maximum temperatures, duration of drought periods, intensity of rainfall/snowfall events and wind strength. These local extremes, rather than average climatic conditions, are closely linked to woody plant survival, as trees cope with such events over long lifespans. While the xylem provides trees with structural strength and is considered the most robust part of a tree's structure, it is also the most physiologically vulnerable as tree survival depends on its ability to sustain water supply to the tree crown under variable environmental conditions. Many structural, functional and biological tree properties evolved to protect xylem from loss of transport function because of embolism or to restore xylem transport capacity following embolism formation. How 'the new climate normal' conditions will affect these evolved strategies is yet to be seen. Our understanding of xylem physiology and current conceptual models describing embolism formation and plant recovery from water stress, however, can provide insight into near-future challenges that woody plants will face. In addition, knowledge of species-specific properties of xylem function may help guide mitigation of climate change impacts on woody plants in natural and agricultural tree communities.
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Affiliation(s)
- Maciej A Zwieniecki
- Department of Plant Sciences, University of California - Davis, Davis, CA, 95616, USA
| | - Francesca Secchi
- Department of Plant Sciences, University of California - Davis, Davis, CA, 95616, USA
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31
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Frank D, Reichstein M, Bahn M, Thonicke K, Frank D, Mahecha MD, Smith P, van der Velde M, Vicca S, Babst F, Beer C, Buchmann N, Canadell JG, Ciais P, Cramer W, Ibrom A, Miglietta F, Poulter B, Rammig A, Seneviratne SI, Walz A, Wattenbach M, Zavala MA, Zscheischler J. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts. GLOBAL CHANGE BIOLOGY 2015; 21:2861-80. [PMID: 25752680 PMCID: PMC4676934 DOI: 10.1111/gcb.12916] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/24/2015] [Indexed: 05/19/2023]
Abstract
Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global upscaling of the impacts of climate extremes on global carbon-climate feedbacks.
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Affiliation(s)
- Dorothea Frank
- Max Planck Institute for Biogeochemistry07745, Jena, Germany
- Correspondence: Dorothea Frank, tel. + 49 3641 576284, fax + 49 3641 577200, e-mail:
| | | | - Michael Bahn
- Institute of Ecology, University of Innsbruck6020, Innsbruck, Austria
| | - Kirsten Thonicke
- Potsdam Institute for Climate Impact Research (PIK) e.V.14773, Potsdam, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB)14195, Berlin, Germany
| | - David Frank
- Swiss Federal Research Institute WSL8903, Birmensdorf, Switzerland
- Oeschger Centre for Climate Change Research, University of BernCH-3012, Bern, Switzerland
| | | | - Pete Smith
- Institute of Biological and Environmental Sciences, University of Aberdeen23 St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Marijn van der Velde
- Ecosystems Services and Management Program, International Institute of Applied Systems Analysis (IIASA)A-2361, Laxenburg, Austria
| | - Sara Vicca
- Research Group of Plant and Vegetation Ecology, Biology Department, University of AntwerpWilrijk, Belgium
| | - Flurin Babst
- Potsdam Institute for Climate Impact Research (PIK) e.V.14773, Potsdam, Germany
- Laboratory of Tree-Ring Research, The University of Arizona1215 E Lowell St, Tucson, AZ, 85721, USA
| | - Christian Beer
- Max Planck Institute for Biogeochemistry07745, Jena, Germany
- Department of Environmental Science and Analytical Chemistry (ACES), Bolin Centre for Climate Research, Stockholm University10691, Stockholm, Sweden
| | | | - Josep G Canadell
- Global Carbon Project, CSIRO Oceans and Atmosphere FlagshipGPO Box 3023, Canberra, ACT, 2601, Australia
| | - Philippe Ciais
- IPSL – Laboratoire des Sciences du Climat et de l’Environnement CEA-CNRS-UVSQ91191, Gif sur Yvette, France
| | - Wolfgang Cramer
- Institut Méditerranéen de Biodiversité et d’Ecologie marine et continentale (IMBE), Aix Marseille Université, CNRS, IRD, Avignon UniversitéAix-en-Provence, France
| | - Andreas Ibrom
- Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU)Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Franco Miglietta
- IBIMET-CNRVia Caproni, 8, 50145, Firenze, Italy
- FoxLab, Fondazione E.MachVia Mach 1, 30158, San Michele a/Adige, Trento, Italy
| | - Ben Poulter
- IPSL – Laboratoire des Sciences du Climat et de l’Environnement CEA-CNRS-UVSQ91191, Gif sur Yvette, France
| | - Anja Rammig
- Oeschger Centre for Climate Change Research, University of BernCH-3012, Bern, Switzerland
