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Eller CB, Rowland L, Oliveira RS, Bittencourt PRL, Barros FV, da Costa ACL, Meir P, Friend AD, Mencuccini M, Sitch S, Cox P. Modelling tropical forest responses to drought and El Niño with a stomatal optimization model based on xylem hydraulics. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170315. [PMID: 30297470 PMCID: PMC6178424 DOI: 10.1098/rstb.2017.0315] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2018] [Indexed: 11/12/2022] Open
Abstract
The current generation of dynamic global vegetation models (DGVMs) lacks a mechanistic representation of vegetation responses to soil drought, impairing their ability to accurately predict Earth system responses to future climate scenarios and climatic anomalies, such as El Niño events. We propose a simple numerical approach to model plant responses to drought coupling stomatal optimality theory and plant hydraulics that can be used in dynamic global vegetation models (DGVMs). The model is validated against stand-scale forest transpiration (E) observations from a long-term soil drought experiment and used to predict the response of three Amazonian forest sites to climatic anomalies during the twentieth century. We show that our stomatal optimization model produces realistic stomatal responses to environmental conditions and can accurately simulate how tropical forest E responds to seasonal, and even long-term soil drought. Our model predicts a stronger cumulative effect of climatic anomalies in Amazon forest sites exposed to soil drought during El Niño years than can be captured by alternative empirical drought representation schemes. The contrasting responses between our model and empirical drought factors highlight the utility of hydraulically-based stomatal optimization models to represent vegetation responses to drought and climatic anomalies in DGVMs.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Cleiton B Eller
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | - Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | - Fernanda V Barros
- Department of Plant Biology, Institute of Biology, UNICAMP, Campinas, Brazil
| | | | - Patrick Meir
- Research School of Biology, Australian National University, Canberra, Australia
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
| | - Andrew D Friend
- Department of Geography, University of Cambridge, Cambridge, UK
| | | | - Stephen Sitch
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Peter Cox
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
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202
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Fontes CG, Dawson TE, Jardine K, McDowell N, Gimenez BO, Anderegg L, Negrón-Juárez R, Higuchi N, Fine PVA, Araújo AC, Chambers JQ. Dry and hot: the hydraulic consequences of a climate change-type drought for Amazonian trees. Philos Trans R Soc Lond B Biol Sci 2018; 373:20180209. [PMID: 30297481 PMCID: PMC6178441 DOI: 10.1098/rstb.2018.0209] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2018] [Indexed: 11/12/2022] Open
Abstract
How plants respond physiologically to leaf warming and low water availability may determine how they will perform under future climate change. In 2015-2016, an unprecedented drought occurred across Amazonia with record-breaking high temperatures and low soil moisture, offering a unique opportunity to evaluate the performances of Amazonian trees to a severe climatic event. We quantified the responses of leaf water potential, sap velocity, whole-tree hydraulic conductance (Kwt), turgor loss and xylem embolism, during and after the 2015-2016 El Niño for five canopy-tree species. Leaf/xylem safety margins (SMs), sap velocity and Kwt showed a sharp drop during warm periods. SMs were negatively correlated with vapour pressure deficit, but had no significant relationship with soil water storage. Based on our calculations of canopy stomatal and xylem resistances, the decrease in sap velocity and Kwt was due to a combination of xylem cavitation and stomatal closure. Our results suggest that warm droughts greatly amplify the degree of trees' physiological stress and can lead to mortality. Given the extreme nature of the 2015-2016 El Niño and that temperatures are predicted to increase, this work can serve as a case study of the possible impact climate warming can have on tropical trees.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.
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Affiliation(s)
- Clarissa G Fontes
- Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94720, USA
- Ecosystem Science Division, Department of Science, Policy and Management, Environmental University of California Berkeley, Berkeley, CA, USA
| | - Kolby Jardine
- Climate Science Department, Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 74, Berkeley, CA 94720, USA
- Ciências de Florestas Tropicais, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus-AM 69067-375, Brazil
| | - Nate McDowell
- Pacific Northwest National Laboratory, Richland, WA, USA
| | - Bruno O Gimenez
- Ciências de Florestas Tropicais, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus-AM 69067-375, Brazil
| | - Leander Anderegg
- Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Robinson Negrón-Juárez
- Climate Science Department, Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 74, Berkeley, CA 94720, USA
| | - Niro Higuchi
- Ciências de Florestas Tropicais, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus-AM 69067-375, Brazil
| | - Paul V A Fine
- Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Alessandro C Araújo
- Department of Global Ecology, Carnegie Institution for Science, 260 Panama St., Stanford, CA 94305, USA
- Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, Belém, Pará 66095-100, Brazil
| | - Jeffrey Q Chambers
- Climate Science Department, Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 74, Berkeley, CA 94720, USA
- Department of Geography, University of California Berkeley, 507 McCone Hall #4740, Berkeley, CA 94720, USA
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203
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Lima TRA, Carvalho ECD, Martins FR, Oliveira RS, Miranda RS, Müller CS, Pereira L, Bittencourt PRL, Sobczak JCMSM, Gomes-Filho E, Costa RC, Araújo FS. Lignin composition is related to xylem embolism resistance and leaf life span in trees in a tropical semiarid climate. New Phytol 2018; 219:1252-1262. [PMID: 29767841 DOI: 10.1111/nph.15211] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [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: 12/04/2017] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Wood properties influence the leaf life span (LL) of tree crowns. As lignin is an important component of wood and the water transport system, we investigated its relationship with embolism resistance and the LL of several tree species in a seasonally dry tropical ecosystem. We determined total lignin and the monomer contents of guaiacyl (G) and syringyl (S) and related them to wood traits and xylem vulnerability to embolism (Ψ50 ) for the most common species of the Brazilian semiarid, locally known as Caatinga. Leaf life span was negatively related to Ψ50 and positively related to S : G, which was negatively related to Ψ50 . This means that greater S : G increases LL by reducing Ψ50 . Lignin content was not correlated with any variable. We found two apparently unrelated axes of drought resistance. One axis, associated with lignin monomeric composition, increases LL in the dry season as a result of lower xylem embolism vulnerability. The other, associated with wood density and stem water content, helps leafless trees to withstand drought and allows them to resprout at the end of the dry season. The monomeric composition of lignin (S : G) is therefore an important functional wood attribute affecting several key functional aspects of tropical tree species in a semiarid climate.
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Affiliation(s)
- Taysla R A Lima
- Ecology and Natural Resources Post-Graduate Program, Department of Biology, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil
| | - Ellen C D Carvalho
- Department of Biology, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil
| | - Fernando R Martins
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Rafael S Miranda
- Federal University of Piauí (UFPI/CPCE), Campus Professora Cinobelina Elvas, 64900-000, Bom Jesus, PI, Brazil
| | - Caroline S Müller
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Luciano Pereira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Paulo R L Bittencourt
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Jullyana C M S M Sobczak
- Institute of Rural Development, University of International Integration of African-Brazilian Lusophony, 62790-000, Redenção, CE, Brazil
| | - Enéas Gomes-Filho
- Department of Biochemistry and Molecular Biology, Federal University of Ceará, 60440-554, Fortaleza, CE, Brazil
| | - Rafael C Costa
- Department of Biology, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil
| | - Francisca S Araújo
- Department of Biology, Federal University of Ceará, 60440-900, Fortaleza, CE, Brazil
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204
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Hölttä T, Dominguez Carrasco MDR, Salmon Y, Aalto J, Vanhatalo A, Bäck J, Lintunen A. Water relations in silver birch during springtime: How is sap pressurised? Plant Biol (Stuttg) 2018; 20:834-847. [PMID: 29732663 DOI: 10.1111/plb.12838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 03/14/2018] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
Positive sap pressures are produced in the xylem of birch trees in boreal conditions during the time between the thawing of the soil and bud break. During this period, xylem embolisms accumulated during wintertime are refilled with water. The mechanism for xylem sap pressurization and its environmental drivers are not well known. We measured xylem sap flow, xylem sap pressure, xylem sap osmotic concentration, xylem and whole stem diameter changes, and stem and root non-structural carbohydrate concentrations, along with meteorological conditions at two sites in Finland during and after the sap pressurisation period. The diurnal dynamics of xylem sap pressure and sap flow during the sap pressurisation period varied, but were more often opposite to the diurnal pattern after bud burst, i.e. sap pressure increased and sap flow rate mostly decreased when temperature increased. Net conversion of soluble sugars to starch in the stem and roots occurred during the sap pressurisation period. Xylem sap osmotic pressure was small in comparison to total sap pressure, and it did not follow changes in environmental conditions or tree water relations. Based on these findings, we suggest that xylem sap pressurisation and embolism refilling occur gradually over a few weeks through water transfer from parenchyma cells to xylem vessels during daytime, and then the parenchyma are refilled mostly during nighttime by water uptake from soil. Possible drivers for water transfer from parenchyma cells to vessels are discussed. Also the functioning of thermal dissipation probes in conditions of changing stem water content is discussed.
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Affiliation(s)
- T Hölttä
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - M D R Dominguez Carrasco
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - Y Salmon
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Department of Physics, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - J Aalto
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Hyytiälä Forestry Station, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - A Vanhatalo
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - J Bäck
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
| | - A Lintunen
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki, Finland
- Department of Physics, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
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205
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Brinkmann N, Seeger S, Weiler M, Buchmann N, Eugster W, Kahmen A. Employing stable isotopes to determine the residence times of soil water and the temporal origin of water taken up by Fagus sylvatica and Picea abies in a temperate forest. New Phytol 2018; 219:1300-1313. [PMID: 29888480 DOI: 10.1111/nph.15255] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [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: 11/07/2017] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
We assessed how the seasonal variability of precipitation δ2 H and δ18 O is propagated into soil and xylem waters of temperate trees, applied a hydrological model to estimate the residence time distribution of precipitation in the soil, and identified the temporal origin of water taken up by Picea abies and Fagus sylvatica over 4 yr. Residence times of precipitation in the soil varied between a few days and several months and increased with soil depth. On average, 50% of water consumed by trees throughout a year had precipitated during the growing season, while 40% had precipitated in the preceding winter or even earlier. Importantly, we detected subtle differences with respect to the temporal origin of water used by the two species. We conclude that both current precipitation and winter precipitation are important for the water supply of temperate trees and that winter precipitation could buffer negative impacts of spring or summer droughts. Our study additionally provides the means to obtain realistic estimates of source water δ2 H and δ18 O values for trees from precipitation isotope data, which is essential for improving model-based interpretations of δ18 O and δ2 H values in plants.
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Affiliation(s)
- Nadine Brinkmann
- Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, Zurich, 8092, Switzerland
- Department of Environmental Sciences - Botany, University Basel, Schönbeinstrasse 6, Basel, 4056, Switzerland
| | - Stefan Seeger
- Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz 1, Freiburg, 79098, Germany
| | - Markus Weiler
- Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz 1, Freiburg, 79098, Germany
| | - Nina Buchmann
- Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, Zurich, 8092, Switzerland
| | - Werner Eugster
- Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, Zurich, 8092, Switzerland
| | - Ansgar Kahmen
- Department of Environmental Sciences - Botany, University Basel, Schönbeinstrasse 6, Basel, 4056, Switzerland
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206
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García-Cervigón AI, Olano JM, von Arx G, Fajardo A. Xylem adjusts to maintain efficiency across a steep precipitation gradient in two coexisting generalist species. Ann Bot 2018; 122:461-472. [PMID: 29800073 PMCID: PMC6110345 DOI: 10.1093/aob/mcy088] [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: 03/07/2018] [Accepted: 05/07/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND AND AIMS Trees adjust the configuration of their conductive system in response to changes in water availability, maximizing efficiency in wet environments and increasing safety in dry habitats. However, evidence of this general trend is not conclusive. Generalist species growing across broad climatic gradients provide an ideal framework to assess intra-specific xylem adjustments under contrasting environmental conditions. Our aims were to compare the response of xylem traits to variations in precipitation of two co-occurring generalist tree species, and to assess climate control on xylem trait variability and co-ordination. METHODS We evaluated xylem traits of Embothrium coccineum (Proteaceae, evergreen) and Nothofagus antarctica (Nothofagaceae, deciduous) in three areas across an abrupt precipitation gradient, from 500 to 2500 mm, in southern Chile. We measured wood density, vessel lumen area and density, percentage of conductive area and vessel grouping, and estimated the hydraulic function from anatomical measurements in 60 individuals per species. KEY RESULTS Both species shared a common pattern of response along the precipitation gradient, with an increase in vessel density with dryness, but without changes in estimated hydraulic conductivity. Xylem traits in E. coccineum were more variable and more responsive to the climate gradient, decreasing vessel lumen area and increasing wood density, whereas vessel grouping showed contrasting patterns between species. Additionally, the analysis of trait co-ordination at the individual level revealed a tighter co-ordination among xylem traits in E. coccineum. CONCLUSIONS Estimated xylem efficiency was maintained in combination with different levels of expected xylem safety within species. Reduction in vessel lumen area was compensated through large increases in vessel density, thus breaking the trade-off between xylem efficiency and safety. Otherwise, the existence of alternative internal adjustments in coexisting species to face similar climatic constraints might increase resilience of temperate forests against unpredictable changes in climatic conditions.
