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Salmon Y, Torres-Ruiz JM, Poyatos R, Martinez-Vilalta J, Meir P, Cochard H, Mencuccini M. Balancing the risks of hydraulic failure and carbon starvation: a twig scale analysis in declining Scots pine. PLANT, CELL & ENVIRONMENT 2015; 38:2575-88. [PMID: 25997464 PMCID: PMC4989476 DOI: 10.1111/pce.12572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 05/04/2023]
Abstract
Understanding physiological processes involved in drought-induced mortality is important for predicting the future of forests and for modelling the carbon and water cycles. Recent research has highlighted the variable risks of carbon starvation and hydraulic failure in drought-exposed trees. However, little is known about the specific responses of leaves and supporting twigs, despite their critical role in balancing carbon acquisition and water loss. Comparing healthy (non-defoliated) and unhealthy (defoliated) Scots pine at the same site, we measured the physiological variables involved in regulating carbon and water resources. Defoliated trees showed different responses to summer drought compared with non-defoliated trees. Defoliated trees maintained gas exchange while non-defoliated trees reduced photosynthesis and transpiration during the drought period. At the branch scale, very few differences were observed in non-structural carbohydrate concentrations between health classes. However, defoliated trees tended to have lower water potentials and smaller hydraulic safety margins. While non-defoliated trees showed a typical response to drought for an isohydric species, the physiology appears to be driven in defoliated trees by the need to maintain carbon resources in twigs. These responses put defoliated trees at higher risk of branch hydraulic failure and help explain the interaction between carbon starvation and hydraulic failure in dying trees.
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Affiliation(s)
- Yann Salmon
- School of Geosciences, University of Edinburgh, Edinburgh, EH93JN, UK
| | - José M Torres-Ruiz
- BIOGECO, UMR 1202, Université de Bordeaux, F-33615, Pessac, France
- UMR 1202 BIOGECO, INRA, 33612, Cestas, France
| | | | - Jordi Martinez-Vilalta
- Campus de UAB, CREAF, 08193, Barcelona, Spain
- Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Spain
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, EH93JN, UK
- Research School of Biology, Australian National University, ACT 2601, Canberra, Australian Capital Territory, Australia
| | - Hervé Cochard
- INRA, UMR547 PIAF, Clermont Université, F-63100, Clermont-Ferrand, France
| | - Maurizio Mencuccini
- School of Geosciences, University of Edinburgh, Edinburgh, EH93JN, UK
- ICREA, CREAF, 08193, Barcelona, Spain
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102
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Maguire AJ, Kobe RK. Drought and shade deplete nonstructural carbohydrate reserves in seedlings of five temperate tree species. Ecol Evol 2015; 5:5711-21. [PMID: 27069619 PMCID: PMC4813112 DOI: 10.1002/ece3.1819] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/12/2015] [Accepted: 10/14/2015] [Indexed: 11/06/2022] Open
Abstract
Plants that store nonstructural carbohydrates (NSC) may rely on carbon reserves to survive carbon‐limiting stress, assuming that reserves can be mobilized. We asked whether carbon reserves decrease in resource stressed seedlings, and if NSC allocation is related to species' relative stress tolerances. We tested the effects of stress (shade, drought, and defoliation) on NSC in seedlings of five temperate tree species (Acer rubrum Marsh., Betula papyrifera Marsh., Fraxinus americana L., Quercus rubra L., and Quercus velutina Lam.). In a greenhouse experiment, seedlings were subjected to combinations of shade, drought, and defoliation. We harvested seedlings over 32–97 days and measured biomass and NSC concentrations in stems and roots to estimate depletion rates. For all species and treatments, except for defoliation, seedling growth and NSC accumulation ceased. Shade and drought combined caused total NSC decreases in all species. For shade or drought alone, only some species experienced decreases. Starch followed similar patterns as total NSC, but soluble sugars increased under drought for drought‐tolerant species. These results provide evidence that species deplete stored carbon in response to carbon limiting stress and that species differences in NSC response may be important for understanding carbon depletion as a buffer against shade‐ and drought‐induced mortality.
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Affiliation(s)
- Andrea J Maguire
- Department of Plant Biology Michigan State University East Lansing Michigan
| | - Richard K Kobe
- Department of Plant Biology Michigan State University East Lansing Michigan; Graduate Program in Ecology, Evolutionary Biology and Behavior Michigan State University East Lansing Michigan; Department Forestry Michigan State University East Lansing Michigan
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103
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Adams HD, Collins AD, Briggs SP, Vennetier M, Dickman LT, Sevanto SA, Garcia-Forner N, Powers HH, McDowell NG. Experimental drought and heat can delay phenological development and reduce foliar and shoot growth in semiarid trees. GLOBAL CHANGE BIOLOGY 2015; 21:4210-20. [PMID: 26149972 DOI: 10.1111/gcb.13030] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 05/26/2015] [Indexed: 05/16/2023]
Abstract
Higher temperatures associated with climate change are anticipated to trigger an earlier start to the growing season, which could increase the terrestrial C sink strength. Greater variability in the amount and timing of precipitation is also expected with higher temperatures, bringing increased drought stress to many ecosystems. We experimentally assessed the effects of higher temperature and drought on the foliar phenology and shoot growth of mature trees of two semiarid conifer species. We exposed field-grown trees to a ~45% reduction in precipitation with a rain-out structure ('drought'), a ~4.8 °C temperature increase with open-top chambers ('heat'), and a combination of both simultaneously ('drought + heat'). Over the 2013 growing season, drought, heat, and drought + heat treatments reduced shoot and needle growth in piñon pine (Pinus edulis) by ≥39%, while juniper (Juniperus monosperma) had low growth and little response to these treatments. Needle emergence on primary axis branches of piñon pine was delayed in heat, drought, and drought + heat treatments by 19-57 days, while secondary axis branches were less likely to produce needles in the heat treatment, and produced no needles at all in the drought + heat treatment. Growth of shoots and needles, and the timing of needle emergence correlated inversely with xylem water tension and positively with nonstructural carbohydrate concentrations. Our findings demonstrate the potential for delayed phenological development and reduced growth with higher temperatures and drought in tree species that are vulnerable to drought and reveal potential mechanistic links to physiological stress responses. Climate change projections of an earlier and longer growing season with higher temperatures, and consequent increases in terrestrial C sink strength, may be incorrect for regions where plants will face increased drought stress with climate change.