- Institute of Biological and Environmental Sciences, University of Aberdeen23 St Machar Drive, Aberdeen, AB24 3UU, UK
| | | | - Ariane Walz
- Institute of Earth and Environmental Science, University of Potsdam14476, Potsdam, Germany
| | - Martin Wattenbach
- Helmholtz Centre Potsdam, GFZ German Research Centre For Geosciences14473, Potsdam, Germany
| | - Miguel A Zavala
- Forest Ecology and Restoration Group, Universidad de AlcaláAlcalá de Henares, Madrid, Spain
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32
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Charrier G, Pramsohler M, Charra‐Vaskou K, Saudreau M, Améglio T, Neuner G, Mayr S. Ultrasonic emissions during ice nucleation and propagation in plant xylem. THE NEW PHYTOLOGIST 2015; 207:570-8. [PMID: 25756189 PMCID: PMC5024006 DOI: 10.1111/nph.13361] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 02/10/2015] [Indexed: 05/09/2023]
Abstract
Ultrasonic acoustic emission analysis enables nondestructive monitoring of damage in dehydrating or freezing plant xylem. We studied acoustic emissions (AE) in freezing stems during ice nucleation and propagation, by combining acoustic and infrared thermography techniques and controlling the ice nucleation point. Ultrasonic activity in freezing samples of Picea abies showed two distinct phases: the first on ice nucleation and propagation (up to 50 AE s(-1) ; reversely proportional to the distance to ice nucleation point), and the second (up to 2.5 AE s(-1) ) after dissipation of the exothermal heat. Identical patterns were observed in other conifer and angiosperm species. The complex AE patterns are explained by the low water potential of ice at the ice-liquid interface, which induced numerous and strong signals. Ice propagation velocities were estimated via AE (during the first phase) and infrared thermography. Acoustic activity ceased before the second phase probably because the exothermal heating and the volume expansion of ice caused decreasing tensions. Results indicate cavitation events at the ice front leading to AE. Ultrasonic emission analysis enabled new insights into the complex process of xylem freezing and might be used to monitor ice propagation in natura.
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Affiliation(s)
- Guillaume Charrier
- Department of BotanyUniversity of InnsbruckSternwartestrasse. 15A‐6020InnsbruckAustria
| | - Manuel Pramsohler
- Department of BotanyUniversity of InnsbruckSternwartestrasse. 15A‐6020InnsbruckAustria
| | - Katline Charra‐Vaskou
- INRAUMR547 PIAFF‐63100Clermont‐FerrandFrance
- Clermont UniversitéUniversité Blaise PascalUMR547 PIAFF‐63100Clermont‐FerrandFrance
| | - Marc Saudreau
- INRAUMR547 PIAFF‐63100Clermont‐FerrandFrance
- Clermont UniversitéUniversité Blaise PascalUMR547 PIAFF‐63100Clermont‐FerrandFrance
| | - Thierry Améglio
- INRAUMR547 PIAFF‐63100Clermont‐FerrandFrance
- Clermont UniversitéUniversité Blaise PascalUMR547 PIAFF‐63100Clermont‐FerrandFrance
| | - Gilbert Neuner
- Department of BotanyUniversity of InnsbruckSternwartestrasse. 15A‐6020InnsbruckAustria
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwartestrasse. 15A‐6020InnsbruckAustria
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33
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Charrier G, Ngao J, Saudreau M, Améglio T. Effects of environmental factors and management practices on microclimate, winter physiology, and frost resistance in trees. FRONTIERS IN PLANT SCIENCE 2015; 6:259. [PMID: 25972877 PMCID: PMC4411886 DOI: 10.3389/fpls.2015.00259] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 04/01/2015] [Indexed: 05/02/2023]
Abstract
Freezing stress is one of the most important limiting factors determining the ecological distribution and production of tree species. Assessment of frost risk is, therefore, critical for forestry, fruit production, and horticulture. Frost risk is substantial when hazard (i.e., exposure to damaging freezing temperatures) intersects with vulnerability (i.e., frost sensitivity). Based on a large number of studies on frost resistance and frost occurrence, we highlight the complex interactive roles of environmental conditions, carbohydrates, and water status in frost risk development. To supersede the classical empirical relations used to model frost hardiness, we propose an integrated ecophysiologically-based framework of frost risk assessment. This framework details the individual or interactive roles of these factors, and how they are distributed in time and space at the individual-tree level (within-crown and across organs). Based on this general framework, we are able to highlight factors by which different environmental conditions (e.g., temperature, light, flood, and drought), and management practices (pruning, thinning, girdling, sheltering, water aspersion, irrigation, and fertilization) influence frost sensitivity and frost exposure of trees.
