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Bonisoli L, Pelicella I, Arru L. Plant ultrasound detection: a cost-effective method for identifying plant ultrasonic emissions. PLANT SIGNALING & BEHAVIOR 2024; 19:2310974. [PMID: 38345027 PMCID: PMC10863351 DOI: 10.1080/15592324.2024.2310974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/22/2024] [Indexed: 02/15/2024]
Abstract
Plants have been observed to produce short ultrasonic emissions (UEs), and current research is focusing on developing noninvasive techniques for recording and analyzing these emissions. A standardized methodology has not been established yet; in this paper we suggest a cost-effective procedure for recording, extracting, and identifying plant UEs using only a single ultrasound microphone, a laptop computer, and open-source software.
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Affiliation(s)
- Luca Bonisoli
- Department of Life Sciences, University of Modena and Reggio Emilia, Reggio Emilia, Italy
| | | | - Laura Arru
- Department of Life Sciences, University of Modena and Reggio Emilia, Reggio Emilia, Italy
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2
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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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3
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Zhang Z, Yu A, Hu W, Wu L, Yang D, Fu L, Wang Z, Kuang H, Wang M. A review on extraction, purification, structural characteristics, biological activities, applications of polysaccharides from Hovenia dulcis Thunb. (Guai Zao). Int J Biol Macromol 2024; 265:131097. [PMID: 38537845 DOI: 10.1016/j.ijbiomac.2024.131097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/18/2024] [Accepted: 03/20/2024] [Indexed: 04/18/2024]
Abstract
Hovenia dulcis Thunb. (H. dulcis) is a widely distributed plant with a long history of cultivation and consumption. As a common plant, it has economic, edible and medicinal value. H. dulcis polysaccharides are one of their main bioactive ingredients and have many health benefits, such as anti-diabetes, antioxidation, anti-glycosylation, anti-fatigue, immune regulation activities and alcoholic liver disease protection activity. In this paper, the research progress of H. dulcis polysaccharides in extraction, purification, structural characteristics, biological activities, existing and potential applications were reviewed, which could provide new valuable insights for future studies.
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Affiliation(s)
- Zhaojiong Zhang
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Aiqi Yu
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Wenjing Hu
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Lihong Wu
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Deqiang Yang
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Lei Fu
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Zhibin Wang
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Haixue Kuang
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China
| | - Meng Wang
- Key Laboratory of Basic and Application Research of Beiyao (Heilongjiang University of Chinese Medicine), Ministry of Education, Heilongjiang University of Chinese Medicine, Harbin 150000, China.
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4
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Li Z, Luo D, Ibrahim MM, Hou E, Wang C. Adaptive strategies to freeze-thaw cycles in branch hydraulics of tree species coexisting in a temperate forest. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108223. [PMID: 38043252 DOI: 10.1016/j.plaphy.2023.108223] [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: 09/06/2023] [Revised: 11/04/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
Freeze-thaw cycles (FTCs) limit the distribution and survival of temperate tree species. Tree species with different wood types coexist in temperate forests and are subjected to the same FTCs. It is essential to understand how these trees differentially cope with xylem hydraulic failure induced by FTCs in the field. The branch hydraulic traits and nonstructural carbohydrate concentration of six coexisting tree species in a temperate forest were measured from mid-winter to early spring when the FTCs occurred from January to April. The percentage loss of hydraulic conductivity (PLC) was lower, and the water potential inducing a 50% loss of hydraulic conductivity (P50) was more negative in tracheid trees than in ring- and diffuse-porous trees, suggesting tracheid trees with narrow tracheid diameters showed less vulnerable to embolism and provided a lower degree of hydraulic failure during FTCs (stronger resistance). Ring-porous trees always showed lower hydraulic conductivity and higher PLC and P50, and these traits did not change during FTCs, suggesting that they might lose the hydraulic functions in winter and abandon the last year xylem. The P50 in diffuse-porous increased after several FTCs (frost fatigue), but that in tracheid species continued to increase (or even decrease) until the end of FTCs (69 cycles), suggesting that tracheid trees were less sensitive to frost fatigue than diffuse-porous trees. Soluble sugar concentration in deciduous trees negatively correlated with PLC at the end of FTCs, indicating that the effect of soluble sugar on refilling embolism occurred in early spring. While the soluble sugar concentration of deciduous trees decreased, that of two evergreen tracheid trees gradually increased, possibly due to the winter photosynthesis of evergreen leaves. Our results suggest temperate trees adopt different strategies to cope with the same FTCs. These findings enrich the understanding of plant hydraulics and carbon physiology in winter and provide insights into the response of different species coexisting in temperate forests under climate change.
