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Losso A, Gauthey A, Choat B, Mayr S. Seasonal variation in the xylem sap composition of six Australian trees and shrubs. AoB Plants 2023; 15:plad064. [PMID: 37899974 PMCID: PMC10601387 DOI: 10.1093/aobpla/plad064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 09/11/2023] [Indexed: 10/31/2023]
Abstract
In recent years, xylem sap composition has been shown to affect xylem hydraulics. However, information on how much xylem sap composition can vary across seasons and specifically under drought stress is still limited. We measured xylem sap chemical composition ([Ca2+], [K+], [Na+], electrical conductivity EC and pH) and surface tension (γ) of six Australian angiosperm trees and shrubs over 1 year, which comprised of exceptional dry and wet periods. Percentage losses of hydraulic conductivity and predawn leaf water potential were also monitored. In all species, measured parameters changed considerably over the annual time course. Ions and pH tended to decrease during winter months whereas γ showed a slight increase. No clear correlation was found between sap and hydraulic parameters, except for pH that was higher when plants suffered higher drought stress levels. Results indicate xylem sap composition to be complex and dynamic, where most variation in its composition seems to be dictated by season, even under severe dry conditions. However, pH might play a role as signals of drought stress.
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Affiliation(s)
- Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797 Penrith, 2751 New South Wales, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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2
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Losso A, Dämon B, Hacke U, Mayr S. High potential for foliar water uptake in early stages of leaf development of three woody angiosperms. Physiol Plant 2023; 175:e13961. [PMID: 37341178 PMCID: PMC10953411 DOI: 10.1111/ppl.13961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/06/2023] [Accepted: 06/16/2023] [Indexed: 06/22/2023]
Abstract
Foliar water uptake (FWU) is a widespread mechanism that may help plants cope with drought stress in a wide range of ecosystems. FWU can be affected by various leaf traits, which change during leaf development. We exposed cut and dehydrated leaves to rainwater and measured FWU, changes in leaf water potential after 19 h of FWU (ΔΨ), minimum leaf conductance (gmin ), and leaf wettability (abaxial and adaxial) of leaves of Acer platanoides, Fagus sylvatica, and Sambucus nigra at three developmental stages: unfolding (2-5-day-old), young (1.5-week-old) and mature leaves (8-week-old). FWU and gmin were higher in younger leaves. ΔΨ corresponded to FWU and gmin in all cases but mature leaves of F. sylvatica, where ΔΨ was highest. Most leaves were highly wettable, and at least one leaf surface (adaxial or abaxial) showed a decrease in wettability from unfolding to mature leaves. Young leaves of all studied species showed FWU (unfolding leaves: 14.8 ± 1.1 μmol m-2 s-1 ), which may improve plant water status and thus counterbalance spring transpirational losses due to high gmin . The high wettability of young leaves probably supported FWU. We observed particularly high FWU and respective high ΔΨ in older leaves of F. sylvatica, possibly aided by trichomes.
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Affiliation(s)
- Adriano Losso
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Birgit Dämon
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Uwe Hacke
- Department of Renewable ResourcesUniversity of AlbertaEdmontonAlbertaCanada
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
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3
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Losso A, Challis A, Gauthey A, Nolan RH, Hislop S, Roff A, Boer MM, Jiang M, Medlyn BE, Choat B. Canopy dieback and recovery in Australian native forests following extreme drought. Sci Rep 2022; 12:21608. [PMID: 36517498 PMCID: PMC9751299 DOI: 10.1038/s41598-022-24833-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
In 2019, south-eastern Australia experienced its driest and hottest year on record, resulting in massive canopy dieback events in eucalypt dominated forests. A subsequent period of high precipitation in 2020 provided a rare opportunity to quantify the impacts of extreme drought and consequent recovery. We quantified canopy health and hydraulic impairment (native percent loss of hydraulic conductivity, PLC) of 18 native tree species growing at 15 sites that were heavily impacted by the drought both during and 8-10 months after the drought. Most species exhibited high PLC during drought (PLC:65.1 ± 3.3%), with no clear patterns across sites or species. Heavily impaired trees (PLC > 70%) showed extensive canopy browning. In the post-drought period, most surviving trees exhibited hydraulic recovery (PLC:26.1 ± 5.1%), although PLC remained high in some trees (50-70%). Regained hydraulic function (PLC < 50%) corresponded to decreased canopy browning indicating improved tree health. Similar drought (37.1 ± 4.2%) and post-drought (35.1 ± 4.4%) percentages of basal area with dead canopy suggested that trees with severely compromised canopies immediately after drought were not able to recover. This dataset provides insights into the impacts of severe natural drought on the health of mature trees, where hydraulic failure is a major contributor in canopy dieback and tree mortality during extreme drought events.
