1
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Tooley EG, Nippert JB, Bachle S, Keen RM. Intra-canopy leaf trait variation facilitates high leaf area index and compensatory growth in a clonal woody encroaching shrub. TREE PHYSIOLOGY 2022; 42:2186-2202. [PMID: 35861679 DOI: 10.1093/treephys/tpac078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
Leaf trait variation enables plants to utilize large gradients of light availability that exist across canopies of high leaf area index (LAI), allowing for greater net carbon gain while reducing light availability for understory competitors. While these canopy dynamics are well understood in forest ecosystems, studies of canopy structure of woody shrubs in grasslands are lacking. To evaluate the investment strategy used by these shrubs, we investigated the vertical distribution of leaf traits and physiology across canopies of Cornus drummondii, the predominant woody encroaching shrub in the Kansas tallgrass prairie. We also examined the impact of disturbance by browsing and grazing on these factors. Our results reveal that leaf mass per area (LMA) and leaf nitrogen per area (Na) varied approximately threefold across canopies of C. drummondii, resulting in major differences in the physiological functioning of leaves. High LMA leaves had high photosynthetic capacity, while low LMA leaves had a novel strategy for maintaining light compensation points below ambient light levels. The vertical allocation of leaf traits in C. drummondii canopies was also modified in response to browsing, which increased light availability at deeper canopy depths. As a result, LMA and Na increased at lower canopy depths, leading to a greater photosynthetic capacity deeper in browsed canopies compared to control canopies. This response, along with increased light availability, facilitated greater photosynthesis and resource-use efficiency deeper in browsed canopies compared to control canopies. Our results illustrate how C. drummondii facilitates high LAI canopies and a compensatory growth response to browsing-both of which are key factors contributing to the success of C. drummondii and other species responsible for grassland woody encroachment.
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Affiliation(s)
- E Greg Tooley
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506, USA
| | - Jesse B Nippert
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506, USA
| | - Seton Bachle
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506, USA
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO 80523, USA
| | - Rachel M Keen
- Division of Biology, Kansas State University, 116 Ackert Hall, Manhattan, KS 66506, USA
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2
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Rooney R, Ishii HR, Cavaleri MA. Intra‐crown variation of leaf mass per area of
Fagus crenata
is driven by light acclimation of leaf thickness and hydraulic acclimation of leaf density. Ecol Res 2022. [DOI: 10.1111/1440-1703.12361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rebecca Rooney
- College of Forest Resources and Environmental Science Michigan Technological University Houghton Michigan USA
- Department of Biology University of Minnesota Duluth Duluth Minnesota USA
| | - H. Roaki Ishii
- Graduate School of Agricultural Science Kobe University Kobe Japan
| | - Molly A. Cavaleri
- College of Forest Resources and Environmental Science Michigan Technological University Houghton Michigan USA
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3
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Chin ARO, Guzmán-Delgado P, Sillett SC, Kerhoulas LP, Ambrose AR, McElrone AR, Zwieniecki MA. Tracheid buckling buys time, foliar water uptake pays it back: Coordination of leaf structure and function in tall redwood trees. PLANT, CELL & ENVIRONMENT 2022; 45:2607-2616. [PMID: 35736139 DOI: 10.1111/pce.14381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 06/19/2022] [Indexed: 06/15/2023]
Abstract
Tracheid buckling may protect leaves in the dynamic environments of forest canopies, where rapid intensifications of evaporative demand, such as those brought on by changes in light availability, can result in sudden increases in transpiration rate. While treetop leaves function in reliably direct light, leaves below the upper crown must tolerate rapid, thermally driven increases in evaporative demand. Using synchrotron-based X-ray microtomography, we visualized impacts of experimentally induced water stress and subsequent fogging on living cells in redwood leaves, adding ecological and functional context through crown-wide explorations of variation in leaf physiology and microclimate. Under drought, leaf transfusion tracheids buckle, releasing water that supplies sufficient temporal reserves for leaves to reduce stomatal conductance safely while stopping the further rise of tension. Tracheid buckling fraction decreases with height and is closely coordinated with transfusion tissue capacity and stomatal conductance to provide temporal reserves optimized for local variation in microclimate. Foliar water uptake fully restores collapsed and air-filled transfusion tracheids in leaves on excised shoots, suggesting that trees may use aerial water sources for recovery. In the intensely variable deep-crown environment, foliar water uptake can allow for repetitive cycles of tracheid buckling and unbuckling, protecting the tree from damaging levels of hydraulic tension and supporting leaf survival.
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Affiliation(s)
- Alana R O Chin
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Paula Guzmán-Delgado
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Stephen C Sillett
- Department of Forestry and Wildland Resources, Humboldt State University, Arcata, California, USA
| | - Lucy P Kerhoulas
- Department of Forestry and Wildland Resources, Humboldt State University, Arcata, California, USA
| | - Anthony R Ambrose
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, USA
| | - Andrew R McElrone
- USDA-ARS & Viticulture and Enology Department, University of California Davis, Davis, California, USA
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, Davis, California, USA
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4
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Zhang JL, Li XG, Xu XH, Chen HP, Li YL, Guy RD. Leaf morphology, photosynthesis and pigments change with age and light regime in savin juniper. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:1097-1108. [PMID: 33756015 DOI: 10.1111/plb.13256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
Savin juniper is an excellent species for desertification control in arid and semi-arid areas, where it typically establishes under the protection of nurse plants. Ultimately, established plants emerge into full light as they grow, and this transition is accompanied by an increase in the preponderance of scale-like versus needle-like leaf forms. To test how age and variable light environments affect shade tolerance in savin juniper, we established a pot study under field conditions, with two age cohorts (1- and 4-year-old rooted scions) and three light regimes (10%, 50% and 100% light transmittance). We measured growth, leaf parameters, photosynthesis, chlorophyll fluorescence and foliar pigments on a monthly basis (seven growing months per year, from 2015 to 2017). Overall, there was little interaction among all variables, and both cohort and light regime had significant effects. Leaf form and spacing varied continuously, tending towards shorter, more closely spaced and more appressed scale leaves with higher dry leaf mass per area in older plants or under higher light. There were no clear age-related patterns in carotenoids but both cohort and light had significant effects on gas exchange and chlorophyll fluorescence variables. We conclude that savin juniper shows an intermediate tolerance to shade that changes with growth in that younger plants were less tolerant of full sun than older plants, consistent with its reliance on nurse plants for ultimate establishment in the open.