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Affiliation(s)
- Henry D Adams
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Adam D Collins
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Samuel P Briggs
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Michel Vennetier
- Irstea, UR Ecosystèmes Méditerranéens et Risques, Le Tholonet Aix-en-Provence, F-13182, France
| | - L Turin Dickman
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Sanna A Sevanto
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Núria Garcia-Forner
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), and Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Spain
| | - Heath H Powers
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
| | - Nate G McDowell
- Earth and Environmental Sciences, Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM, 87545, USA
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104
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Quentin AG, Pinkard EA, Ryan MG, Tissue DT, Baggett LS, Adams HD, Maillard P, Marchand J, Landhäusser SM, Lacointe A, Gibon Y, Anderegg WRL, Asao S, Atkin OK, Bonhomme M, Claye C, Chow PS, Clément-Vidal A, Davies NW, Dickman LT, Dumbur R, Ellsworth DS, Falk K, Galiano L, Grünzweig JM, Hartmann H, Hoch G, Hood S, Jones JE, Koike T, Kuhlmann I, Lloret F, Maestro M, Mansfield SD, Martínez-Vilalta J, Maucourt M, McDowell NG, Moing A, Muller B, Nebauer SG, Niinemets Ü, Palacio S, Piper F, Raveh E, Richter A, Rolland G, Rosas T, Saint Joanis B, Sala A, Smith RA, Sterck F, Stinziano JR, Tobias M, Unda F, Watanabe M, Way DA, Weerasinghe LK, Wild B, Wiley E, Woodruff DR. Non-structural carbohydrates in woody plants compared among laboratories. TREE PHYSIOLOGY 2015; 35:1146-1165. [PMID: 26423132 DOI: 10.1093/treephys/tpv073] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 07/09/2015] [Indexed: 06/05/2023]
Abstract
Non-structural carbohydrates (NSC) in plant tissue are frequently quantified to make inferences about plant responses to environmental conditions. Laboratories publishing estimates of NSC of woody plants use many different methods to evaluate NSC. We asked whether NSC estimates in the recent literature could be quantitatively compared among studies. We also asked whether any differences among laboratories were related to the extraction and quantification methods used to determine starch and sugar concentrations. These questions were addressed by sending sub-samples collected from five woody plant tissues, which varied in NSC content and chemical composition, to 29 laboratories. Each laboratory analyzed the samples with their laboratory-specific protocols, based on recent publications, to determine concentrations of soluble sugars, starch and their sum, total NSC. Laboratory estimates differed substantially for all samples. For example, estimates for Eucalyptus globulus leaves (EGL) varied from 23 to 116 (mean = 56) mg g(-1) for soluble sugars, 6-533 (mean = 94) mg g(-1) for starch and 53-649 (mean = 153) mg g(-1) for total NSC. Mixed model analysis of variance showed that much of the variability among laboratories was unrelated to the categories we used for extraction and quantification methods (method category R(2) = 0.05-0.12 for soluble sugars, 0.10-0.33 for starch and 0.01-0.09 for total NSC). For EGL, the difference between the highest and lowest least squares means for categories in the mixed model analysis was 33 mg g(-1) for total NSC, compared with the range of laboratory estimates of 596 mg g(-1). Laboratories were reasonably consistent in their ranks of estimates among tissues for starch (r = 0.41-0.91), but less so for total NSC (r = 0.45-0.84) and soluble sugars (r = 0.11-0.83). Our results show that NSC estimates for woody plant tissues cannot be compared among laboratories. The relative changes in NSC between treatments measured within a laboratory may be comparable within and between laboratories, especially for starch. To obtain comparable NSC estimates, we suggest that users can either adopt the reference method given in this publication, or report estimates for a portion of samples using the reference method, and report estimates for a standard reference material. Researchers interested in NSC estimates should work to identify and adopt standard methods.
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Affiliation(s)
- Audrey G Quentin
- CSIRO Land and Water, Private Bag 12, Hobart, Tasmania 7001, Australia Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | | | - Michael G Ryan
- Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1401, USA USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO 80521, USA
| | - David T Tissue
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - L Scott Baggett
- USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO 80521, USA
| | - Henry D Adams
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Pascale Maillard
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Centre de Nancy, F-54280 Champenoux, France
| | - Jacqueline Marchand
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Plateforme Technique d'Ecologie Fonctionnelle (OC 081) Centre de Nancy, F-54280 Champenoux, France
| | - Simon M Landhäusser
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - André Lacointe
- INRA, UMR 0547 PIAF, F:63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 0547 PIAF, F:6310 Clermont-Ferrand, France
| | - Yves Gibon
- UMR1332, Biologie du Fruit et Pathologie, INRA, Bordeaux University, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France Plateforme Métabolome du Centre de Génomique Fonctionnelle Bordeaux, MetaboHUB, IBVM, Centre INRA, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France
| | - William R L Anderegg
- Princeton Environmental Institute, Princeton University, Princeton NJ 08540, USA
| | - Shinichi Asao
- Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523-1401, USA
| | - Owen K Atkin
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Marc Bonhomme
- INRA, UMR 0547 PIAF, F:63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 0547 PIAF, F:6310 Clermont-Ferrand, France
| | - Caroline Claye
- Tasmanian Institute of Agriculture, School of Land and Food, Private Bag 98, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Pak S Chow
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | | | - Noel W Davies
- Central Science Laboratory, Private Bag 74, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - L Turin Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Rita Dumbur
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - Kristen Falk
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Lucía Galiano
- Swiss Federal Research Institute WSL, CH-8903 Birmensdorf, Switzerland Institute of Hydrology, Freiburg University, Fahnenbergplatz, D-79098 Freiburg, Germany
| | - José M Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 7610001, Israel
| | - Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, 07745 Jena, Germany
| | - Günter Hoch
- Department of Environmental Sciences - Botany, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland
| | - Sharon Hood
- Division of Biological Sciences, University of Montana, Missoula MT-59812, USA
| | - Joanna E Jones
- Tasmanian Institute of Agriculture, School of Land and Food, Private Bag 98, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Takayoshi Koike
- Silviculture and Forest Ecological Studies, Hokkaido University Sapporo, Hokkaido 060-8589, Japan
| | - Iris Kuhlmann
- Max Planck Institute for Biogeochemistry, Hans-Knöll Str. 10, 07745 Jena, Germany
| | - Francisco Lloret
- CREAF, Cerdanyola del Vallès E-08193 Barcelona, Spain Universidad Autònoma Barcelona, Cerdanyola del Vallès E-08193 Barcelona, Spain
| | - Melchor Maestro
- Instituto Pirenaico de Ecología (IPE-CSIC), Av. Nuestra Señora de la Victoria s/n, 22700 Jaca, Huesca, Spain
| | - Shawn D Mansfield
- Department of Wood Science, University of British Columbia, V6T 1Z4 Vancouver, Canada
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès E-08193 Barcelona, Spain Universidad Autònoma Barcelona, Cerdanyola del Vallès E-08193 Barcelona, Spain
| | - Mickael Maucourt
- Plateforme Métabolome du Centre de Génomique Fonctionnelle Bordeaux, MetaboHUB, IBVM, Centre INRA, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France Université Bordeaux, UMR 1332, Biologie du Fruit et Pathologie, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France
| | - Nathan G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Annick Moing
- UMR1332, Biologie du Fruit et Pathologie, INRA, Bordeaux University, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France Plateforme Métabolome du Centre de Génomique Fonctionnelle Bordeaux, MetaboHUB, IBVM, Centre INRA, 71 avenue Edouard Bourlaux, F-33140 Villenave d'Ornon, France
| | | | - Sergio G Nebauer
- Plant Production Department, Universitat Politécnica de Valéncia, Camino de vera s.n. 46022-Valencia, Spain
| | - Ülo Niinemets
- Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Sara Palacio
- Instituto Pirenaico de Ecología (IPE-CSIC), Av. Nuestra Señora de la Victoria s/n, 22700 Jaca, Huesca, Spain
| | - Frida Piper
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Simpson 471, Coyhaique, Chile
| | - Eran Raveh
- Department of Fruit Trees Sciences, Institute of Plant Sciences, A.R.O., Gilat Research Center, D.N. Negev 85289, Israel
| | - Andreas Richter
- Department of Microbiology and Ecosystem Science, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria
| | | | - Teresa Rosas
- CREAF, Cerdanyola del Vallès E-08193 Barcelona, Spain
| | - Brigitte Saint Joanis
- INRA, UMR 0547 PIAF, F:63100 Clermont-Ferrand, France Clermont Université, Université Blaise Pascal, UMR 0547 PIAF, F:6310 Clermont-Ferrand, France
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula MT-59812, USA
| | - Renee A Smith
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, Postbox 47, 6700 AA, Wageningen, the Netherlands
| | - Joseph R Stinziano
- Department of Biology, Western University, 1151 Richmond Street, London, N6A 5B7, ON, Canada
| | - Mari Tobias
- Department of Plant Physiology, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Faride Unda
- Department of Wood Science, University of British Columbia, V6T 1Z4 Vancouver, Canada
| | - Makoto Watanabe
- Institute of Agriculture, Tokyo University of Agriculture and Technology Fuchu, Tokyo 183-8509, Japan
| | - Danielle A Way
- Department of Biology, Western University, 1151 Richmond Street, London, N6A 5B7, ON, Canada Nicholas School of the Environment, Duke University, Box 90328, Durham, NC 27708, USA
| | - Lasantha K Weerasinghe
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia Faculty of Agriculture, University of Peradeniya, Peradeniya, 20400, Sri Lanka
| | - Birgit Wild
- Department of Microbiology and Ecosystem Science, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria Department of Earth Sciences, University of Gothenburg, Guldhedsgatan 5A, 40530 Gothenburg, Sweden
| | - Erin Wiley
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - David R Woodruff
- USDA Forest Service, Forestry Sciences Laboratory, Corvallis, OR 97331, USA
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105
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Germino MJ. A carbohydrate quandary. TREE PHYSIOLOGY 2015; 35:1141-1145. [PMID: 26507272 DOI: 10.1093/treephys/tpv109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 09/14/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Matthew J Germino
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Boise, ID 83702, USA
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106
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Zwieniecki MA, Secchi F. Threats to xylem hydraulic function of trees under 'new climate normal' conditions. PLANT, CELL & ENVIRONMENT 2015; 38:1713-24. [PMID: 25039674 DOI: 10.1111/pce.12412] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/02/2014] [Accepted: 07/06/2014] [Indexed: 05/23/2023]
Abstract
Climate models predict increases in frequency and intensity of extreme environmental conditions, such as changes to minimum and maximum temperatures, duration of drought periods, intensity of rainfall/snowfall events and wind strength. These local extremes, rather than average climatic conditions, are closely linked to woody plant survival, as trees cope with such events over long lifespans. While the xylem provides trees with structural strength and is considered the most robust part of a tree's structure, it is also the most physiologically vulnerable as tree survival depends on its ability to sustain water supply to the tree crown under variable environmental conditions. Many structural, functional and biological tree properties evolved to protect xylem from loss of transport function because of embolism or to restore xylem transport capacity following embolism formation. How 'the new climate normal' conditions will affect these evolved strategies is yet to be seen. Our understanding of xylem physiology and current conceptual models describing embolism formation and plant recovery from water stress, however, can provide insight into near-future challenges that woody plants will face. In addition, knowledge of species-specific properties of xylem function may help guide mitigation of climate change impacts on woody plants in natural and agricultural tree communities.