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Affiliation(s)
- Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria.
| | - Anthea Challis
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Plant Ecology Research Laboratory PERL, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015, Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
| | - Rachael H Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, NSW, Australia
| | - Samuel Hislop
- Forest Science, NSW Department of Primary Industries, Parramatta, NSW, 2150, Australia
| | - Adam Roff
- Department of Planning, Industry and Environment, Remote Sensing and Landscape Science, 26 Honeysuckle Drive, Newcastle, NSW, 2302, Australia
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- NSW Bushfire Risk Management Research Hub, Wollongong, NSW, Australia
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- College of Life Sciences, Zhejiang University, 866 Yuhangtang Rd, Hangzhou, Zhejiang, China
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia.
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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 Biol (Stuttg) 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Oberleitner F, Hartmann H, Hasibeder R, Huang J, Losso A, Mayr S, Oberhuber W, Wieser G, Bahn M. Amplifying effects of recurrent drought on the dynamics of tree growth and water use in a subalpine forest. Plant Cell Environ 2022; 45:2617-2635. [PMID: 35610775 DOI: 10.1111/pce.14369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/16/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Despite recent advances in our understanding of drought impacts on tree functioning, we lack knowledge about the dynamic responses of mature trees to recurrent drought stress. At a subalpine forest site, we assessed the effects of three years of recurrent experimental summer drought on tree growth and water relations of Larix decidua Mill. and Picea abies (L. Karst.), two common European conifers representative for contrasting water-use strategies. We combined dendrometer and xylem sap flow measurements with analyses of xylem anatomy and non-structural carbohydrates and their carbon-isotope composition. Recurrent drought increased the effects of soil moisture limitation on growth and xylogenesis, and to a lesser extent on xylem sap flow. P. abies showed stronger growth responses to recurrent drought, reduced starch concentrations in branches and increased water-use efficiency when compared to L. decidua. Despite comparatively larger maximum tree water deficits than in P. abies, xylem formation of L. decidua was less affected by drought, suggesting a stronger capacity of rehydration or lower cambial turgor thresholds for growth. Our study shows that recurrent drought progressively increases impacts on mature trees of both species, which suggests that in a future climate increasing drought frequency could impose strong legacies on carbon and water dynamics of treeline species.
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Affiliation(s)
| | - Henrik Hartmann
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Roland Hasibeder
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Jianbei Huang
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Gerhard Wieser
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Department of Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW), Innsbruck, Austria
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
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6
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Ganthaler A, Bär A, Dämon B, Losso A, Nardini A, Dullin C, Tromba G, von Arx G, Mayr S. Alpine dwarf shrubs show high proportions of nonfunctional xylem: Visualization and quantification of species-specific patterns. Plant Cell Environ 2022; 45:55-68. [PMID: 34783044 DOI: 10.1111/pce.14226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
Xylem conductive capacity is a key determinant of plant hydraulic function and intimately linked to photosynthesis and productivity, but can be impeded by temporary or permanent conduit dysfunctions. Here we show that persistent xylem dysfunctions in unstressed plants are frequent in Alpine dwarf shrubs and occur in various but species-specific cross-sectional patterns. Combined synchrotron micro-computed tomography (micro-CT) imaging, xylem staining, and flow measurements in saturated samples of six widespread Ericaceae species evidence a high proportion (19%-50%) of hydraulically nonfunctional xylem areas in the absence of drought stress, with regular distribution of dysfunctions between or within growth rings. Dysfunctions were only partly reversible and reduced the specific hydraulic conductivity to 1.38 to 3.57 ×10-4 m2 s-1 MPa-1 . Decommission of inner growth rings was clearly related to stem age and a higher vulnerability to cavitation of older rings, while the high proportion of nonfunctional conduits in each annual ring needs further investigations. The lower the xylem fraction contributing to the transport function, the higher was the hydraulic efficiency of conducting xylem areas. Improved understanding of the functional lifespan of xylem elements and the prevalence and nature of dysfunctions is critical to correctly assess structure-function relationships and whole-plant hydraulic strategies.