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Affiliation(s)
- Zhimin Li
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin, 150040, China; Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
| | - Dandan Luo
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin, 150040, China
| | - Muhammed Mustapha Ibrahim
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Enqing Hou
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Chuankuan Wang
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin, 150040, China.
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5
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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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6
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Del Stabile F, Marsili V, Forti L, Arru L. Is There a Role for Sound in Plants? PLANTS 2022; 11:plants11182391. [PMID: 36145791 PMCID: PMC9503271 DOI: 10.3390/plants11182391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/05/2022] [Accepted: 09/12/2022] [Indexed: 11/16/2022]
Abstract
Plants have long been considered passive, static, and unchanging organisms, but this view is finally changing. More and more knowledge is showing that plants are aware of their surroundings, and they respond to a surprising variety of stimuli by modifying their growth and development. Plants extensively communicate with the world around them, above and below ground. Although communication through mycorrhizal networks and Volatile Organic Compounds has been known for a long time, acoustic perception and communication are somehow a final frontier of research. Perhaps surprisingly, plants not only respond to sound, they actually seem to emit sound as well. Roots emit audible clicks during growth, and sounds are emitted from xylem vessels, although the nature of these acoustic emissions still needs to be clarified. Even more interesting, there is the possibility that these sounds carry information with ecological implications, such as alerting insects of the hydration state of a possible host plant, and technological implications as well. Monitoring sound emissions could possibly allow careful monitoring of the hydration state of crops, which could mean significantly less water used during irrigation. This review summarizes the current knowledge on sound perception communication in plants and illustrates possible implications and technological applications.
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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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8
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Losso A, Bär A, Unterholzner L, Bahn M, Mayr S. Branch water uptake and redistribution in two conifers at the alpine treeline. Sci Rep 2021; 11:22560. [PMID: 34799592 PMCID: PMC8604952 DOI: 10.1038/s41598-021-00436-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 10/05/2021] [Indexed: 11/21/2022] Open
Abstract
During winter, conifers at the alpine treeline suffer dramatic losses of hydraulic conductivity, which are successfully recovered during late winter. Previous studies indicated branch water uptake to support hydraulic recovery. We analyzed water absorption and redistribution in Picea abies and Larix decidua growing at the treeline by in situ exposure of branches to δ2H-labelled water. Both species suffered high winter embolism rates (> 40-60% loss of conductivity) and recovered in late winter (< 20%). Isotopic analysis showed water to be absorbed over branches and redistributed within the crown during late winter. Labelled water was redistributed over 425 ± 5 cm within the axes system and shifted to the trunk, lower and higher branches (tree height 330 ± 40 cm). This demonstrated relevant branch water uptake and re-distribution in treeline conifers. The extent of water absorption and re-distribution was species-specific, with L. decidua showing higher rates. In natura, melting snow might be the prime source for absorbed and redistributed water, enabling embolism repair and restoration of water reservoirs prior to the vegetation period. Pronounced water uptake in the deciduous L. decidua indicated bark to participate in the process of water absorption.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria.