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Affiliation(s)
- Ana I García-Cervigón
- Departamento de Biología, Universidad de Cádiz, Campus Universitario de Puerto Real, Puerto Real, Spain
- For correspondence. E-mail
| | - José M Olano
- Departamento de Ciencias Agroforestales, EiFAB, Universidad de Valladolid, Soria, Spain
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile
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207
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Knipfer T, Barrios-Masias FH, Cuneo IF, Bouda M, Albuquerque CP, Brodersen CR, Kluepfel DA, McElrone AJ. Variations in xylem embolism susceptibility under drought between intact saplings of three walnut species. Tree Physiol 2018; 38:1180-1192. [PMID: 29850910 DOI: 10.1093/treephys/tpy049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
A germplasm collection containing varied Juglans genotypes holds potential to improve drought resistance of plant materials for commercial production. We used X-ray computed microtomography to evaluate stem xylem embolism susceptibility/repair in relation to vessel anatomical features (size, arrangement, connectivity and pit characteristics) in 2-year-old saplings of three Juglans species. In vivo analysis revealed interspecific variations in embolism susceptibility among Juglans microcarpa, J. hindsii (both native to arid habitats) and J. ailantifolia (native to mesic habitats). Stem xylem of J. microcarpa was more resistant to drought-induced embolism as compared with J. hindsii and J. ailantifolia (differences in embolism susceptibility among older and current year xylem were not detected in any species). Variations in most vessel anatomical traits were negligible among the three species; however, we detected substantial interspecific differences in intervessel pit characteristics. As compared with J. hindsii and J. ailantifolia, low embolism susceptibility in J. microcarpa was associated with smaller pit size in larger diameter vessels, a smaller area of the shared vessel wall occupied by pits, lower pit frequency and no changes in pit characteristics as vessel diameters increased. Changes in amount of embolized vessels following 40 days of re-watering were minor in intact saplings of all three species highlighting that an embolism repair mechanism did not contribute to drought recovery. In conclusion, our data indicate that interspecific variations in drought-induced embolism susceptibility are associated with species-specific pit characteristics, and these traits may provide a future target for breeding efforts aimed at selecting walnut germplasm with improved drought resistance.
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Affiliation(s)
- Thorsten Knipfer
- Department of Viticulture & Enology, University of California, Davis, CA, USA
| | | | - Italo F Cuneo
- Department of Viticulture & Enology, University of California, Davis, CA, USA
| | - Martin Bouda
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
| | | | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
| | - Daniel A Kluepfel
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA, USA
| | - Andrew J McElrone
- Department of Viticulture & Enology, University of California, Davis, CA, USA
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA, USA
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208
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Volaire F, Lens F, Cochard H, Xu H, Chacon-Doria L, Bristiel P, Balachowski J, Rowe N, Violle C, Picon-Cochard C. Embolism and mechanical resistances play a key role in dehydration tolerance of a perennial grass Dactylis glomerata L. Annals of Botany 2018; 122:325-336. [PMID: 29788033 PMCID: PMC6070121 DOI: 10.1093/aob/mcy073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/30/2018] [Indexed: 05/02/2023]
Abstract
Background and Aims More intense droughts under climate change threaten species resilience. Hydraulic strategies determine drought survival in woody plants but have been hardly studied in herbaceous species. We explored the intraspecific variability of hydraulic and morphological traits as indicators of dehydration tolerance in a perennial grass, cocksfoot (Dactylis glomerata), which has a large biogeographical distribution in Europe. Methods Twelve populations of cocksfoot originating from Mediterranean, Temperate and Northern European areas were grown in a controlled environment in pots. Dehydration tolerance, leaf and stem anatomical traits and xylem pressure associated with 88 or 50 % loss of xylem conductance (P88, P50) were measured. Key Results Across the 12 populations of cocksfoot, P50 ranged from -3.06 to - 6.36 MPa, while P88 ranged from -5.06 to -11.6 MPa. This large intraspecific variability of embolism thresholds corresponded with the biogeographical distribution and some key traits of the populations. In particular, P88 was correlated with dehydration tolerance (r = -0.79). The dehydration-sensitive Temperate populations exhibited the highest P88 (-6.1 MPa). The most dehydration-tolerant Mediterranean populations had the greatest leaf dry matter content and leaf fracture toughness, and the lowest P88 (-10.4 MPa). The Northern populations displayed intermediate trait values, potentially attributable to frost resistance. The thickness of metaxylem vessel walls in stems was highly correlated with P50 (r = -0.92), but no trade-off with stem lignification was observed. The relevance of the linkage between hydraulic and stomatal traits is discussed for drought survival in perennial grasses. Conclusions Compared with woody species, the large intraspecific variability in dehydration tolerance and embolism resistance within cocksfoot has consequences for its sensitivity to climate change. To better understand adaptive strategies of herbaceous species to increasing drought and frost requires further exploration of the role of hydraulic and mechanical traits using a larger inter- and intraspecific range of species.
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Affiliation(s)
- Florence Volaire
- INRA, USC 1338, UMR 5175, Centre d'Ecologie Fonctionnelle et Evolutive, Université de Montpellier, Université Paul Valéry, EPHE, 1919 route de Mende, Montpellier, France
| | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, Leiden, The Netherlands
| | - Hervé Cochard
- Université Clermont-Auvergne, INRA, PIAF, Clermont-Ferrand, France
| | - Hueng Xu
- Naturalis Biodiversity Center, Leiden University, Leiden, The Netherlands
| | | | - Pauline Bristiel
- UMR 5175, Centre d'Ecologie Fonctionnelle et Evolutive, Université de Montpellier, Université Paul Valéry, EPHE, 1919 route de Mende, Montpellier, France
| | - Jennifer Balachowski
- UMR 5175, Centre d'Ecologie Fonctionnelle et Evolutive, Université de Montpellier, Université Paul Valéry, EPHE, 1919 route de Mende, Montpellier, France
- Department of Evolution and Ecology, University of California, Davis, CA, USA
| | - Nick Rowe
- Université de Montpellier, UMR-MAP, Montpellier, France
- CNRS 5120, UMR AMAP, Montpellier, France
| | - Cyrille Violle
- UMR 5175, Centre d'Ecologie Fonctionnelle et Evolutive, Université de Montpellier, Université Paul Valéry, EPHE, 1919 route de Mende, Montpellier, France
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209
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Prendin AL, Mayr S, Beikircher B, von Arx G, Petit G. Xylem anatomical adjustments prioritize hydraulic efficiency over safety as Norway spruce trees grow taller. Tree Physiol 2018; 38:1088-1097. [PMID: 29920598 DOI: 10.1093/treephys/tpy065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 05/16/2018] [Indexed: 05/23/2023]
Abstract
As a tree grows taller, the increase in gravitational pressure and path length resistance results in lower water potentials at a given flow rate and higher carbon construction costs to transport a given amount of water to the leaves. We investigated how hydraulic safety and efficiency are coordinated under the constraints of higher cavitation risks and higher carbon construction costs with increasing tree height. We combined measurements of xylem tracheid anatomical traits with the vulnerability to drought-induced embolism and hydraulic conductivity of the apical shoots of 2- to 37-m tall Picea abies trees growing at two sites in the Dolomites (Italian Eastern Alps). We found that the theoretical hydraulic conductivity of the apical shoots increased with tree height at both sites (P < 0.001) as a result of an increase in either total tracheid number or mean hydraulic diameter. The xylem water potential inducing 50% loss of apical conductance significantly increased from small (-4.45 ± 0.20 MPa) to tall trees (-3.65 ± 0.03 MPa) (P = 0.007). The more conductive xylem at the treetop of taller trees allows the full compensation for the height-related hydraulic constraints and minimizes the additional carbon costs of transporting water over a longer path length. The corresponding increase in vulnerability to cavitation shows that hydraulic efficiency is prioritized over safety during height growth.
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Affiliation(s)
- Angela Luisa Prendin
- Department TeSAF-Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, viale dell'Università 16, Legnaro (PD), Italy
| | - Stefan Mayr
- Institut für Botanik, Universität Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Barbara Beikircher
- Institut für Botanik, Universität Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf, Switzerland
- Climatic Change and Climate Impacts, Institute for Environmental Sciences, 66 Boulevard Carl-Vogt, Geneva, Switzerland
| | - Giai Petit
- Department TeSAF-Department of Territorio e Sistemi Agro-Forestali, Università degli Studi di Padova, viale dell'Università 16, Legnaro (PD), Italy
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Zadworny M, Comas LH, Eissenstat DM. Linking fine root morphology, hydraulic functioning and shade tolerance of trees. Ann Bot 2018; 122:239-250. [PMID: 29897405 PMCID: PMC6070046 DOI: 10.1093/aob/mcy054] [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: 11/30/2017] [Accepted: 03/28/2018] [Indexed: 05/17/2023]
Abstract
Background and Aims Understanding root traits and their trade-off with other plant processes is important for understanding plant functioning in natural ecosystems as well as agricultural systems. The aim of the present study was to determine the relationship between root morphology and the hydraulic characteristics of several orders of fine roots (<2 mm) for species differing in shade tolerance (low, moderate and high). Methods The morphological, anatomical and hydraulic traits across five distal root orders were measured in species with different levels of shade tolerance and life history strategies. The species studied were Acer negundo, Acer rubrum, Acer saccharum, Betula alleghaniensis, Betula lenta, Quercus alba, Quercus rubra, Pinus strobus and Pinus virginiana. Key Results Compared with shade-tolerant species, shade-intolerant species produced thinner absorptive roots with smaller xylem lumen diameters and underwent secondary development less frequently, suggesting that they had shorter life spans. Shade-tolerant species had greater root specific hydraulic conductance among these roots due to having larger diameter xylems, although these roots had a lower calculated critical tension for conduit collapse. In addition, shade-intolerant species exhibited greater variation in hydraulic conductance across different root growth rings in woody transport roots of the same root order as compared with shade-tolerant species. Conclusions Plant growth strategies were extended to include root hydraulic properties. It was found that shade intolerance in trees was associated with conservative root hydraulics but greater plasticity in number of xylem conduits and hydraulic conductance. Root traits of shade-intolerant species were consistent with the ability to proliferate roots quickly for rapid water uptake needed to support rapid shoot growth, while minimizing risk in uncertain environments.
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Affiliation(s)
- Marcin Zadworny
- Institute of Dendrology, Polish Academy of Sciences, Parkowa, Kórnik, Poland
| | - Louise H Comas
- USDA-ARS Water Management Research Unit, Fort Collins, CO, USA
| | - David M Eissenstat
- Intercollege Graduate Degree Program in Plant Biology, Penn State University, University Park, PA, USA
- Department of Ecosystem Science and Management, Penn State University, University Park, PA, USA
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211
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Li X, Blackman CJ, Rymer PD, Quintans D, Duursma RA, Choat B, Medlyn BE, Tissue DT. Xylem embolism measured retrospectively is linked to canopy dieback in natural populations of Eucalyptus piperita following drought. Tree Physiol 2018; 38:1193-1199. [PMID: 29757423 DOI: 10.1093/treephys/tpy052] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/18/2018] [Indexed: 06/08/2023]
Abstract
Manipulative experiments have suggested that embolism-induced hydraulic impairment underpins widespread tree mortality during extreme drought, yet in situ evidence is rare. One month after drought-induced leaf and branch dieback was observed in field populations of Eucalyptus piperita Sm. in the Blue Mountains (Australia), we measured the level of native stem embolism and characterized the extent of leaf death in co-occurring dieback and healthy (non-dieback) trees. We found that canopy dieback-affected trees showed significantly higher levels of native embolism (26%) in tertiary order branchlets than healthy trees (11%). Furthermore, there was a significant positive correlation (R2 = 0.51) between the level of leaf death and the level of native embolism recorded in branchlets from dieback-affected trees. This retrospective study suggests that hydraulic failure was the primary mechanism of leaf and branch dieback in response to a natural drought event in the field. It also suggests that post-drought embolism refilling is minimal or absent in this species of eucalypt.
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Affiliation(s)
- Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Chris J Blackman
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Paul D Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Desi Quintans
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Remko A Duursma
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW, Australia
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212
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Gerrienne P, Cascales-Minana B, Prestianni C, Steemans P, Cheng-Sen L. Lilingostrobus chaloneri gen. et sp. nov., a Late Devonian woody lycopsid from Hunan, China. PLoS One 2018; 13:e0198287. [PMID: 29995908 PMCID: PMC6050970 DOI: 10.1371/journal.pone.0198287] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 05/09/2018] [Indexed: 11/18/2022] Open
Abstract
Lycopsids are a minor component of current terrestrial herbaceous floras.
However, lycopsid fossil diversity shows a great diversity and disparity
including heterosporous woody plants, e.g. the giant isoetaleans that populated
the extensive Pennsylvanian wetlands. The earliest known isoetaleans come from
late Devonian localities from China. Here, we describe Lilingostrobus
chaloneri gen. et sp. nov., a new isoetalean lycopsid from the
Upper Devonian (Famennian) Xikuangshan Formation of China (Hunan Province, South
China), which adds to the already impressive diversity of the Devonian lycopsids
from China. Lilingostrobus shows an unusual combination of
characters. This new plant is pseudoherbaceous, with a possible tufted habit,
and consists of narrow axes with rare isotomies. The stem includes small
quantities of secondary xylem. Each fertile axis bears one terminal strobilus
comprising sporophylls ending in a very long upturned lamina. Microspores and
putative megaspores have been found, but whether the plant has mono- or
bisporangiate strobili is unknown. Importantly, our cladistic analysis
identifies Lilingostrobus as a direct precursor of Isoetales,
which provides new insights into the early evolution of lycopsids.