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Affiliation(s)
- J-L Zhang
- College of Forestry, Hebei Agricultural University, Baoding, China
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, Canada
| | - X-G Li
- College of Forestry, Hebei Agricultural University, Baoding, China
| | - X-H Xu
- College of Forestry, Hebei Agricultural University, Baoding, China
| | - H-P Chen
- College of Forestry, Hebei Agricultural University, Baoding, China
| | - Y-L Li
- College of Forestry, Hebei Agricultural University, Baoding, China
| | - R D Guy
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, Canada
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5
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Qiu T, Aravena MC, Andrus R, Ascoli D, Bergeron Y, Berretti R, Bogdziewicz M, Boivin T, Bonal R, Caignard T, Calama R, Julio Camarero J, Clark CJ, Courbaud B, Delzon S, Donoso Calderon S, Farfan-Rios W, Gehring CA, Gilbert GS, Greenberg CH, Guo Q, Hille Ris Lambers J, Hoshizaki K, Ibanez I, Journé V, Kilner CL, Kobe RK, Koenig WD, Kunstler G, LaMontagne JM, Ledwon M, Lutz JA, Motta R, Myers JA, Nagel TA, Nuñez CL, Pearse IS, Piechnik Ł, Poulsen JR, Poulton-Kamakura R, Redmond MD, Reid CD, Rodman KC, Scher CL, Schmidt Van Marle H, Seget B, Sharma S, Silman M, Swenson JJ, Swift M, Uriarte M, Vacchiano G, Veblen TT, Whipple AV, Whitham TG, Wion AP, Wright SJ, Zhu K, Zimmerman JK, Żywiec M, Clark JS. Is there tree senescence? The fecundity evidence. Proc Natl Acad Sci U S A 2021; 118:e2106130118. [PMID: 34400503 PMCID: PMC8403963 DOI: 10.1073/pnas.2106130118] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small trees in regression models. We combined global fecundity data, including a substantial representation of large trees. We compared size-fecundity relationships against traditional allometric scaling with diameter and two models based on crown architecture. All allometric models fail to describe the declining rate of increase in fecundity with diameter found for 80% of 597 species in our analysis. The strong evidence of declining fecundity, beyond what can be explained by crown architectural change, is consistent with physiological decline. A downward revision of projected fecundity of large trees can improve the next generation of forest dynamic models.
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Affiliation(s)
- Tong Qiu
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | - Marie-Claire Aravena
- Universidad de Chile, Facultad de Ciencias Forestales y de la Conservación de la Naturaleza (FCFCN), La Pintana, 8820808 Santiago, Chile
| | - Robert Andrus
- Department of Geography, University of Colorado, Boulder, CO 80309
| | - Davide Ascoli
- Department of Agriculture, Forest and Food Sciences, University of Torino, 10095 Grugliasco, TO, Italy
| | - Yves Bergeron
- Forest Research Institute, University of Quebec in Abitibi-Temiscamingue, Rouyn-Noranda, QC J9X 5E4, Canada
- Department of Biological Sciences, University of Quebec in Abitibi-Temiscamingue, Rouyn-Noranda, QC H2L 2C4, Canada
| | - Roberta Berretti
- Department of Agriculture, Forest and Food Sciences, University of Torino, 10095 Grugliasco, TO, Italy
| | - Michal Bogdziewicz
- Department of Systematic Zoology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Thomas Boivin
- l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Ecologie des Forets Mediterranennes, 84000 Avignon, France
| | - Raul Bonal
- Department of Biodiversity, Ecology and Evolution, Complutense University of Madrid, 28040 Madrid, Spain
| | - Thomas Caignard
- Université Bordeaux, l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Biodiversity, Genes, and Communities (BIOGECO), 33615 Pessac, France
| | - Rafael Calama
- Centro de Investigación Forestal - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CIFOR), 28040 Madrid, Spain
| | - J Julio Camarero
- Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas (IPE-CSIC), 50059 Zaragoza, Spain
| | - Connie J Clark
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | - Benoit Courbaud
- Université Grenoble Alpes, l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Laboratoire EcoSystémes et Sociétés En Montagne (LESSEM), 38402 St.-Martin-d'Heres, France
| | - Sylvain Delzon
- Université Bordeaux, l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Biodiversity, Genes, and Communities (BIOGECO), 33615 Pessac, France
| | - Sergio Donoso Calderon
- Universidad de Chile, Facultad de Ciencias Forestales y de la Conservación de la Naturaleza (FCFCN), La Pintana, 8820808 Santiago, Chile
| | - William Farfan-Rios
- Center for Conservation and Sustainable Development, Missouri Botanical Garden, Washington University in Saint Louis, St. Louis, MO 63110
| | - Catherine A Gehring
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011
| | - Gregory S Gilbert
- Department of Environmental Studies, University of California, Santa Cruz, CA 95064
| | - Cathryn H Greenberg
- Bent Creek Experimental Forest, US Department of Agriculture Forest Service, Asheville, NC 28801
| | - Qinfeng Guo
- Eastern Forest Environmental Threat Assessment Center, US Department of Agriculture Forest Service, Research Triangle Park, NC 27709
| | - Janneke Hille Ris Lambers
- Department of Environmental Systems Science, Eidgenössische Technische Hochschule Zurich, 8092 Zurich, Switzerland
| | - Kazuhiko Hoshizaki
- Department of Biological Environment, Akita Prefectural University, Akita 010-0195, Japan
| | - Ines Ibanez
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI 48109
| | - Valentin Journé
- Université Grenoble Alpes, l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Laboratoire EcoSystémes et Sociétés En Montagne (LESSEM), 38402 St.-Martin-d'Heres, France
| | | | - Richard K Kobe
- Department of Plant Biology, Program in Ecology, Evolutionary Biology, and Behavior, Michigan State University, East Lansing, MI 48824
- Department of Forestry, Michigan State University, East Lansing, MI 48824
| | - Walter D Koenig
- Hastings Reservation, University of California Berkeley, Carmel Valley, CA 93924
| | - Georges Kunstler
- Université Grenoble Alpes, l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Laboratoire EcoSystémes et Sociétés En Montagne (LESSEM), 38402 St.-Martin-d'Heres, France
| | | | - Mateusz Ledwon
- Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, 31-016 Krakow, Poland
| | - James A Lutz
- Department of Wildland Resources, Utah State University, Logan, UT 84322
- Ecology Center, Utah State University, Logan, UT 84322