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Affiliation(s)
- Maciej A Zwieniecki
- Department of Plant Sciences, University of California - Davis, Davis, CA, 95616, USA
| | - Francesca Secchi
- Department of Plant Sciences, University of California - Davis, Davis, CA, 95616, USA
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107
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Gaylord ML, Kolb TE, McDowell NG. Mechanisms of piñon pine mortality after severe drought: a retrospective study of mature trees. TREE PHYSIOLOGY 2015; 35:806-816. [PMID: 26048753 DOI: 10.1093/treephys/tpv038] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 04/11/2015] [Indexed: 06/04/2023]
Abstract
Conifers have incurred high mortality during recent global-change-type drought(s) in the western USA. Mechanisms of drought-related tree mortality need to be resolved to support predictions of the impacts of future increases in aridity on vegetation. Hydraulic failure, carbon starvation and lethal biotic agents are three potentially interrelated mechanisms of tree mortality during drought. Our study compared a suite of measurements related to these mechanisms between 49 mature piñon pine (Pinus edulis Engelm.) trees that survived severe drought in 2002 (live trees) and 49 trees that died during the drought (dead trees) over three sites in Arizona and New Mexico. Results were consistent over all sites indicating common mortality mechanisms over a wide region rather than site-specific mechanisms. We found evidence for an interactive role of hydraulic failure, carbon starvation and biotic agents in tree death. For the decade prior to the mortality event, dead trees had twofold greater sapwood cavitation based on frequency of aspirated tracheid pits observed with scanning electron microscopy (SEM), smaller inter-tracheid pit diameter measured by SEM, greater diffusional constraints to photosynthesis based on higher wood δ(13)C, smaller xylem resin ducts, lower radial growth and more bark beetle (Coleoptera: Curculionidae) attacks than live trees. Results suggest that sapwood cavitation, low carbon assimilation and low resin defense predispose piñon pine trees to bark beetle attacks and mortality during severe drought. Our novel approach is an important step forward to yield new insights into how trees die via retrospective analysis.
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Affiliation(s)
- Monica L Gaylord
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA Present address: Forest Health Protection, USDA Forest Service, Flagstaff, AZ 86001, USA
| | - Thomas E Kolb
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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108
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O'Grady AP, Mitchell PJ. Looking forward, looking back: capturing drought in flagrante delicto and uncovering its broader consequences for forest ecosystems. TREE PHYSIOLOGY 2015; 35:803-805. [PMID: 26311305 DOI: 10.1093/treephys/tpv072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- A P O'Grady
- CSIRO Land and Water Flagship, Private Bag 12, Hobart, Tasmania 7001, Australia
| | - P J Mitchell
- CSIRO Land and Water Flagship, Private Bag 12, Hobart, Tasmania 7001, Australia
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109
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Sperry JS, Love DM. What plant hydraulics can tell us about responses to climate-change droughts. THE NEW PHYTOLOGIST 2015; 207:14-27. [PMID: 25773898 DOI: 10.1111/nph.13354] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/30/2015] [Indexed: 05/02/2023]
Abstract
Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at-risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration 'supply function' is used to predict a water 'loss function' by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply-loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D, drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought-induced loss of plant hydraulic conductance (k), canopy G, carbon assimilation, and productivity. Data lead to the 'chronic stress hypothesis' wherein > 60% loss of k increases mortality by multiple mechanisms. Supply-loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large-scale modeling.
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Affiliation(s)
- John S Sperry
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - David M Love
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
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110
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Duan H, O'Grady AP, Duursma RA, Choat B, Huang G, Smith RA, Jiang Y, Tissue DT. Drought responses of two gymnosperm species with contrasting stomatal regulation strategies under elevated [CO2] and temperature. TREE PHYSIOLOGY 2015; 35:756-70. [PMID: 26063706 DOI: 10.1093/treephys/tpv047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/28/2015] [Indexed: 05/06/2023]
Abstract
Future climate regimes characterized by rising [CO2], rising temperatures and associated droughts may differentially affect tree growth and physiology. However, the interactive effects of these three factors are complex because elevated [CO2] and elevated temperature may generate differential physiological responses during drought. To date, the interactive effects of elevated [CO2] and elevated temperature on drought-induced tree mortality remain poorly understood in gymnosperm species that differ in stomatal regulation strategies. Water relations and carbon dynamics were examined in two species with contrasting stomatal regulation strategies: Pinus radiata D. Don (relatively isohydric gymnosperm; regulating stomata to maintain leaf water potential above critical thresholds) and Callitris rhomboidea R. Br (relatively anisohydric gymnosperm; allowing leaf water potential to decline as the soil dries), to assess response to drought as a function of [CO2] and temperature. Both species were grown in two [CO2] (C(a) (ambient, 400 μl l(-1)) and C(e) (elevated, 640 μl l(-1))) and two temperature (T(a) (ambient) and T(e) (ambient +4 °C)) treatments in a sun-lit glasshouse under well-watered conditions. Drought plants were then exposed to a progressive drought until mortality. Prior to mortality, extensive xylem cavitation occurred in both species, but significant depletion of non-structural carbohydrates was not observed in either species. Te resulted in faster mortality in P. radiata, but it did not modify the time-to-mortality in C. rhomboidea. C(e) did not delay the time-to-mortality in either species under drought or T(e) treatments. In summary, elevated temperature (+4 °C) had greater influence than elevated [CO2] (+240 μl l(-1)) on drought responses of the two studied gymnosperm species, while stomatal regulation strategies did not generally affect the relative contributions of hydraulic failure and carbohydrate depletion to mortality under severe drought.