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Affiliation(s)
- Philippe Gerrienne
- Palaeobiogeology-Palaeobotany-Palaeopalynology, UR Geology, University of
Liège, Liège, Belgium
| | | | - Cyrille Prestianni
- OD Earth and Life, Royal Belgian Institute of Natural Sciences, Brussels,
Belgium
| | - Philippe Steemans
- Palaeobiogeology-Palaeobotany-Palaeopalynology, UR Geology, University of
Liège, Liège, Belgium
| | - Li Cheng-Sen
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of
Botany, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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213
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Skelton RP, Dawson TE, Thompson SE, Shen Y, Weitz AP, Ackerly D. Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks. Plant Physiol 2018; 177:1066-1077. [PMID: 29789436 PMCID: PMC6052988 DOI: 10.1104/pp.18.00103] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/11/2018] [Indexed: 05/05/2023]
Abstract
Although recent findings suggest that xylem embolism represents a significant, drought-induced damaging process in land plants, substantial debate surrounds the capacity of long-vesseled, ring-porous species to resist embolism. We investigated whether recent methodological developments could help resolve this controversy within Quercus, a long-vesseled, ring-porous temperate angiosperm genus, and shed further light on the importance of xylem vulnerability to embolism as an indicator of drought tolerance. We used the optical technique to quantify leaf and stem xylem vulnerability to embolism of eight Quercus species from the Mediterranean-type climate region of California to examine absolute measures of resistance to embolism as well as any potential hydraulic segmentation between tissue types. We demonstrated that our optical assessment reflected flow impairment for a subset of our sample species by quantifying changes in leaf hydraulic conductance in dehydrating branches. Air-entry water potential varied 2-fold in leaves, ranging from -1.7 ± 0.25 MPa to -3.74 ± 0.23 MPa, and 4-fold in stems, ranging from -1.17 ± 0.04 MPa to -4.91 ± 0.3 MPa. Embolism occurred earlier in leaves than in stems in only one out of eight sample species, and plants always lost turgor before experiencing stem embolism. Our results show that long-vesseled North American Quercus species are more resistant to embolism than previously thought and support the hypothesis that avoiding stem embolism is a critical component of drought tolerance in woody trees. Accurately quantifying xylem vulnerability to embolism is essential for understanding species distributions along aridity gradients and predicting plant mortality during drought.
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Affiliation(s)
- Robert Paul Skelton
- Department of Integrative Biology, University of California, Berkeley, California 94720
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, California 94720
| | - Sally E Thompson
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720
| | - Yuzheng Shen
- Department of Integrative Biology, University of California, Berkeley, California 94720
| | - Andrew P Weitz
- Department of Integrative Biology, University of California, Berkeley, California 94720
| | - David Ackerly
- Department of Integrative Biology, University of California, Berkeley, California 94720
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214
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Yin XH, Sterck F, Hao GY. Divergent hydraulic strategies to cope with freezing in co-occurring temperate tree species with special reference to root and stem pressure generation. New Phytol 2018; 219:530-541. [PMID: 29682759 DOI: 10.1111/nph.15170] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [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: 11/27/2017] [Accepted: 03/18/2018] [Indexed: 05/23/2023]
Abstract
Some temperate tree species mitigate the negative impacts of frost-induced xylem cavitation by restoring impaired hydraulic function via positive pressures, and may therefore be more resistant to frost fatigue (the phenomenon that post-freezing xylem becomes more susceptible to hydraulic dysfunction) than nonpressure-generating species. We test this hypothesis and investigate underlying anatomical/physiological mechanisms. Using a common garden experiment, we studied key hydraulic traits and detailed xylem anatomical characteristics of 18 sympatric tree species. These species belong to three functional groups, that is, one generating both root and stem pressures (RSP), one generating only root pressure (RP), and one unable to generate such pressures (NP). The three functional groups diverged substantially in hydraulic efficiency, resistance to drought-induced cavitation, and frost fatigue resistance. Most notably, RSP and RP were more resistant to frost fatigue than NP, but this was at the cost of reduced hydraulic conductivity for RSP and reduced resistance to drought-induced cavitation for RP. Our results show that, in environments with strong frost stress: these groups diverge in hydraulic functioning following multiple trade-offs between hydraulic efficiency, resistance to drought and resistance to frost fatigue; and how differences in anatomical characteristics drive such divergence across species.
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Affiliation(s)
- Xiao-Han Yin
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, the Netherlands
| | - Guang-You Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
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215
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Sevanto S, Ryan M, Dickman LT, Derome D, Patera A, Defraeye T, Pangle RE, Hudson PJ, Pockman WT. Is desiccation tolerance and avoidance reflected in xylem and phloem anatomy of two coexisting arid-zone coniferous trees? Plant Cell Environ 2018; 41:1551-1564. [PMID: 29569276 DOI: 10.1111/pce.13198] [Citation(s) in RCA: 3] [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: 04/28/2017] [Revised: 02/28/2018] [Accepted: 03/06/2018] [Indexed: 06/08/2023]
Abstract
Plants close their stomata during drought to avoid excessive water loss, but species differ in respect to the drought severity at which stomata close. The stomatal closure point is related to xylem anatomy and vulnerability to embolism, but it also has implications for phloem transport and possibly phloem anatomy to allow sugar transport at low water potentials. Desiccation-tolerant plants that close their stomata at severe drought should have smaller xylem conduits and/or fewer and smaller interconduit pits to reduce vulnerability to embolism but more phloem tissue and larger phloem conduits compared with plants that avoid desiccation. These anatomical differences could be expected to increase in response to long-term reduction in precipitation. To test these hypotheses, we used tridimensional synchroton X-ray microtomograph and light microscope imaging of combined xylem and phloem tissues of 2 coniferous species: one-seed juniper (Juniperus monosperma) and piñon pine (Pinus edulis) subjected to precipitation manipulation treatments. These species show different xylem vulnerability to embolism, contrasting desiccation tolerance, and stomatal closure points. Our results support the hypothesis that desiccation tolerant plants require higher phloem transport capacity than desiccation avoiding plants, but this can be gained through various anatomical adaptations in addition to changing conduit or tissue size.
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Affiliation(s)
- Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Bikini Atoll Road MS J535, Los Alamos, NM, 87545, USA
| | - Max Ryan
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Bikini Atoll Road MS J535, Los Alamos, NM, 87545, USA
| | - L Turin Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Bikini Atoll Road MS J535, Los Alamos, NM, 87545, USA
| | - Dominique Derome
- Laboratory for Multiscale Studies in Building Physics, Swiss Federal Laboratories for Material Science and Technology (Empa), Ueberlandstrasse 129, 8600, Duebendorf, Switzerland
| | - Alessandra Patera
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen, Switzerland
- Centre d'Imagerie BioMedicale, Ecole Polytechnique Federale de Lausanne, 1015, Lausanne, Switzerland
| | - Thijs Defraeye
- Laboratory for Multiscale Studies in Building Physics, Swiss Federal Laboratories for Material Science and Technology (Empa), Ueberlandstrasse 129, 8600, Duebendorf, Switzerland
- Chair of Building Physics, ETH Zurich, Stefano-Franscini-Platz 5, 8093, Zurich, Switzerland
| | - Robert E Pangle
- Department of Biology, University of New Mexico, Castetter Hall 1480, Yale Boulevard NE, Albuquerque, NM, 87131, USA
| | - Patrick J Hudson
- Department of Biology, University of New Mexico, Castetter Hall 1480, Yale Boulevard NE, Albuquerque, NM, 87131, USA
| | - William T Pockman
- Department of Biology, University of New Mexico, Castetter Hall 1480, Yale Boulevard NE, Albuquerque, NM, 87131, USA
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216
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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 Physiol 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] [What about the content of this article? (0)] [Affiliation(s)] [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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217
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De Deurwaerder H, Hervé-Fernández P, Stahl C, Burban B, Petronelli P, Hoffman B, Bonal D, Boeckx P, Verbeeck H. Liana and tree below-ground water competition-evidence for water resource partitioning during the dry season. Tree Physiol 2018; 38:1071-1083. [PMID: 29509954 PMCID: PMC6025208 DOI: 10.1093/treephys/tpy002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 07/04/2017] [Revised: 11/15/2017] [Accepted: 01/08/2018] [Indexed: 05/21/2023]
Abstract
To date, reasons for the increase in liana abundance and biomass in the Neotropics are still unclear. One proposed hypothesis suggests that lianas, in comparison with trees, are more adaptable to drought conditions. Moreover, previous studies have assumed that lianas have a deeper root system, which provides access to deeper soil layers, thereby making them less susceptible to drought stress. The dual stable water isotope approach (δ18O and δ2H) enables below-ground vegetation competition for water to be studied. Based on the occurrence of a natural gradient in soil water isotopic signatures, with enriched signatures in shallow soil relative to deep soil, the origin of vegetation water sources can be derived. Our study was performed on canopy trees and lianas reaching canopy level in tropical forests of French Guiana. Our results show liana xylem water isotopic signatures to be enriched in heavy isotopes in comparison with those from trees, indicating differences in water source depths and a more superficial root activity for lianas during the dry season. This enables them to efficiently capture dry season precipitation. Our study does not support the liana deep root water extraction hypothesis. Additionally, we provide new insights into water competition between tropical canopy lianas and trees. Results suggest that this competition is mitigated during the dry season due to water resource partitioning.
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Affiliation(s)
- Hannes De Deurwaerder
- CAVElab—Computational and Applied Vegetation Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent, Belgium
- Corresponding author ()
| | - Pedro Hervé-Fernández
- Laboratory of Hydrology and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Gent, Belgium
- Isotope Bioscience Laboratory—ISOFYS, Faculty of Bioscience Engineering, Gent University, Coupure Links 653, Gent, Belgium
| | - Clément Stahl
- INRA, UMR EcoFoG, CNRS, Cirad, AgroParisTech, Université des Antilles, Université de Guyane, Kourou, France
| | - Benoit Burban
- INRA, UMR EcoFoG, CNRS, Cirad, AgroParisTech, Université des Antilles, Université de Guyane, Kourou, France
| | - Pascal Petronelli
- Cirad UMR Ecofog (AgrosParisTech, CNRS, INRA, Univ Guyane), Campus Agronomique, Kourou, French Guiana
| | - Bruce Hoffman
- The Amazon Conservation Team - Suriname Program, Doekhieweg Oost 24, Paramaribo, Suriname
| | - Damien Bonal
- Université de Lorraine, AgroParisTech, INRA, UMR Silva, Nancy, France
| | - Pascal Boeckx
- Isotope Bioscience Laboratory—ISOFYS, Faculty of Bioscience Engineering, Gent University, Coupure Links 653, Gent, Belgium
| | - Hans Verbeeck
- CAVElab—Computational and Applied Vegetation Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent, Belgium
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218
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Wason JW, Anstreicher KS, Stephansky N, Huggett BA, Brodersen CR. Hydraulic safety margins and air-seeding thresholds in roots, trunks, branches and petioles of four northern hardwood trees. New Phytol 2018; 219:77-88. [PMID: 29663388 DOI: 10.1111/nph.15135] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 12/22/2017] [Accepted: 02/28/2018] [Indexed: 05/23/2023]
Abstract
During drought, xylem sap pressures can approach or exceed critical thresholds where gas embolisms form and propagate through the xylem network, leading to systemic hydraulic dysfunction. The vulnerability segmentation hypothesis (VSH) predicts that low-investment organs (e.g. leaf petioles) should be more vulnerable to embolism spread compared to high-investment, perennial organs (e.g. trunks, stems), as a means of mitigating embolism spread and excessive negative pressures in the perennial organs. We tested this hypothesis by measuring air-seeding thresholds using the single-vessel air-injection method and calculating hydraulic safety margins in four northern hardwood tree species of the northeastern United States, in both saplings and canopy height trees, and at five points along the soil-plant-atmosphere continuum. Acer rubrum was the most resistant to air-seeding and generally supported the VSH. However, Fagus grandifolia, Fraxinus americana and Quercus rubra showed little to no variation in air-seeding thresholds across organ types within each species. Leaf-petiole xylem operated at water potentials close to or exceeding their hydraulic safety margins in all species, whereas roots, trunks and stems of A. rubrum, F. grandifolia and Q. rubra operated within their safety margins, even during the third-driest summer in the last 100 yr.