| | - Renzo Motta
- Department of Agriculture, Forest and Food Sciences, University of Torino, 10095 Grugliasco, TO, Italy
| | - Jonathan A Myers
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
| | - Thomas A Nagel
- Department of Forestry and Renewable Forest Resources, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Chase L Nuñez
- Department for the Ecology of Animal Societies, Max Planck Institute of Animal Behavior, 78457 Konstanz, Germany
| | - Ian S Pearse
- US Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526
| | - Łukasz Piechnik
- W. Szafer Institute of Botany, Polish Academy of Sciences, 31-512 Krakow, Poland
| | - John R Poulsen
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | | | - Miranda D Redmond
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO 80523
| | - Chantal D Reid
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | - Kyle C Rodman
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706
| | - C Lane Scher
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | - Harald Schmidt Van Marle
- Universidad de Chile, Facultad de Ciencias Forestales y de la Conservación de la Naturaleza (FCFCN), La Pintana, 8820808 Santiago, Chile
| | - Barbara Seget
- W. Szafer Institute of Botany, Polish Academy of Sciences, 31-512 Krakow, Poland
| | - Shubhi Sharma
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | - Miles Silman
- Department of Biology, Wake Forest University, Winston-Salem, NC 27106
| | | | - Margaret Swift
- Nicholas School of the Environment, Duke University, Durham, NC 27708
| | - Maria Uriarte
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027
| | - Giorgio Vacchiano
- Department of Agricultural and Environmental Sciences - Production, Territory, Agroenergy (DISAA), University of Milan, 20133 Milano, Italy
| | - Thomas T Veblen
- Department of Geography, University of Colorado, Boulder, CO 80309
| | - Amy V Whipple
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011
| | - Thomas G Whitham
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011
| | - Andreas P Wion
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO 80523
| | - S Joseph Wright
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panama
| | - Kai Zhu
- Department of Environmental Studies, University of California, Santa Cruz, CA 95064
| | - Jess K Zimmerman
- Department of Environmental Sciences, University of Puerto Rico, Rio Piedras, Puerto Rico, United States 00936
| | - Magdalena Żywiec
- W. Szafer Institute of Botany, Polish Academy of Sciences, 31-512 Krakow, Poland
| | - James S Clark
- Nicholas School of the Environment, Duke University, Durham, NC 27708;
- Université Grenoble Alpes, l'Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Laboratoire EcoSystémes et Sociétés En Montagne (LESSEM), 38402 St.-Martin-d'Heres, France
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6
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Kerhoulas LP, Hammons DT, Kerhoulas NJ. Bigleaf Maple Within-Crown Leaf Morphology and Seasonal Physiology. NORTHWEST SCIENCE 2020. [DOI: 10.3955/046.094.0207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Lucy P. Kerhoulas
- Department of Forestry and Wildland Resources, Humboldt State University, 1 Harpst Street, Arcata, California 95521
| | - David T. Hammons
- Department of Forestry and Wildland Resources, Humboldt State University, 1 Harpst Street, Arcata, California 95521
| | - Nicholas J. Kerhoulas
- Department of Wildlife, Humboldt State University, 1 Harpst Street, Arcata, California 95521
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7
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Oke TA, Turetsky MR. Evaluating
Sphagnum
traits in the context of resource economics and optimal partitioning theories. OIKOS 2020. [DOI: 10.1111/oik.07195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tobi A. Oke
- Marine Science Inst., The Univ. of Texas Austin 750 Channel View Drive Port Aransas TX 78373 USA
| | - Merritt R. Turetsky
- Inst. of Arctic and Alpine Research, Univ. of Colorado Boulder, Boulder, CO, USA, and: Dept of Integrative Biology, Univ. of Guelph Guelph ON Canada
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8
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Kerhoulas LP, Weisgrau AS, Hoeft EC, Kerhoulas NJ. Vertical gradients in foliar physiology of tall Picea sitchensis trees. TREE PHYSIOLOGY 2020; 40:321-332. [PMID: 31976529 DOI: 10.1093/treephys/tpz137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 11/28/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
In tall conifers, leaf structure can vary dramatically with height due to decreasing water potential (Ψ) and increasing light availability. This variation in leaf structure can have physiological consequences such as increased respiratory costs, reduced internal carbon dioxide conductance rates and ultimately reduced maximum photosynthetic rates (Amax). In Picea sitchensis (Bong.) Carrière, the leaf structure varies along the vertical gradient in ways that suggest compensatory changes to enhance photosynthesis, and this variation seems to be driven largely by light availability rather than by Ψ. These trends in leaf structure coupled with remarkably fast growth rates and dependence on moist environments inspire two important questions about P. sitchensis: (i) does foliar water uptake minimize the adverse effects of decreasing Ψ with height on leaf structure, and (ii) do trends in leaf structure increase photosynthetic rates despite increasing height? To answer these questions, we measured foliar water uptake capacity, predawn (Ψpd) and midday water potential and gas-exchange rates as they varied between 25- and 89-m heights in 300-year-old P. sitchensis trees in northwestern California. Our major findings for P. sitchensis include the following: (i) foliar water uptake capacity was quite high relative to published values for other woody species; (ii) foliar water uptake capacity increased between the crown base and treetop; (iii) wet season Ψpd was higher than predicted by the gravitational potential gradient, indicating foliar water uptake; and (iv) the maximum photosynthetic rate increased with height, presumably due to shifts in leaf structure between the crown base and treetop, mitigating height-related decreases in Amax. These findings suggest that together, the use of fog, dew and rain deposits on leaves and shifts in the leaf structure to conserve and possibly enhance photosynthetic capacity likely contribute to the rapid growth rates measured in this species.
