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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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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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3
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Knüver T, Bär A, Ganthaler A, Gebhardt T, Grams TEE, Häberle K, Hesse BD, Losso A, Tomedi I, Mayr S, Beikircher B. Recovery after long-term summer drought: Hydraulic measurements reveal legacy effects in trunks of Picea abies but not in Fagus sylvatica. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1240-1253. [PMID: 35611757 PMCID: PMC10084041 DOI: 10.1111/plb.13444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Climate change is expected to increase the frequency and intensity of summer droughts. Sufficient drought resistance, the ability to acclimate to and/or recover after drought, is thus crucial for forest tree species. However, studies on the hydraulics of mature trees during and after drought in natura are scarce. In this study, we analysed trunk water content (electrical resistivity: ER) and further hydraulic (water potential, sap flow density, specific hydraulic conductivity, vulnerability to embolism) as well as wood anatomical traits (tree ring width, conduit diameter, conduit wall reinforcement) of drought-stressed (artificially induced summer drought via throughfall-exclusion) and unstressed Picea abies and Fagus sylvatica trees. In P. abies, ER indicated a strong reduction in trunk water content after 5 years of summer drought, corresponding to significantly lower pre-dawn leaf water potential and xylem sap flow density. Vulnerability to embolism tended to be higher in drought-stressed trees. In F. sylvatica, only small differences between drought-stressed and control trees were observed. Re-watering led to a rapid increase in water potentials and xylem sap flow of both drought-stressed trees, and to increased growth rates in the next growing season. ER analyses revealed lower trunk water content in P. abies trees growing on throughfall-exclusion plots even 1 year after re-watering, indicating a limited capacity to restore internal water reserves. Results demonstrated that P. abies is more susceptible to recurrent summer drought than F. sylvatica, and can exhibit long-lasting and pronounced legacy effects in trunk water reserves.
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Affiliation(s)
- T. Knüver
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - A. Bär
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - A. Ganthaler
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - T. Gebhardt
- Technical University of MunichSchool of Life SciencesProfessorship for Land Surface‐Atmosphere Interactions AG Ecophysiology of PlantsFreisingGermany
| | - T. E. E. Grams
- Technical University of MunichSchool of Life SciencesProfessorship for Land Surface‐Atmosphere Interactions AG Ecophysiology of PlantsFreisingGermany
| | - K.‐H. Häberle
- Technical University of MunichSchool of Life SciencesChair of Restoration EcologyFreisingGermany
| | - B. D. Hesse
- Technical University of MunichSchool of Life SciencesProfessorship for Land Surface‐Atmosphere Interactions AG Ecophysiology of PlantsFreisingGermany
| | - A. Losso
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityRichmondAustralia
| | - I. Tomedi
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - S. Mayr
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - B. Beikircher
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
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Lamacque L, Sabin F, Améglio T, Herbette S, Charrier G. Detection of acoustic events in lavender for measuring xylem vulnerability to embolism and cellular damage. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3699-3710. [PMID: 35176148 DOI: 10.1093/jxb/erac061] [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: 08/16/2021] [Accepted: 02/15/2022] [Indexed: 06/14/2023]
Abstract
Acoustic emission analysis is promising to investigate the physiological events leading to drought-induced injury and mortality. However, their nature and source are not fully understood, making this technique difficult to use as a direct measure of the loss of xylem hydraulic conductance. Acoustic emissions were recorded during severe dehydration in lavender plants (Lavandula angustifolia) and compared with the dynamics of embolism development and cell damage. The timing and characteristics of acoustic signals from two independent recording systems were compared by principal component analysis (PCA). Changes in water potential, branch diameter, loss of hydraulic conductance, and cellular damage were also measured to quantify drought-induced damages. Two distinct phases of acoustic emissions were observed during dehydration: the first one associated with a rapid loss of diameter and a significant increase in loss of xylem conductance (90%), and the second with slower changes in diameter and a significant increase in cellular damage. Based on PCA, a developed algorithm discriminated hydraulic-related acoustic signals from other sources, proposing a reconstruction of hydraulic vulnerability curves. Cellular damage preceded by hydraulic failure seems to lead to a lack of recovery. The second acoustic phase would allow detection of plant mortality.