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Affiliation(s)
- Honglang Duan
- Institute of Ecology and Environmental Science, Nanchang Institute of Technology, Nanchang, Jiangxi 330099, China
| | - Anthony P O'Grady
- CSIRO Land and Water Flagship, Private Bag 12, Hobart, Tasmania 7001, Australia
| | - Remko A Duursma
- Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Guomin Huang
- Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Renee A Smith
- Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Yanan Jiang
- Institute of Ecology and Environmental Science, Nanchang Institute of Technology, Nanchang, Jiangxi 330099, China
| | - David T Tissue
- Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury Campus, Locked Bag 1797, Penrith, NSW 2751, Australia
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111
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Zeppel MJB, Harrison SP, Adams HD, Kelley DI, Li G, Tissue DT, Dawson TE, Fensham R, Medlyn BE, Palmer A, West AG, McDowell NG. Drought and resprouting plants. THE NEW PHYTOLOGIST 2015; 206:583-9. [PMID: 27283977 DOI: 10.1111/nph.13205] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 10/29/2014] [Indexed: 05/05/2023]
Abstract
Many species have the ability to resprout vegetatively after a substantial loss of biomass induced by environmental stress, including drought. Many of the regions characterised by ecosystems where resprouting is common are projected to experience more frequent and intense drought during the 21st Century. However, in assessments of ecosystem response to drought disturbance there has been scant consideration of the resilience and post-drought recovery of resprouting species. Systematic differences in hydraulic and allocation traits suggest that resprouting species are more resilient to drought-stress than nonresprouting species. Evidence suggests that ecosystems dominated by resprouters recover from disturbance more quickly than ecosystems dominated by nonresprouters. The ability of resprouters to avoid mortality and withstand drought, coupled with their ability to recover rapidly, suggests that the impact of increased drought stress in ecosystems dominated by these species may be small. The strategy of resprouting needs to be modelled explicitly to improve estimates of future climate-change impacts on the carbon cycle, but this will require several important knowledge gaps to be filled before resprouting can be properly implemented.
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Affiliation(s)
- Melanie J B Zeppel
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Sandy P Harrison
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
- School of Archaeology, Geography and Environmental Sciences (SAGES), Reading University, Whiteknights, Reading, RG6 6AB, UK
| | - Henry D Adams
- Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Douglas I Kelley
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Guangqi Li
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Rod Fensham
- Queensland Herbarium, Environmental Protection Agency, Towong, QLD, Australia
| | - Belinda E Medlyn
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Anthony Palmer
- Centre for African Conservation Ecology, Nelson Mandela Metropolitan University, Private Bag, 77000, Port Elizabeth, South Africa
| | - Adam G West
- Department of Botany, University of Cape Town, Rondebosch, South Africa
| | - Nate G McDowell
- Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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112
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Dickman LT, McDowell NG, Sevanto S, Pangle RE, Pockman WT. Carbohydrate dynamics and mortality in a piñon-juniper woodland under three future precipitation scenarios. PLANT, CELL & ENVIRONMENT 2015; 38:729-39. [PMID: 25159277 DOI: 10.1111/pce.12441] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 08/07/2014] [Indexed: 05/16/2023]
Abstract
Drought-induced forest mortality is an increasing global problem with wide-ranging consequences, yet mortality mechanisms remain poorly understood. Depletion of non-structural carbohydrate (NSC) stores has been implicated as an important mechanism in drought-induced mortality, but experimental field tests are rare. We used an ecosystem-scale precipitation manipulation experiment to evaluate leaf and twig NSC dynamics of two co-occurring conifers that differ in patterns of stomatal regulation of water loss and recent mortality: the relatively desiccation-avoiding piñon pine (Pinus edulis) and the relatively desiccation-tolerant one-seed juniper (Juniperus monosperma). Piñon pine experienced 72% mortality after 13-25 months of experimental drought and juniper experienced 20% mortality after 32-47 months. Juniper maintained three times more NSC in the foliage than twigs, and converted NSC to glucose and fructose under drought, consistent with osmoregulation requirements to maintain higher stomatal conductance during drought than piñon. Despite these species differences, experimental drought caused decreased leaf starch content in dying trees of both species (P < 0.001). Average dry-season leaf starch content was also a good predictor of drought-survival time for both species (R(2) = 0.93). These results, along with observations of drought-induced reductions to photosynthesis and growth, support carbon limitation as an important process during mortality of these two conifer species.
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Affiliation(s)
- Lee T Dickman
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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113
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Meddens AJH, Hicke JA, Macalady AK, Buotte PC, Cowles TR, Allen CD. Patterns and causes of observed piñon pine mortality in the southwestern United States. THE NEW PHYTOLOGIST 2015; 206:91-97. [PMID: 25494578 DOI: 10.1111/nph.13193] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/21/2014] [Indexed: 06/04/2023]
Abstract
Recently, widespread piñon pine die-off occurred in the southwestern United States. Here we synthesize observational studies of this event and compare findings to expected relationships with biotic and abiotic factors. Agreement exists on the occurrence of drought, presence of bark beetles and increased mortality of larger trees. However, studies disagree about the influences of stem density, elevation and other factors, perhaps related to study design, location and impact of extreme drought. Detailed information about bark beetles is seldom reported and their role is poorly understood. Our analysis reveals substantial limits to our knowledge regarding the processes that produce mortality patterns across space and time, indicating a poor ability to forecast mortality in response to expected increases in future droughts.
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Affiliation(s)
- Arjan J H Meddens
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Jeffrey A Hicke
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Alison K Macalady
- School of Geography and Development and Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721-0076, USA
| | - Polly C Buotte
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Travis R Cowles
- Department of Geography, University of Idaho, Moscow, ID, 83844-3021, USA
| | - Craig D Allen
- US Geological Survey, Fort Collins Science Center, Jemez Mountains Field Station, Los Alamos, NM, 87544, USA
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114
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Pangle RE, Limousin JM, Plaut JA, Yepez EA, Hudson PJ, Boutz AL, Gehres N, Pockman WT, McDowell NG. Prolonged experimental drought reduces plant hydraulic conductance and transpiration and increases mortality in a piñon-juniper woodland. Ecol Evol 2015; 5:1618-38. [PMID: 25937906 PMCID: PMC4409411 DOI: 10.1002/ece3.1422] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 01/15/2015] [Accepted: 01/20/2015] [Indexed: 01/06/2023] Open
Abstract
Plant hydraulic conductance (ks) is a critical control on whole-plant water use and carbon uptake and, during drought, influences whether plants survive or die. To assess long-term physiological and hydraulic responses of mature trees to water availability, we manipulated ecosystem-scale water availability from 2007 to 2013 in a piñon pine (Pinus edulis) and juniper (Juniperus monosperma) woodland. We examined the relationship between ks and subsequent mortality using more than 5 years of physiological observations, and the subsequent impact of reduced hydraulic function and mortality on total woody canopy transpiration (EC) and conductance (GC). For both species, we observed significant reductions in plant transpiration (E) and ks under experimentally imposed drought. Conversely, supplemental water additions increased E and ks in both species. Interestingly, both species exhibited similar declines in ks under the imposed drought conditions, despite their differing stomatal responses and mortality patterns during drought. Reduced whole-plant ks also reduced carbon assimilation in both species, as leaf-level stomatal conductance (gs) and net photosynthesis (An) declined strongly with decreasing ks. Finally, we observed that chronically low whole-plant ks was associated with greater canopy dieback and mortality for both piñon and juniper and that subsequent reductions in woody canopy biomass due to mortality had a significant impact on both daily and annual canopy EC and GC. Our data indicate that significant reductions in ks precede drought-related tree mortality events in this system, and the consequence is a significant reduction in canopy gas exchange and carbon fixation. Our results suggest that reductions in productivity and woody plant cover in piñon–juniper woodlands can be expected due to reduced plant hydraulic conductance and increased mortality of both piñon pine and juniper under anticipated future conditions of more frequent and persistent regional drought in the southwestern United States.