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Affiliation(s)
- Andrea Ganthaler
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Andreas Bär
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Birgit Dämon
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
| | - Christian Dullin
- Elettra-Sincrotrone Trieste, Basovizza, Italy
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
- Diagnostic and Interventional Radiology, University Hospital, Heidelberg, Germany
| | | | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
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7
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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8
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Beikircher B, Sack L, Ganthaler A, Losso A, Mayr S. Hydraulic-stomatal coordination in tree seedlings: tight correlation across environments and ontogeny in Acer pseudoplatanus. New Phytol 2021; 232:1297-1310. [PMID: 34176137 DOI: 10.1111/nph.17585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
Hydraulic conductance is recognized as a major determinant of gas exchange and productivity. However, whether this also applies to seedlings, a critically important stage for vegetation regeneration, has been largely unknown. We analyzed the hydraulic and stomatal conductance of leaves and shoots for 6-wk-old Acer pseudoplatanus seedlings emerging in different lowland and treeline habitats and under glasshouse conditions, respectively, as well as on 9-, 15- and 18-wk-old plants, and related findings to leaf and xylem anatomical traits. Treeline seedlings had higher leaf area-specific shoot hydraulic conductance (Kshoot-L ), and stomatal conductance (gs ), associated with wider xylem conduits, lower leaf area and higher stomatal density than lowland and glasshouse-grown plants. Across the first 18 wk of development, seedlings increased four-fold in absolute shoot hydraulic conductance (Kshoot ) and declined by half in Kshoot-L , with correlated shifts in xylem and leaf anatomy. Distal leaves had higher leaf hydraulic conductance (Kleaf ) and gs compared to basal leaves. Seedlings show strong variation across growth environments and ontogenetic shifts in hydraulic and anatomical parameters. Across growth sites, ontogenetic stages and leaf orders, gs was tightly correlated with Kshoot-L and Kleaf , balancing hydraulic supply with demand for the earliest stages of seedling establishment.
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Affiliation(s)
- Barbara Beikircher
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California (UCLA), 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestr. 15, Innsbruck, 6020, Austria
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Feng F, Losso A, Tyree M, Zhang S, Mayr S. Cavitation fatigue in conifers: a study on eight European species. Plant Physiol 2021; 186:1580-1590. [PMID: 33905499 PMCID: PMC8260135 DOI: 10.1093/plphys/kiab170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/27/2021] [Indexed: 06/12/2023]
Abstract
After drought-induced embolism and repair, tree xylem may be weakened against future drought events (cavitation fatigue). As there are few data on cavitation fatigue in conifers available, we quantified vulnerability curves (VCs) after embolism/repair cycles on eight European conifer species. We induced 50% and 100% loss of conductivity (LC) with a cavitron, and analyzed VCs. Embolism repair was obtained by vacuum infiltration. All species demonstrated complete embolism repair and a lack of any cavitation fatigue after 50% LC . After 100% LC, European larch (Larix decidua), stone pine (Pinus cembra), Norway spruce (Picea abies), and silver fir (Abies alba) remained unaffected, while mountain pine (Pinus mugo), yew (Taxus baccata), and common juniper (Juniperus communis) exhibited 0.4-0.9 MPa higher vulnerability to embolism. A small cavitation fatigue observed in Scots pine (Pinus sylvestris) was probably biased by incomplete embolism repair, as indicated by a correlation of vulnerability shifts and conductivity restoration. Our data demonstrate that cavitation fatigue in conifers is species-specific and depends on the intensity of preceding LC. The lack of fatigue effects after moderate LC, and relevant effects in only three species after high LC, indicate that conifers are relatively resistant against cavitation fatigue. This is remarkable considering the complex and delicate conifer pit architecture and may be important considering climate change projections.
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Affiliation(s)
- Feng Feng
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, Shaanxi 711600, China
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck 6020, Austria
| | - Melvin Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Shuoxin Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, Shaanxi 711600, China
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck 6020, Austria
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10
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Nolan RH, Gauthey A, Losso A, Medlyn BE, Smith R, Chhajed SS, Fuller K, Song M, Li X, Beaumont LJ, Boer MM, Wright IJ, Choat B. Hydraulic failure and tree size linked with canopy die-back in eucalypt forest during extreme drought. New Phytol 2021; 230:1354-1365. [PMID: 33629360 DOI: 10.1111/nph.17298] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 02/17/2021] [Indexed: 06/12/2023]
Abstract
Eastern Australia was subject to its hottest and driest year on record in 2019. This extreme drought resulted in massive canopy die-back in eucalypt forests. The role of hydraulic failure and tree size on canopy die-back in three eucalypt tree species during this drought was examined. We measured pre-dawn and midday leaf water potential (Ψleaf ), per cent loss of stem hydraulic conductivity and quantified hydraulic vulnerability to drought-induced xylem embolism. Tree size and tree health was also surveyed. Trees with most, or all, of their foliage dead exhibited high rates of native embolism (78-100%). This is in contrast to trees with partial canopy die-back (30-70% canopy die-back: 72-78% native embolism), or relatively healthy trees (little evidence of canopy die-back: 25-31% native embolism). Midday Ψleaf was significantly more negative in trees exhibiting partial canopy die-back (-2.7 to -6.3 MPa), compared with relatively healthy trees (-2.1 to -4.5 MPa). In two of the species the majority of individuals showing complete canopy die-back were in the small size classes. Our results indicate that hydraulic failure is strongly associated with canopy die-back during drought in eucalypt forests. Our study provides valuable field data to help constrain models predicting mortality risk.