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Affiliation(s)
- Jay W Wason
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | | | | | - Brett A Huggett
- Department of Biology, Bates College, Lewiston, ME, 04240, USA
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
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219
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Blackman CJ, Gleason SM, Cook AM, Chang Y, Laws CA, Westoby M. The links between leaf hydraulic vulnerability to drought and key aspects of leaf venation and xylem anatomy among 26 Australian woody angiosperms from contrasting climates. Ann Bot 2018; 122:59-67. [PMID: 29668853 PMCID: PMC6025239 DOI: 10.1093/aob/mcy051] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [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: 12/12/2017] [Accepted: 03/18/2018] [Indexed: 05/13/2023]
Abstract
Background and Aims The structural properties of leaf venation and xylem anatomy strongly influence leaf hydraulics, including the ability of leaves to maintain hydraulic function during drought. Here we examined the strength of the links between different leaf venation traits and leaf hydraulic vulnerability to drought (expressed as P50leaf by rehydration kinetics) in a diverse group of 26 woody angiosperm species, representing a wide range of leaf vulnerabilities, from four low-nutrient sites with contrasting rainfall across eastern Australia. Methods For each species we measured key aspects of leaf venation design, xylem anatomy and leaf morphology. We also assessed for the first time the scaling relationships between hydraulically weighted vessel wall thickness (th) and lumen breadth (bh) across vein orders and habitats. Key Results Across species, variation in P50leaf was strongly correlated with the ratio of vessel wall thickness (th) to lumen breadth (bh) [(t/b)h; an index of conduit reinforcement] at each leaf vein order. Concomitantly, the scaling relationship between th and bh was similar across vein orders, with a log-log slope less than 1 indicating greater xylem reinforcement in smaller vessels. In contrast, P50leaf was not related to th and bh individually, to major vein density (Dvmajor) or to leaf size. Principal components analysis revealed two largely orthogonal trait groupings linked to variation in leaf size and drought tolerance. Conclusions Our results indicate that xylem conduit reinforcement occurs throughout leaf venation, and remains closely linked to leaf drought tolerance irrespective of leaf size.
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Affiliation(s)
- Chris J Blackman
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Sean M Gleason
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- USDA-ARS, Water Management and Systems Research Unit, Fort Collins, CO, USA
| | - Alicia M Cook
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Yvonne Chang
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Claire A Laws
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
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220
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Zhang W, Feng F, Tyree MT. Seasonality of cavitation and frost fatigue in Acer mono Maxim. Plant Cell Environ 2018; 41:1278-1286. [PMID: 29220549 DOI: 10.1111/pce.13117] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 06/04/2017] [Revised: 11/25/2017] [Accepted: 11/27/2017] [Indexed: 05/23/2023]
Abstract
Although cavitation is common in plants, it is unknown whether the cavitation resistance of xylem is seasonally constant or variable. We tested the changes in cavitation resistance of Acer mono before and after a controlled cavitation-refilling and freeze-thaw cycles for a whole year. Cavitation resistance was determined from 'vulnerability curves' showing the percent loss of conductivity versus xylem tension. Cavitation fatigue was defined as a reduction of cavitation resistance following a cavitation-refilling cycle, whereas frost fatigue was caused by a freeze-thaw cycle. A. mono developed seasonal changes in native embolisms; values were relatively high during winter but relatively low and constant throughout the growing season. Cavitation fatigue occurred and changed seasonally during the 12-month cycle; the greatest fatigue response occurred during summer and the weakest during winter, and the transitions occurred during spring and autumn. A. mono was highly resistant to frost damage during the relatively mild winter months; however, a quite different situation occurred during the growing season, as the seasonal trend of frost fatigue was strikingly similar to that of cavitation fatigue. Seasonality changes in cavitation resistance may be caused by seasonal changes in the mechanical properties of the pit membranes.
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Affiliation(s)
- Wen Zhang
- College of Forestry, Northwest A&F University, Yangling, 712100, China
| | - Feng Feng
- College of Forestry, Northwest A&F University, Yangling, 712100, China
| | - Melvin T Tyree
- College of Forestry, Northwest A&F University, Yangling, 712100, China
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221
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Yin P, Cai J. New possible mechanisms of embolism formation when measuring vulnerability curves by air injection in a pressure sleeve. Plant Cell Environ 2018; 41:1361-1368. [PMID: 29424925 DOI: 10.1111/pce.13163] [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: 10/19/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 05/29/2023]
Abstract
Since 1988, researchers have exposed stems to positive pressures to displace water in vessels and measure the impact of applied pressure on hydraulic conductivity. The pressure-sleeve technique has been used in more than 60 publications to measure vulnerability curves (VCs), which are a measure of how water stress impacts the ability of plants to transport water because water stress induces embolism in vessels that blocks water flow. It is thought that the positive pressure in a sleeve required to induce 50% loss of conductivity (PLC), P50 , is the same magnitude as the tension that causes 50% PLC, T50 , where the tension can be induced by either bench-top dehydration or by a centrifuge technique. The unifying concept that P50 = T50 and that the entire VC is the same regardless of method is referred to as the air-seeding hypothesis. In the current study, we performed experiments to further test the air-seeding hypothesis in pressure sleeves and concluded that an "effervescence" mechanism caused embolism formation under positive pressure. This mechanism explains why VCs measured using positive pressure do not always match VCs obtained by other methods that induce water tension.
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Affiliation(s)
- Pengxian Yin
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jing Cai
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
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222
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Balzano A, Čufar K, Battipaglia G, Merela M, Prislan P, Aronne G, De Micco V. Xylogenesis reveals the genesis and ecological signal of IADFs in Pinus pinea L. and Arbutus unedo L. Ann Bot 2018; 121:1231-1242. [PMID: 29415209 PMCID: PMC5946860 DOI: 10.1093/aob/mcy008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 12/13/2017] [Accepted: 01/22/2018] [Indexed: 05/31/2023]
Abstract
Background and Aims Mediterranean trees have patterns of cambial activity with one or more pauses per year, leading to intra-annual density fluctuations (IADFs) in tree rings. We analysed xylogenesis (January 2015-January 2016) in Pinus pinea L. and Arbutus unedo L., co-occurring at a site on Mt. Vesuvius (southern Italy), to identify the cambial productivity and timing of IADF formation. Methods Dendrochronological methods and quantitative wood anatomy were applied and enabled IADF identification and classification. Key Results We showed that cambium in P. pinea was productive throughout the calendar year. From January to March 2015, post-cambial (enlarging) earlywood-like tracheids were observed, which were similar to transition tracheids. The beginning of the tree ring was therefore not marked by a sharp boundary between latewood of the previous year and the new xylem produced. True earlywood tracheids were formed in April. L-IADFs were formed in autumn, with earlywood-like cells in latewood. In A. unedo, a double pause in cell production was observed, in summer and winter, leading to L-IADFs in autumn as well. Moreover, the formation of more than one IADF was observed in A. unedo. Conclusions Despite having completely different wood formation models and different life strategies, the production of earlywood, latewood and IADF cells was strongly controlled by climatic factors in the two species. Such cambial production patterns need to be taken into account in dendroecological studies to interpret climatic signals in wood from Mediterranean trees.
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Affiliation(s)
- A Balzano
- University of Naples Federico II, Department of Agricultural Sciences, Portici (Naples), Italy
- University of Ljubljana, Biotechnical Faculty, Department of Wood Science and Technology, Ljubljana, Slovenia
| | - K Čufar
- University of Ljubljana, Biotechnical Faculty, Department of Wood Science and Technology, Ljubljana, Slovenia
| | - G Battipaglia
- University of Campania Luigi Vanvitelli, Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Caserta, Italy
- Ecole Pratique des Hautes Etudes (PALECO EPHE), Institut des Sciences de l’Evolution–Montpellier UMR 5554 CNRS, Université de Montpellier, Montpellier, France
| | - M Merela
- University of Ljubljana, Biotechnical Faculty, Department of Wood Science and Technology, Ljubljana, Slovenia
| | - P Prislan
- Slovenian Forestry Institute, Ljubljana, Slovenia
| | - G Aronne
- University of Naples Federico II, Department of Agricultural Sciences, Portici (Naples), Italy
| | - V De Micco
- University of Naples Federico II, Department of Agricultural Sciences, Portici (Naples), Italy
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223
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González-Muñoz N, Sterck F, Torres-Ruiz JM, Petit G, Cochard H, von Arx G, Lintunen A, Caldeira MC, Capdeville G, Copini P, Gebauer R, Grönlund L, Hölttä T, Lobo-do-Vale R, Peltoniemi M, Stritih A, Urban J, Delzon S. Quantifying in situ phenotypic variability in the hydraulic properties of four tree species across their distribution range in Europe. PLoS One 2018; 13:e0196075. [PMID: 29715289 PMCID: PMC5929519 DOI: 10.1371/journal.pone.0196075] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 04/05/2018] [Indexed: 01/29/2023] Open
Abstract
Many studies have reported that hydraulic properties vary considerably between tree species, but little is known about their intraspecific variation and, therefore, their capacity to adapt to a warmer and drier climate. Here, we quantify phenotypic divergence and clinal variation for embolism resistance, hydraulic conductivity and branch growth, in four tree species, two angiosperms (Betula pendula, Populus tremula) and two conifers (Picea abies, Pinus sylvestris), across their latitudinal distribution in Europe. Growth and hydraulic efficiency varied widely within species and between populations. The variability of embolism resistance was in general weaker than that of growth and hydraulic efficiency, and very low for all species but Populus tremula. In addition, no and weak support for a safety vs. efficiency trade-off was observed for the angiosperm and conifer species, respectively. The limited variability of embolism resistance observed here for all species except Populus tremula, suggests that forest populations will unlikely be able to adapt hydraulically to drier conditions through the evolution of embolism resistance.
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Affiliation(s)
| | - F. Sterck
- Forest Ecology and Forest Management Group, Wageningen University & Research, Wageningen, The Netherlands
| | | | - G. Petit
- Università degli Studi di Padova, Dep. TeSAF, Legnaro (PD), Italy
| | - H. Cochard
- PIAF, INRA, Université Clermont-Auvergne, Clermont-Ferrand, France
| | - G. von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Climatic Change and Climate Impacts, Institute for Environmental Sciences, Geneva, Switzerland
| | - A. Lintunen
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - M. C. Caldeira
- Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, Lisboa, Portugal
| | - G. Capdeville
- BIOGECO, INRA, Université de Bordeaux, Pessac, France
| | - P. Copini
- Forest Ecology and Forest Management Group, Wageningen University & Research, Wageningen, The Netherlands
- Wageningen Environmental Research (Alterra), Wageningen, The Netherlands
| | - R. Gebauer
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University, Zemědělská 3, Brno, Czech Republic
| | - L. Grönlund
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - T. Hölttä
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - R. Lobo-do-Vale
- Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, Lisboa, Portugal
| | - M. Peltoniemi
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, Helsinki, Finland
| | - A. Stritih
- Swiss Federal Institute of Technology ETH, Planning of Landscape and Urban Systems, Zurich, Switzerland
| | - J. Urban
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University, Zemědělská 3, Brno, Czech Republic
| | - S. Delzon
- BIOGECO, INRA, Université de Bordeaux, Pessac, France
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224
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Santiago LS, De Guzman ME, Baraloto C, Vogenberg JE, Brodie M, Hérault B, Fortunel C, Bonal D. Coordination and trade-offs among hydraulic safety, efficiency and drought avoidance traits in Amazonian rainforest canopy tree species. New Phytol 2018; 218:1015-1024. [PMID: 29457226 DOI: 10.1111/nph.15058] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [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: 09/08/2017] [Accepted: 01/17/2018] [Indexed: 05/18/2023]
Abstract
Predicting responses of tropical forests to climate change-type drought is challenging because of high species diversity. Detailed characterization of tropical tree hydraulic physiology is necessary to evaluate community drought vulnerability and improve model parameterization. Here, we measured xylem hydraulic conductivity (hydraulic efficiency), xylem vulnerability curves (hydraulic safety), sapwood pressure-volume curves (drought avoidance) and wood density on emergent branches of 14 common species of Eastern Amazonian canopy trees in Paracou, French Guiana across species with the densest and lightest wood in the plot. Our objectives were to evaluate relationships among hydraulic traits to identify strategies and test the ability of easy-to-measure traits as proxies for hard-to-measure hydraulic traits. Xylem efficiency was related to capacitance, sapwood water content and turgor loss point, and other drought avoidance traits, but not to xylem safety (P50 ). Wood density was correlated (r = -0.57 to -0.97) with sapwood pressure-volume traits, forming an axis of hydraulic strategy variation. In contrast to drier sites where hydraulic safety plays a greater role, tropical trees in this humid tropical site varied along an axis with low wood density, high xylem efficiency and high capacitance at one end of the spectrum, and high wood density and low turgor loss point at the other.