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Affiliation(s)
- Lia Lamacque
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
- Institut Technique Interprofessionnel Plantes à Parfum, Médicinal, Aromatiques et Industrielles, 26740 Montboucher-sur-Jabron, France
- CNRS Aix-Marseille University, France
| | - Florian Sabin
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Stéphane Herbette
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Guillaume Charrier
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
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5
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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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6
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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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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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De Baerdemaeker NJF, Arachchige KNR, Zinkernagel J, Van den Bulcke J, Van Acker J, Schenk HJ, Steppe K. The stability enigma of hydraulic vulnerability curves: addressing the link between hydraulic conductivity and drought-induced embolism. TREE PHYSIOLOGY 2019; 39:1646-1664. [PMID: 31274162 DOI: 10.1093/treephys/tpz078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/29/2019] [Accepted: 06/13/2019] [Indexed: 05/29/2023]
Abstract
Maintaining xylem water transport under drought is vital for plants, but xylem failure does occur when drought-induced embolisms form and progressively spread through the xylem. The hydraulic method is widely considered the gold standard to quantify drought-induced xylem embolism. The method determines hydraulic conductivity (Kh) in cut branch samples, dehydrated to specific drought levels, by pushing water through them. The technique is widely considered for its reliable Kh measurements, but there is some uncertainty in the literature over how to define stable Kh and how that relates to the degree of xylem embolism formation. Therefore, the most common setup for this method was extended to measure four parameters: (i) inlet Kh, (ii) outlet Kh, (iii) radial flow from xylem to surrounding living tissue and (iv) the pressure difference across the sample. From a strictly theoretical viewpoint, hydraulic steady state, where inflow equals outflow and radial flow is zero, will result in stable Kh. Application of the setup to Malus domestica Borkh. branches showed that achieving hydraulic steady state takes considerable time (up to 300 min) and that time to reach steady state increased with declining xylem water potentials. During each experimental run, Kh and xylem water potentials dynamically increased, which was supported by X-ray computed microtomography visualizations of embolism refilling under both high- (8 kPa) and low-pressure (2 kPa) heads. Supplying pressurized water can hence cause artificial refilling of vessels, which makes it difficult to achieve a truly stable Kh in partially embolized xylem.
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Affiliation(s)
- Niels J F De Baerdemaeker
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | | | - Jana Zinkernagel
- Department of Vegetable Crops, Hochschule Geisenheim University, 65366 Geisenheim, Germany
| | - Jan Van den Bulcke
- UGCT-Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Joris Van Acker
- UGCT-Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - H Jochen Schenk
- Plants and H2O Laboratory, Department of Biological Science, California State University Fullerton, PO Box 6850, Fullerton, CA 92834-6850, USA
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
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Khait I, Obolski U, Yovel Y, Hadany L. Sound perception in plants. Semin Cell Dev Biol 2019; 92:134-138. [PMID: 30965110 DOI: 10.1016/j.semcdb.2019.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 03/29/2019] [Indexed: 12/21/2022]
Abstract
Can plants perceive sound? And what sounds are they likely to be "listening" to? The environment of plants includes many informative sounds, produced by biotic and abiotic sources. An ability to respond to these sounds could thus have a significant adaptive value for plants. We suggest the term phytoacoustics to describe the emerging field exploring sound emission and sound detection in plants, and review the recent studies published on these topics. We describe evidence of plant responses to sounds, varying from changes in gene expression to changes in pathogen resistance and nectar composition. The main focus of this review is the effect of airborne sounds on living plants. We also review work on sound emissions by plants, and plant morphological adaptations to sound. Finally, we discuss the ecological contexts where response to sound would be most advantageous to plants.
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Affiliation(s)
- I Khait
- School of Plant Sciences and Food Security, Tel-Aviv University, Tel-Aviv, Israel
| | - U Obolski
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Y Yovel
- School of Zoology, Tel-Aviv University, Tel-Aviv, Israel
| | - L Hadany
- School of Plant Sciences and Food Security, Tel-Aviv University, Tel-Aviv, Israel.
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De Baerdemaeker NJF, Stock M, Van den Bulcke J, De Baets B, Van Hoorebeke L, Steppe K. X-ray microtomography and linear discriminant analysis enable detection of embolism-related acoustic emissions. PLANT METHODS 2019; 15:153. [PMID: 31889977 PMCID: PMC6916244 DOI: 10.1186/s13007-019-0543-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/05/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND Acoustic emission (AE) sensing is in use since the late 1960s in drought-induced embolism research as a non-invasive and continuous method. It is very well suited to assess a plant's vulnerability to dehydration. Over the last couple of years, AE sensing has further improved due to progress in AE sensors, data acquisition methods and analysis systems. Despite these recent advances, it is still challenging to detect drought-induced embolism events in the AE sources registered by the sensors during dehydration, which sometimes questions the quantitative potential of AE sensing. RESULTS In quest of a method to separate embolism-related AE signals from other dehydration-related signals, a 2-year-old potted Fraxinus excelsior L. tree was subjected to a drought experiment. Embolism formation was acoustically measured with two broadband point-contact AE sensors while simultaneously being visualized by X-ray computed microtomography (µCT). A machine learning method was used to link visually detected embolism formation by µCT with corresponding AE signals. Specifically, applying linear discriminant analysis (LDA) on the six AE waveform parameters amplitude, counts, duration, signal strength, absolute energy and partial power in the range 100-200 kHz resulted in an embolism-related acoustic vulnerability curve (VCAE-E) better resembling the standard µCT VC (VCCT), both in time and in absolute number of embolized vessels. Interestingly, the unfiltered acoustic vulnerability curve (VCAE) also closely resembled VCCT, indicating that VCs constructed from all registered AE signals did not compromise the quantitative interpretation of the species' vulnerability to drought-induced embolism formation. CONCLUSION Although machine learning could detect similar numbers of embolism-related AE as µCT, there still is insufficient model-based evidence to conclusively attribute these signals to embolism events. Future research should therefore focus on similar experiments with more in-depth analysis of acoustic waveforms, as well as explore the possibility of Fast Fourier transformation (FFT) to remove non-embolism-related AE signals.