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Affiliation(s)
- Rachael H Nolan
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Bushfire Risk Management Research Hub, Wollongong, NSW, 2522, Australia
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Adriano Losso
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, 6020, Austria
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Rhiannon Smith
- Ecosystem Management, University of New England, Armidale, NSW, 2351, Australia
| | - Shubham S Chhajed
- Department of Biological Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
| | - Kathryn Fuller
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Bushfire Risk Management Research Hub, Wollongong, NSW, 2522, Australia
| | - Magnolia Song
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Xine Li
- Department of Biological Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
- Department of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, 225009, China
| | - Linda J Beaumont
- Department of Biological Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
| | - Matthias M Boer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
- Bushfire Risk Management Research Hub, Wollongong, NSW, 2522, Australia
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Macquarie Park, NSW, 2109, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
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11
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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12
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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 (Berl 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] [What about the content of this article? (0)] [Affiliation(s)] [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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13
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Bär A, Hamacher M, Ganthaler A, Losso A, Mayr S. Electrical resistivity tomography: patterns in Betula pendula, Fagus sylvatica, Picea abies and Pinus sylvestris. Tree Physiol 2019; 39:1262-1271. [PMID: 31070766 DOI: 10.1093/treephys/tpz052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 04/27/2019] [Indexed: 05/12/2023]
Abstract
Electrical resistivity (ER) tomography is a promising technique to minimally invasively study stems of living trees. It allows insights into xylem properties based on the cross-sectional distribution of ER that is governed by the wood's electrical conductance. In this study, ER measurements were carried out on four forest tree species, Betula pendula, Fagus sylvatica, Picea abies and Pinus sylvestris, to demonstrate interspecific, intraspecific and within-tree variation of ER tomograms. Further, ER patterns were linked to xylem moisture content (MC), electrolyte content and density obtained from wood core analyses. The ER patterns of both coniferous species, P. abies and P. sylvestris, were found to be more homogenous and concentric compared with the complex tomograms of angiosperms. However, the ER range of coniferous trees showed considerable intraspecific variation. Measurements near ground level showed pronounced effects on ER tomograms, highlighting the importance of the chosen measurement height. A strong relation between ER and wood density was found in F. sylvatica while ER patterns of conifers were mainly influenced by MC. Results demonstrate a high species specificity of ER tomograms and of respective influencing xylem traits. They underline the importance of reference measurements for a correct interpretation of ER studies.
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Affiliation(s)
- Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Monika Hamacher
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
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15
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Beikircher B, Losso A, Gemassmer M, Jansen S, Mayr S. Does fertilization explain the extraordinary hydraulic behaviour of apple trees? J Exp Bot 2019; 70:1915-1925. [PMID: 30793193 PMCID: PMC6436149 DOI: 10.1093/jxb/erz070] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 02/07/2019] [Indexed: 05/13/2023]
Abstract
Fertilization of woody plants plays a central role in agriculture and forestry, but little is known about how plant water relations are thereby affected. Here we investigated the impact of fertilization on tree hydraulics, and xylem and pit anatomy in the high-yield apple cultivars Golden and Red Delicious. In fertilized trees of Golden Delicious, specific hydraulic conductivity of branch xylem, hydraulic conductance of the root system, and maximum stomatal conductance increased considerably. In Red Delicious, differences between fertilized and control trees were less pronounced. In both cultivars, xylem embolism resistance of fertilized trees was significantly lower and stomatal closure occurred at lower water potentials. Furthermore, water potential at turgor loss point and osmotic potential at full saturation were higher and cell wall elasticity was lower in fertilized plants, suggesting reduced drought tolerance of leaves. Anatomical differences were observed regarding conduit diameters, cell wall reinforcement, pit membrane thickness, pit chamber depth, and stomatal pore length, with more pronounced differences in Golden Delicious. The findings reveal altered hydraulic behaviour in both apple cultivars upon fertilization. The increased vulnerability to hydraulic failure might pose a considerable risk for apple productivity under a changing climate, which should be considered for future cultivation and management practices.