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Affiliation(s)
| | - Jérôme Ngao
- INRA, Clermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, Clermont-Ferrand, France
| | - Marc Saudreau
- INRA, Clermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, Clermont-Ferrand, France
| | - Thierry Améglio
- INRA, Clermont-Ferrand, France
- Clermont Université, Université Blaise Pascal, Clermont-Ferrand, France
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34
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Kasuga J, Charrier G, Uemura M, Améglio T. Characteristics of ultrasonic acoustic emissions from walnut branches during freeze-thaw-induced embolism formation. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1965-75. [PMID: 25662846 PMCID: PMC4669555 DOI: 10.1093/jxb/eru543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Ultrasonic acoustic emission (UAE) methods have been applied for the detection of freeze-thaw-induced embolism formation in water conduits of tree species. Until now, however, the exact source(s) of UAE has not been identified especially in angiosperm species, in which xylem tissues are composed of diverse types of cells. In this study, UAE was recorded from excised branches of walnut (Juglans regia cv. Franquette) during freeze-thaw cycles, and attempts were made to characterize UAEs generated by cavitation events leading to embolism formation according to their properties. During freeze-thaw cycles, a large number of UAEs were generated from the sample segments. However, the cumulative numbers of total UAE during freeze-thawing were not correlated with the percentage loss of hydraulic conductivity after thawing, suggesting that the sources of UAE were not only cavitation leading to embolism formation in vessels. Among the UAEs, cumulative numbers of UAEs with absolute energy >10.0 fJ strongly correlated with the increase in percentage loss of hydraulic conductivity. The high absolute energy of the UAEs might reflect the formation of large bubbles in the large lumen of vessels. Therefore, UAEs generated by cavitation events in vessels during freeze-thawing might be distinguished from other signals according to their magnitudes of absolute energy. On the other hand, the freezing of xylem parenchyma cells was followed by a certain number of UAEs. These results indicate the possibility that UAE methods can be applied to the detection of both freeze-thaw-induced embolism and supercooling breakdown in parenchyma cells in xylem.
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Affiliation(s)
- Jun Kasuga
- Institut National de la Recherche Agronomique, UMR 547 PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 547 PIAF, F-63100 Clermont-Ferrand, France Department of Agro-Environmental Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan
| | - Guillaume Charrier
- Institut National de la Recherche Agronomique, UMR 547 PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 547 PIAF, F-63100 Clermont-Ferrand, France Department of Botany, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Matsuo Uemura
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan
| | - Thierry Améglio
- Institut National de la Recherche Agronomique, UMR 547 PIAF, F-63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 547 PIAF, F-63100 Clermont-Ferrand, France
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35
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Lintunen A, Lindfors L, Kolari P, Juurola E, Nikinmaa E, Hölttä T. Bursts of CO2 released during freezing offer a new perspective on avoidance of winter embolism in trees. ANNALS OF BOTANY 2014; 114:1711-8. [PMID: 25252688 PMCID: PMC4649691 DOI: 10.1093/aob/mcu190] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 08/13/2014] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND AIMS Woody plants can suffer from winter embolism as gas bubbles are formed in the water-conducting conduits when freezing occurs: gases are not soluble in ice, and the bubbles may expand and fill the conduits with air during thawing. A major assumption usually made in studies of winter embolism formation is that all of the gas dissolved in the xylem sap is trapped within the conduits and forms bubbles during freezing. The current study tested whether this assumption is actually valid, or whether efflux of gases from the stem during freezing reduces the occurrence of embolism. METHODS CO2 efflux measurements were conducted during freezing experiments for saplings of three Scots pine (Pinus sylvestris) and three Norway spruce (Picea abies) trees under laboratory conditions, and the magnitudes of the freezing-related bursts of CO2 released from the stems were analysed using a previously published mechanistic model of CO2 production, storage, diffusion and efflux from a tree stem. The freezing-related bursts of CO2 released from a mature Scots pine tree growing in field conditions were also measured and analysed. KEY RESULTS Substantial freezing-related bursts of CO2 released from the stem were found to occur during both the laboratory experiments and under field conditions. In the laboratory, the fraction of CO2 released from the stem ranged between 27 and 96 % of the total CO2 content within the stem. CONCLUSIONS All gases dissolved in the xylem sap are not trapped within the ice in the stem during freezing, as has previously been assumed, thus adding a new dimension to the understanding of winter embolism formation. The conduit water volume not only determines the volume of bubbles formed during freezing, but also the efficiency of gas efflux out of the conduit during the freezing process.