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Affiliation(s)
- Robert E Pangle
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Jean-Marc Limousin
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE, UMR5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE 1919 Route de Mende, Montpellier Cedex 5, 34293, France
| | - Jennifer A Plaut
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Enrico A Yepez
- Departamento de Ciencias del Agua y del Medio Ambiente, Instituto Tecnológico de Sonora Ciudad Obregón, Sonora, 85000, Mexico
| | - Patrick J Hudson
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Amanda L Boutz
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Nathan Gehres
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - William T Pockman
- Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque, New Mexico, 87131-0001
| | - Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Laboratory Los Alamos, New Mexico, 87545
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115
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Aguadé D, Poyatos R, Gómez M, Oliva J, Martínez-Vilalta J. The role of defoliation and root rot pathogen infection in driving the mode of drought-related physiological decline in Scots pine (Pinus sylvestris L.). TREE PHYSIOLOGY 2015; 35:229-42. [PMID: 25724949 DOI: 10.1093/treephys/tpv005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 01/16/2015] [Indexed: 05/23/2023]
Abstract
Drought-related tree die-off episodes have been observed in all vegetated continents. Despite much research effort, however, the multiple interactions between carbon starvation, hydraulic failure and biotic agents in driving tree mortality under field conditions are still not well understood. We analysed the seasonal variability of non-structural carbohydrates (NSCs) in four organs (leaves, branches, trunk and roots), the vulnerability to embolism in roots and branches, native embolism (percentage loss of hydraulic conductivity (PLC)) in branches and the presence of root rot pathogens in defoliated and non-defoliated individuals in a declining Scots pine (Pinus sylvestris L.) population in the NE Iberian Peninsula in 2012, which included a particularly dry and warm summer. No differences were observed between defoliated and non-defoliated pines in hydraulic parameters, except for a higher vulnerability to embolism at pressures below -2 MPa in roots of defoliated pines. No differences were found between defoliation classes in branch PLC. Total NSC (TNSC, soluble sugars plus starch) values decreased during drought, particularly in leaves. Defoliation reduced TNSC levels across tree organs, especially just before (June) and during (August) drought. Root rot infection by the fungal pathogen Onnia P. Karst spp. was detected but it did not appear to be associated to tree defoliation. However, Onnia infection was associated with reduced leaf-specific hydraulic conductivity and sapwood depth, and thus contributed to hydraulic impairment, especially in defoliated pines. Infection was also associated with virtually depleted root starch reserves during and after drought in defoliated pines. Moreover, defoliated and infected trees tended to show lower basal area increment. Overall, our results show the intertwined nature of physiological mechanisms leading to drought-induced mortality and the inherent difficulty of isolating their contribution under field conditions.
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Affiliation(s)
- D Aguadé
- CREAF, Cerdanyola del Vallès, E-08193 Barcelona, Spain Universitat Autònoma Barcelona, Cerdanyola del Vallès, E-08193 Barcelona, Spain
| | - R Poyatos
- CREAF, Cerdanyola del Vallès, E-08193 Barcelona, Spain
| | - M Gómez
- Forest Science Centre of Catalonia, Solsona, Catalonia, Spain
| | - J Oliva
- Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Box 7026, S-750 07 Uppsala, Sweden
| | - J Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, E-08193 Barcelona, Spain Universitat Autònoma Barcelona, Cerdanyola del Vallès, E-08193 Barcelona, Spain
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116
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Savi T, Bertuzzi S, Branca S, Tretiach M, Nardini A. Drought-induced xylem cavitation and hydraulic deterioration: risk factors for urban trees under climate change? THE NEW PHYTOLOGIST 2015; 205:1106-1116. [PMID: 25354036 DOI: 10.1111/nph.13112] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/14/2014] [Indexed: 05/23/2023]
Abstract
Urban trees help towns to cope with climate warming by cooling both air and surfaces. The challenges imposed by the urban environment, with special reference to low water availability due to the presence of extensive pavements, result in high rates of mortality of street trees, that can be increased by climatic extremes. We investigated the water relations and xylem hydraulic safety/efficiency of Quercus ilex trees growing at urban sites with different percentages of surrounding impervious pavements. Seasonal changes of plant water potential and gas exchange, vulnerability to cavitation and embolism level, and morpho-anatomical traits were measured. We found patterns of increasing water stress and vulnerability to drought at increasing percentages of impervious pavement cover, with a consequent reduction in gas exchange rates, decreased safety margins toward embolism development, and increased vulnerability to cavitation, suggesting the occurrence of stress-induced hydraulic deterioration. The amount of impermeable surface and chronic exposure to water stress influence the site-specific risk of drought-induced dieback of urban trees under extreme drought. Besides providing directions for management of green spaces in towns, our data suggest that xylem hydraulics is key to a full understanding of the responses of urban trees to global change.
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Affiliation(s)
- Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy
| | - Stefano Bertuzzi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy
| | - Salvatore Branca
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy
| | - Mauro Tretiach
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste, 34127, Italy
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117
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O'Brien MJ, Burslem DFRP, Caduff A, Tay J, Hector A. Contrasting nonstructural carbohydrate dynamics of tropical tree seedlings under water deficit and variability. THE NEW PHYTOLOGIST 2015; 205:1083-1094. [PMID: 25358235 DOI: 10.1111/nph.13134] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/20/2014] [Indexed: 06/04/2023]
Abstract
Drought regimes can be characterized by the variability in the quantity of rainfall and the duration of rainless periods. However, most research on plant response to drought has ignored the impacts of rainfall variation, especially with regard to the influence of nonstructural carbohydrates (NSCs) in promoting drought resistance. To test the hypothesis that these components of drought differentially affect NSC dynamics and seedling resistance, we tracked NSC in plant tissues of tropical tree seedlings in response to manipulations of the volume and frequency of water applied. NSC concentrations decreased in woody tissues under infrequent-high watering but increased under no watering. A faster decline of growth relative to stomatal conductance in the no watering treatment was consistent with NSC accumulation as a result of an uncoupling of growth and photosynthesis, while usage of stored NSCs in woody tissues to maintain function may account for the NSC decline under infrequent-high watering. NSCs, and specifically stem NSCs, contributed to drought resistance under severe water deficits, while NSCs had a less clear role in drought resistance to variability in water availability. The contrasting response of NSCs to water variability and deficit indicates that unique processes support seedling resistance to these components of drought.