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Affiliation(s)
- Barbara Beikircher
- University of Innsbruck, Institute of Botany, Sternwartestrasse, Innsbruck, Austria
| | - Adriano Losso
- University of Innsbruck, Institute of Botany, Sternwartestrasse, Innsbruck, Austria
| | - Marilena Gemassmer
- University of Innsbruck, Institute of Botany, Sternwartestrasse, Innsbruck, Austria
| | - Steven Jansen
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee, Ulm, Germany
| | - Stefan Mayr
- University of Innsbruck, Institute of Botany, Sternwartestrasse, Innsbruck, Austria
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16
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Losso A, Bär A, Dämon B, Dullin C, Ganthaler A, Petruzzellis F, Savi T, Tromba G, Nardini A, Mayr S, Beikircher B. Insights from in vivo micro-CT analysis: testing the hydraulic vulnerability segmentation in Acer pseudoplatanus and Fagus sylvatica seedlings. New Phytol 2019; 221:1831-1842. [PMID: 30347122 PMCID: PMC6492020 DOI: 10.1111/nph.15549] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/14/2018] [Indexed: 05/23/2023]
Abstract
The seedling stage is the most susceptible one during a tree's life. Water relations may be crucial for seedlings due to their small roots, limited water buffers and the effects of drought on water transport. Despite obvious relevance, studies on seedling xylem hydraulics are scarce as respective methodical approaches are limited. Micro-CT scans of intact Acer pseudoplatanus and Fagus sylvatica seedlings dehydrated to different water potentials (Ψ) allowed the simultaneous observation of gas-filled versus water-filled conduits and the calculation of percentage loss of conductivity (PLC) in stems, roots and leaves (petioles or main veins). Additionally, anatomical analyses were performed and stem PLC measured with hydraulic techniques. In A. pseudoplatanus, petioles showed a higher Ψ at 50% PLC (Ψ50 -1.13MPa) than stems (-2.51 MPa) and roots (-1.78 MPa). The main leaf veins of F. sylvatica had similar Ψ50 values (-2.26 MPa) to stems (-2.74 MPa) and roots (-2.75 MPa). In both species, no difference between root and stems was observed. Hydraulic measurements on stems closely matched the micro-CT based PLC calculations. Micro-CT analyses indicated a species-specific hydraulic architecture. Vulnerability segmentation, enabling a disconnection of the hydraulic pathway upon drought, was observed in A. pseudoplatanus but not in the especially shade-tolerant F. sylvatica. Hydraulic patterns could partly be related to xylem anatomical traits.
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Affiliation(s)
- Adriano Losso
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Andreas Bär
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Birgit Dämon
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Christian Dullin
- Institute for Diagnostic and Interventional RadiologyUniversity Medical Center GoettingenRobert‐Koch‐Straße 40Göttingen37075Germany
- Max‐Plank‐Institute for Experimental MedicineHermann‐Rein‐Straße 3Göttingen37075Germany
- Elettra‐Sincrotrone TriesteArea Science ParkTriesteBasovizza34149Italy
| | - Andrea Ganthaler
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Francesco Petruzzellis
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Tadeja Savi
- Department of Crop SciencesDivision of Viticulture and PomologyUniversity of Natural Resources and Life Sciences ViennaKonrad Lorenzstrasse 24TullnA‐3430Austria
| | - Giuliana Tromba
- Elettra‐Sincrotrone TriesteArea Science ParkTriesteBasovizza34149Italy
| | - Andrea Nardini
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Barbara Beikircher
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
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17
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Ganthaler A, Sailer J, Bär A, Losso A, Mayr S. Noninvasive Analysis of Tree Stems by Electrical Resistivity Tomography: Unraveling the Effects of Temperature, Water Status, and Electrode Installation. Front Plant Sci 2019; 10:1455. [PMID: 31798610 PMCID: PMC6865845 DOI: 10.3389/fpls.2019.01455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 10/18/2019] [Indexed: 05/12/2023]
Abstract
The increasing demand for tree and forest health monitoring due to ongoing climate change requires new future-oriented and nondestructive measurement techniques. Electrical resistivity (ER) tomography represents a promising and innovative approach, as it allows insights into living trees based on ER levels and ER cross-sectional distribution patterns of stems. However, it is poorly understood how external factors, such as temperature, tree water status, and electrode installation affect ER tomograms. In this study, ER measurements were carried out on three angiosperms (Betula pendula, Fagus sylvatica, Populus nigra) and three conifers (Larix decidua, Picea abies, Pinus cembra) exposed to temperatures between -10 and 30°C and to continuous dehydration down to -6.3 MPa in a laboratory