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Affiliation(s)
- Niels J. F. De Baerdemaeker
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Michiel Stock
- KERMIT, Department of Data Analysis and Mathematical Modelling, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Jan Van den Bulcke
- UGent-Woodlab-Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
- Ghent University Centre for X-Ray Tomography (UGCT), Proeftuinstraat 86, 9000 Ghent, Belgium
| | - Bernard De Baets
- KERMIT, Department of Data Analysis and Mathematical Modelling, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Luc Van Hoorebeke
- Ghent University Centre for X-Ray Tomography (UGCT), Proeftuinstraat 86, 9000 Ghent, Belgium
- Radiation Physics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
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11
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Doinikov AA, Dollet B, Marmottant P. Cavitation in a liquid-filled cavity surrounded by an elastic medium: Intercoupling of cavitation events in neighboring cavities. Phys Rev E 2018; 98:013108. [PMID: 30110874 DOI: 10.1103/physreve.98.013108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Indexed: 11/07/2022]
Abstract
The subject of the present theoretical study is the dynamics of a cavitation bubble in a spherical liquid-filled cavity surrounded by an infinite elastic solid. Two objectives are pursued. The first is to derive equations for the velocity and pressure fields throughout the liquid filling the cavity and equations for the stress and strain fields throughout the solid medium surrounding the cavity. This derivation is based on the results of our previous paper [A. A. Doinikov et al., Phys. Rev. E 97, 013108 (2018)10.1103/PhysRevE.97.013108], where equations for the evolution of a bubble inside a cavity were derived. The second objective is to apply the equations obtained at the first step of the study to ascertain if the cavitation process in one cavity can trigger the nucleation in a neighboring cavity. To this end, we consider a neighboring cavity in which a cavitation bubble is absent. We derive equations that describe the disturbance of the liquid pressure inside the second cavity, assuming this disturbance to be caused by the cavitation process in the first cavity. The developed theory is then used to perform numerical simulations. The results of the simulations show that the magnitude of the background negative pressure inside the second cavity increases at the second half period of the pressure disturbance, which in turn enhances the probability of nucleation in the second cavity.
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Affiliation(s)
| | - Benjamin Dollet
- LIPhy UMR 5588, CNRS/Université Grenoble-Alpes, Grenoble F-38401, France
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12
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Zhang Y, Lamarque LJ, Torres-Ruiz JM, Schuldt B, Karimi Z, Li S, Qin DW, Bittencourt P, Burlett R, Cao KF, Delzon S, Oliveira R, Pereira L, Jansen S. Testing the plant pneumatic method to estimate xylem embolism resistance in stems of temperate trees. TREE PHYSIOLOGY 2018; 38:1016-1025. [PMID: 29474679 PMCID: PMC6025199 DOI: 10.1093/treephys/tpy015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/19/2018] [Accepted: 01/31/2018] [Indexed: 05/23/2023]
Abstract
Methods to estimate xylem embolism resistance generally rely on hydraulic measurements, which can be far from straightforward. Recently, a pneumatic method based on air flow measurements of terminal branch ends was proposed to construct vulnerability curves by linking the amount of air extracted from a branch with the degree of embolism. We applied this novel technique for 10 temperate tree species, including six diffuse, two ring-porous and two gymnosperm species, and compared the pneumatic curves with hydraulic ones obtained from either the flow-centrifuge or the hydraulic-bench dehydration method. We found that the pneumatic method provides a good estimate of the degree of xylem embolism for all angiosperm species. The xylem pressure at 50% and 88% loss of hydraulic conductivity (i.e., Ψ50 and Ψ88) based on the methods applied showed a strongly significant correlation for all eight angiosperms. However, the pneumatic method showed significantly reduced Ψ50 values for the two conifers. Our findings suggest that the pneumatic method could provide a fast and accurate approach for angiosperms due to its convenience and feasibility, at least within the range of embolism resistances covered by our samples.