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Affiliation(s)
- Michael J O'Brien
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - David F R P Burslem
- Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, UK
| | - Alexa Caduff
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - John Tay
- School of International Tropical Forestry, University Malaysia Sabah, Jalan UMS, 88400, Kota Kinabalu, Sabah, Malaysia
| | - Andy Hector
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
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118
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Hartmann H, Adams HD, Anderegg WRL, Jansen S, Zeppel MJB. Research frontiers in drought-induced tree mortality: crossing scales and disciplines. THE NEW PHYTOLOGIST 2015; 205:965-969. [PMID: 25580653 DOI: 10.1111/nph.13246] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Henrik Hartmann
- Department of Biogeochemical Processes, Max-Planck Institute for Biogeochemistry, Hans-Knoll Str. 10, 07745, Jena, Germany
| | - Henry D Adams
- Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - William R L Anderegg
- Princeton Environmental Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Steven Jansen
- Institute for Systematic Botany and Ecology, Ulm University, D-89081, Ulm, Germany
| | - Melanie J B Zeppel
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
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119
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Atkin O. New Phytologist and the 'fate' of carbon in terrestrial ecosystems. THE NEW PHYTOLOGIST 2015; 205:1-3. [PMID: 25427215 DOI: 10.1111/nph.13185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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120
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Camarero JJ, Gazol A, Sangüesa-Barreda G, Oliva J, Vicente-Serrano SM. To die or not to die: early warnings of tree dieback in response to a severe drought. JOURNAL OF ECOLOGY 2015. [PMID: 0 DOI: 10.1111/1365-2745.12295] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- J. Julio Camarero
- ARAID; Instituto Pirenaico de Ecología (IPE-CSIC); Avda. Montañana 1005 50192 Zaragoza Spain
- Departament d'Ecologia; Universitat de Barcelona; Avda. Diagonal 645 08028 Barcelona Spain
| | - Antonio Gazol
- Instituto Pirenaico de Ecología (IPE-CSIC); Avda. Montañana 1005 50192 Zaragoza Spain
| | | | - Jonàs Oliva
- Department of Forest Mycology and Plant Pathology; Swedish University of Agricultural Sciences; Box 7026 S-750 07 Uppsala Sweden
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121
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Balducci L, Deslauriers A, Giovannelli A, Beaulieu M, Delzon S, Rossi S, Rathgeber CBK. How do drought and warming influence survival and wood traits of Picea mariana saplings? JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:377-89. [PMID: 25371502 PMCID: PMC4265170 DOI: 10.1093/jxb/eru431] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Warming and drought will occur with increased frequency and intensity at high latitudes in the future. How heat and water stress can influence tree mortality is incompletely understood. The aim of this study was to evaluate how carbon resources, stem hydraulics, and wood anatomy and density determine the ability of black spruce saplings to survive daytime or night-time warming (+ 6 °C in comparison with control) in combination with a drought period. Plant water relations, the dynamics of non-structural carbohydrates and starch, mortality rate, and wood anatomy and density of saplings were monitored. Warming, in conjunction with 25 d of water deficit, increased sapling mortality (10% and 20% in night-time and daytime warming, respectively) compared with the control conditions (0.8%). Drought substantially decreased gas exchange, and also pre-dawn and mid-day leaf water potential to values close to -3MPa which probably induced xylem embolism (xylem air entry point, P₁₂, being on average around -3MPa for this species). In addition, the recovery of gas exchange never reached the initial pre-stress levels, suggesting a possible loss of xylem hydraulic conductivity associated with cavitation. Consequently, mortality may be due to xylem hydraulic failure. Warmer temperatures limited the replenishment of starch reserves after their seasonal minimum. Lighter wood was formed during the drought period, reflecting a lower carbon allocation to cell wall formation, preventing the adaptation of the hydraulic system to drought. Saplings of black spruce experienced difficulty in adapting under climate change conditions, which might compromise their survival in the future.
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Affiliation(s)
- Lorena Balducci
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC G7H2B1, Canada
| | - Annie Deslauriers
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC G7H2B1, Canada
| | | | - Marilène Beaulieu
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC G7H2B1, Canada
| | - Sylvain Delzon
- INRA-University of Bordeaux, UMR BIOGECO, Bat-B2, Avenue des Facultés, 33405 Talence-France
| | - Sergio Rossi
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l'Université, Chicoutimi, QC G7H2B1, Canada
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122
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Pederson N, Dyer JM, McEwan RW, Hessl AE, Mock CJ, Orwig DA, Rieder HE, Cook BI. The legacy of episodic climatic events in shaping temperate, broadleaf forests. ECOL MONOGR 2014. [DOI: 10.1890/13-1025.1] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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123
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Song X, Farquhar GD, Gessler A, Barbour MM. Turnover time of the non-structural carbohydrate pool influences δ18O of leaf cellulose. PLANT, CELL & ENVIRONMENT 2014; 37:2500-7. [PMID: 24611760 DOI: 10.1111/pce.12309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 06/03/2023]
Abstract
Certainty regarding the degree to which organic molecules exchange oxygen with local water during plant cellulose synthesis (p(ex)) is necessary for cellulose oxygen isotope (δ(18)O(cell))-based applications in environmental and ecological studies. However, the currently accepted notion that p(ex) is a constant of ca. 0.42 appears inconsistent with biochemical theory, which predicts that marked variation may be present in p(ex), in relation to variation in the turnover time (τ) of the carbohydrate pool available for cellulose synthesis. The above prediction was tested in the present study with the analysis of data collected from leaves of Ricinus communis grown in controlled environmental conditions that varied in light intensity and vapour pressure deficit. The results revealed the existence of considerable variation in both p(ex) and τ across plants in the various growth environments. Moreover, despite uncertainties in estimates of the proportion of source water in the synthesis water (p(x)) and of the biochemical fractionation factor (ε(o)), our experiment yielded strong evidence that p(ex) exhibits a significant, positive relationship with τ, consistent with biochemical theory. The observed variation in p(ex) in association with τ has important implications for the interpretation of δ(18)O(cell) data in environmental/ecological studies.
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Affiliation(s)
- Xin Song
- Faculty of Agriculture and Environment, University of Sydney, Narellan, New South Wales, 2567, Australia
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124
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Marler TE, Lindström AJ. Free sugar profile in cycads. FRONTIERS IN PLANT SCIENCE 2014; 5:526. [PMID: 25339967 PMCID: PMC4188140 DOI: 10.3389/fpls.2014.00526] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/17/2014] [Indexed: 05/08/2023]
Abstract
The sugars fructose, glucose, maltose, and sucrose were quantified in seven tissues of Zamia muricata Willd. to determine their distribution throughout various organs of a model cycad species, and in lateral structural roots of 18 cycad species to determine the variation in sugar concentration and composition among species representing every cycad genus. Taproot and lateral structural roots contained more sugars than leaf, stem, female strobilus, or coralloid roots. For example, taproot sugar concentration was 6.4-fold greater than stem sugar concentration. The dominant root sugars were glucose and fructose, and the only detected stem sugar was sucrose. Sucrose also dominated the sugar profile for leaflet and coralloid root tissue, and fructose was the dominant sugar in female strobilus tissue. Maltose was a minor constituent of taproot, leaflet, and female strobilus tissue, but absent in other tissues. The concentration of total free sugars and each of the four sugars did not differ among genera or families. Stoichiometric relationships among the sugars, such as the quotient hexoses/disaccharides, differed among organs and families. Although anecdotal reports on cycad starch have been abundant due to its historical use as human food and the voluminous medical research invested into cycad neurotoxins, this is the first report on the sugar component of the non-structural carbohydrate profile of cycads. Fructose, glucose, and sucrose are abundant in cycad tissues, with their relative abundance highly contrasting among organs. Their importance as forms of carbon storage, messengers of information, or regulators of cycad metabolism have not been determined to date.
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Affiliation(s)
- Thomas E. Marler
- Western Pacific Tropical Research Center, College of Natural and Applied Sciences, University of GuamMangilao, Guam
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125
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Oliva J, Stenlid J, Martínez-Vilalta J. The effect of fungal pathogens on the water and carbon economy of trees: implications for drought-induced mortality. THE NEW PHYTOLOGIST 2014; 203:1028-1035. [PMID: 24824859 DOI: 10.1111/nph.12857] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- Jonàs Oliva
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, S-750 07, Uppsala, Sweden
| | - Jan Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Box 7026, S-750 07, Uppsala, Sweden
| | - Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès 08193, Barcelona, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès 08193, Barcelona, Spain
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126
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Duan H, Duursma RA, Huang G, Smith RA, Choat B, O'Grady AP, Tissue DT. Elevated [CO2] does not ameliorate the negative effects of elevated temperature on drought-induced mortality in Eucalyptus radiata seedlings. PLANT, CELL & ENVIRONMENT 2014; 37:1598-613. [PMID: 24372529 DOI: 10.1111/pce.12260] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 05/19/2023]
Abstract
It has been reported that elevated temperature accelerates the time-to-mortality in plants exposed to prolonged drought, while elevated [CO(2)] acts as a mitigating factor because it can reduce stomatal conductance and thereby reduce water loss. We examined the interactive effects of elevated [CO(2)] and temperature on the inter-dependent carbon and hydraulic characteristics associated with drought-induced mortality in Eucalyptus radiata seedlings grown in two [CO(2)] (400 and 640 μL L(-1)) and two temperature (ambient and ambient +4 °C) treatments. Seedlings were exposed to two controlled drying and rewatering cycles, and then water was withheld until plants died. The extent of xylem cavitation was assessed as loss of stem hydraulic conductivity. Elevated temperature triggered more rapid mortality than ambient temperature through hydraulic failure, and was associated with larger water use, increased drought sensitivities of gas exchange traits and earlier occurrence of xylem cavitation. Elevated [CO(2)] had a negligible effect on seedling response to drought, and did not ameliorate the negative effects of elevated temperature on drought. Our findings suggest that elevated temperature and consequent higher vapour pressure deficit, but not elevated [CO(2)], may be the primary contributors to drought-induced seedling mortality under future climates.