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Affiliation(s)
- Lucy P Kerhoulas
- Department of Forestry and Wildland Resources, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, USA
| | - Ariel S Weisgrau
- Department of Forestry and Wildland Resources, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, USA
| | - Emily C Hoeft
- Department of Biological Sciences, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, USA
| | - Nicholas J Kerhoulas
- Department of Wildlife, Humboldt State University, 1 Harpst Street, Arcata, CA 95521, USA
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9
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Flexas J, Carriquí M. Photosynthesis and photosynthetic efficiencies along the terrestrial plant's phylogeny: lessons for improving crop photosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:964-978. [PMID: 31833133 DOI: 10.1111/tpj.14651] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 11/12/2019] [Accepted: 12/03/2019] [Indexed: 05/08/2023]
Abstract
Photosynthesis is the basis of all life on Earth. Surprisingly, until very recently, data on photosynthesis, photosynthetic efficiencies, and photosynthesis limitations in terrestrial land plants other than spermatophytes were very scarce. Here we provide an updated data compilation showing that maximum photosynthesis rates (expressed either on an area or dry mass basis) progressively scale along the land plant's phylogeny, from lowest values in bryophytes to largest in angiosperms. Unexpectedly, both photosynthetic water (WUE) and nitrogen (PNUE) use efficiencies also scale positively through the phylogeny, for which it has been commonly reported that these two efficiencies tend to trade-off between them when comparing different genotypes or a single species subject to different environmental conditions. After providing experimental evidence that these observed trends are mostly due to an increased mesophyll conductance to CO2 - associated with specific anatomical changes - along the phylogeny, we discuss how these findings on a large phylogenetic scale can provide useful information to address potential photosynthetic improvements in crops in the near future.
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Affiliation(s)
- Jaume Flexas
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears - Instituto de Investigaciones Agroambientales y de Economía del Agua (UIB-INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Spain
| | - Marc Carriquí
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears - Instituto de Investigaciones Agroambientales y de Economía del Agua (UIB-INAGEA), Carretera de Valldemossa Km 7.5, 07122, Palma, Spain
- School of Biological Sciences, University of Tasmania, Private Bag 51, 7001, Hobart, TAS, Australia
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10
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Dynamic Simulation of the Crown Net Photosynthetic Rate for Young Larix olgensis Henry Trees. FORESTS 2019. [DOI: 10.3390/f10040321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Numerical integration of the instantaneous net photosynthetic rate (An) is a common method for calculating the long-term CO2 uptake of trees, and accurate dynamic simulation of the crown An has been receiving substantial attention. Tree characteristics are challenging to assess given their aerodynamically coarse crown properties, spatiotemporal variation in leaf functional traits and microenvironments. Therefore, the variables associated with the dynamic variations in the crown An must be identified. The relationships of leaf temperature (Tleaf), the vapor pressure deficit (VPD), leaf mass per area (LMA) and the relative depth into the crown (RDINC) with the parameters of the photosynthetic light-response (PLR) model of Larix olgensis Henry were analyzed. The LMA, RDINC and VPD were highly correlated with the maximum net photosynthetic rate (Amax). The VPD was the key variable that mainly determined the variation in the apparent quantum yield (AQY). Tleaf exhibited a significant exponential correlation with the dark respiration rate (Rd). According to the above correlations, the crown PLR model of L. olgensis trees was constructed by linking VPD, LMA and RDINC to the original PLR equation. The model performed well, with a high coefficient of determination (R2) value (0.883) and low root mean square error (RMSE) value (1.440 μmol m−2 s−1). The extinction coefficient (k) of different pseudowhorls within a crown was calculated by the Beer–Lambert equation based on the observed photosynthetically active radiation (PAR) distribution. The results showed that k was not a constant value but varied with the RDINC, solar elevation angle (ψ) and cumulative leaf area of the whole crown (CLA). Thus, we constructed a k model by reparameterizing the power function of RDINC with the ψ and CLA, and the PAR distribution within a crown was therefore well estimated (R2 = 0.698 and RMSE = 174.4 μmol m−2 s−1). Dynamic simulation of the crown An for L. olgensis trees was achieved by combining the crown PLR model and dynamic PAR distribution model. Although the models showed some weakened physiological biochemical processes during photosynthesis, they enabled the estimation of long-term CO2 uptake for an L. olgensis plantation, and the results could be easily fitted to gas-exchange measurements.
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11
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Spatial and Seasonal Variations of Standardized Photosynthetic Parameters under Different Environmental Conditions for Young Planted Larix olgensis Henry Trees. FORESTS 2018. [DOI: 10.3390/f9090522] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Understanding the spatial and seasonal variations in leaf physiology is critical for accurately modeling the carbon uptake, physiological processes and growth of entire canopies and stands. For a 17-year-old Larix olgensis Henry plantation, vertical whorl-by-whorl sampling and analyses of seasonally repeated measurements of major photosynthetic parameters were conducted, and the correlations between photosynthetic parameters and environmental conditions, leaf morphological traits and spatial position within the crown were analyzed. According to the correlations, the photosynthetic parameters were standardized based on the environmental conditions to avoid the influence of the changing environment on the patterns of spatial and seasonal variations of photosynthetic parameters. The results showed that the standardized light-saturated net photosynthetic rate (SPmax), standardized dark respiration (SRd) and standardized stomatal conductance under saturated light (Sgs-sat) were all negatively related to the relative depth into the crown (RDINC) throughout the growing season. However, their vertical patterns were different during the development of the phenological phase. In addition, different gradients of environmental conditions also influenced the values and the range of the vertical variation in photosynthesis. High temperature and low humidity usually resulted in smaller values and weaker vertical variations of SPmax and Sgs-sat, but larger values and more obvious vertical variations in SRd. SPmax and Sgs-sat usually exhibited a parabolic seasonal pattern in different vertical positions within the crown; however, SRd generally followed a concave pattern. These seasonal patterns were all weaker with increasing RDINC. Different environments also exhibited a significant influence on the seasonal patterns of photosynthesis. We suggested that standardization is necessary before analyzing spatial and seasonal variations. A single environmental condition could not represent the spatial and seasonal patterns under all gradients of the environment. Spatial and seasonal variations should be simultaneously analyzed because they are related to each other.