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Affiliation(s)
- A Lintunen
- Department of Forest Sciences, University of Helsinki, Post Office Box 27, FI-00014, Helsinki, Finland
| | - L Lindfors
- Department of Forest Sciences, University of Helsinki, Post Office Box 27, FI-00014, Helsinki, Finland Department of Physics, University of Helsinki, Post Office Box 64, FI-00014, Helsinki, Finland
| | - P Kolari
- Department of Forest Sciences, University of Helsinki, Post Office Box 27, FI-00014, Helsinki, Finland Department of Physics, University of Helsinki, Post Office Box 64, FI-00014, Helsinki, Finland
| | - E Juurola
- Department of Forest Sciences, University of Helsinki, Post Office Box 27, FI-00014, Helsinki, Finland Department of Physics, University of Helsinki, Post Office Box 64, FI-00014, Helsinki, Finland
| | - E Nikinmaa
- Department of Forest Sciences, University of Helsinki, Post Office Box 27, FI-00014, Helsinki, Finland
| | - T Hölttä
- Department of Forest Sciences, University of Helsinki, Post Office Box 27, FI-00014, Helsinki, Finland
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36
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Augusto L, Davies TJ, Delzon S, De Schrijver A. The enigma of the rise of angiosperms: can we untie the knot? Ecol Lett 2014; 17:1326-38. [PMID: 24975818 DOI: 10.1111/ele.12323] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/02/2014] [Accepted: 06/10/2014] [Indexed: 11/29/2022]
Abstract
Multiple hypotheses have been put forward to explain the rise of angiosperms to ecological dominance following the Cretaceous. A unified scheme incorporating all these theories appears to be an inextricable knot of relationships, processes and plant traits. Here, we revisit these hypotheses, categorising them within frameworks based on plant carbon economy, resistance to climatic stresses, nutrient economy, biotic interactions and diversification. We maintain that the enigma remains unresolved partly because our current state of knowledge is a result of the fragmentary nature of palaeodata. This lack of palaeodata limits our ability to draw firm conclusions. Nonetheless, based on consistent results, some inferences may be drawn. Our results indicate that a complex multidriver hypothesis may be more suitable than any single-driver theory. We contend that plant carbon economy and diversification may have played an important role during the early stages of gymnosperms replacement by angiosperms in fertile tropical sites. Plant tolerance to climatic stresses, plant nutrition, biotic interactions and diversification may have played a role in later stages of angiosperm expansion within temperate and harsh environments. The angiosperm knot remains partly tied, but to unravel it entirely will only be feasible if new discoveries are made by scientific communities.
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Affiliation(s)
- L Augusto
- INRA, Bordeaux Sciences Agro, UMR 1391 ISPA, Villenave d'Ornon, 33882, France
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37
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Charrier G, Charra-Vaskou K, Kasuga J, Cochard H, Mayr S, Améglio T. Freeze-thaw stress: effects of temperature on hydraulic conductivity and ultrasonic activity in ten woody angiosperms. PLANT PHYSIOLOGY 2014; 164:992-8. [PMID: 24344170 PMCID: PMC3912121 DOI: 10.1104/pp.113.228403] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Freeze-thaw events can affect plant hydraulics by inducing embolism. This study analyzed the effect of temperature during the freezing process on hydraulic conductivity and ultrasonic emissions (UE). Stems of 10 angiosperms were dehydrated to a water potential at 12% percentage loss of hydraulic conductivity (PLC) and exposed to freeze-thaw cycles. The minimal temperature of the frost cycle correlated positively with induced PLC, whereby species with wider conduits (hydraulic diameter) showed higher freeze-thaw-induced PLC. Ultrasonic activity started with the onset of freezing and increased with decreasing subzero temperatures, whereas no UE were recorded during thawing. The temperature at which 50% of UE were reached varied between -9.1°C and -31.0°C across species. These findings indicate that temperatures during freezing are of relevance for bubble formation and air seeding. We suggest that species-specific cavitation thresholds are reached during freezing due to the temperature-dependent decrease of water potential in the ice, while bubble expansion and the resulting PLC occur during thawing. UE analysis can be used to monitor the cavitation process and estimate freeze-thaw-induced PLC.
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38
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Charrier G, Cochard H, Améglio T. Evaluation of the impact of frost resistances on potential altitudinal limit of trees. TREE PHYSIOLOGY 2013; 33:891-902. [PMID: 24052567 DOI: 10.1093/treephys/tpt062] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Winter physiology of woody plants is a key issue in temperate biomes. Here, we investigated different frost resistance mechanisms on 1-year-old branches of 11 European tree species from November until budburst: (i) frost hardiness of living cells (by electrolyte leakage method), (ii) winter embolism sensitivity (by percentage loss of conductivity: PLC) and (iii) phenological variation of budburst (by thermal time to budburst). These ecophysiological traits were analyzed according to the potential altitudinal limit, which is highly related to frost exposure. Seasonal frost hardiness and PLC changes are relatively different across species. Maximal PLC observed in winter (PLCMax) was the factor most closely related to potential altitudinal limit. Moreover, PLCMax was related to the mean hydraulic diameter of vessels (indicating embolism sensitivity) and to osmotic compounds (indicating ability of living cells to refill xylem conducting elements). Winter embolism formation seems to be counterbalanced by active refilling from living cells. These results enabled us to model potential altitudinal limit according to three of the physiological/anatomical parameters studied. Monitoring different frost resistance strategies brings new insights to our understanding of the altitudinal limits of trees.