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Affiliation(s)
- Louis S Santiago
- Department of Botany & Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA, 92521, USA
- Smithsonian Tropical Research Institute, Balboa, Ancón, Panamá, Republic of Panamá
| | - Mark E De Guzman
- Department of Botany & Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA, 92521, USA
| | - Christopher Baraloto
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
| | - Jacob E Vogenberg
- Department of Botany & Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA, 92521, USA
| | - Max Brodie
- Department of Botany & Plant Sciences, University of California, 2150 Batchelor Hall, Riverside, CA, 92521, USA
| | - Bruno Hérault
- CIRAD, UMR Ecologie des Forêts de Guyane, Kourou, 97379, France
| | - Claire Fortunel
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | - Damien Bonal
- INRA, UMR Silva, AgroParisTech, Université de Lorraine, 54000, Nancy, France
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225
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Ahmad HB, Lens F, Capdeville G, Burlett R, Lamarque LJ, Delzon S. Intraspecific variation in embolism resistance and stem anatomy across four sunflower (Helianthus annuus L.) accessions. Physiol Plant 2018; 163:59-72. [PMID: 29057474 DOI: 10.1111/ppl.12654] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/04/2017] [Accepted: 10/17/2017] [Indexed: 05/27/2023]
Abstract
Drought-induced xylem embolism is a key process closely related to plant mortality during extreme drought events. However, this process has been poorly investigated in crop species to date, despite the observed decline of crop productivity under extreme drought conditions. Interspecific variation in hydraulic traits has frequently been reported, but less is known about intraspecific variation in crops. We assessed the intraspecific variability of embolism resistance in four sunflower (Helianthus annuus L.) accessions grown in well-watered conditions. Vulnerability to embolism was determined by the in situ flow-centrifuge method (cavitron), and possible trade-offs between xylem safety, xylem efficiency and growth were assessed. The relationship between stem anatomy and hydraulic traits was also investigated. Mean P50 was -3 MPa, but significant variation was observed between accessions, with values ranging between -2.67 and -3.22 MPa. Embolism resistance was negatively related to growth and positively related to xylem-specific hydraulic conductivity. There is, therefore, a trade-off between hydraulic safety and growth but not between hydraulic safety and efficiency. Finally, we found that a few anatomical traits, such as vessel density and the area of the vessel lumen relative to that of the secondary xylem, were related to embolism resistance, whereas stem tissue lignification was not. Further investigations are now required to investigate the link between the observed variability of embolism resistance and yield, to facilitate the identification of breeding strategies to improve yields in an increasingly arid world.
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Affiliation(s)
- Hafiz B Ahmad
- BIOGECO, INRA, University of Bordeaux, Cestas, France
| | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, PO Box 9517, Leiden, the Netherlands
| | | | - Régis Burlett
- BIOGECO, INRA, University of Bordeaux, Cestas, France
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226
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Rodriguez-Dominguez CM, Carins Murphy MR, Lucani C, Brodribb TJ. Mapping xylem failure in disparate organs of whole plants reveals extreme resistance in olive roots. New Phytol 2018; 218:1025-1035. [PMID: 29528498 DOI: 10.1111/nph.15079] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [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: 11/20/2017] [Accepted: 02/04/2018] [Indexed: 05/25/2023]
Abstract
The capacity of plant species to resist xylem cavitation is an important determinant of resistance to drought, mortality thresholds, geographic distribution and productivity. Unravelling the role of xylem cavitation vulnerability in plant evolution and adaptation requires a clear understanding of how this key trait varies between the tissues of individuals and between individuals of species. Here, we examine questions of variation within individuals by measuring how cavitation moves between organs of individual plants. Using multiple cameras placed simultaneously on roots, stems and leaves, we were able to record systemic xylem cavitation during drying of individual olive plants. Unlike previous studies, we found a consistent pattern of root > stem > leaf in terms of xylem resistance to cavitation. The substantial variation in vulnerability to cavitation, evident among individuals, within individuals and within tissues of olive seedlings, was coordinated such that plants with more resistant roots also had more resistant leaves. Preservation of root integrity means that roots can continue to supply water for the regeneration of drought-damaged aerial tissues after post-drought rain. Furthermore, coordinated variation in vulnerability between leaf, stem and root in olive plants suggests a strong selective pressure to maintain a fixed order of cavitation during drought.
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Affiliation(s)
| | - Madeline R Carins Murphy
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
| | - Christopher Lucani
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
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227
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Abstract
In salinized soils in which chloride (Cl-) is the dominant salt anion, growth of plants that tolerate only low concentrations of salt (glycophytes) is disturbed by Cl- toxicity. Chlorotic discolorations precede necrotic lesions, causing yield reductions. Little is known about the effects of Cl- toxicity on these dysfunctions. A lack of understanding exists regarding (i) the molecular and physiological mechanisms that lead to Cl--induced damage and (ii) the adaptive aspects of induced tolerance to Cl- salinity. Here, mechanistic explanations for the Cl--induced stress responses are proposed and novel ideas and strategies by which glycophytic plants avoid the excessive accumulation of Cl- are reviewed. New experiments are suggested to test the proposed hypotheses. Cl- salinity constrains global food security and thus we urgently need more research into the causes and consequences of Cl- salinity.
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Affiliation(s)
- Christoph-Martin Geilfus
- Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg 1, D-14195 Berlin, Germany
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228
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Zhu J, Dai Z, Vivin P, Gambetta GA, Henke M, Peccoux A, Ollat N, Delrot S. A 3-D functional-structural grapevine model that couples the dynamics of water transport with leaf gas exchange. Ann Bot 2018; 121:833-848. [PMID: 29293870 PMCID: PMC5906973 DOI: 10.1093/aob/mcx141] [Citation(s) in RCA: 3] [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: 05/24/2017] [Accepted: 11/01/2017] [Indexed: 05/03/2023]
Abstract
Background and Aims Predicting both plant water status and leaf gas exchange under various environmental conditions is essential for anticipating the effects of climate change on plant growth and productivity. This study developed a functional-structural grapevine model which combines a mechanistic understanding of stomatal function and photosynthesis at the leaf level (i.e. extended Farqhuhar-von Caemmerer-Berry model) and the dynamics of water transport from soil to individual leaves (i.e. Tardieu-Davies model). Methods The model included novel features that account for the effects of xylem embolism (fPLC) on leaf hydraulic conductance and residual stomatal conductance (g0), variable root and leaf hydraulic conductance, and the microclimate of individual organs. The model was calibrated with detailed datasets of leaf photosynthesis, leaf water potential, xylem sap abscisic acid (ABA) concentration and hourly whole-plant transpiration observed within a soil drying period, and validated with independent datasets of whole-plant transpiration under both well-watered and water-stressed conditions. Key Results The model well captured the effects of radiation, temperature, CO2 and vapour pressure deficit on leaf photosynthesis, transpiration, stomatal conductance and leaf water potential, and correctly reproduced the diurnal pattern and decline of water flux within the soil drying period. In silico analyses revealed that decreases in g0 with increasing fPLC were essential to avoid unrealistic drops in leaf water potential under severe water stress. Additionally, by varying the hydraulic conductance along the pathway (e.g. root and leaves) and changing the sensitivity of stomatal conductance to ABA and leaf water potential, the model can produce different water use behaviours (i.e. iso- and anisohydric). Conclusions The robust performance of this model allows for modelling climate effects from individual plants to fields, and for modelling plants with complex, non-homogenous canopies. In addition, the model provides a basis for future modelling efforts aimed at describing the physiology and growth of individual organs in relation to water status.
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Affiliation(s)
- Junqi Zhu
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Zhanwu Dai
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Philippe Vivin
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Gregory A Gambetta
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Michael Henke
- Department of Ecoinformatics, Biometrics and Forest Growth, University of Göttingen, Göttingen, Germany
| | - Anthony Peccoux
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Nathalie Ollat
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
| | - Serge Delrot
- EGFV, Bordeaux Sciences Agro, INRA, Université de Bordeaux, Villenave d’Ornon, France
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229
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Abstract
PREMISE OF THE STUDY While tradeoffs among mechanical and conductive functions have been well investigated in woody stems, these tradeoffs are relatively unexplored in petioles, the structural link between stems and laminas. We investigated size-independent scaling relationships between cross-sectional areas of structural and vascular tissues, relationships between tissue areas of xylem and phloem, vessel packing within xylem, and scaling of vascular and structural tissues with lamina traits. METHODS We examined allometric relationships among petiole tissues and as a function of lamina and petiole size variation on eleven species of Pelargonium. From transverse sections of methacrylate-embedded tissue, we measured the cross-sectional areas of all tissues within the petiole and vessel lumen, and cell wall areas of each vessel. Allometric scaling relationships were analyzed using standardized major axis regressions. KEY RESULTS Pelargonium petiole vessels were packed as predicted by Sperry's packing rule for woody stems. In contrast to woody stems, there was no evidence of a tradeoff between vessel area and fiber area. Within cross-sections, more xylem was produced than phloem. Among bundles, xylem and phloem scaling relationships varied with bundle position. Except for lamina dry mass and petiole fiber cross-sectional area, petiole and lamina traits were independent. CONCLUSIONS Petioles share vascular tissue traits with stems despite derivation from leaf primordia. We did not find evidence for a tradeoff between structural and vascular tissues, in part because fibers occur outside the xylem. We propose this separation of conduction and support underlies observed developmental and evolutionary plasticity in petioles.
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Affiliation(s)
- Dustin M Ray
- University of Connecticut, Ecology and Evolutionary Biology Department, 75 N. Eagleville Road, Unit 3043, Storrs, ConnecticutT, 06269, U.S.A
| | - Cynthia S Jones
- University of Connecticut, Ecology and Evolutionary Biology Department, 75 N. Eagleville Road, Unit 3043, Storrs, ConnecticutT, 06269, U.S.A
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Fernández-Pérez L, Villar-Salvador P, Martínez-Vilalta J, Toca A, Zavala MA. Distribution of pines in the Iberian Peninsula agrees with species differences in foliage frost tolerance, not with vulnerability to freezing-induced xylem embolism. Tree Physiol 2018; 38:507-516. [PMID: 29325114 DOI: 10.1093/treephys/tpx171] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/09/2017] [Indexed: 06/07/2023]
Abstract
Drought and frosts are major determinants of plant functioning and distribution. Both stresses can cause xylem embolism and foliage damage. The objective of this study was to analyse if the distribution of six common pine species along latitudinal and altitudinal gradients in Europe is related to their interspecific differences in frost tolerance and to the physiological mechanisms underlying species-specific frost tolerance. We also evaluate if frost tolerance depends on plant water status. We studied survival to a range of freezing temperatures in 2-year-old plants and assessed the percentage loss of hydraulic conductivity (PLC) due xylem embolism formation and foliage damage determined by needle electrolyte leakage (EL) after a single frost cycle to -15 °C and over a range of predawn water potential (ψpd) values. Species experiencing cold winters in their range (Pinus nigra J.F. Arnold, Pinus sylvestris L. and Pinus uncinata Raymond ex A. DC.) had the highest frost survival rates and lowest needle EL and soluble sugar (SS) concentration. In contrast, the pines inhabiting mild or cool winter locations (especially Pinus halepensis Mill. and Pinus pinea L. and, to a lesser extent, Pinus pinaster Ait.) had the lowest frost survival and highest needle EL and SS values. Freezing-induced PLC was very low and differences among species were not related to frost damage. Reduction in ψpd decreased leaf frost damage in P. pinea and P. sylvestris, increased it in P. uncinata and had a neutral effect on the rest of the species. This study demonstrates that freezing temperatures are a major environmental driver for pine distribution and suggests that interspecific differences in leaf frost sensitivity rather than vulnerability to freezing-induced embolism or SS explain pine juvenile frost survival.
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Affiliation(s)
- Laura Fernández-Pérez
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Pedro Villar-Salvador
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Campus UAB, Edifici C, Cerdanyola del Vallès 08193, Barcelona, Spain
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Univ. Autònoma Barcelona, Edifici C, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Andrei Toca
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Miguel A Zavala
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
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231
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Bär A, Nardini A, Mayr S. Post-fire effects in xylem hydraulics of Picea abies, Pinus sylvestris and Fagus sylvatica. New Phytol 2018; 217:1484-1493. [PMID: 29193122 DOI: 10.1111/nph.14916] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [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: 07/05/2017] [Accepted: 10/23/2017] [Indexed: 06/07/2023]
Abstract
Recent studies on post-fire tree mortality suggest a role for heat-induced alterations of the hydraulic system. We analyzed heat effects on xylem hydraulics both in the laboratory and at a forest site hit by fire. Stem vulnerability to drought-induced embolism and hydraulic conductivity were measured in Picea abies, Pinus sylvestris and Fagus sylvatica. Control branches were compared with samples experimentally exposed to 90°C or damaged by a natural forest fire. In addition, xylem anatomical changes were examined microscopically. Experimental heating caused structural changes in the xylem and increased vulnerability in all species. The largest shifts in vulnerability thresholds (1.3 MPa) were observed in P. sylvestris. F. sylvatica also showed heat-induced reductions (49%) in hydraulic conductivity. At the field site, increased vulnerability was observed in damaged branches of P. sylvestris and F. sylvatica, and the xylem of F. sylvatica was 39% less conductive in damaged than in undamaged branches. These results provide evidence for heat-induced impairment of tree hydraulics after fire. The effects recorded at the forest fire site corresponded to those obtained in laboratory experiments, and revealed pronounced hydraulic risks in P. sylvestris and F. sylvatica. Knowledge of species-specific hydraulic impairments induced by fire and heat is a prerequisite for accurate estimation of post-fire mortality risks.