experiment. Additionally, effects of removal of peripheral tissues (periderm, phloem, cambium) and electrode installation were tested. Temperature changes above the freezing point did not affect ER distribution patterns but average ER levels, which increased exponentially and about 2.5-fold from 30 to 0°C in all species. In contrast, freezing of stems caused a pronounced raise of ER, especially in peripheral areas. With progressive tree dehydration, average ER increased in all species except in B. pendula, and measured resistivities in the peripheral stem areas of both angiosperms and conifers were clearly linearly related to the tree water status. Removal of the periderm resulted in a slight decrease of high ER peaks. Installation of electrodes for a short period of 32-72 h before conducting the tomography caused small distortions in tomograms. Distortions became serious after long-term installation for several months, while mean ER was only slightly affected. The present study confirms that ER tomography of tree stems is sensitive to temperature and water status. Results help to improve ER tomogram interpretation and suggest that ER analyses may be suitable to nondestructively determinate the hydraulic status of trees. They thus provide a solid basis for further technological developments to enable presymptomatic detection of physiological stress in standing trees.
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18
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Petruzzellis F, Pagliarani C, Savi T, Losso A, Cavalletto S, Tromba G, Dullin C, Bär A, Ganthaler A, Miotto A, Mayr S, Zwieniecki MA, Nardini A, Secchi F. The pitfalls of in vivo imaging techniques: evidence for cellular damage caused by synchrotron X-ray computed micro-tomography. New Phytol 2018; 220:104-110. [PMID: 30040128 DOI: 10.1111/nph.15368] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 07/04/2018] [Indexed: 05/26/2023]
Abstract
Synchrotron X-ray computed micro-tomography (microCT) has emerged as a promising noninvasive technique for in vivo monitoring of xylem function, including embolism build-up under drought and hydraulic recovery following re-irrigation. Yet, the possible harmful effects of ionizing radiation on plant tissues have never been quantified. We specifically investigated the eventual damage suffered by stem living cells of three different species exposed to repeated microCT scans. Stem samples exposed to one, two or three scans were used to measure cell membrane and RNA integrity, and compared to controls never exposed to X-rays. Samples exposed to microCT scans suffered serious alterations to cell membranes, as revealed by marked increase in relative electrolyte leakage, and also underwent severe damage to RNA integrity. The negative effects of X-rays were apparent in all species tested, but the magnitude of damage and the minimum number of scans inducing negative effects were species-specific. Our data show that multiple microCT scans lead to disruption of fundamental cellular functions and processes. Hence, microCT investigation of phenomena that depend on physiological activity of living cells may produce erroneous results and lead to incorrect conclusions.
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Affiliation(s)
- Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Chiara Pagliarani
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, 10135, Torino, Italy
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
- Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 24, A-3430, Tulln, Vienna, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Silvia Cavalletto
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Giuliana Tromba
- Elettra Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy
| | - Christian Dullin
- Elettra Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
- Max-Plank-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - 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
| | - Andrea Miotto
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, One Shields Ave, Davis, CA, 95616, USA
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Francesca Secchi
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
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19
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Ganthaler A, Losso A, Mayr S. Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce. Plant Pathol 2018; 67:1122-1130. [PMID: 29861507 PMCID: PMC5969058 DOI: 10.1111/ppa.12842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri, a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n = 62) and by the use of a semiprofessional quadcopter (n = 13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background (R2 = 0.87) and with black background (R2 = 0.95), juvenile plants (R2 = 0.94), and top views and side views of entire tree crowns of adult trees (R2 = 0.98 and 0.88, respectively). Results underline that a well-defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time-efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.