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia.
| | - Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | | | - Michael Bahn
- Department of Ecology, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
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Unterholzner L, Carrer M, Bär A, Beikircher B, Dämon B, Losso A, Prendin AL, Mayr S. Juniperus communis populations exhibit low variability in hydraulic safety and efficiency. TREE PHYSIOLOGY 2020; 40:1668-1679. [PMID: 32785622 DOI: 10.1093/treephys/tpaa103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
The performance and distribution of woody species strongly depend on their adjustment to environmental conditions based on genotypic and phenotypic properties. Since more intense and frequent drought events are expected due to climate change, xylem hydraulic traits will play a key role under future conditions, and thus, knowledge of hydraulic variability is of key importance. In this study, we aimed to investigate the variability in hydraulic safety and efficiency of the conifer shrub Juniperus communis based on analyses along an elevational transect and a common garden approach. We studied (i) juniper plants growing between 700 and 2000 m a.s.l. Innsbruck, Austria, and (ii) plants grown in the Innsbruck botanical garden (Austria) from seeds collected at different sites across Europe (France, Austria, Ireland, Germany and Sweden). Due to contrasting environmental conditions at different elevation and provenance sites and the wide geographical study area, pronounced variation in xylem hydraulics was expected. Vulnerability to drought-induced embolisms (hydraulic safety) was assessed via the Cavitron and ultrasonic acoustic emission techniques, and the specific hydraulic conductivity (hydraulic efficiency) via flow measurements. Contrary to our hypothesis, relevant variability in hydraulic safety and efficiency was neither observed across elevations, indicating a low phenotypic variation, nor between provenances, despite expected genotypic differences. Interestingly, the provenance from the most humid and warmest site (Ireland) and the northernmost provenance (Sweden) showed the highest and the lowest embolism resistance, respectively. The hydraulic conductivity was correlated with plant height, which indicates that observed variation in hydraulic traits was mainly related to morphological differences between plants. We encourage future studies to underlie anatomical traits and the role of hydraulics for the broad ecological amplitude of J. communis.
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Affiliation(s)
| | - Marco Carrer
- Department TeSAF, Università degli Studi di Padova, Legnaro (PD) 35122, Italy
| | - Andreas Bär
- Institut für Botanik, Universität Innsbruck, Innsbruck 6020, Austria
| | | | - Birgit Dämon
- Institut für Botanik, Universität Innsbruck, Innsbruck 6020, Austria
| | - Adriano Losso
- Institut für Botanik, Universität Innsbruck, Innsbruck 6020, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW 2753, Australia
| | | | - Stefan Mayr
- Institut für Botanik, Universität Innsbruck, Innsbruck 6020, Austria
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Losso A, Sailer J, Bär A, Ganthaler A, Mayr S. Insights into trunks of Pinus cembra L.: analyses of hydraulics via electrical resistivity tomography. TREES (BERLIN, GERMANY : WEST) 2020; 34:999-1008. [PMID: 32848296 PMCID: PMC7437670 DOI: 10.1007/s00468-020-01976-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/03/2020] [Indexed: 05/31/2023]
Abstract
KEY MESSAGE The lack of elevational changes in electrical resistivity in Pinus cembra trunks indicated consistent growth and hydraulics across elevations. Though, electrical resistivity tomograms exhibited pronounced temperature-driven seasonal changes. ABSTRACT Alpine conifers growing at high elevation are exposed to low temperatures, which may limit xylogenesis and cause pronounced seasonal changes in tree hydraulics. Electrical resistivity (ER) tomography enables minimal invasive monitoring of stems in situ. We used this technique to analyze Pinus cembra trunks along a 400 m elevational gradient up to the timberline and over seasons. Furthermore, ER data of earlywood across tree rings were compared with the respective specific hydraulic conductivity (K S), measured on extracted wood cores. ER tomograms revealed pronounced changes over the year and a strong correlation between average ER (ERmean) and air and xylem temperatures. Surprisingly, no elevational changes in ERmean, earlywood ER or K S were observed. ER data corresponded to variation in earlywood K S, which decreased from the youngest (ca. 4-5 cm2s-1 MPa-1) to the oldest tree rings (0.63 ± 0.22 cm2s-1 MPa-1). The lack of changes in ER data and earlywood K S along the study transect indicated consistent growth patterns and no major changes in structural and functional hydraulic traits across elevation. The constant decrease in earlywood K S with tree ring age throughout all elevations highlights the hydraulic relevance of the outermost tree rings in P. cembra. Seasonal measurements demonstrated pronounced temperature effects on ER, and we thus recommend a detailed monitoring of trunk temperatures for ER tomography.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW 2753 Australia