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Affiliation(s)
- Honglang Duan
- Hawkesbury Institute for the Environment, Hawkesbury Campus, University of Western Sydney, Locked Bag 1797, Penrith, New South Wales, 2751, Australia
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127
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Mencuccini M. Temporal scales for the coordination of tree carbon and water economies during droughts. TREE PHYSIOLOGY 2014; 34:439-42. [PMID: 24798658 DOI: 10.1093/treephys/tpu029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- M Mencuccini
- School of GeoSciences, University of Edinburgh, West Mains Road, Edinburgh EH3JU, UK ICREA at CREAF, Cerdanyola del Vallès, Barcelona, Spain
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128
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Mitchell PJ, O'Grady AP, Hayes KR, Pinkard EA. Exposure of trees to drought-induced die-off is defined by a common climatic threshold across different vegetation types. Ecol Evol 2014; 4:1088-101. [PMID: 24772285 PMCID: PMC3997324 DOI: 10.1002/ece3.1008] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 01/22/2014] [Accepted: 01/25/2014] [Indexed: 12/30/2022] Open
Abstract
Increases in drought and temperature stress in forest and woodland ecosystems are thought to be responsible for the rise in episodic mortality events observed globally. However, key climatic drivers common to mortality events and the impacts of future extreme droughts on tree survival have not been evaluated. Here, we characterize climatic drivers associated with documented tree die-off events across Australia using standardized climatic indices to represent the key dimensions of drought stress for a range of vegetation types. We identify a common probabilistic threshold associated with an increased risk of die-off across all the sites that we examined. We show that observed die-off events occur when water deficits and maximum temperatures are high and exist outside 98% of the observed range in drought intensity; this threshold was evident at all sites regardless of vegetation type and climate. The observed die-off events also coincided with at least one heat wave (three consecutive days above the 90th percentile for maximum temperature), emphasizing a pivotal role of heat stress in amplifying tree die-off and mortality processes. The joint drought intensity and maximum temperature distributions were modeled for each site to describe the co-occurrence of both hot and dry conditions and evaluate future shifts in climatic thresholds associated with the die-off events. Under a relatively dry and moderate warming scenario, the frequency of droughts capable of inducing significant tree die-off across Australia could increase from 1 in 24 years to 1 in 15 years by 2050, accompanied by a doubling in the occurrence of associated heat waves. By defining commonalities in drought conditions capable of inducing tree die-off, we show a strong interactive effect of water and high temperature stress and provide a consistent approach for assessing changes in the exposure of ecosystems to extreme drought events.
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Affiliation(s)
- Patrick J Mitchell
- CSIRO Ecosystem Sciences and Climate Adaptation Flagship College Rd, Sandy Bay, TAS, Australia
| | - Anthony P O'Grady
- CSIRO Ecosystem Sciences and Climate Adaptation Flagship College Rd, Sandy Bay, TAS, Australia
| | - Keith R Hayes
- CSIRO Computational Informatics, Castray Esplanade Hobart, TAS, Australia
| | - Elizabeth A Pinkard
- CSIRO Ecosystem Sciences and Climate Adaptation Flagship College Rd, Sandy Bay, TAS, Australia
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129
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Hartmann H, Ziegler W, Kolle O, Trumbore S. Thirst beats hunger - declining hydration during drought prevents carbon starvation in Norway spruce saplings. THE NEW PHYTOLOGIST 2013; 200:340-349. [PMID: 23692181 DOI: 10.1111/nph.12331] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 04/14/2013] [Indexed: 05/08/2023]
Abstract
Drought-induced tree mortality results from an interaction of several mechanisms. Plant water and carbon relations are interdependent and assessments of their individual contributions are difficult. Because drought always affects both plant hydration and carbon assimilation, it is challenging to disentangle their concomitant effects on carbon balance and carbon translocation. Here, we report results of a manipulation experiment specifically designed to separate drought effects on carbon and water relations from those on carbon translocation. In a glasshouse experiment, we manipulated the carbon balance of Norway spruce saplings exposed to either drought or carbon starvation (CO2 withdrawal), or both treatments, and compared the dynamics of carbon exchange, allocation and storage in different tissues. Drought killed trees much faster than did carbon starvation. Storage C pools were not depleted at death for droughted trees as they were for starved, well-watered trees. Hence drought has a significant detrimental effect on a plant's ability to utilize stored carbon. Unless they can be transported to where they are needed, sufficient carbon reserves alone will not assure survival of a drought except under specific conditions, such as moderate drought, or in species that maintain plant water relations required for carbon re-mobilization.
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Affiliation(s)
- Henrik Hartmann
- Max Planck Institute for Biogeochemistry, Hans Knoll Str. 10, 07745, Jena, Germany
| | - Waldemar Ziegler
- Max Planck Institute for Biogeochemistry, Hans Knoll Str. 10, 07745, Jena, Germany
| | - Olaf Kolle
- Max Planck Institute for Biogeochemistry, Hans Knoll Str. 10, 07745, Jena, Germany
| | - Susan Trumbore
- Max Planck Institute for Biogeochemistry, Hans Knoll Str. 10, 07745, Jena, Germany
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130
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Clifford MJ, Royer PD, Cobb NS, Breshears DD, Ford PL. Precipitation thresholds and drought-induced tree die-off: insights from patterns of Pinus edulis mortality along an environmental stress gradient. THE NEW PHYTOLOGIST 2013; 200:413-421. [PMID: 23772860 DOI: 10.1111/nph.12362] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 05/15/2013] [Indexed: 06/02/2023]
Abstract
Recent regional tree die-off events appear to have been triggered by a combination of drought and heat - referred to as 'global-change-type drought'. To complement experiments focused on resolving mechanisms of drought-induced tree mortality, an evaluation of how patterns of tree die-off relate to highly spatially variable precipitation is needed. Here, we explore precipitation relationships with a die-off event of pinyon pine (Pinus edulis Engelm.) in southwestern North America during the 2002-2003 global-change-type drought. Pinyon die-off and its relationship with precipitation was quantified spatially along a precipitation gradient in north-central New Mexico with standard field plot measurements of die-off combined with canopy cover derived from normalized burn ratio (NBR) from Landsat imagery. Pinyon die-off patterns revealed threshold responses to precipitation (cumulative 2002-2003) and vapor pressure deficit (VPD), with little to no mortality (< 10%) above 600 mm and below warm season VPD of c. 1.7 kPa. [Correction added after online publication 17 June 2013; in the preceding sentence, the word 'below' has been inserted.] Our results refine how precipitation patterns within a region influence pinyon die-off, revealing a precipitation and VPD threshold for tree mortality and its uncertainty band where other factors probably come into play - a response type that influences stand demography and landscape heterogeneity and is of general interest, yet has not been documented.