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Coble AP, Cavaleri MA. Vertical leaf mass per area gradient of mature sugar maple reflects both height-driven increases in vascular tissue and light-driven increases in palisade layer thickness. TREE PHYSIOLOGY 2017; 37:1337-1351. [PMID: 28338906 DOI: 10.1093/treephys/tpx016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 02/11/2017] [Indexed: 06/06/2023]
Abstract
A key trait used in canopy and ecosystem function modeling, leaf mass per area (LMA), is influenced by changes in both leaf thickness and leaf density (LMA = Thickness × Density). In tall trees, LMA is understood to increase with height through two primary mechanisms: (i) increasing palisade layer thickness (and thus leaf thickness) in response to light and/or (ii) reduced cell expansion and intercellular air space in response to hydrostatic constraints, leading to increased leaf density. Our objective was to investigate within-canopy gradients in leaf anatomical traits in order to understand environmental factors that influence leaf morphology in a sugar maple (Acer saccharum Marshall) forest canopy. We teased apart the effects of light and height on anatomical traits by sampling at exposed and closed canopies that had different light conditions at similar heights. As expected, palisade layer thickness responded strongly to cumulative light exposure. Mesophyll porosity, however, was weakly and negatively correlated with light and height (i.e., hydrostatic gradients). Reduced mesophyll porosity was not likely caused by limitations on cell expansion; in fact, epidermal cell width increased with height. Palisade layer thickness was better related to LMA, leaf density and leaf thickness than was mesophyll porosity. Vein diameter and fraction of vascular tissue also increased with height and LMA, density and thickness, revealing that greater investment in vascular and support tissue may be a third mechanism for increased LMA with height. Overall, decreasing mesophyll porosity with height was likely due to palisade cells expanding into the available air space and also greater investments in vascular and support tissue, rather than a reduction of cell expansion due to hydrostatic constraints. Our results provide evidence that light influences both palisade layer thickness and mesophyll porosity and indicate that hydrostatic gradients influence leaf vascular and support tissues in mature Acer saccharum trees.
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Affiliation(s)
- Adam P Coble
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, James Hall, Room 114, Durham, NH 03824, USA
| | - Molly A Cavaleri
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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Coble AP, Fogel ML, Parker GG. Canopy gradients in leaf functional traits for species that differ in growth strategies and shade tolerance. TREE PHYSIOLOGY 2017; 37:1415-1425. [PMID: 28486656 DOI: 10.1093/treephys/tpx048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 04/27/2017] [Indexed: 05/13/2023]
Abstract
In temperate deciduous forests, vertical gradients in leaf mass per area (LMA) and area-based leaf nitrogen (Narea) are strongly controlled by gradients in light availability. While there is evidence that hydrostatic constraints on leaf development may diminish LMA and Narea responses to light, inherent differences among tree species may also influence leaf developmental and morphological response to light. We investigated vertical gradients in LMA, Narea and leaf carbon isotope composition (δ13C) for three temperate deciduous species (Carpinus caroliniana Walter, Fagus grandifolia Ehrh., Liriodendron tulipifera L.) that differed in growth strategy (e.g., indeterminate and determinate growth), shade tolerance and leaf area to sapwood ratio (Al:As). Leaves were sampled across a broad range of light conditions within three vertical layers of tree crowns to maximize variation in light availability at each height and to minimize collinearity between light and height. All species displayed similar responses to light with respect to Narea and δ13C, but not for LMA. Light was more important for gradients in LMA for the shade-tolerant (C. caroliniana) and -intolerant (L. tulipifera) species with indeterminate growth, and height (e.g., hydrostatic gradients) and light were equally important for the shade-tolerant (F. grandifolia) species with determinate growth. Fagus grandifolia had a higher morphological plasticity in response to light, which may offer a competitive advantage in occupying a broader range of light conditions throughout the canopy. Differences in responses to light and height for the taller tree species, L. tulipifera and F. grandifolia, may be attributed to differences in growth strategy or Al:As, which may alter morphological and functional responses to light availability. While height was important in F. grandifolia, height was no more robust in predicting LMA than light in any of the species, confirming the strong role of light availability in determining LMA for temperate deciduous species.
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Affiliation(s)
- Adam P Coble
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, James Hall Room 114, Durham, NH 03824,USA
| | - Marilyn L Fogel
- Department of Earth Sciences, University of California Riverside, 900 University Ave., Riverside, CA 92521, USA
| | - Geoffrey G Parker
- Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, MD 21037, USA
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Recchia I, Sparla F, Pupillo P. Photosynthetic properties of spring geophytes assessed by chlorophyll fluorescence analysis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 118:510-518. [PMID: 28759847 DOI: 10.1016/j.plaphy.2017.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/23/2017] [Accepted: 07/23/2017] [Indexed: 06/07/2023]
Abstract
Since spring ephemerals are credited to be all "sun" species with unusually elevate photosynthesis, in contrast to shade-tolerant trees and understory geophytes with a long aboveground cycle, we examined the photosynthetic efficiency of 6 woody species, 9 long-cycle geophytes, and 8 spring ephemeral geophytes using blue flashes of increasing energy with the Imaging PAM fluorometer. Several parameters were obtained: quantum yield of electron transport (ΦETR) or of PSII (ΦPSII), maximum measured photosynthesis rate (ETRhv), maximum extrapolated rate of photosynthesis (ETRem), half-saturating photon flux density (KPAR), and in some cases photochemical (qP) and non-photochemical quenching (NPQ). Results confirm the ecological consistency of the three plant groups, with internal differences. Woody species have low ETRem and KPAR values with good ΦETR; long-cycle herbs have low ETRem and ΦETR and moderate KPAR values; spring ephemerals have elevate ΦETR, ETRem and KPAR values. The mean ETRem of ephemerals of 91 μmol m-2 s-1 exceeds that of long-cycle herbs 2.9-fold and woody species 4.8-fold, and corresponds to 19 μmol CO2 m-2 s-1 by assuming an ETR/ΦCO2 ratio of 4.7. Highest photosynthesis rates and KPAR were exhibited by five ephemerals (Eranthis, Erythronium, Narcissus, Scilla, Tulipa) with peak ETRem values equivalent to ∼40 μmol CO2 m-2 s-1 or ∼60 μmol CO2 (g Chl)-1 s-1 ("sun" species). According to a new, fluorescence based heliophily index, all trees and five long-cycle herbs were definitely "shade" species, while four long-cycle herbs and three ephemerals were intermediate shade-tolerant.