| | - Julia Sailer
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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11
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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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12
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Losso A, Anfodillo T, Ganthaler A, Kofler W, Markl Y, Nardini A, Oberhuber W, Purin G, Mayr S. Robustness of xylem properties in conifers: analyses of tracheid and pit dimensions along elevational transects. TREE PHYSIOLOGY 2018; 38:212-222. [PMID: 29309674 DOI: 10.1093/treephys/tpx168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
In alpine regions, tree hydraulics are limited by low temperatures that restrict xylem growth and induce winter frost drought and freezing stress. While several studies have dealt with functional limitations, data on elevational changes in functionally relevant xylem anatomical parameters are still scarce. In wood cores of Pinus cembra L. and Picea abies (L.) Karst. trunks, harvested along five elevational transects, xylem anatomical parameters (tracheid hydraulic diameter dh, wall reinforcement (t/b)2), pit dimensions (pit aperture Da, pit membrane Dm and torus Dt diameters) and respective functional indices (torus overlap O, margo flexibility) were measured. In both species, tracheid diameters decreased and (t/b)2 increased with increasing elevation, while pit dimensions and functional indices remained rather constant (P. cembra: Dt 10.3 ± 0.2 μm, O 0.477 ± 0.005; P. abies: Dt 9.30 ± 0.18 μm, O 0.492 ± 0.005). However, dh increased with tree height following a power trajectory with an exponent of 0.21, and also pit dimensions increased with tree height (exponents: Dm 0.18; Dt 0.14; Da 0.11). Observed elevational trends in xylem structures were predominantly determined by changes in tree size. Tree height-related changes in anatomical traits showed a remarkable robustness, regardless of the distributional ranges of study species. Despite increasing stress intensities towards the timberline, no adjustment in hydraulic safety at the pit level was observed.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Tommaso Anfodillo
- Dipartimento Territorio e Sistemi Agro Forestali, Università degli Studi di Padova, 35020 Legnaro, PD, Italy
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Werner Kofler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Yvonne Markl
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Gerhard Purin
- Sportgymnasium Dornbirn, Messestraße 4, 6850 Dornbirn, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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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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14
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Venturas MD, Sperry JS, Hacke UG. Plant xylem hydraulics: What we understand, current research, and future challenges. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:356-389. [PMID: 28296168 DOI: 10.1111/jipb.12534] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/09/2017] [Indexed: 05/22/2023]
Abstract
Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connection with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality.
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Affiliation(s)
- Martin D Venturas
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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15
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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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16
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Elevational trends in hydraulic efficiency and safety of Pinus cembra roots. Oecologia 2015; 180:1091-102. [PMID: 26678990 PMCID: PMC4943587 DOI: 10.1007/s00442-015-3513-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 11/17/2015] [Indexed: 11/25/2022]
Abstract
In alpine regions, elevational gradients in environmental parameters
are reflected by structural and functional changes in plant traits. Elevational
changes in plant water relations have also been demonstrated, but comparable
information on root hydraulics is generally lacking. We analyzed the hydraulic
efficiency (specific hydraulic conductivity ks, entire root system conductance KR) and vulnerability to drought-induced embolism (water
potential at 50 % loss of conductivity Ψ50) of the roots of Pinus
cembra trees growing along an elevational transect of 600 m. Hydraulic
parameters of the roots were compared with those of the stem and related to
anatomical traits {mean conduit diameter (d),
wall reinforcement [(t/b)2]}. We hypothesized that
temperature-related restrictions in root function would cause a progressive
limitation of hydraulic efficiency and safety with increasing elevation. We found
that both root ks and KR decreased from low (1600 m a.s.l.: ks
5.6 ± 0.7 kg m−1 s−1 MPa−1,
KR
0.049 ± 0.005 kg m−2 s −1 MPa−1)
to high elevation (2100 m a.s.l.: ks
4.2 ± 0.6 kg m−1 s−1 MPa−1,
KR
0.035 ± 0.006 kg m−2 s−1 MPa−1),
with small trees showing higher KR than large trees. ks was higher in roots than in stems
(0.5 ± 0.05 kg m−1s−1MPa−1).