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Affiliation(s)
- Michael J Clifford
- Earth and Environmental Science Department, Lehigh University, Bethlehem, PA, 18015, USA
| | - Patrick D Royer
- Columbia Basin Groundwater Management Area, Kennewick, WA, 99366, USA
- Intera Geoscience and Engineering, Richland, WA, 99354, USA
| | - Neil S Cobb
- Merriam-Powell Center for Environmental Research, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - David D Breshears
- Department of Ecology & Evolutionary Biology, School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Paulette L Ford
- USDA Forest Service Rocky Mountain Research Station, Albuquerque, NM, 87102, USA
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131
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McDowell NG, Ryan MG, Zeppel MJB, Tissue DT. Feature: Improving our knowledge of drought-induced forest mortality through experiments, observations, and modeling. THE NEW PHYTOLOGIST 2013; 200:289-293. [PMID: 24050629 DOI: 10.1111/nph.12502] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Nate G McDowell
- Earth and Environmental Sciences Division, Los Alamos National Lab, Los Alamos, NM, 87545, USA
| | - Michael G Ryan
- Natural Resource Ecology Lab, Colorado State University, Fort Collins, CO, 80523-1499, USA
- USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO, 80526, USA
| | - Melanie J B Zeppel
- Department of Biological Sciences, Macquarie University, 2109, Sydney, NSW, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW, 2753, Australia
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132
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Duan H, Amthor JS, Duursma RA, O'Grady AP, Choat B, Tissue DT. Carbon dynamics of eucalypt seedlings exposed to progressive drought in elevated [CO2] and elevated temperature. TREE PHYSIOLOGY 2013; 33:779-792. [PMID: 23963410 DOI: 10.1093/treephys/tpt061] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Elevated [CO2] and temperature may alter the drought responses of tree seedling growth, photosynthesis, respiration and total non-structural carbohydrate (TNC) status depending on drought intensity and duration. Few studies have addressed these important climatic interactions or their consequences. We grew Eucalyptus globulus Labill. seedlings in two [CO2] concentrations (400 and 640 μl l(-1)) and two temperatures (28/17 and 32/21 °C) (day/night) in a sun-lit glasshouse, and grew them in well-watered conditions or exposed them to two drought treatments having undergone different previous water conditions (i.e., rewatered drought and sustained drought). Progressive drought in both drought treatments led to similar limitations in growth, photosynthesis and respiration, but reductions in TNC concentration were not observed. Elevated [CO2] ameliorated the impact of the drought during the moderate drought phase (i.e., Day 63 to Day 79) by increasing photosynthesis and enhancing leaf and whole-plant TNC content. In contrast, elevated temperature exacerbated the impact of the drought during the moderate drought phase by reducing photosynthesis, increasing leaf respiration and decreasing whole-plant TNC content. Extreme drought (i.e., Day 79 to Day 103) eliminated [CO2] and temperature effects on plant growth, photosynthesis and respiration. The combined effects of elevated [CO2] and elevated temperature on moderate drought stressed seedlings were reduced with progressive drought, with no sustained effects on growth despite greater whole-plant TNC content.
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Affiliation(s)
- Honglang Duan
- Hawkesbury Institute for the Environment, University of Western Sydney, Richmond, NSW 2753, Australia
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133
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Adams HD, Williams AP, Xu C, Rauscher SA, Jiang X, McDowell NG. Empirical and process-based approaches to climate-induced forest mortality models. FRONTIERS IN PLANT SCIENCE 2013; 4:438. [PMID: 24312103 PMCID: PMC3826075 DOI: 10.3389/fpls.2013.00438] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 10/14/2013] [Indexed: 05/07/2023]
Affiliation(s)
- Henry D. Adams
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
- *Correspondence:
| | - A. Park Williams
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Chonggang Xu
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Sara A. Rauscher
- Theoretical Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Xiaoyan Jiang
- Atmospheric Chemistry Division, National Center for Atmospheric ResearchBoulder, CO, USA
| | - Nate G. McDowell
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
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134
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Breshears DD, Adams HD, Eamus D, McDowell NG, Law DJ, Will RE, Williams AP, Zou CB. The critical amplifying role of increasing atmospheric moisture demand on tree mortality and associated regional die-off. FRONTIERS IN PLANT SCIENCE 2013; 4:266. [PMID: 23935600 PMCID: PMC3731633 DOI: 10.3389/fpls.2013.00266] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/02/2013] [Indexed: 05/03/2023]
Affiliation(s)
- David D. Breshears
- The School of Natural Resources and the Environment, The University of ArizonaTucson, AZ, USA
- Department of Ecology and Evolutionary Biology, The University of ArizonaTucson, AZ, USA
| | - Henry D. Adams
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Derek Eamus
- School of the Environment, University of Technology SydneySydney, NSW, Australia
| | - Nate G. McDowell
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Darin J. Law
- The School of Natural Resources and the Environment, The University of ArizonaTucson, AZ, USA
- *Correspondence:
| | - Rodney E. Will
- Department of Natural Resource Ecology and Management, Oklahoma State UniversityStillwater, OK, USA
| | - A. Park Williams
- Earth and Environmental Sciences Division, Los Alamos National LaboratoryLos Alamos, NM, USA
| | - Chris B. Zou
- Department of Natural Resource Ecology and Management, Oklahoma State UniversityStillwater, OK, USA
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135
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Rosas T, Galiano L, Ogaya R, Peñuelas J, Martínez-Vilalta J. Dynamics of non-structural carbohydrates in three Mediterranean woody species following long-term experimental drought. FRONTIERS IN PLANT SCIENCE 2013; 4:400. [PMID: 24130568 PMCID: PMC3795346 DOI: 10.3389/fpls.2013.00400] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 09/20/2013] [Indexed: 05/08/2023]
Abstract
Stored non-structural carbohydrates (NSC) have been proposed as a key determinant of drought resistance in plants. However, the evidence for this role is controversial, as it comes mostly from observational, short-term studies. Here, we take advantage of a long-term experimental throughfall reduction to elucidate the response of NSC to increased drought 14 years after the beginning of the treatment in three Mediterranean resprouter trees (Quercus ilex L., Arbutus unedo L. and Phillyrea latifolia L.). In addition, we selected 20 Q. ilex individuals outside the experimental plots to directly assess the relationship between defoliation and NSC at the individual level. We measured the seasonal course of NSC concentrations in leaves, branches and lignotuber in late winter, late spring, summer, and autumn 2012. Total concentrations of NSC were highest in the lignotuber for all species. In the long-term drought experiment we found significant depletion in concentrations of total NSC in treatment plots only in the lignotuber of A. unedo. At the same time, A. unedo was the only species showing a significant reduction in BAI under the drought treatment during the 14 years of the experiment. By contrast, Q. ilex just reduced stem growth only during the first 4 years of treatment and P. latifolia remained unaffected over the whole study period. However, we found a clear association between the concentrations of NSC and defoliation in Q. ilex individuals sampled outside the experimental plots, with lower total concentrations of NSC and lower proportion of starch in defoliated individuals. Taken together, our results suggest that stabilizing processes, probably at the stand level, may have been operating in the long-term to mitigate any impact of drought on NSC levels, and highlight the necessity to incorporate long-term experimental studies of plant responses to drought.
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Affiliation(s)
- Teresa Rosas
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF)Cerdanyola del Vallès, Spain
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de BarcelonaCerdanyola del Vallès, Spain
- *Correspondence: Teresa Rosas, Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Universitat Autònoma de Barcelona, Edifici C, Cerdanyola del Vallès 08193, Spain e-mail:
| | - Lucía Galiano
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF)Cerdanyola del Vallès, Spain
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de BarcelonaCerdanyola del Vallès, Spain
- Leibniz Centre for Agricultural Landscape Research (ZALF), Institute for Landscape BiogeochemistryMüncheberg, Germany
| | - Romà Ogaya
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF)Cerdanyola del Vallès, Spain
- Consejo Superior de Investigaciones Científicas, Global Ecology Unit CREAF-CEAB-CSIC-UABCerdanyola del Vallès, Spain
| | - Josep Peñuelas
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF)Cerdanyola del Vallès, Spain
- Consejo Superior de Investigaciones Científicas, Global Ecology Unit CREAF-CEAB-CSIC-UABCerdanyola del Vallès, Spain
| | - Jordi Martínez-Vilalta
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF)Cerdanyola del Vallès, Spain
- Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autònoma de BarcelonaCerdanyola del Vallès, Spain
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