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39
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Beikircher B, Mayr S. Winter peridermal conductance of apple trees: lammas shoots and spring shoots compared. TREES (BERLIN, GERMANY : WEST) 2013; 27:707-715. [PMID: 23794789 PMCID: PMC3688303 DOI: 10.1007/s00468-012-0826-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 11/29/2012] [Accepted: 12/03/2012] [Indexed: 05/10/2023]
Abstract
Lammas shoots are flushes formed by some woody species later in the growing season. Having less time to develop, tissue formation is suggested to be incomplete leading to a higher peridermal water loss during consecutive months. In this study, we analysed morphological and anatomical parameters, peridermal conductance to water vapour and the level of native embolism in mid-winter and late-winter of lammas shoots and normal spring shoots of the apple varieties Malus domestica 'Gala' and 'Nicoter'. Lammas shoots showed a significantly higher shoot cross-sectional area due to larger pith and corticular parenchyma areas. In contrast, phloem was significantly thicker in spring shoots. No pronounced differences were observed in xylem and collenchyma thickness or mean hydraulic conduit diameter. The phellem of spring shoots was composed of more suberinised cells compared to lammas shoots, which led to a significantly higher peridermal conductance in the latter. The amount of native embolism in mid-winter did not differ between shoot types, but in late-winter lammas shoots were more embolised than spring shoots. Data show that the restricted vegetation period of lammas shoots affects their development and, in consequence, their transpiration shield. This may also pose a risk for winter desiccation.
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Affiliation(s)
- B. Beikircher
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - S. Mayr
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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Brodersen CR, McElrone AJ, Choat B, Lee EF, Shackel KA, Matthews MA. In vivo visualizations of drought-induced embolism spread in Vitis vinifera. PLANT PHYSIOLOGY 2013; 161:1820-9. [PMID: 23463781 PMCID: PMC3613458 DOI: 10.1104/pp.112.212712] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 03/04/2013] [Indexed: 05/02/2023]
Abstract
Long-distance water transport through plant xylem is vulnerable to hydraulic dysfunction during periods of increased tension on the xylem sap, often coinciding with drought. While the effects of local and systemic embolism on plant water transport and physiology are well documented, the spatial patterns of embolism formation and spread are not well understood. Using a recently developed nondestructive diagnostic imaging tool, high-resolution x-ray computed tomography, we documented the dynamics of drought-induced embolism in grapevine (Vitis vinifera) plants in vivo, producing the first three-dimensional, high-resolution, time-lapse observations of embolism spread. Embolisms formed first in the vessels surrounding the pith at stem water potentials of approximately -1.2 megapascals in drought experiments. As stem water potential decreased, embolisms spread radially toward the epidermis within sectored vessel groupings via intervessel connections and conductive xylem relays, and infrequently (16 of 629 total connections) through lateral connections into adjacent vessel sectors. Theoretical loss of conductivity calculated from the high-resolution x-ray computed tomography images showed good agreement with previously published nuclear magnetic resonance imaging and hydraulic conductivity experiments also using grapevine. Overall, these data support a growing body of evidence that xylem organization is critically important to the isolation of drought-induced embolism spread and confirm that air seeding through the pit membranes is the principle mechanism of embolism spread.
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Affiliation(s)
- Craig Robert Brodersen
- Horticultural Sciences Department-Citrus Research and Education Center, University of Florida, Lake Alfred, Florida 33850, USA.
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Nagai S, Utsumi Y. The function of intercellular spaces along the ray parenchyma in sapwood, intermediate wood, and heartwood of Cryptomeria japonica (Cupressaceae). AMERICAN JOURNAL OF BOTANY 2012; 99:1553-1561. [PMID: 22917949 DOI: 10.3732/ajb.1200160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY Intercellular spaces along ray parenchyma (ISRP) are common in many conifer xylems, but their function is uncertain because the in-situ structural network among ISRP, ray parenchyma, and tracheids has not been evaluated. Analysis of water distribution in ISRP from sapwood to heartwood is needed to elucidate the function of ISRP in sapwood, intermediate wood, and heartwood. METHODS We used cryo-scanning electron microscopy, x-ray photography, and water content measurement in xylem to analyze the presence of liquids in ISRP, ray parenchyma, and tracheids from sapwood to heartwood in Cryptomeria japonica (Cupressaceae). KEY RESULTS In sapwood, almost all ISRP were empty. "Cingulate-cavitated regions", which lose water along the tangential direction within one annual ring, formed in the earlywood tracheids, and their frequency increased toward the inner annual rings, whereas ray parenchyma cells were alive and not involved in the partial cavitation. In intermediate wood, almost all ISRP and earlywood tracheids and many of the ray cells were empty, and only some latewood tracheids retained liquid in their lumina. The ISRP were connected with tracheids via gas-filled ray parenchyma cells. CONCLUSIONS The ISRP work as a pathway of gas for aspiration of ray parenchyma cells in sapwood. On the other hand, the occurrence of a gas network between ISRP, ray parenchyma, and tracheids facilitates cavitation of tracheids, resulting in the generation of low-moisture, intermediate wood.
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Affiliation(s)
- Satoshi Nagai
- Forestry Technology Institute, Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, Ikaba 430, Yamasaki, Shiso, Hyogo 671-2515, Japan.