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Affiliation(s)
- Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Andrea Nardini
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
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232
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Eller CB, de V Barros F, Bittencourt PRL, Rowland L, Mencuccini M, Oliveira RS. Xylem hydraulic safety and construction costs determine tropical tree growth. Plant Cell Environ 2018; 41:548-562. [PMID: 29211923 DOI: 10.1111/pce.13106] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [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: 04/24/2017] [Accepted: 11/17/2017] [Indexed: 05/25/2023]
Abstract
Faster growth in tropical trees is usually associated with higher mortality rates, but the mechanisms underlying this relationship are poorly understood. In this study, we investigate how tree growth patterns are linked with environmental conditions and hydraulic traits, by monitoring the cambial growth of 9 tropical cloud forest tree species coupled with numerical simulations using an optimization model. We find that fast-growing trees have lower xylem safety margins than slow-growing trees and this pattern is not necessarily linked to differences in stomatal behaviour or environmental conditions when growth occurs. Instead, fast-growing trees have xylem vessels that are more vulnerable to cavitation and lower density wood. We propose the growth - xylem vulnerability trade-off represents a wood hydraulic economics spectrum similar to the classic leaf economic spectrum, and show through numerical simulations that this trade-off can emerge from the coordination between growth rates, wood density, and xylem vulnerability to cavitation. Our results suggest that vulnerability to hydraulic failure might be related with the growth-mortality trade-off in tropical trees, determining important life history differences. These findings are important in furthering our understanding of xylem hydraulic functioning and its implications on plant carbon economy.
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Affiliation(s)
- Cleiton B Eller
- Department of Plant Biology, Institute of Biology, UNICAMP, 6109, Campinas, Brazil
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, EX4 4RJ, Exeter, UK
| | - Fernanda de V Barros
- Department of Plant Biology, Institute of Biology, UNICAMP, 6109, Campinas, Brazil
| | | | - Lucy Rowland
- Department of Geography, College of Life and Environmental Sciences, University of Exeter, EX4 4RJ, Exeter, UK
| | - Maurizio Mencuccini
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
- CREAF, Cerdanyola del Valles, 08193, Barcelona, Spain
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, UNICAMP, 6109, Campinas, Brazil
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233
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Ployet R, Soler M, Carocha V, Ladouce N, Alves A, Rodrigues JC, Harvengt L, Marque C, Teulières C, Grima-Pettenati J, Mounet F. Long cold exposure induces transcriptional and biochemical remodelling of xylem secondary cell wall in Eucalyptus. Tree Physiol 2018. [PMID: 28633295 DOI: 10.1093/treephys/tpx062] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Although eucalypts are the most planted hardwood trees worldwide, the majority of them are frost sensitive. The recent creation of frost-tolerant hybrids such as Eucalyptus gundal plants (E. gunnii × E. dalrympleana hybrids), now enables the development of industrial plantations in northern countries. Our objective was to evaluate the impact of cold on the wood structure and composition of these hybrids, and on the biosynthetic and regulatory processes controlling their secondary cell-wall (SCW) formation. We used an integrated approach combining histology, biochemical characterization and transcriptomic profiling as well as gene co-expression analyses to investigate xylem tissues from Eucalyptus hybrids exposed to cold conditions. Chilling temperatures triggered the deposition of thicker and more lignified xylem cell walls as well as regulation at the transcriptional level of SCW genes. Most genes involved in lignin biosynthesis, except those specifically dedicated to syringyl unit biosynthesis, were up-regulated. The construction of a co-expression network enabled the identification of both known and potential new SCW transcription factors, induced by cold stress. These regulators at the crossroads between cold signalling and SCW formation are promising candidates for functional studies since they may contribute to the tolerance of E. gunnii × E. dalrympleana hybrids to cold.
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Affiliation(s)
- Raphael Ployet
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
| | - Marçal Soler
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
| | - Victor Carocha
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
- Instituto de Tecnologia de Química Biológica (ITQB), Biotecnologia de Células Vegetais, Av. da Republica, 2781-157 Oeiras, Portugal
| | - Nathalie Ladouce
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
| | - Ana Alves
- Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
| | - José-Carlos Rodrigues
- Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
| | - Luc Harvengt
- FCBA, Biotechnology and Advanced Silviculture Department, Genetics and Biotechnology Team, F-33610 Cestas, France
| | - Christiane Marque
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
| | - Chantal Teulières
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
| | - Jacqueline Grima-Pettenati
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
| | - Fabien Mounet
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 31326 Castanet-Tolosan, France
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234
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Li X, Blackman CJ, Choat B, Duursma RA, Rymer PD, Medlyn BE, Tissue DT. Tree hydraulic traits are coordinated and strongly linked to climate-of-origin across a rainfall gradient. Plant Cell Environ 2018; 41:646-660. [PMID: 29314083 DOI: 10.1111/pce.13129] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [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: 09/25/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 05/18/2023]
Abstract
Plant hydraulic traits capture the impacts of drought stress on plant function, yet vegetation models lack sufficient information regarding trait coordination and variation with climate-of-origin across species. Here, we investigated key hydraulic and carbon economy traits of 12 woody species in Australia from a broad climatic gradient, with the aim of identifying the coordination among these traits and the role of climate in shaping cross-species trait variation. The influence of environmental variation was minimized by a common garden approach, allowing us to factor out the influence of environment on phenotypic variation across species. We found that hydraulic traits (leaf turgor loss point, stomatal sensitivity to drought [Pgs ], xylem vulnerability to cavitation [Px ], and branch capacitance [Cbranch ]) were highly coordinated across species and strongly related to rainfall and aridity in the species native distributional range. In addition, trade-offs between drought tolerance and plant growth rate were observed across species. Collectively, these results provide critical insight into the coordination among hydraulic traits in modulating drought adaptation and will significantly advance our ability to predict drought vulnerability in these dominant trees species.
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Affiliation(s)
- Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - Chris J Blackman
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - Remko A Duursma
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - Paul D Rymer
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
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235
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Jacobsen AL, Valdovinos-Ayala J, Pratt RB. Functional lifespans of xylem vessels: Development, hydraulic function, and post-function of vessels in several species of woody plants. Am J Bot 2018; 105:142-150. [PMID: 29570215 DOI: 10.1002/ajb2.1029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [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: 08/01/2017] [Accepted: 10/31/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Xylem vessels transition through different stages during their functional lifespan, including expansion and development of vessel elements, transition to vessel hydraulic functionality, and eventual transition to post-functionality. We used information on vessel development and function to develop a model of vessel lifespan for woody plants. METHODS We examined vessel functional lifespan using repeated anatomical sampling throughout the growing season, combined with active-xylem staining to evaluate vessel hydraulic transport functionality. These data were combined with a literature review. The transitions between vessel functional lifespans for several species are illustrated, including grapevine (Vitis vinifera L., Vitaceae), English oak (Quercus robur L., Fagaceae), American chestnut [Castanea dentata (Marshall) Borkh.; Fagaceae], and several arid and semi-arid shrub species. KEY RESULTS In intact woody plants, development and maturation of vessel elements may be gradual. Once hydraulically functional, vessel elements connect to form a vessel network that is responsible for bulk hydraulic flow through the xylem. Vessels become nonfunctional due to the formation of gas emboli. In some species and under some conditions, vessel functionality of embolized conduits may be restored through refilling. Blockages, such as tyloses, gels, or gums, indicate permanent losses in hydraulic functional capacity; however, there may be some interesting exceptions to permanent loss of functionality for gel-based blockages. CONCLUSIONS The gradual development and maturation of vessel elements in woody plants, variation in the onset of functionality between different populations of vessels throughout the growing season, and differences in the timing of vessel transitions to post-functionality are important aspects of plant hydraulic function.
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Affiliation(s)
- Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| | - Jessica Valdovinos-Ayala
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
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236
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Yin XH, Hao GY. [Divergence between ring- and diffuse-porous wood types in broadleaf trees of Changbai Mountains results in substantial differences in hydraulic traits.]. Ying Yong Sheng Tai Xue Bao 2018; 29:352-360. [PMID: 29692047 DOI: 10.13287/j.1001-9332.201802.035] [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] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hydraulic characteristics of trees are strongly influenced by their xylem structures. The divergence in wood type between ring-porous and diffuse-porous species is expected to lead to significantly different hydraulic architecture between these two functional groups. However, there is a lack of comprehensive comparative studies in hydraulic traits between the two groups, in that no study has compared the whole-shoot level hydraulic conductance and detailed pit-level xylem anatomy has not been reported yet. In the present study, detailed hydraulic related traits were stu-died in three ring-porous and four diffuse-porous tree species commonly found in the broadleaf tree species of the Changbai Mountains, including whole-shoot hydraulic conductance (Kshoot), resis-tance to drought-induced embolism (P50), and detailed tissue- and pit-level anatomical characteristics. Our results showed that: 1) consistent with the differences in stem hydraulic conductivity, ring-porous species showed significantly higher Kshoot but significantly lower resistance to drought-induced embolism, i.e., higher P50, indicating a trade-off between hydraulic efficiency and safety in those two functional groups; 2) consistent with their significant divergence in hydraulic functions, the two functional groups showed significant differences in a suite of xylem anatomical characteristics at both the tissue and pit levels, such as maximum vessel length, vessel diameter, pit aperture area and aperture fraction; 3) significant correlations were identified between xylem structural characteristics and between structure and functions across both functional groups, indicating that differences in hydraulic functions were underlain by divergences in a suite structural traits. The competing structural requirements between different hydraulic traits, such as between shoot hydraulic conductance and resistance to drought-induced embolism, reflected the biophysical constraints of xylem design that could not fulfill multiple requirements of xylem functioning at the same time.
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Affiliation(s)
- Xiao Han Yin
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, Liaoning, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guang You Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, Liaoning, China
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237
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Stojnic S, Suchocka M, Benito-Garzón M, Torres-Ruiz JM, Cochard H, Bolte A, Cocozza C, Cvjetkovic B, de Luis M, Martinez-Vilalta J, Ræbild A, Tognetti R, Delzon S. Variation in xylem vulnerability to embolism in European beech from geographically marginal populations. Tree Physiol 2018; 38:173-185. [PMID: 29182720 DOI: 10.1093/treephys/tpx128] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [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: 04/14/2017] [Accepted: 09/23/2017] [Indexed: 05/22/2023]
Abstract
Climate change is expected to increase the frequency and intensity of droughts and heatwaves in Europe, leading to effects on forest growth and major forest dieback events due to hydraulic failure caused by xylem embolism. Inter-specific variability in embolism resistance has been studied in detail, but little is known about intra-specific variability, particularly in marginal populations. We evaluated 15 European beech populations, mostly from geographically marginal sites of the species distribution range, focusing particularly on populations from the dry southern margin. We found small, but significant differences in resistance to embolism between populations, with xylem pressures causing 50% loss of hydraulic conductivity ranging from -2.84 to -3.55 MPa. Significant phenotypic clines of increasing embolism resistance with increasing temperature and aridity were observed: the southernmost beech populations growing in a warmer drier climate and with lower habitat suitability have higher resistance to embolism than those from Northern Europe growing more favourable conditions. Previous studies have shown that there is little or no difference in embolism resistance between core populations, but our findings show that marginal populations have developed ways of protecting their xylem based on either evolution or plasticity.
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Affiliation(s)
- S Stojnic
- University of Novi Sad, Institute of Lowland Forestry and Environment, 21000 Novi Sad, Republic of Serbia
| | - M Suchocka
- Warsaw University of Life Sciences, Landscape University Department, 02-787 Warsaw, Poland
| | | | | | - H Cochard
- Université Clermont Auvergne, INRA, PIAF, F-63000 Clermont-Ferrand, France
| | - A Bolte
- Thünen Institute of Forest Ecosystems, 16225 Eberswalde, Germany
| | - C Cocozza
- Institute for Sustainable Plant Protection (IPSP), National Research Council (CNR), Sesto Fiorentino, Italy
| | - B Cvjetkovic
- University of Banja Luka, Faculty of Forestry, Stepe Stepanovica 75A, 78000 Banja Luka, Bosnia and Herzegovina
| | - M de Luis
- Departamento de Geografía y Ordenación del Territorio-IUCA, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009, Zaragoza, Spain
| | - J Martinez-Vilalta
- CREAF-Université Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - A Ræbild
- Department of Geoscience and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg, Denmark
| | - R Tognetti
- Dipartimento di Bioscienze e Territorio, Università degli Studi del Molise, Pesche, and The EFI Project Centre on Mountain Forests (MOUNTFOR), Edmund Mach Foundation, San Michele all'Adige, Italy
| | - S Delzon
- BIOGECO INRA, University Bordeaux, 33615 Pessac, France
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238
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Marañón-Jiménez S, Van den Bulcke J, Piayda A, Van Acker J, Cuntz M, Rebmann C, Steppe K. X-ray computed microtomography characterizes the wound effect that causes sap flow underestimation by thermal dissipation sensors. Tree Physiol 2018; 38:287-301. [PMID: 28981912 DOI: 10.1093/treephys/tpx103] [Citation(s) in RCA: 3] [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: 05/08/2017] [Accepted: 08/04/2017] [Indexed: 05/26/2023]
Abstract
Insertion of thermal dissipation (TD) sap flow sensors in living tree stems causes damage of the wood tissue, as is the case with other invasive methods. The subsequent wound formation is one of the main causes of underestimation of tree water-use measured by TD sensors. However, the specific alterations in wood anatomy in response to inserted sensors have not yet been characterized, and the linked dysfunctions in xylem conductance and sensor accuracy are still unknown. In this study, we investigate the anatomical mechanisms prompting sap flow underestimation and the dynamic process of wound formation. Successive sets of TD sensors were installed in the early, mid and end stage of the growing season in diffuse- and ring-porous trees, Fagus sylvatica (Linnaeus) and Quercus petraea ((Mattuschka) Lieblein), respectively. The trees were cut in autumn and additional sensors were installed in the cut stem segments as controls without wound formation. The wounded area and volume surrounding each sensor was then visually determined by X-ray computed microtomography (X-ray microCT). This technique allowed the characterization of vessel anatomical transformations such as tyloses formation, their spatial distribution and quantification of reduction in conductive area. MicroCT scans showed considerable formation of tyloses that reduced the conductive area of vessels surrounding the inserted TD probes, thus causing an underestimation in sap flux density (SFD) in both beech and oak. Discolored wood tissue was ellipsoidal, larger in the radial plane, more extensive in beech than in oak, and also for sensors installed for longer times. However, the severity of anatomical transformations did not always follow this pattern. Increased wound size with time, for example, did not result in larger SFD underestimation. This information helps us to better understand the mechanisms involved in wound effects with TD sensors and allows the provision of practical recommendations to reduce biases associated with wounding in field sap flow measurements.