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Affiliation(s)
- Ya Zhang
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, Germany
| | - Laurent J Lamarque
- BIOGECO, INRA, University of Bordeaux, Pessac, France
- EGFV, INRA, University of Bordeaux, Villenave d’Ornon, France
| | | | - Bernhard Schuldt
- Albrecht-von-Haller-Institute for Plant Sciences, Göttingen University, Göttingen, Germany
| | - Zohreh Karimi
- Department of Biology, Faculty of Science, Golestan University, Gorgan, Iran
| | - Shan Li
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, Germany
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, PR China
| | - De-Wen Qin
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, PR China
| | - Paulo Bittencourt
- Department of Plant Biology, Institute of Biology, PO Box 6109, University of Campinas – UNICAMP, Campinas, SP, Brazil
| | - Régis Burlett
- BIOGECO, INRA, University of Bordeaux, Pessac, France
| | - Kun-Fang Cao
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, PR China
| | | | - Rafael Oliveira
- Department of Plant Biology, Institute of Biology, PO Box 6109, University of Campinas – UNICAMP, Campinas, SP, Brazil
| | - Luciano Pereira
- Department of Plant Biology, Institute of Biology, PO Box 6109, University of Campinas – UNICAMP, Campinas, SP, Brazil
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, Germany
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Doinikov AA, Dollet B, Marmottant P. Model for the growth and the oscillation of a cavitation bubble in a spherical liquid-filled cavity enclosed in an elastic medium. Phys Rev E 2018; 97:013108. [PMID: 29448487 DOI: 10.1103/physreve.97.013108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Indexed: 06/08/2023]
Abstract
Equations are derived that describe the growth and subsequent damped oscillation of a cavitation bubble in a liquid-filled cavity surrounded by an elastic solid. It is assumed that the nucleation and the growth of the bubble are caused by an initial negative pressure in the cavity. The liquid is treated as viscous and compressible. The obtained equations allow one to model, by numerical computation, the growth and the oscillation of the bubble in the cavity and the oscillation of the cavity surface. It is shown that the equilibrium radius reached by the growing bubble decreases when the absolute magnitude of the initial negative pressure decreases. It is also found that the natural frequency of the bubble oscillation increases with increasing bubble radius. This result is of special interest because in an unbounded liquid, the natural frequency of a bubble is known to behave oppositely, namely it decreases with increasing bubble radius.
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Affiliation(s)
| | - Benjamin Dollet
- LIPhy UMR 5588, CNRS/Université Grenoble-Alpes, Grenoble F-38401, France
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14
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De Baerdemaeker NJF, Salomón RL, De Roo L, Steppe K. Sugars from woody tissue photosynthesis reduce xylem vulnerability to cavitation. THE NEW PHYTOLOGIST 2017; 216:720-727. [PMID: 28921550 DOI: 10.1111/nph.14787] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/13/2017] [Indexed: 05/23/2023]
Abstract
Reassimilation of internal CO2 via woody tissue photosynthesis has a substantial effect on tree carbon income and wood production. However, little is known about its role in xylem vulnerability to cavitation and its implications in drought-driven tree mortality. Young trees of Populus nigra were subjected to light exclusion at the branch and stem levels. After 40 d, measurements of xylem water potential, diameter variation and acoustic emission (AE) were performed in detached branches to obtain acoustic vulnerability curves to cavitation following bench-top dehydration. Acoustic vulnerability curves and derived AE50 values (i.e. water potential at which 50% of cavitation-related acoustic emissions occur) differed significantly between light-excluded and control branches (AE50,light-excluded = -1.00 ± 0.13 MPa; AE50,control = -1.45 ± 0.09 MPa; P = 0.007) denoting higher vulnerability to cavitation in light-excluded trees. Woody tissue photosynthesis represents an alternative and immediate source of nonstructural carbohydrates (NSC) that confers lower xylem vulnerability to cavitation via sugar-mediated mechanisms. Embolism repair and xylem structural changes could not explain this observation as the amount of cumulative AE and basic wood density did not differ between treatments. We suggest that woody tissue assimilates might play a role in the synthesis of xylem surfactants for nanobubble stabilization under tension.
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Affiliation(s)
- Niels J F De Baerdemaeker
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium
| | - Roberto Luis Salomón
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium
| | - Linus De Roo
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium
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15
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Water (stress) models and deficit irrigation: System-theoretical description and causality mapping. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.07.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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16
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Drysdale C, Doinikov AA, Marmottant P. Radiation dynamics of a cavitation bubble in a liquid-filled cavity surrounded by an elastic solid. Phys Rev E 2017; 95:053104. [PMID: 28618494 DOI: 10.1103/physreve.95.053104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Indexed: 06/07/2023]
Abstract
A specific cavitation phenomenon occurs inside the stems of trees. The internal pressure in tree conduits can drop down to significant negative values, which causes the nucleation of bubbles. The bubbles exhibit high-frequency oscillations just after their nucleation. In the present study, this phenomenon is modeled by taking into account acoustic waves produced by bubble oscillations. A dispersion equation is derived, which is then used to calculate the resonance frequency and the attenuation coefficient of the bubble oscillations. Radiation damping is found to be predominant in comparison with viscous damping, except for very small bubbles. A typical number of oscillation cycles before the complete damping of the oscillation is found to be of the order of 10, as observed for cavitation bubbles in biomimetic synthetic trees.