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Sevanto S, Holbrook NM, Ball MC. Freeze/Thaw-induced embolism: probability of critical bubble formation depends on speed of ice formation. FRONTIERS IN PLANT SCIENCE 2012; 3:107. [PMID: 22685446 PMCID: PMC3368182 DOI: 10.3389/fpls.2012.00107] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 05/07/2012] [Indexed: 05/18/2023]
Abstract
Bubble formation in the conduits of woody plants sets a challenge for uninterrupted water transportation from the soil up to the canopy. Freezing and thawing of stems has been shown to increase the number of air-filled (embolized) conduits, especially in trees with large conduit diameters. Despite numerous experimental studies, the mechanisms leading to bubble formation during freezing have not been addressed theoretically. We used classical nucleation theory and fluid mechanics to show which mechanisms are most likely to be responsible for bubble formation during freezing and what parameters determine the likelihood of the process. Our results confirm the common assumption that bubble formation during freezing is most likely due to gas segregation by ice. If xylem conduit walls are not permeable to the salts expelled by ice during the freezing process, osmotic pressures high enough for air seeding could be created. The build-up rate of segregated solutes in front of the ice-water interface depends equally on conduit diameter and freezing velocity. Therefore, bubble formation probability depends on these variables. The dependence of bubble formation probability on freezing velocity means that the experimental results obtained for cavitation threshold conduit diameters during freeze/thaw cycles depend on the experimental setup; namely sample size and cooling rate. The velocity dependence also suggests that to avoid bubble formation during freezing trees should have narrow conduits where freezing is likely to be fast (e.g., branches or outermost layer of the xylem). Avoidance of bubble formation during freezing could thus be one piece of the explanation why xylem conduit size of temperate and boreal zone trees varies quite systematically.
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Affiliation(s)
- Sanna Sevanto
- Department of Organismic and Evolutionary Biology, Harvard University Cambridge, MA, USA
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Michaletz ST, Johnson EA, Tyree MT. Moving beyond the cambium necrosis hypothesis of post-fire tree mortality: cavitation and deformation of xylem in forest fires. THE NEW PHYTOLOGIST 2012; 194:254-263. [PMID: 22276783 DOI: 10.1111/j.1469-8137.2011.04021.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
• It is widely assumed that post-fire tree mortality results from necrosis of phloem and vascular cambium in stems, despite strong evidence that reduced xylem conductivity also plays an important role. • In this study, experiments with Populus balsamifera were used to demonstrate two mechanisms by which heat reduces the hydraulic conductivity of xylem: air seed cavitation and conduit wall deformation. Heat effects on air seed cavitation were quantified using air injection experiments that isolate potential temperature-dependent changes in sap surface tension and pit membrane pore diameters. Heat effects on conduit wall structure were demonstrated using air conductivity measurements and light microscopy. • Heating increased vulnerability to cavitation because sap surface tension varies inversely with temperature. Heating did not affect cavitation via changes in pit membrane pore diameters, but did cause significant reductions in xylem air conductivity that were associated with deformation of conduit walls (probably resulting from thermal softening of viscoelastic cell wall polymers). • Additional work is required to understand the relative roles of cavitation and deformation in the reduction of xylem conductivity, and how reduced xylem conductivity in roots, stems, and branches correlates and interacts with foliage and root necroses to cause tree mortality. Future research should also examine how heat necrosis of ray parenchyma cells affects refilling of embolisms that occur during and after the fire event.
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Affiliation(s)
- S T Michaletz
- Department of Biological Sciences and Biogeoscience Institute, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - E A Johnson
- Department of Biological Sciences and Biogeoscience Institute, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - M T Tyree
- Department of Renewable Resources, 444 Earth Sciences Building, University of Alberta, Edmonton, Alberta T6G 2E3, Canada
- Northern Research Station, US Forest Service, 705 Spear St, S. Burlington, VT 05403, USA
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Nardini A, Salleo S, Jansen S. More than just a vulnerable pipeline: xylem physiology in the light of ion-mediated regulation of plant water transport. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:4701-18. [PMID: 21765173 DOI: 10.1093/jxb/err208] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Major restrictions to the hydraulic conductance of xylem (K(XYL)) in vascular plants have traditionally been attributed to anatomical constraints. More recently, changes in the cationic concentration of xylem sap have been suggested to be responsible for short-term changes in K(XYL) based on data for 35 dicot species, and very few gymnosperms and ferns, indicating that xylem water transport may no longer be considered as an entirely passive process. Recent studies have revealed that this so-called ionic effect: (i) varies from little or no increase to >30%, (ii) is species specific, (iii) changes on a seasonal basis, (iv) depends on the cationic concentration, (v) is enhanced in embolized stems, and (vi) is positively correlated with vessel grouping. Furthermore, the ionic effect has been suggested to play functional roles in planta with respect to: (i) phloem-mediated control of xylem hydraulic properties, (ii) compensation of cavitation-induced loss of hydraulic conductance, with the result of optimizing light and water utilization, and (iii) differential regulation of water delivery to branches exposed to different levels of light. Pits are likely to play a key role in the ionic effect, which has largely been explained as a consequence of the poly-electrolytic nature and hydrogel properties of the pectic matrix of interconduit pit membranes, despite little evidence that pit membrane pectins remain present after cell hydrolysis. More research is needed to address the ionic effect in more species, physico-chemical properties of pit membranes, and how the ionic effect may increase xylem hydraulic conductance 'on demand'.