Ψ50 values were similar across elevations and overall less
negative in roots (Ψ50 −3.6 ± 0.1 MPa) than in stems (Ψ50 −3.9 ± 0.1 MPa). In roots, large-diameter tracheids were
lacking at high elevation and (t/b)2 increased, while d did not change. The elevational decrease in root
hydraulic efficiency reflects a limitation in timberline tree hydraulics. In
contrast, hydraulic safety was similar across elevations, indicating that avoidance
of hydraulic failure is important for timberline trees. As hydraulic patterns can
only partly be explained by the anatomical parameters studied, limitations and/or
adaptations at the pit level are likely.
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17
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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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18
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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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19
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Suuronen JP, Peura M, Fagerstedt K, Serimaa R. Visualizing water-filled versus embolized status of xylem conduits by desktop x-ray microtomography. PLANT METHODS 2013; 9:11. [PMID: 23566373 PMCID: PMC3716634 DOI: 10.1186/1746-4811-9-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 03/22/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND The hydraulic conductivity of the stem is a major factor limiting the capability of trees to transport water from the soil to transpiring leaves. During drought conditions, the conducting capacity of xylem can be reduced by some conduits being filled with gas, i.e. embolized. In order to understand the dynamics of embolism formation and repair, considerable attention has been given to developing reliable and accurate methods for quantifying the phenomenon. In the past decade, non-destructive imaging of embolism formation in living plants has become possible. Magnetic resonance imaging has been used to visualize the distribution of water within the stem, but in most cases it is not possible to resolve individual cells. Recently, high-resolution synchrotron x-ray microtomography has been introduced as a tool to visualize the water contents of individual cells in vivo, providing unprecedented insight into the dynamics of embolism repair. We have investigated the potential of an x-ray tube -based microtomography setup to visualize and quantify xylem embolism and embolism repair in water-stressed young saplings and shoot tips of Silver and Curly birch (Betula pendula and B. pendula var. carelica). RESULTS From the microtomography images, the water-filled versus gas-filled status of individual xylem conduits can be seen, and the proportion of stem cross-section that consists of embolized tissue can be calculated. Measuring the number of embolized vessels in the imaged area is a simple counting experiment. In the samples investigated, wood fibers were cavitated in a large proportion of the xylem cross-section shortly after watering of the plant was stopped, but the number of embolized vessels remained low several days into a drought period. Under conditions of low evaporative demand, also refilling of previously embolized conduits was observed. CONCLUSIONS Desktop x-ray microtomography is shown to be an effective method for evaluating the water-filled versus embolized status of the stem xylem in a small living sapling. Due to its non-destructive nature, the risk of inducing embolisms during sampling is greatly reduced. Compared with synchrotron imaging beamlines, desktop microtomography offers easier accessibility, while maintaining sufficient resolution to visualize the water contents of individual cells.
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Affiliation(s)
| | - Marko Peura
- Department of Physics, University of Helsinki, P.O.B. 64, Helsinki, FI-00014, Finland
- Present address: Central Administration, University of Helsinki, P.O.B. 33, Helsinki, FI-00014, Finland
| | - Kurt Fagerstedt
- Department of Biosciences, University of Helsinki, P.O.B. 65, Helsinki, FI-00014, Finland
| | - Ritva Serimaa
- Department of Physics, University of Helsinki, P.O.B. 64, Helsinki, FI-00014, Finland
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20
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Lucas WJ, Groover A, Lichtenberger R, Furuta K, Yadav SR, Helariutta Y, He XQ, Fukuda H, Kang J, Brady SM, Patrick JW, Sperry J, Yoshida A, López-Millán AF, Grusak MA, Kachroo P. The plant vascular system: evolution, development and functions. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:294-388. [PMID: 23462277 DOI: 10.1111/jipb.12041] [Citation(s) in RCA: 400] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essential functions performed by the vascular system, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.
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Affiliation(s)
- William J Lucas
- Department of Plant Biology, College of Biological Sciences, University of California, Davis, CA 95616, USA.
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21
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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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