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17
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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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18
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Kratochvil HG, Pollirer M. Acoustic effects during photosynthesis of aquatic plants enable new research opportunities. Sci Rep 2017; 7:44526. [PMID: 28291222 PMCID: PMC5349586 DOI: 10.1038/srep44526] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 02/10/2017] [Indexed: 11/10/2022] Open
Abstract
Measurements of photosynthetic processes in hydrophytes mostly involve photosynthometers, which capture the escaping gas for subsequent analysis The most common method to detect changes in the rate of photosynthetic processes is to count the series of escaping gas bubbles. The emerging bubbles are either simply counted or they are recorded using light barriers, which is very difficult because of their small size and often varying ascent rate. The gas bubbles generated during photosynthesis by aquatic plants produce distinctive sound pulses when leaving the plants. These acoustic side effects enable completely new and highly accurate measurements. The frequency and reaction time changes of the pulses caused by external influences are therefore accurately detectable. The precise time measurements enable registering and evaluating the curves as reactions to changes in physical or chemical environmental conditions. We show that such acoustic analyses open completely new research opportunities for plant physiology.
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Affiliation(s)
- Helmut G Kratochvil
- Dep. Integrative Zoologie, University of Vienna, Althanstr. 14, A-1090 Wien, Austria
| | - Michael Pollirer
- Dep. Integrative Zoologie, University of Vienna, Althanstr. 14, A-1090 Wien, Austria
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19
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Nolf M, Rosani A, Ganthaler A, Beikircher B, Mayr S. Herb Hydraulics: Inter- and Intraspecific Variation in Three Ranunculus Species. PLANT PHYSIOLOGY 2016; 170:2085-94. [PMID: 26896395 PMCID: PMC4825137 DOI: 10.1104/pp.15.01664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/05/2016] [Indexed: 05/02/2023]
Abstract
The requirements of the water transport system of small herbaceous species differ considerably from those of woody species. Despite their ecological importance for many biomes, knowledge regarding herb hydraulics remains very limited. We compared key hydraulic features (vulnerability to drought-induced hydraulic decline, pressure-volume relations, onset of cellular damage, in situ variation of water potential, and stomatal conductance) of three Ranunculus species differing in their soil humidity preferences and ecological amplitude. All species were very vulnerable to water stress (50% reduction in whole-leaf hydraulic conductance [kleaf] at -0.2 to -0.8 MPa). In species with narrow ecological amplitude, the drought-exposed Ranunculus bulbosus was less vulnerable to desiccation (analyzed via loss of kleaf and turgor loss point) than the humid-habitat Ranunculus lanuginosus Accordingly, water stress-exposed plants from the broad-amplitude Ranunculus acris revealed tendencies toward lower vulnerability to water stress (e.g. osmotic potential at full turgor, cell damage, and stomatal closure) than conspecific plants from the humid site. We show that small herbs can adjust to their habitat conditions on interspecific and intraspecific levels in various hydraulic parameters. The coordination of hydraulic thresholds (50% and 88% loss of kleaf, turgor loss point, and minimum in situ water potential) enabled the study species to avoid hydraulic failure and damage to living cells. Reversible recovery of hydraulic conductance, desiccation-tolerant seeds, or rhizomes may allow them to prioritize toward a more efficient but vulnerable water transport system while avoiding the severe effects that water stress poses on woody species.
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Affiliation(s)
- Markus Nolf
- Institute of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | - Andrea Rosani
- Institute of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | - Andrea Ganthaler
- Institute of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Stefan Mayr
- Institute of Botany, University of Innsbruck, 6020 Innsbruck, Austria
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20
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Acoustic Emissions to Measure Drought-Induced Cavitation in Plants. APPLIED SCIENCES-BASEL 2016. [DOI: 10.3390/app6030071] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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21
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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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22
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Nolf M, Creek D, Duursma R, Holtum J, Mayr S, Choat B. Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species. PLANT, CELL & ENVIRONMENT 2015; 38:2652-61. [PMID: 26032606 DOI: 10.1111/pce.12581] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 05/15/2015] [Accepted: 05/18/2015] [Indexed: 05/05/2023]
Abstract
Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50 ) was lost at -2.1 to -3.1 MPa in stems and at -1.7 to -2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 - stem P50 ) were very narrow at -0.4 to -1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf hydraulics were finely tuned to avoid embolism formation in the xylem.