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Affiliation(s)
- Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, Italia.
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Choat B, Medek DE, Stuart SA, Pasquet-Kok J, Egerton JJG, Salari H, Sack L, Ball MC. Xylem traits mediate a trade-off between resistance to freeze-thaw-induced embolism and photosynthetic capacity in overwintering evergreens. THE NEW PHYTOLOGIST 2011; 191:996-1005. [PMID: 21627664 DOI: 10.1111/j.1469-8137.2011.03772.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Hydraulic traits were studied in temperate, woody evergreens in a high-elevation heath community to test for trade-offs between the delivery of water to canopies at rates sufficient to sustain photosynthesis and protection against disruption to vascular transport caused by freeze-thaw-induced embolism. Freeze-thaw-induced loss in hydraulic conductivity was studied in relation to xylem anatomy, leaf- and sapwood-specific hydraulic conductivity and gas exchange characteristics of leaves. We found evidence that a trade-off between xylem transport capacity and safety from freeze-thaw-induced embolism affects photosynthetic activity in overwintering evergreens. The mean hydraulically weighted xylem vessel diameter and sapwood-specific conductivity correlated with susceptibility to freeze-thaw-induced embolism. There was also a strong correlation of hydraulic supply and demand across species; interspecific differences in stomatal conductance and CO(2) assimilation rates were correlated linearly with sapwood- and leaf-specific hydraulic conductivity. Xylem vessel anatomy mediated an apparent trade-off between resistance to freeze-thaw-induced embolism and hydraulic and photosynthetic capacity during the winter. These results point to a new role for xylem functional traits in determining the degree to which species can maintain photosynthetic carbon gain despite freezing events and cold winter temperatures.
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Affiliation(s)
- Brendan Choat
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Danielle E Medek
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Stephanie A Stuart
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Jessica Pasquet-Kok
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - John J G Egerton
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Hooman Salari
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
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Petit G, Anfodillo T, Carraro V, Grani F, Carrer M. Hydraulic constraints limit height growth in trees at high altitude. THE NEW PHYTOLOGIST 2011; 189:241-52. [PMID: 20840508 DOI: 10.1111/j.1469-8137.2010.03455.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
• Low temperatures limit the fixation of photosynthates and xylogenesis. Here, we hypothesized that reduced longitudinal growth in trees at high altitude is related to the lower hydraulic efficiency of the transport system. • Apical buds of Norway spruce (Picea abies) trees at high and low elevation were heated during 2006 and 2007. At the end of the experiment, trees were felled. Longitudinal increments and tracheid lumen areas were measured along the stem. Apical hydraulic conductivity (k) was estimated from anatomical data. • Before heating, high-altitude trees showed fewer (P = 0.002) and smaller (P = 0.008) apical conduits, and therefore reduced k (P = 0.016) and stem elongation (P < 0.0001), in comparison with trees at low elevation. After 2 yr of heating, k increased at both high (P = 0.014) and low (P = 0.047) elevation. Only high-altitude trees showed increased stem elongation, which reached the same magnitude as that of controls at low elevation (P = 0.735). Heating around the apical shoots did not appear to induce significant changes in conduit dimension along the rest of the stem. • The total number and size of xylem elements at the stem apex are strongly constrained by low temperatures. Trees at high altitude are therefore prevented from building up an efficient transport system, and their reduced longitudinal growth reflects strong hydraulic limitations.
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Affiliation(s)
- Giai Petit
- Università degli Studi di Padova, Department Territorio e Sistemi Agro-Forestali, Legnaro (PD), Italy.
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Herbette S, Wortemann R, Awad H, Huc R, Cochard H, Barigah TS. Insights into xylem vulnerability to cavitation in Fagus sylvatica L.: phenotypic and environmental sources of variability. TREE PHYSIOLOGY 2010; 30:1448-55. [PMID: 20935319 DOI: 10.1093/treephys/tpq079] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Xylem vulnerability to cavitation is a key parameter in understanding drought resistance of trees. We determined the xylem water pressure causing 50% loss of hydraulic conductivity (P(50)), a proxy of vulnerability to cavitation, and we evaluated the variability of this trait at tree and population levels for Fagus sylvatica. We checked for the effects of light on vulnerability to cavitation of stem segments together with a time series variation of P(50). Full sunlight-exposed stem segments were less vulnerable to cavitation than shade-exposed ones. We found no clear seasonal change of P(50), suggesting that this trait was designed for a restricted period. P(50) varied for populations settled along a latitudinal gradient, but not for those sampled along an altitudinal gradient. Moreover, mountainside exposure seemed to play a major role in the vulnerability to cavitation of beech populations, as we observed the differences along north-facing sides but not on south-facing sides. Unexpectedly, both north-facing mountainside and northern populations appeared less vulnerable than those grown on the southern mountainside or in the South of France. These results on beech populations were discussed with respect to the results at within-tree level.