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Affiliation(s)
- Irene Recchia
- Department of Pharmacy and Biotechnology FaBiT, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Francesca Sparla
- Department of Pharmacy and Biotechnology FaBiT, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Paolo Pupillo
- Department of Pharmacy and Biotechnology FaBiT, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
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Veromann-Jürgenson LL, Tosens T, Laanisto L, Niinemets Ü. Extremely thick cell walls and low mesophyll conductance: welcome to the world of ancient living! JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:1639-1653. [PMID: 28419340 PMCID: PMC5441924 DOI: 10.1093/jxb/erx045] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Mesophyll conductance is thought to be an important photosynthetic limitation in gymnosperms, but they currently constitute the most understudied plant group in regard to the extent to which photosynthesis and intrinsic water use efficiency are limited by mesophyll conductance. A comprehensive analysis of leaf gas exchange, photosynthetic limitations, mesophyll conductance (calculated by three methods previously used for across-species comparisons), and the underlying ultra-anatomical, morphological and chemical traits in 11 gymnosperm species varying in evolutionary history was performed to gain insight into the evolution of structural and physiological controls on photosynthesis at the lower return end of the leaf economics spectrum. Two primitive herbaceous species were included in order to provide greater evolutionary context. Low mesophyll conductance was the main limiting factor of photosynthesis in the majority of species. The strongest sources of limitation were extremely thick mesophyll cell walls, high chloroplast thickness and variation in chloroplast shape and size, and the low exposed surface area of chloroplasts per unit leaf area. In gymnosperms, the negative relationship between net assimilation per mass and leaf mass per area reflected an increased mesophyll cell wall thickness, whereas the easy-to-measure integrative trait of leaf mass per area failed to predict the underlying ultrastructural traits limiting mesophyll conductance.
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Affiliation(s)
- Linda-Liisa Veromann-Jürgenson
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Tiina Tosens
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Lauri Laanisto
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
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Coble AP, VanderWall B, Mau A, Cavaleri MA. How vertical patterns in leaf traits shift seasonally and the implications for modeling canopy photosynthesis in a temperate deciduous forest. TREE PHYSIOLOGY 2016; 36:1077-1091. [PMID: 27246164 DOI: 10.1093/treephys/tpw043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Leaf functional traits are used in modeling forest canopy photosynthesis (Ac) due to strong correlations between photosynthetic capacity, leaf mass per area (LMA) and leaf nitrogen per area (Narea). Vertical distributions of these traits may change over time in temperate deciduous forests as a result of acclimation to light, which may result in seasonal changes in Ac To assess both spatial and temporal variations in key traits, we measured vertical profiles of Narea and LMA from leaf expansion through leaf senescence in a sugar maple (Acer saccharum Marshall) forest. To investigate mechanisms behind coordinated changes in leaf morphology and function, we also measured vertical variation in leaf carbon isotope composition (δ(13)C), predawn turgor pressure, leaf water potential and osmotic potential. Finally, we assessed potential biases in Ac estimations by parameterizing models with and without vertical and seasonal Narea variations following leaf expansion. Our data are consistent with the hypothesis that hydrostatic constraints on leaf morphology drive the vertical increase in LMA with height early in the growing season; however, LMA in the upper canopy continued to increase over time during light acclimation, indicating that light is primarily driving gradients in LMA later in the growing season. Models with no seasonal variation in Narea overestimated Ac by up to 11% early in the growing season, while models with no vertical variation in Narea overestimated Ac by up to 60% throughout the season. According to the multilayer model, the upper 25% of leaf area contributed to over 50% of Ac, but when gradients of intercellular CO2, as estimated from δ(13)C, were accounted for, the upper 25% of leaf area contributed to 26% of total Ac Our results suggest that ignoring vertical variation of key traits can lead to considerable overestimation of Ac.
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Affiliation(s)
- Adam P Coble
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA Department of Natural Resources and the Environment, University of New Hampshire, 56 College Rd, Durham, NH 03824, USA
| | - Brittany VanderWall
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Alida Mau
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
| | - Molly A Cavaleri
- School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA
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Ambrose AR, Baxter WL, Wong CS, Burgess SSO, Williams CB, Næsborg RR, Koch GW, Dawson TE. Hydraulic constraints modify optimal photosynthetic profiles in giant sequoia trees. Oecologia 2016; 182:713-30. [DOI: 10.1007/s00442-016-3705-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 08/12/2016] [Indexed: 01/09/2023]
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18
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Light-exposed shoots of seven coexisting deciduous species show common photosynthetic responses to tree height. Oecologia 2016; 182:373-83. [PMID: 27262582 DOI: 10.1007/s00442-016-3664-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/20/2016] [Indexed: 10/21/2022]
Abstract
Functional traits of light-exposed leaves have been reported to show tree height-dependent change. However, it remains unknown how plastic response of leaf traits to tree height is linked with shoot-level carbon gain. To answer this question, we examined the photosynthetic properties of fully lit current-year shoots in crown tops with various heights for seven deciduous broad-leaved species dominated in a cool-temperate forest in northern Japan. We measured leaf mass, stomatal conductance, nitrogen content, light-saturated net photosynthetic rate (all per leaf lamina area), foliar stable carbon isotope ratio, and shoot mass allocation to leaf laminae. We employed hierarchical Bayesian models to simultaneously quantify inter-trait relationships for all species. We found that leaf and shoot traits were co-varied in association with height, and that there was no quantitative inter-specific difference in leaf- and shoot-level plastic responses to height. Nitrogen content increased and stomatal conductance decreased with height. Reflecting these antagonistic responses to height, photosynthetic rate was almost unchanged with height. Photosynthetic rate divided by stomatal conductance as a proxy of photosynthetic water use efficiency sufficiently explained the variation of foliar carbon isotope ratio. The increase in mass allocation to leaves in a shoot compensated for the height-dependent decline in photosynthetic rate per leaf lamina mass. Consequently, photosynthetic gain at the scale of current-year shoot mass was kept unchanged with tree height. We suggest that the convergent responses of shoot functional traits across species reflect common requirements for trees coexisting in a forest.
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Chin ARO, Sillett SC. Phenotypic plasticity of leaves enhances water-stress tolerance and promotes hydraulic conductivity in a tall conifer. AMERICAN JOURNAL OF BOTANY 2016; 103:796-807. [PMID: 27208348 DOI: 10.3732/ajb.1600110] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 03/30/2016] [Indexed: 06/05/2023]
Abstract
PREMISE OF THE STUDY Leaves respond to environmental signals and acclimate to local conditions until their ecological limits are reached. Understanding the relationships between anatomical variation in leaves and the availability of water and light improves our ability to predict ecosystem-level impacts of foliar response to climate change, as it expands our knowledge of tree physiology. METHODS We examined foliar anatomy and morphology of the largest plant species, Sequoiadendron giganteum, from leafy shoot samples collected throughout crowns of trees up to 95 m tall and assessed the functionality of within-crown variation with a novel drought/recovery experiment. KEY RESULTS We found phenotypic variation in response to water availability in 13 anatomical traits of Sequoiadendron leaves. Shoot expansion was constrained by the hydrostatic gradient of maximum water potential, while functional traits supporting succulence and toughness were associated with sites of peak hydraulic limitation. Water-stress tolerance in experimental shoots increased dramatically with height. CONCLUSION We propose a heat-sink function for transfusion tissue and uncover a suite of traits suggesting rapid hydraulic throughput and flexibility in water-stress tolerance investments as strategies that help this montane species reach such enormous size. Responses to water stress alter the amount of carbon stored in foliage and the rate of the eventual release of carbon.