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Affiliation(s)
- Markus Nolf
- Institute of Botany, University of Innsbruck, 6020, Innsbruck, Austria
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, 2753, Australia
| | - Danielle Creek
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, 2753, Australia
| | - Remko Duursma
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, 2753, Australia
| | - Joseph Holtum
- School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, 4811, Australia
| | - Stefan Mayr
- Institute of Botany, University of Innsbruck, 6020, Innsbruck, Austria
| | - Brendan Choat
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales, 2753, Australia
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Ponomarenko A, Vincent O, Pietriga A, Cochard H, Badel É, Marmottant P. Ultrasonic emissions reveal individual cavitation bubbles in water-stressed wood. J R Soc Interface 2015; 11:rsif.2014.0480. [PMID: 25056212 DOI: 10.1098/rsif.2014.0480] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Under drought conditions, the xylem of trees that conducts ascending sap produces ultrasonic emissions whose exact origin is not clear. We introduce a new method to record simultaneously both acoustic events and optical observation of the xylem conduits within slices of wood that were embedded in a transparent material setting a hydric stress. In this article, we resolved the rapid development of all cavitation bubbles and demonstrated that each ultrasound emission was linked to the nucleation of one single bubble, whose acoustic energy is an increasing function of the size of the conduit where nucleation occurred and also of the hydric stress. We modelled these observations by the fact that water columns in conduits store elastic energy and release it into acoustic waves when they are broken by cavitation bubbles. Water columns are thus elastic, and not rigid, 'wires of water' set under tension by hydric stresses. Cavitation bubbles are at the origin of an embolism, whose development was followed in our experiments. Such an embolism of sap circulation can result in a fatal condition for living trees. These findings provide new insights for the non-destructive monitoring of embolisms within trees, and suggest a new approach to study porous media under hydric stress.
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Affiliation(s)
- A Ponomarenko
- Laboratoire Interdisciplinaire de Physique, LIPhy, CNRS et Université de Grenoble, Grenoble Cedex, France
| | - O Vincent
- Laboratoire Interdisciplinaire de Physique, LIPhy, CNRS et Université de Grenoble, Grenoble Cedex, France
| | - A Pietriga
- Laboratoire Interdisciplinaire de Physique, LIPhy, CNRS et Université de Grenoble, Grenoble Cedex, France
| | - H Cochard
- INRA, UMR 547 PIAF, 63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 547 PIAF, 63177, Aubière, France
| | - É Badel
- INRA, UMR 547 PIAF, 63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 547 PIAF, 63177, Aubière, France
| | - P Marmottant
- Laboratoire Interdisciplinaire de Physique, LIPhy, CNRS et Université de Grenoble, Grenoble Cedex, France
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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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25
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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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26
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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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27
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Rosner S. A new type of vulnerability curve: is there truth in vine? TREE PHYSIOLOGY 2015; 35:410-4. [PMID: 25240728 DOI: 10.1093/treephys/tpu080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/17/2014] [Indexed: 05/23/2023]
Affiliation(s)
- Sabine Rosner
- Institute of Botany, BOKU Vienna, Gregor Mendel Str. 33, A-1180 Vienna, Austria
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28
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Abstract
Water transport in plants is based on a metastable system as the xylem "works" at negative water potentials (ψ). At critically low ψ, water columns can break and cause embolism. According to the air-seeding hypothesis, this occurs by air entry via the pits. We studied the formation of embolism in dehydrating xylem sections of Juniperus virginiana (Cupressaceae), which were monitored microscopically and via ultrasonic emission analyses. After replacement of water by air in outer tracheid layers, a complex movement of air-water menisci into tracheids was found. With decreasing ψ, pits started to aspirate and the speed of menisci movements increased. In one experiment, an airseeding event could be detected at a pit. The onset of ultrasonic activity was observed when pits started to close, and ultrasonic emission ceased at intense dehydration. Experiments clearly indicated that predictions of the air-seeding hypothesis are correct: At low ψ, pit mechanisms to prevent air entry failed and air spread into tracheids. ψ fluctuations caused complex movements of air-water menisci and pits, and at low ψ, air-seeding caused ultrasonic emissions. Main insights are presented in a video.
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29
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McCulloh KA, Johnson DM, Meinzer FC, Woodruff DR. The dynamic pipeline: hydraulic capacitance and xylem hydraulic safety in four tall conifer species. PLANT, CELL & ENVIRONMENT 2014; 37:1171-83. [PMID: 24289816 DOI: 10.1111/pce.12225] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Recent work has suggested that plants differ in their relative reliance on structural avoidance of embolism versus maintenance of the xylem water column through dynamic traits such as capacitance, but we still know little about how and why species differ along this continuum. It is even less clear how or if different parts of a plant vary along this spectrum. Here we examined how traits such as hydraulic conductivity or conductance, xylem vulnerability curves, and capacitance differ in trunks, large- and small-diameter branches, and foliated shoots of four species of co-occurring conifers. We found striking similarities among species in most traits, but large differences among plant parts. Vulnerability to embolism was high in shoots, low in small- and large-diameter branches, and high again in the trunks. Safety margins, defined as the pressure causing 50% loss of hydraulic conductivity or conductance minus the midday water potential, were large in small-diameter branches, small in trunks and negative in shoots. Sapwood capacitance increased with stem diameter, and was correlated with stem vulnerability, wood density and latewood proportion. Capacitive release of water is a dynamic aspect of plant hydraulics that is integral to maintenance of long-distance water transport.