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Affiliation(s)
- Stephane Herbette
- Université Blaise Pascal, UMR 547 PIAF, avenue des Landais, F-63177 Aubière, France.
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Zweifel R, Eugster W, Etzold S, Dobbertin M, Buchmann N, Häsler R. Link between continuous stem radius changes and net ecosystem productivity of a subalpine Norway spruce forest in the Swiss Alps. THE NEW PHYTOLOGIST 2010; 187:819-30. [PMID: 20497351 DOI: 10.1111/j.1469-8137.2010.03301.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
*Continuous stem radius changes (DR) include growth and water-related processes on the individual tree level. DR is assumed to provide carbon turnover information complementary to net ecosystem productivity (NEP) which integrates fluxes over the entire forest ecosystem. Here, we investigated the unexpectedly close relationship between NEP and DR and asked for causalities. *NEP (positive values indicate carbon sink) measured by eddy covariance over 11 yr was analysed at three time scales alongside automated point dendrometer DR data from a Swiss subalpine Norway spruce forest. *On annual and monthly scales, the remarkably close relationship between NEP and DR was positive, whereas on a half-hourly scale the relationship was negative. Gross primary production (GPP) had a similar explanatory power at shorter time scales, but was significantly less correlated with DR on an annual scale. *The causal explanation for the NEP-DR relationship is still fragmentary; however, it is partially attributable to the following: radial stem growth with a strong effect on monthly and annual increases in NEP and DR; frost-induced bark tissue dehydration with a parallel decrease in both measures on a monthly scale; and transpiration-induced DR shrinkage which is negatively correlated with assimilation and thus with NEP on a half-hourly scale.
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Affiliation(s)
- R Zweifel
- Swiss Federal Research Institute WSL, Forest Ecosystem Processes, Birmensdorf, Switzerland.
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Mayr S, Sperry JS. Freeze-thaw-induced embolism in Pinus contorta: centrifuge experiments validate the 'thaw-expansion hypothesis' but conflict with ultrasonic emission data. THE NEW PHYTOLOGIST 2010; 185:1016-24. [PMID: 20028475 DOI: 10.1111/j.1469-8137.2009.03133.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
*The 'thaw-expansion hypothesis' postulates that xylem embolism is caused by the formation of gas bubbles on freezing and their expansion on thawing. We evaluated the hypothesis using centrifuge experiments and ultrasonic emission monitoring in Pinus contorta. *Stem samples were exposed to freeze-thaw cycles at varying xylem pressure (P) in a centrifuge before the percentage loss of hydraulic conductivity (PLC) was measured. Ultrasonic acoustic emissions were registered on samples exposed to freeze-thaw cycles in a temperature chamber. *Freeze-thaw exposure of samples spun at -3 MPa induced a PLC of 32% (one frost cycle) and 50% (two cycles). An increase in P to -0.5 MPa during freezing had no PLC effect, whereas increased P during thaw lowered PLC to 7%. Ultrasonic acoustic emissions were observed during freezing and thawing at -3 MPa, but not in air-dried or water-saturated samples. A decrease in minimum temperature caused additional ultrasonic acoustic emissions, but had no effect on PLC. *The centrifuge experiments indicate that the 'thaw-expansion hypothesis' correctly describes the embolization process. Possible explanations for the increase in PLC on repeated frost cycles and for the ultrasonic acoustic emissions observed during freezing and with decreasing ice temperature are discussed.
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Affiliation(s)
- Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria.
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50
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Fonti P, von Arx G, García-González I, Eilmann B, Sass-Klaassen U, Gärtner H, Eckstein D. Studying global change through investigation of the plastic responses of xylem anatomy in tree rings. THE NEW PHYTOLOGIST 2010; 185:42-53. [PMID: 19780986 DOI: 10.1111/j.1469-8137.2009.03030.x] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Variability in xylem anatomy is of interest to plant scientists because of the role water transport plays in plant performance and survival. Insights into plant adjustments to changing environmental conditions have mainly been obtained through structural and functional comparative studies between taxa or within taxa on contrasting sites or along environmental gradients. Yet, a gap exists regarding the study of hydraulic adjustments in response to environmental changes over the lifetimes of plants. In trees, dated tree-ring series are often exploited to reconstruct dynamics in ecological conditions, and recent work in which wood-anatomical variables have been used in dendrochronology has produced promising results. Environmental signals identified in water-conducting cells carry novel information reflecting changes in regional conditions and are mostly related to short, sub-annual intervals. Although the idea of investigating environmental signals through wood anatomical time series goes back to the 1960s, it is only recently that low-cost computerized image-analysis systems have enabled increased scientific output in this field. We believe that the study of tree-ring anatomy is emerging as a promising approach in tree biology and climate change research, particularly if complemented by physiological and ecological studies. This contribution presents the rationale, the potential, and the methodological challenges of this innovative approach.
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Affiliation(s)
- Patrick Fonti
- WSL Swiss Federal Research Institute, Dendro Sciences Unit, Zürcherstr. 111, CH-8903 Birmensdorf, Switzerland.
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