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Affiliation(s)
- A. Ganthaler
- Department of BotanyUniversity InnsbruckSternwartestrasse 15InnsbruckA‐6020Austria
| | - A. Losso
- Department of BotanyUniversity InnsbruckSternwartestrasse 15InnsbruckA‐6020Austria
| | - S. Mayr
- Department of BotanyUniversity InnsbruckSternwartestrasse 15InnsbruckA‐6020Austria
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20
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Savi T, Miotto A, Petruzzellis F, Losso A, Pacilè S, Tromba G, Mayr S, Nardini A. Drought-induced embolism in stems of sunflower: A comparison of in vivo micro-CT observations and destructive hydraulic measurements. Plant Physiol Biochem 2017; 120:24-29. [PMID: 28968592 DOI: 10.1016/j.plaphy.2017.09.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 05/23/2023]
Abstract
Vulnerability curves (VCs) are a useful tool to investigate the susceptibility of plants to drought-induced hydraulic failure, and several experimental techniques have been used for their measurement. The validity of the bench dehydration method coupled to hydraulic measurements, considered as a 'golden standard', has been recently questioned calling for its validation with non-destructive methods. We compared the VCs of a herbaceous crop plant (Helianthus annuus) obtained during whole-plant dehydration followed by i) hydraulic flow measurements in stem segments (classical destructive method) or by ii) in vivo micro-CT observations of stem xylem conduits in intact plants. The interpolated P50 values (xylem water potential inducing 50% loss of hydraulic conductance) were -1.74 MPa and -0.87 MPa for the hydraulic and the micro-CT VC, respectively. Interpolated P20 values were similar, while P50 and P80 were significantly different, as evidenced by non-overlapping 95% confidence intervals. Our results did not support the tension-cutting artefact, as no overestimation of vulnerability was observed when comparing the hydraulic VC to that obtained with in vivo imaging. After one scan, 25% of plants showed signs of x-ray induced damage, while three successive scans caused the formation of a circular brownish scar in all tested plants. Our results support the validity of hydraulic measurements of samples excised under tension provided standard sampling and handling protocols are followed, but also show that caution is needed when investigating vital plant processes with x-ray imaging.
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Affiliation(s)
- Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy.
| | - Andrea Miotto
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Adriano Losso
- Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020 Innsbruck, Austria
| | - Serena Pacilè
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy; Dipartimento di Ingegneria e Architettura, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Stefan Mayr
- Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020 Innsbruck, Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
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22
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Losso A, Beikircher B, Dämon B, Kikuta S, Schmid P, Mayr S. Xylem Sap Surface Tension May Be Crucial for Hydraulic Safety. Plant Physiol 2017; 175:1135-1143. [PMID: 28982780 PMCID: PMC5664478 DOI: 10.1104/pp.17.01053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/02/2017] [Indexed: 05/05/2023]
Abstract
The surface tension (γ) of xylem sap plays a key role in stabilizing air-water interfaces at the pits between water- and gas-filled conduits to avoid air seeding at low water potentials. We studied seasonal changes in xylem sap γ in Picea abies and Pinus mugo growing at the alpine timberline. We analyzed their vulnerability to drought-induced embolism using solutions of different γ and estimated the potential effect of seasonal changes in γ on hydraulic vulnerability. In both species, xylem sap γ showed distinct seasonal courses between about 50 and 68 mn m-1 Solutions with low γ caused higher vulnerability to drought-induced xylem embolism. The water potential at 50% loss of hydraulic conductivity in P. abies and P. mugo was -3.35 and -3.86 MPa at γ of 74 mn m-1 but -2.11 and -2.09 MPa at 45 mn m-1 This indicates up to about 1 MPa seasonal variation in 50% loss of hydraulic conductivity. The results revealed pronounced effects of changes in xylem sap γ on the hydraulic safety of trees in situ. These effects also are relevant in vulnerability analyses, where the use of standard solutions with high γ overestimates hydraulic safety. Thus, γ should be considered carefully in hydraulic studies.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Birgit Dämon
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | - Silvia Kikuta
- Institute of Botany, University of Natural Resources and Life Sciences, BOKU Vienna, 1180 Vienna, Austria
| | - Peter Schmid
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
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23
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Charrier G, Nolf M, Leitinger G, Charra-Vaskou K, Losso A, Tappeiner U, Améglio T, Mayr S. Monitoring of Freezing Dynamics in Trees: A Simple Phase Shift Causes Complexity. Plant Physiol 2017; 173:2196-2207. [PMID: 28242655 PMCID: PMC5373037 DOI: 10.1104/pp.16.01815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/20/2017] [Indexed: 05/10/2023]
Abstract
During winter, trees have to cope with harsh conditions, including extreme freeze-thaw stress. This study focused on ice nucleation and propagation, related water shifts and xylem cavitation, as well as cell damage and was based on in situ monitoring of xylem (thermocouples) and surface temperatures (infrared imaging), ultrasonic emissions, and dendrometer analysis. Field experiments during late winter on Picea abies growing at the alpine timberline revealed three distinct freezing patterns: (1) from the top of the tree toward the base, (2) from thin branches toward the main stem's top and base, and (3) from the base toward the top. Infrared imaging showed freezing within branches from their base toward distal parts. Such complex freezing causes dynamic and heterogenous patterns in water potential and probably in cavitation. This study highlights the interaction between environmental conditions upon freezing and thawing and demonstrates the enormous complexity of freezing processes in trees. Diameter shrinkage, which indicated water fluxes within the stem, and acoustic emission analysis, which indicated cavitation events near the ice front upon freezing, were both related to minimum temperature and, upon thawing, related to vapor pressure deficit and soil temperature. These complex patterns, emphasizing the common mechanisms between frost and drought stress, shed new light on winter tree physiology.