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Affiliation(s)
- S Marañón-Jiménez
- University of Granada, Department of Applied Physics, Av. Fuentenueva s/n, 18071 Granada, Spain
| | - J Van den Bulcke
- UGCT - Woodlab-UGent, Laboratory of Wood Technology, Department of Forest and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - A Piayda
- UFZ, Helmholtz Centre for Environmental Research, Department Computational Hydrosystems, Permoserstraße 15, 04318 Leipzig, Germany
- Thünen Institute of Climate-Smart Agriculture, Bundesallee 50, 38116 Braunschweig, Germany
| | - J Van Acker
- UGCT - Woodlab-UGent, Laboratory of Wood Technology, Department of Forest and Water Management, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Gent, Belgium
| | - M Cuntz
- UFZ, Helmholtz Centre for Environmental Research, Department Computational Hydrosystems, Permoserstraße 15, 04318 Leipzig, Germany
- INRA, Université de Lorraine, UMR1137 Ecologie et Ecophysiologie Forestières, 54280 Champenoux, France
| | - C Rebmann
- UFZ, Helmholtz Centre for Environmental Research, Department Computational Hydrosystems, Permoserstraße 15, 04318 Leipzig, Germany
| | - K Steppe
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
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239
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Prislan P, Cufar K, De Luis M, Gricar J. Precipitation is not limiting for xylem formation dynamics and vessel development in European beech from two temperate forest sites. Tree Physiol 2018; 38:186-197. [PMID: 29325135 DOI: 10.1093/treephys/tpx167] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [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: 05/29/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
We investigated the dynamics of xylem differentiation processes and vessel characteristics in Fagus sylvatica L. to evaluate the plasticity of xylem structures under different environmental conditions. In 2008-10, analyses were performed on microcores collected weekly from two temperate sites: Menina planina (1200 m above sea level (a.s.l.)) and Panska reka (400 m a.s.l.). The duration between the onset and end of major cell differentiation steps and vessel characteristics (i.e., density, VD; mean diameter, MVD; mean area, MVA; and theoretic conductivity area, TCA) were analysed in the first and last quarters of the xylem rings, also in respect of local weather conditions (precipitation, temperature). Although the onset, duration and end of xylem formation phases differed between the two sites, the time spans between the successive wood formation phases were similar. Significant differences in MVD, MVA and TCA values were found between the first and last quarters of xylem increment, regardless of the site and year. Vessel density, on the other hand, depended on xylem-ring width and differed significantly between the sites, being about 30% higher at the high elevation site, in beech trees with 54% narrower xylem rings. Vessel density in the first quarter of the xylem ring showed a positive correlation with the onset of cell expansion, whereas a negative correlation of VD with the cessation of cell production was found in the last quarter of xylem increment. This may be explained by year-to-year differences in the timing of cambial reactivation and leaf development, which effect hormonal regulation of radial growth. No significant linkage between intra-annual weather conditions and conduit characteristics was found. It can thus be presumed that precipitation is not a limiting factor for xylem growth and cell differentiation in beech at the two temperate study sites and sites across Europe with similar weather conditions.
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Affiliation(s)
- Peter Prislan
- Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
| | - Katarina Cufar
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia
| | - Martin De Luis
- Department of Geography and Regional Planning, University of Zaragoza-IUCA, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain
| | - Jožica Gricar
- Slovenian Forestry Institute, Vecna pot 2, SI-1000 Ljubljana, Slovenia
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240
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Ohtsuka A, Sack L, Taneda H. Bundle sheath lignification mediates the linkage of leaf hydraulics and venation. Plant Cell Environ 2018; 41:342-353. [PMID: 29044569 DOI: 10.1111/pce.13087] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [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: 06/18/2017] [Revised: 09/23/2017] [Accepted: 09/28/2017] [Indexed: 06/07/2023]
Abstract
The lignification of the leaf vein bundle sheath (BS) has been observed in many species and would reduce conductance from xylem to mesophyll. We hypothesized that lignification of the BS in lower-order veins would provide benefits for water delivery through the vein hierarchy but that the lignification of higher-order veins would limit transport capacity from xylem to mesophyll and leaf hydraulic conductance (Kleaf ). We further hypothesized that BS lignification would mediate the relationship of Kleaf to vein length per area. We analysed the dependence of Kleaf , and its light response, on the lignification of the BS across vein orders for 11 angiosperm tree species. Eight of 11 species had lignin deposits in the BS of the midrib, and two species additionally only in their secondary veins, and for six species up to their minor veins. Species with lignification of minor veins had a lower hydraulic conductance of xylem and outside-xylem pathways and lower Kleaf . Kleaf could be strongly predicted by vein length per area and highest lignified vein order (R2 = .69). The light-response of Kleaf was statistically independent of BS lignification. The lignification of the BS is an important determinant of species variation in leaf and thus whole plant water transport.
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Affiliation(s)
- Akihiro Ohtsuka
- Asahi Kasei Corporation, Tokyo, 100-8550, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, 113-0033, Japan
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241
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Ooeda H, Terashima I, Taneda H. Intra-specific trends of lumen and wall resistivities of vessels within the stem xylem vary among three woody plants. Tree Physiol 2018; 38:223-231. [PMID: 29036681 DOI: 10.1093/treephys/tpx114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 01/07/2017] [Accepted: 08/21/2017] [Indexed: 06/07/2023]
Abstract
Water flow through xylem vessels encounters hydraulic resistance when passing through the vessel lumen and end wall. Comparative studies have reported that lumen and end wall resistivities co-limit water flow through stem xylem in several angiosperm woody species that have vessels of different average diameter and length. This study examined the intra-specific relationship between the lumen and end wall resistivities (Rlumen and Rwall) for vessels within the stem xylem using three deciduous angiosperm woody species found in temperate forest. Morus australis Poir. and Acer rufinerve Siebold et Zucc. are early- and late-successional species, and Vitis coignetiae Pulliat ex Planch is a woody liana. According to the Hagen-Poiseuille equation, Rlumen is proportional to the fourth power of vessel diameter (D), whereas vessel length (L) and inter-vessel pit area (Apit) determine Rwall. To estimate Rlumen and Rwall, the scaling relationships between the L and D and between Apit and D were measured. The scaling exponents between L and D were 1.47, 3.19 and 2.86 for A. rufinerve, M. australis and V. coignetiae, respectively, whereas those between Apit and D were 0.242, 2.11 and 2.68, respectively. Unlike the inter-specific relationships, the wall resistivity fraction (Rwall/(Rlumen + Rwall)) within xylem changed depending on D. In M. australis and V. coignetiae, this fraction decreased with increasing D, while in A. rufinerve, it increased with D. Vessels with a high wall resistivity fraction have high Rwall and total resistivity but are expected to have low susceptibility to xylem cavitation due to a small cumulative Apit. In contrast, vessels with a low wall resistivity fraction have low Rwall and total resistivity but high susceptibility to xylem cavitation. Because the wall resistivity fraction varies with D, the stem xylem contains vessels with different hydraulic efficiencies and safety to xylem cavitation. These features produce differences in the hydraulic properties of plants with different life forms.
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Affiliation(s)
- Hiroki Ooeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Simplex Inc., 1-23-1, Toranomon, Minato-ku, Tokyo 105-6319, Japan
| | - Ichiro Terashima
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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242
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Schenk HJ, Espino S, Rich-Cavazos SM, Jansen S. From the sap's perspective: The nature of vessel surfaces in angiosperm xylem. Am J Bot 2018; 105:172-185. [PMID: 29578294 DOI: 10.1002/ajb2.1034] [Citation(s) in RCA: 18] [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: 07/29/2017] [Accepted: 12/14/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Xylem sap in angiosperms moves under negative pressure in conduits and cell wall pores that are nanometers to micrometers in diameter, so sap is always very close to surfaces. Surfaces matter for water transport because hydrophobic ones favor nucleation of bubbles, and surface chemistry can have strong effects on flow. Vessel walls contain cellulose, hemicellulose, lignin, pectins, proteins, and possibly lipids, but what is the nature of the inner, lumen-facing surface that is in contact with sap? METHODS Vessel lumen surfaces of five angiosperms from different lineages were examined via transmission electron microscopy and confocal and fluorescence microscopy, using fluorophores and autofluorescence to detect cell wall components. Elemental composition was studied by energy-dispersive X-ray spectroscopy, and treatments with phospholipase C (PLC) were used to test for phospholipids. KEY RESULTS Vessel surfaces consisted mainly of lignin, with strong cellulose signals confined to pit membranes. Proteins were found mainly in inter-vessel pits and pectins only on outer rims of pit membranes and in vessel-parenchyma pits. Continuous layers of lipids were detected on most vessel surfaces and on most pit membranes and were shown by PLC treatment to consist at least partly of phospholipids. CONCLUSIONS Vessel surfaces appear to be wettable because lignin is not strongly hydrophobic and a coating with amphiphilic lipids would render any surface hydrophilic. New questions arise about these lipids and their possible origins from living xylem cells, especially about their effects on surface tension, surface bubble nucleation, and pit membrane function.
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Susana Espino
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Sarah M Rich-Cavazos
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
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243
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
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244
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Johnson D, Eckart P, Alsamadisi N, Noble H, Martin C, Spicer R. Polar auxin transport is implicated in vessel differentiation and spatial patterning during secondary growth in Populus. Am J Bot 2018; 105:186-196. [PMID: 29578291 DOI: 10.1002/ajb2.1035] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 10/18/2017] [Accepted: 01/24/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Dimensions and spatial distribution of vessels are critically important features of woody stems, allowing for adaptation to different environments through their effects on hydraulic efficiency and vulnerability to embolism. Although our understanding of vessel development is poor, basipetal transport of auxin through the cambial zone may play an important role. METHODS Stems of Populus tremula ×alba were treated with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) in a longitudinal strip along the length of the lower stem. Vessel lumen diameter, circularity, and length; xylem growth; tension wood area; and hydraulic conductivity before and after a high pressure flush were determined on both NPA-treated and control plants. KEY RESULTS NPA-treated stems formed aberrant vessels that were short, small in diameter, highly clustered, and angular in cross section, whereas xylem formed on the untreated side of the stem contained typical vessels that were similar to those of controls. NPA-treated stems had reduced specific conductivity relative to controls, but this difference was eliminated by the high-pressure flush. The control treatment (lanolin + dimethyl sulfoxide) reduced xylem growth and increased tension wood formation, but never produced the aberrant vessel patterning seen in NPA-treated stems. CONCLUSIONS These results are consistent with a model of vessel development in which basipetal polar auxin transport through the xylem-side cambial derivatives is required for proper expansion and patterning of vessels and demonstrate that reduced auxin transport can produce stems with altered stem hydraulic properties.
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Affiliation(s)
- Dan Johnson
- Department of Botany, Connecticut College, New London, CT 06320, USA
| | - Phoebe Eckart
- Department of Botany, Connecticut College, New London, CT 06320, USA
| | - Noah Alsamadisi
- Department of Botany, Connecticut College, New London, CT 06320, USA
| | | | - Celia Martin
- Department of Biology, Connecticut College, New London, CT 06320, USA
| | - Rachel Spicer
- Department of Botany, Connecticut College, New London, CT 06320, USA
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245
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Morris H, Plavcová L, Gorai M, Klepsch MM, Kotowska M, Jochen Schenk H, Jansen S. Vessel-associated cells in angiosperm xylem: Highly specialized living cells at the symplast-apoplast boundary. Am J Bot 2018; 105:151-160. [PMID: 29578292 DOI: 10.1002/ajb2.1030] [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: 07/10/2017] [Accepted: 11/13/2017] [Indexed: 05/13/2023]
Abstract
BACKGROUND Vessel-associated cells (VACs) are highly specialized, living parenchyma cells that are in direct contact with water-conducting, dead vessels. The contact may be sparse or in large tight groups of parenchyma that completely surrounds vessels. VACs differ from vessel distant parenchyma in physiology, anatomy, and function and have half-bordered pits at the vessel-parenchyma juncture. The distinct anatomy of VACs is related to the exchange of substances to and from the water-transport system, with the cells long thought to be involved in water transport in woody angiosperms, but where direct experimental evidence is lacking. SCOPE This review focuses on our current knowledge of VACs regarding anatomy and function, including hydraulic capacitance, storage of nonstructural carbohydrates, symplastic and apoplastic interactions, defense against pathogens and frost, osmoregulation, and the novel hypothesis of surfactant production. Based on microscopy, we visually represent how VACs vary in dimensions and general appearance between species, with special attention to the protoplast, amorphous layer, and the vessel-parenchyma pit membrane. CONCLUSIONS An understanding of the relationship between VACs and vessels is crucial to tackling questions related to how water is transported over long distances in xylem, as well as defense against pathogens. New avenues of research show how parenchyma-vessel contact is related to vessel diameter and a new hypothesis may explain how surfactants arising from VAC can allow water to travel under negative pressure. We also reinforce the message of connectivity between VAC and other cells between xylem and phloem.