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Affiliation(s)
- Alana R O Chin
- Department of Natural Resources, American River College, 4700 College Oak Drive, Sacramento, California 95841 USA
| | - Stephen C Sillett
- Department of Forestry and Wildland Resources, Humboldt State University, 1 Harpst Street, Arcata, California 95521 USA
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Ambrose AR, Baxter WL, Wong CS, Næsborg RR, Williams CB, Dawson TE. Contrasting drought-response strategies in California redwoods. TREE PHYSIOLOGY 2015; 35:453-469. [PMID: 25787330 DOI: 10.1093/treephys/tpv016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 01/30/2015] [Indexed: 06/04/2023]
Abstract
We compared the physiology and growth of seedlings originating from different Sequoia sempervirens (D. Don.) Endl. (coast redwood) and Sequoiadendron giganteum (Lindl.) Buchh. (giant sequoia) populations subjected to progressive drought followed by a recovery period in a controlled greenhouse experiment. Our objective was to examine how multiple plant traits interact to influence the response of seedlings of each species and seed population to a single drought and recovery cycle. We measured soil and plant water status, leaf gas exchange, stem embolism and growth of control (well-watered) and drought-stressed (water withheld) seedlings from each population at the beginning, middle and end of a 6-week drought period and again 2 weeks after re-watering. The drought had a significant effect on many aspects of seedling performance, but water-stressed seedlings regained most physiological functioning by the end of the recovery period. Sequoiadendron seedlings exhibited a greater degree of isohydry (water status regulation), lower levels of stem embolism, higher biomass allocation to roots and lower sensitivity of growth to drought compared with Sequoia. Only minor intra-specific differences were observed among populations. Our results show that seedlings of the two redwood species exhibit contrasting drought-response strategies that align with the environmental conditions these trees experience in their native habitats, and demonstrate trade-offs and coordination among traits affecting plant water use, carbon gain and growth under drought.
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Affiliation(s)
- Anthony R Ambrose
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Wendy L Baxter
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Christopher S Wong
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Rikke R Næsborg
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Cameron B Williams
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
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Coble AP, Cavaleri MA. Light acclimation optimizes leaf functional traits despite height-related constraints in a canopy shading experiment. Oecologia 2015; 177:1131-43. [DOI: 10.1007/s00442-015-3219-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 01/03/2015] [Indexed: 11/29/2022]
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Pärnik T, Ivanova H, Keerberg O, Vardja R, Niinemets U. Tree age-dependent changes in photosynthetic and respiratory CO2 exchange in leaves of micropropagated diploid, triploid and hybrid aspen. TREE PHYSIOLOGY 2014; 34:585-594. [PMID: 24898219 DOI: 10.1093/treephys/tpu043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The growth rate of triploid European aspen (Populus tremula L.) and hybrid aspen (P. tremula × Populus tremuloides Michx.) significantly exceeds that of diploid aspen, but the underlying physiological controls of the superior growth rates of these genotypes are not known. We tested the hypothesis that the superior growth rate of triploid and hybrid aspen reflects their greater net photosynthesis rate. Micropropagated clonal plants varying in age from 2.5 to 19 months were used to investigate the ploidy and plant age interaction. The quantum yield of net CO2 fixation (Φ) in leaves of young 2.5-month-old hybrid aspen was lower than that of diploid and triploid trees. However, Φ in 19-month-old hybrid aspen was equal to that in triploid aspen and higher than that in diploid aspen. Φ and the rate of light-saturated net photosynthesis (ANS) increased with plant age, largely due to higher leaf dry mass per unit area in older plants. ANS in leaves of 19-month-old trees was highest in hybrid, medium in triploid and lowest in diploid aspen. Light-saturated photosynthesis had a broad temperature optimum between 20 and 35 °C. Rate of respiration in the dark (RDS) did not vary among the genotypes in 2.5-month-old plants, and the shape of the temperature response was also similar. RDS increased with plant age, but RDS was still not significantly different among the leaves of 19-month-old diploid and triploid aspen, but it was significantly lower in leaves of 19-month-old hybrid plants. The initial differences in the growth of plants with different ploidy were minor up to the age of 19 months, but during the next 2 years, the growth rate of hybrid aspen exceeded that of triploid plants by 2.7 times and of diploid plants by five times, in line with differences in ANS of 19-month-old plants of these species. It is suggested that differences in photosynthesis and growth became more pronounced with tree aging, indicating that ontogeny plays a key role in the expression of superior traits determining the productivity of given genotypes.
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Affiliation(s)
- Tiit Pärnik
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Hiie Ivanova
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Olav Keerberg
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Rael Vardja
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
| | - Ulo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51014 Tartu, Estonia
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Ishii HR, Azuma W, Kuroda K, Sillett SC. Pushing the limits to tree height: could foliar water storage compensate for hydraulic constraints inSequoia sempervirens? Funct Ecol 2014. [DOI: 10.1111/1365-2435.12284] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- H. Roaki Ishii
- Graduate School of Agricultural Science; Kobe University; Kobe Japan
- Department of Forestry and Wildland Resources; Humboldt State University; Arcata CA USA
| | - Wakana Azuma
- Graduate School of Agricultural Science; Kobe University; Kobe Japan
| | - Keiko Kuroda
- Graduate School of Agricultural Science; Kobe University; Kobe Japan
| | - Stephen C. Sillett
- Department of Forestry and Wildland Resources; Humboldt State University; Arcata CA USA
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Nolan RH, Mitchell PJ, Bradstock RA, Lane PNJ. Structural adjustments in resprouting trees drive differences in post-fire transpiration. TREE PHYSIOLOGY 2014; 34:123-136. [PMID: 24536069 DOI: 10.1093/treephys/tpt125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Following disturbance many woody species are capable of resprouting new foliage, resulting in a reduced leaf-to-sapwood area ratio and altered canopy structure. We hypothesized that such changes would promote adjustments in leaf physiology, resulting in higher rates of transpiration per unit leaf area, consistent with the mechanistic framework proposed by Whitehead et al. (Whitehead D, Jarvis PG, Waring RH (1984) Stomatal conductance, transpiration and resistance to water uptake in a Pinus sylvestris spacing experiment. Can J For Res 14:692-700). We tested this in Eucalyptus obliqua L'Hér following a wildfire by comparing trees with unburnt canopies with trees that had been subject to 100% canopy scorch and were recovering their leaf area via resprouting. In resprouting trees, foliage was distributed along the trunk and on lateral branches, resulting in shorter hydraulic path lengths. We evaluated measurements of whole-tree transpiration and structural and physiological traits expected to drive any changes in transpiration. We used these structural and physiological measurements to parameterize the Whitehead et al. equation, and found that the expected ratio of transpiration per unit leaf area between resprouting and unburnt trees was 3.41. This is similar to the observed ratio of transpiration per unit leaf area, measured from sapflow observations, which was 2.89 (i.e., resprouting trees had 188% higher transpiration per unit leaf area). Foliage at low heights (<2 m) was found to be significantly different to foliage in the tree crown (14-18 m) in a number of traits, including higher specific leaf area, midday leaf water potential and higher rates of stomatal conductance and photosynthesis. We conclude that these post-fire adjustments in resprouting trees help to drive increased stomatal conductance and hydraulic efficiency, promoting the rapid return of tree-scale transpiration towards pre-disturbance levels. These transient patterns in canopy transpiration have important implications for modelling stand-level water fluxes in forests capable of resprouting, which is frequently done on the basis of the leaf area index.