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Affiliation(s)
- Guillaume Charrier
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.);
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.);
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.);
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.);
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Markus Nolf
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Georg Leitinger
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Katline Charra-Vaskou
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Adriano Losso
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Ulrike Tappeiner
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Thierry Améglio
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
| | - Stefan Mayr
- Department of Botany and Department of Ecology, University of Innsbruck, A-6020 Innsbruck, Austria (G.C., M.N., G.L., A.L., U.T., S.M.)
- Bordeaux Science Agro, Institut des Sciences de la Vigne et du Vin, Ecophysiologie et Génomique Fonctionnelle de la Vigne, Unité Mixte de Recherche 1287, F-33140 Villenave d'Ornon, France (G.C.)
- BIOGECO, Institut National de la Recherche Agronomique, Université Bordeaux, 33610 Cestas, France (G.C.)
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, New South Wales 2753, Australia (M.N.)
- Université Clermont Auvergne, Institut National de la Recherche Agronomique, PIAF, F-6300 Clermont-Ferrand, France (K.C.-V., T.A.); and
- Institute for Alpine Environment, European Academy Bozen, 39100 Bozen/Bolzano, Italy (U.T.)
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24
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Nardini A, Savi T, Losso A, Petit G, Pacilè S, Tromba G, Mayr S, Trifilò P, Lo Gullo MA, Salleo S. X-ray microtomography observations of xylem embolism in stems of Laurus nobilis are consistent with hydraulic measurements of percentage loss of conductance. New Phytol 2017; 213:1068-1075. [PMID: 27735069 DOI: 10.1111/nph.14245] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 09/02/2016] [Indexed: 06/06/2023]
Abstract
Drought-induced xylem embolism is a serious threat to plant survival under future climate scenarios. Hence, accurate quantification of species-specific vulnerability to xylem embolism is a key to predict the impact of climate change on vegetation. Low-cost hydraulic measurements of embolism rate have been suggested to be prone to artefacts, thus requiring validation by direct visualization of the functional status of xylem conduits using nondestructive imaging techniques, such as X-ray microtomography (microCT). We measured the percentage loss of conductance (PLC) of excised stems of Laurus nobilis (laurel) dehydrated to different xylem pressures, and compared results with direct observation of gas-filled vs water-filled conduits at a synchrotron-based microCT facility using a phase contrast imaging modality. Theoretical PLC calculated on the basis of microCT observations in stems of laurel dehydrated to different xylem pressures overall were in agreement with hydraulic measurements, revealing that this species suffers a 50% loss of xylem hydraulic conductance at xylem pressures averaging -3.5 MPa. Our data support the validity of estimates of xylem vulnerability to embolism based on classical hydraulic techniques. We discuss possible causes of discrepancies between data gathered in this study and those of recent independent reports on laurel hydraulics.
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Affiliation(s)
- Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Adriano Losso
- Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020, Innsbruck, Austria
| | - Giai Petit
- Dipartimento Territorio e Sistemi Agro-forestali, Università degli Studi di Padova, Viale dell'Università 16, 35020, Legnaro (PD), Italy
| | - Serena Pacilè
- Dipartimento di Ingegneria e Architettura, Università di Trieste, Piazzale Europa 1, 34127, Trieste, Italy
- Elettra-Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy
| | - Stefan Mayr
- Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020, Innsbruck, Austria
| | - Patrizia Trifilò
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, Università di Messina, Salita F. Stagno D'Alcontres 31, 98166, Messina, Italy
| | - Maria A Lo Gullo
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, Università di Messina, Salita F. Stagno D'Alcontres 31, 98166, Messina, Italy
| | - Sebastiano Salleo
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
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