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Affiliation(s)
- Hugh Morris
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Laboratory for Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Testing and Research, St. Gallen, Switzerland
| | - Lenka Plavcová
- University of Hradec Králové, Department of Biology, Faculty of Science, Rokitanského 62, 500 03, Hradec Králové, Czech Republic
| | - Mustapha Gorai
- University of Gabes, Higher Institute of Applied Biology of Medenine, Medenine, 4119, Tunisia
| | - Matthias M Klepsch
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Martyna Kotowska
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Macquarie University, Department of Biological Sciences, North Ryde, NSW, 2109, Australia
| | - H Jochen Schenk
- California State University Fullerton, Department of Biological Science, 800 N. State College Blvd., Fullerton, CA, 92831-3599, USA
| | - Steven Jansen
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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246
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Granda E, Alla AQ, Laskurain NA, Loidi J, Sánchez-Lorenzo A, Camarero JJ. Coexisting oak species, including rear-edge populations, buffer climate stress through xylem adjustments. Tree Physiol 2018; 38:159-172. [PMID: 29300954 DOI: 10.1093/treephys/tpx157] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 05/02/2017] [Accepted: 11/17/2017] [Indexed: 05/12/2023]
Abstract
The ability of trees to cope with climate change is a pivotal feature of forest ecosystems, especially for rear-edge populations facing warm and dry conditions. To evaluate current and future forests threats, a multi-proxy focus on the growth, anatomical and physiological responses to climate change is needed. We examined the long-term xylem adjustments to climate variability of the temperate Quercus robur L. at its rear edge and the sub-Mediterranean Quercus pyrenaica Willd. Both species coexist at a mesic (ME, humid and warmer) and a xeric (XE, dry and cooler) site in northern Spain, the latter experiencing increasing temperatures in recent decades. We compared xylem traits at each site and assessed their trends, relationships and responses to climate (1960-2008). Traits included basal area increment, earlywood vessel hydraulic diameter, density and theoretical-specific hydraulic conductivity together with latewood oxygen (δ18O) stable isotopes and δ13C-derived water-use efficiency (iWUE). Quercus robur showed the highest growth at ME, likely through enhanced cambial activity. Quercus pyrenaica had higher iWUE at XE compared with ME, but limited plasticity of anatomical xylem traits was found for the two oak species. Similar physiological performance was found for both species. The iWUE augmented in recent years especially at XE, likely explained by stomatal closure given the increasing δ18O signal in response to drier and sunnier growing seasons. Overall, traits were more correlated at XE than at ME. The iWUE improvements were linked to higher growth up to a threshold (~85 μmol mol-1) after which reduced growth was found at XE. Our results are consistent with Q. pyrenaica and Q. robur coexisting at the central and dry edge of the climatic species distribution, respectively, showing similar responses to buffer warmer conditions. In fact, the observed adjustments found for Q. robur point towards growth stability of similar rear-edge oak populations under warmer climate conditions.
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Affiliation(s)
- E Granda
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain
| | - A Q Alla
- Fakulteti i Shkencave Pyjore, Universiteti Bujqësor i Tiranës, Kodër-Kamëz 1029, Tirana, Albania
| | - N A Laskurain
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - J Loidi
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - A Sánchez-Lorenzo
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain
| | - J J Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avenida Montañana 1005, 50080 Zaragoza, Spain
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247
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Tomasella M, Beikircher B, Häberle KH, Hesse B, Kallenbach C, Matyssek R, Mayr S. Acclimation of branch and leaf hydraulics in adult Fagus sylvatica and Picea abies in a forest through-fall exclusion experiment. Tree Physiol 2018; 38:198-211. [PMID: 29177459 DOI: 10.1093/treephys/tpx140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [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: 07/11/2017] [Accepted: 10/03/2017] [Indexed: 05/26/2023]
Abstract
Decreasing water availability due to climate change poses the question of whether and to what extent tree species are able to hydraulically acclimate and how hydraulic traits of stems and leaves are coordinated under drought. In a through-fall exclusion experiment, hydraulic acclimation was analyzed in a mixed forest stand of Fagus sylvatica L. and Picea abies (L.) Karst. In drought-stressed (TE, through-fall exclusion over 2 years) and control (CO) trees, hydraulic vulnerability was studied in branches as well as in leaves (F. sylvatica) and end-twigs (P. abies, entirely formed during the drought period) sampled at the same height in sun-exposed portions of the tree crown. In addition, relevant xylem anatomical traits and leaf pressure-volume relations were analyzed. The TE trees reached pre-dawn water potentials down to -1.6 MPa. In both species, water potentials at 50% loss of xylem hydraulic conductivity were ~0.4 MPa more negative in TE than in CO branches. Foliage hydraulic vulnerability (expressed as water potential at 50% loss of leaf/end-twig hydraulic conductance) and water potential at turgor loss point were also, respectively, 0.4 and 0.5 MPa lower in TE trees. Minor differences were observed in conduit mean hydraulic diameter and cell wall reinforcement. Our findings indicate significant and fast hydraulic acclimation under relatively mild drought in both tree species. Acclimation was well coordinated between branches and foliage, which might be essential for survival and productivity of mature trees under future drought periods.
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Affiliation(s)
- Martina Tomasella
- Department of Ecology and Ecosystem Management, Chair for Ecophysiology of Plants, Technical University of Munich, Hans-Carl-von-Carlowitz Platz 2, 85354 Freising, Germany
| | - Barbara Beikircher
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Karl-Heinz Häberle
- Department of Ecology and Ecosystem Management, Chair for Ecophysiology of Plants, Technical University of Munich, Hans-Carl-von-Carlowitz Platz 2, 85354 Freising, Germany
| | - Benjamin Hesse
- Department of Ecology and Ecosystem Management, Chair for Ecophysiology of Plants, Technical University of Munich, Hans-Carl-von-Carlowitz Platz 2, 85354 Freising, Germany
| | - Christian Kallenbach
- Department of Ecology and Ecosystem Management, Chair for Ecophysiology of Plants, Technical University of Munich, Hans-Carl-von-Carlowitz Platz 2, 85354 Freising, Germany
| | - Rainer Matyssek
- Department of Ecology and Ecosystem Management, Chair for Ecophysiology of Plants, Technical University of Munich, Hans-Carl-von-Carlowitz Platz 2, 85354 Freising, Germany
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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248
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Pfautsch S, Aspinwall MJ, Drake JE, Chacon-Doria L, Langelaan RJA, Tissue DT, Tjoelker MG, Lens F. Traits and trade-offs in whole-tree hydraulic architecture along the vertical axis of Eucalyptus grandis. Ann Bot 2018; 121:129-141. [PMID: 29325002 PMCID: PMC5786253 DOI: 10.1093/aob/mcx137] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [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: 05/12/2017] [Accepted: 10/06/2017] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS Sapwood traits like vessel diameter and intervessel pit characteristics play key roles in maintaining hydraulic integrity of trees. Surprisingly little is known about how sapwood traits covary with tree height and how such trait-based variation could affect the efficiency of water transport in tall trees. This study presents a detailed analysis of structural and functional traits along the vertical axes of tall Eucalyptus grandis trees. METHODS To assess a wide range of anatomical and physiological traits, light and electron microscopy was used, as well as field measurements of tree architecture, water use, stem water potential and leaf area distribution. KEY RESULTS Strong apical dominance of water transport resulted in increased volumetric water supply per unit leaf area with tree height. This was realized by continued narrowing (from 250 to 20 µm) and an exponential increase in frequency (from 600 to 13 000 cm-2) of vessels towards the apex. The widest vessels were detected at least 4 m above the stem base, where they were associated with the thickest intervessel pit membranes. In addition, this study established the lower limit of pit membrane thickness in tall E. grandis at ~375 nm. This minimum thickness was maintained over a large distance in the upper stem, where vessel diameters continued to narrow. CONCLUSIONS The analyses of xylem ultrastructure revealed complex, synchronized trait covariation and trade-offs with increasing height in E. grandis. Anatomical traits related to xylem vessels and those related to architecture of pit membranes were found to increase efficiency and apical dominance of water transport. This study underlines the importance of studying tree hydraulic functioning at organismal scale. Results presented here will improve understanding height-dependent structure-function patterns in tall trees.
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Affiliation(s)
- Sebastian Pfautsch
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- For correspondence. E-mail
| | - Michael J Aspinwall
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- Department of Biology, University of North Florida, Jacksonville, FL, USA
| | - John E Drake
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- College of Environmental Science and Forestry, State University of New York, Syracuse, NY, USA
| | | | - Rob J A Langelaan
- Naturalis Biodiversity Center, Leiden University, Leiden, The Netherlands
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, Leiden, The Netherlands
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249
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Yazaki K, Takanashi T, Kanzaki N, Komatsu M, Levia DF, Kabeya D, Tobita H, Kitao M, Ishida A. Pine wilt disease causes cavitation around the resin canals and irrecoverable xylem conduit dysfunction. J Exp Bot 2018; 69:589-602. [PMID: 29240955 DOI: 10.1093/jxb/erx417] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Physiological mechanisms of irreversible hydraulic dysfunction in seedlings infected with pine wilt disease (PWD) are still unclear. We employed cryo-scanning electron microscopy (cryo-SEM) to investigate the temporal and spatial changes in water distribution within the xylem of the main stem of 2-year-old Japanese black pine seedlings infested by pine wood nematodes (PWNs). Our experiment was specifically designed to compare the water relations among seedlings subjected to the following water treatment and PWN combinations: (i) well-watered versus prolonged drought (no PWNs); and (ii) well-watered with PWNs versus water-stressed with PWNs (four treatments in total). Cryo-SEM imaging observations chronicled the development of patchy cavitations in the xylem tracheids of the seedlings influenced by PWD. With the progression of drought, many pit membranes of bordered pits in the xylem of the main stem were aspirated with the decrease in water potential without xylem cavitation, indicating that hydraulic segmentation may exist between tracheids. This is the first study to demonstrate conclusively that explosive and irreversible cavitations occurred around the hydraulically vulnerable resin canals with the progression of PWD. Our findings provide a more comprehensive understanding of stressors on plant-water relations that may eventually better protect trees from PWD and assist with the breeding of trees more tolerant to PWD.
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Affiliation(s)
- Kenichi Yazaki
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Takuma Takanashi
- Department of Forest Entomology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute (FFPRI), Kyoto, Japan
| | - Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Delphis F Levia
- Departments of Geography and Plant & Soil Science, University of Delaware, USA
| | - Daisuke Kabeya
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Hiroyuki Tobita
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Mitsutoshi Kitao
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Sappro, Japan
| | - Atsushi Ishida
- Center for Ecological Research, Kyoto University, Otsu, Japan
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250
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Perdiguero P, Sobrino-Plata J, Venturas M, Martín JA, Gil L, Collada C. Gene expression trade-offs between defence and growth in English elm induced by Ophiostoma novo-ulmi. Plant Cell Environ 2018; 41:198-214. [PMID: 29034465 DOI: 10.1111/pce.13085] [Citation(s) in RCA: 3] [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: 12/17/2016] [Revised: 09/12/2017] [Accepted: 09/21/2017] [Indexed: 06/07/2023]
Abstract
Wilt diseases caused by vascular pathogens include some of the most damaging stresses affecting trees. Dutch elm disease (DED), caused by the fungus Ophiostoma novo-ulmi, destroyed most of North American and European elm populations in the 20th century. The highly susceptible English elm, also known as Atinian clone, suffered the highest mortality rates during the last pandemic event, probably due to its lack of genetic diversity. To study the DED pathosystem, we inoculated English elm ramets with O. novo-ulmi and evaluated xylem anatomy, molecular response, and disease symptoms. The high DED susceptibility of the clone was linked to xylem structure. The transcript levels changed significantly for 1,696 genes during O. novo-ulmi invasion. Genes covering different steps of the plant immune system were identified, many of which showed homology with Arabidopsis thaliana genes involved in systemic acquired resistance. Induction of several pathogenesis-related proteins and repression of fasciclin-like arabinogalactan proteins and other cell wall biosynthesis pathways evidence unbalanced costs between growth and defence mechanisms far from the inoculation point. This study sheds light on elm molecular defence mechanisms against DED.
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Affiliation(s)
- Pedro Perdiguero
- GENFOR, Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
- iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901, Oeiras, Portugal
| | - Juan Sobrino-Plata
- GENFOR, Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
| | - Martin Venturas
- GENFOR, Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
- Biology Department, University of Utah, Salt Lake City, UT, 84112, USA
| | - Juan Antonio Martín
- GENFOR, Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
| | - Luis Gil
- GENFOR, Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
| | - Carmen Collada
- GENFOR, Grupo de Investigación en Genética, Fisiología e Historia Forestal, Universidad Politécnica de Madrid (UPM), 28040, Madrid, Spain
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