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Affiliation(s)
- Katherine A McCulloh
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
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30
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Rockwell FE, Wheeler JK, Holbrook NM. Cavitation and its discontents: opportunities for resolving current controversies. PLANT PHYSIOLOGY 2014; 164:1649-60. [PMID: 24501002 PMCID: PMC3982731 DOI: 10.1104/pp.113.233817] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/02/2014] [Indexed: 05/18/2023]
Abstract
Cavitation has long been recognized as a key constraint on the structure and functional integrity of the xylem. Yet, recent results call into question how well we understand cavitation in plants. Here, we consider embolism formation in angiosperms at two scales. The first focuses on how air-seeding occurs at the level of pit membranes, raising the question of whether capillary failure is an appropriate physical model. The second addresses methodological uncertainties that affect our ability to infer the formation of embolism and its reversal in plant stems. Overall, our goal is to open up fresh perspectives on the structure-function relationships of xylem.
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Affiliation(s)
- Fulton E. Rockwell
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853 (F.E.R.); and
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (J.K.W., N.M.H.)
| | - James K. Wheeler
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853 (F.E.R.); and
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (J.K.W., N.M.H.)
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31
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Cochard H, Badel E, Herbette S, Delzon S, Choat B, Jansen S. Methods for measuring plant vulnerability to cavitation: a critical review. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4779-91. [PMID: 23888067 DOI: 10.1093/jxb/ert193] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Xylem cavitation resistance has profound implications for plant physiology and ecology. This process is characterized by a 'vulnerability curve' (VC) showing the variation of the percentage of cavitation as a function of xylem pressure potential. The shape of this VC varies from 'sigmoidal' to 'exponential'. This review provides a panorama of the techniques that have been used to generate such a curve. The techniques differ by (i) the way cavitation is induced (e.g. bench dehydration, centrifugation, or air injection), and (ii) the way cavitation is measured (e.g. percentage loss of conductivity (PLC) or acoustic emission), and a nomenclature is proposed based on these two methods. A survey of the literature of more than 1200 VCs was used to draw statistics on the usage of these methods and on their reliability and validity. Four methods accounted for more than 96% of all curves produced so far: bench dehydration-PLC, centrifugation-PLC, pressure sleeve-PLC, and Cavitron. How the shape of VCs varies across techniques and species xylem anatomy was also analysed. Strikingly, it was found that the vast majority of curves obtained with the reference bench dehydration-PLC method are 'sigmoidal'. 'Exponential' curves were more typical of the three other methods and were remarkably frequent for species having large xylem conduits (ring-porous), leading to a substantial overestimation of the vulnerability of cavitation for this functional group. We suspect that 'exponential' curves may reflect an open-vessel artefact and call for more precautions with the usage of the pressure sleeve and centrifugation techniques.
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Affiliation(s)
- Hervé Cochard
- INRA, UMR 547 PIAF, F-63100 Clermont-Ferrand, France
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32
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Wolkerstorfer SV, Rosner S, Hietz P. An improved method and data analysis for ultrasound acoustic emissions and xylem vulnerability in conifer wood. PHYSIOLOGIA PLANTARUM 2012; 146:184-91. [PMID: 22380570 DOI: 10.1111/j.1399-3054.2012.01605.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The vulnerability of the xylem to cavitation is an important trait in plant drought resistance and has been quantified by several methods. We present a modified method for the simultaneous measurement of cavitations, recorded as ultrasound acoustic emissions (UAEs), and the water potential, measured with a thermocouple psychrometer, in small samples of conifer wood. Analyzing the amplitude of the individual signals showed that a first phase, during which the mean amplitude increased, was followed by a second phase with distinctly lower signal amplitudes. We provide a method to separate the two groups of signals and show that for many samples plausible vulnerability curves require rejecting late low-energy UAEs. These very likely do not result from cavitations. This method was used to analyze the differences between juvenile wood, and early and late mature wood in Picea abies (L.) Karst. Juvenile earlywood was more resistant to cavitation than mature earlywood or latewood, which we relate to the tracheid anatomy of the samples.
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Affiliation(s)
- Silviya V Wolkerstorfer
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences BOKU, A-1180 Vienna, Austria.
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33
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Charra-Vaskou K, Badel E, Burlett R, Cochard H, Delzon S, Mayr S. Hydraulic efficiency and safety of vascular and non-vascular components in Pinus pinaster leaves. TREE PHYSIOLOGY 2012; 32:1161-1170. [PMID: 22907978 DOI: 10.1093/treephys/tps071] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Leaves, the distal section of the soil-plant-atmosphere continuum, exhibit the lowest water potentials in a plant. In contrast to angiosperm leaves, knowledge of the hydraulic architecture of conifer needles is scant. We investigated the hydraulic efficiency and safety of Pinus pinaster needles, comparing different techniques. The xylem hydraulic conductivity (k(s)) and embolism vulnerability (P(50)) of both needle and stem were measured using the cavitron technique. The conductance and vulnerability of whole needles were measured via rehydration kinetics, and Cryo-SEM and 3D X-ray microtomographic observations were used as reference tools to validate physical measurements. The needle xylem of P. pinaster had lower hydraulic efficiency (k(s) = 2.0 × 10(-4) m(2) MPa(-1) s(-1)) and safety (P(50) = - 1.5 MPa) than stem xylem (k(s) = 7.7 × 10(-4) m(2) MPa(-1) s(-1); P(50) = - 3.6 to - 3.2 MPa). P(50) of whole needles (both extra-vascular and vascular pathways) was - 0.5 MPa, suggesting that non-vascular tissues were more vulnerable than the xylem. During dehydration to - 3.5 MPa, collapse and embolism in xylem tracheids, and gap formation in surrounding tissues were observed. However, a discrepancy in hydraulic and acoustic results appeared compared with visualizations, arguing for greater caution with these techniques when applied to needles. Our results indicate that the most distal parts of the water transport pathway are limiting for hydraulics of P. pinaster. Needle tissues exhibit a low hydraulic efficiency and low hydraulic safety, but may also act to buffer short-term water deficits, thus preventing xylem embolism.
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Affiliation(s)
- Katline Charra-Vaskou
- Department of Botany, University of Innsbruck, Sternwartestr. 15, A-6020 Innsbruck, Austria.
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Johnson DM, McCulloh KA, Woodruff DR, Meinzer FC. Evidence for xylem embolism as a primary factor in dehydration-induced declines in leaf hydraulic conductance. PLANT, CELL & ENVIRONMENT 2012; 35:760-9. [PMID: 21999411 DOI: 10.1111/j.1365-3040.2011.02449.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Hydraulic conductance of leaves (K(leaf)) typically decreases with increasing water stress and recent studies have proposed different mechanisms responsible for decreasing K(leaf) . We measured K(leaf) concurrently with ultrasonic acoustic emissions (UAEs) in dehydrating leaves of several species to determine whether declining K(leaf) was associated with xylem embolism. In addition, we performed experiments in which the surface tension of water in the leaf xylem was reduced by using a surfactant solution. Finally, we compared the hydraulic vulnerability of entire leaves with the leaf lamina in three species. Leaf hydraulic vulnerability based on rehydration kinetics and UAE was very similar, except in Quercus garryana. However, water potentials corresponding to the initial decline in K(leaf) and the onset of UAE in Q. garryana were similar. In all species tested, reducing the surface tension of water caused K(leaf) to decline at less negative water potentials compared with leaves supplied with water. Microscopy revealed that as the fraction of embolized xylem increased, K(leaf) declined sharply in Q. garryana. Measurements on leaf discs revealed that reductions in lamina hydraulic conductance with dehydration were not as great as those observed in intact leaves, suggesting that embolism was the primary mechanism for reductions in K(leaf) during dehydration.
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Affiliation(s)
- Daniel M Johnson
- Nicholas School of the Environment, Duke University, Durham, NC 27708, USA.
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35
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Barnard DM, Meinzer FC, Lachenbruch B, McCulloh KA, Johnson DM, Woodruff DR. Climate-related trends in sapwood biophysical properties in two conifers: avoidance of hydraulic dysfunction through coordinated adjustments in xylem efficiency, safety and capacitance. PLANT, CELL & ENVIRONMENT 2011; 34:643-654. [PMID: 21309793 DOI: 10.1111/j.1365-3040.2010.02269.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: 05/30/2023]
Abstract
In the Pacific north-west, the Cascade Mountain Range blocks much of the precipitation and maritime influence of the Pacific Ocean, resulting in distinct climates east and west of the mountains. The current study aimed to investigate relationships between water storage and transport properties in populations of Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) adapted to both climates. Sapwood thickness, capacitance, vulnerability to embolism, and axial and radial conductivity were measured on samples collected from trunks of mature trees. The sapwood of ponderosa pine was three to four times thicker than Douglas-fir. Radial conductivity was higher in west-side populations of both species, but axial conductivity was higher in the east-side populations and in Douglas-fir. Eastern populations of both species had sapwood that was more vulnerable to embolism than west-side populations. Sapwood capacitance was similar between species, but was about twice as great in east-side populations (580 kg m⁻³ MPa⁻¹) as in west-side populations (274 kg m⁻³ MPa⁻¹). Capacitance was positively correlated with both mean embolism pressure and axial conductivity across species and populations, suggesting that coordinated adjustments in xylem efficiency, safety and water storage capacity may serve to avoid embolism along a gradient of increasing aridity.
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Affiliation(s)
- David M Barnard
- Department of Horticulture and Landscape Architecture, Colorado State University, 111 Shepardson, 1173 Campus Delivery, Fort Collins, CO 80523-1173, USA.
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