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Affiliation(s)
- Rachael H Nolan
- Department of Forest and Ecosystem Science, The University of Melbourne, 221 Bouverie St, Parkville, VIC 3010, Australia
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Kerhoulas LP, Kolb TE, Hurteau MD, Koch GW. Managing climate change adaptation in forests: a case study from the U.S. Southwest. J Appl Ecol 2013. [DOI: 10.1111/1365-2664.12139] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Lucy P. Kerhoulas
- Department of Biological Sciences; Merriam-Powell Center for Environmental Research; Northern Arizona University; P.O. Box 5640 Flagstaff AZ 86011 USA
| | - Thomas E. Kolb
- School of Forestry; Northern Arizona University; P.O. Box 15018 Flagstaff AZ 86011 USA
| | - Matthew D. Hurteau
- Department of Ecosystem Science and Management; Pennsylvania State University; 306 Forest Resources Building University Park PA 16802 USA
| | - George W. Koch
- Department of Biological Sciences; Merriam-Powell Center for Environmental Research; Northern Arizona University; P.O. Box 5640 Flagstaff AZ 86011 USA
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Ishii H, Azuma W, Nabeshima E. The need for a canopy perspective to understand the importance of phenotypic plasticity for promoting species coexistence and light-use complementarity in forest ecosystems. Ecol Res 2013. [DOI: 10.1007/s11284-012-1025-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Tosens T, Niinemets Ü, Westoby M, Wright IJ. Anatomical basis of variation in mesophyll resistance in eastern Australian sclerophylls: news of a long and winding path. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:5105-19. [PMID: 22888123 PMCID: PMC3430992 DOI: 10.1093/jxb/ers171] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In sclerophylls, photosynthesis is particularly strongly limited by mesophyll diffusion resistance from substomatal cavities to chloroplasts (r(m)), but the controls on diffusion limits by integral leaf variables such as leaf thickness, density, and dry mass per unit area and by the individual steps along the diffusion pathway are imperfectly understood. To gain insight into the determinants of r(m) in leaves with varying structure, the full CO(2) physical diffusion pathway was analysed in 32 Australian species sampled from sites contrasting in soil nutrients and rainfall, and having leaf structures from mesophytic to strongly sclerophyllous. r(m) was estimated based on combined measurements of gas exchange and chlorophyll fluorescence. In addition, r(m) was modelled on the basis of detailed anatomical measurements to separate the importance of different serial resistances affecting CO(2) diffusion into chloroplasts. The strongest sources of variation in r(m) were S(c)/S, the exposed surface area of chloroplasts per unit leaf area, and mesophyll cell wall thickness, t(cw). The strong correlation of r(m) with t(cw) could not be explained by cell wall thickness alone, and most likely arose from a further effect of cell wall porosity. The CO(2) drawdown from intercellular spaces to chloroplasts was positively correlated with t(cw), suggesting enhanced diffusional limitations in leaves with thicker cell walls. Leaf thickness and density were poorly correlated with S(c)/S, indicating that widely varying combinations of leaf anatomical traits occur at given values of leaf integrated traits, and suggesting that detailed anatomical studies are needed to predict r(m) for any given species.
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Affiliation(s)
- Tiina Tosens
- Department of Biological Sciences, Macquarie University, New South Wales 2109, Australia.
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Flexas J, Barbour MM, Brendel O, Cabrera HM, Carriquí M, Díaz-Espejo A, Douthe C, Dreyer E, Ferrio JP, Gago J, Gallé A, Galmés J, Kodama N, Medrano H, Niinemets Ü, Peguero-Pina JJ, Pou A, Ribas-Carbó M, Tomás M, Tosens T, Warren CR. Mesophyll diffusion conductance to CO2: an unappreciated central player in photosynthesis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 193-194:70-84. [PMID: 22794920 DOI: 10.1016/j.plantsci.2012.05.009] [Citation(s) in RCA: 358] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/08/2012] [Accepted: 05/20/2012] [Indexed: 05/20/2023]
Abstract
Mesophyll diffusion conductance to CO(2) is a key photosynthetic trait that has been studied intensively in the past years. The intention of the present review is to update knowledge of g(m), and highlight the important unknown and controversial aspects that require future work. The photosynthetic limitation imposed by mesophyll conductance is large, and under certain conditions can be the most significant photosynthetic limitation. New evidence shows that anatomical traits, such as cell wall thickness and chloroplast distribution are amongst the stronger determinants of mesophyll conductance, although rapid variations in response to environmental changes might be regulated by other factors such as aquaporin conductance. Gaps in knowledge that should be research priorities for the near future include: how different is mesophyll conductance among phylogenetically distant groups and how has it evolved? Can mesophyll conductance be uncoupled from regulation of the water path? What are the main drivers of mesophyll conductance? The need for mechanistic and phenomenological models of mesophyll conductance and its incorporation in process-based photosynthesis models is also highlighted.
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Affiliation(s)
- Jaume Flexas
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
| | - Margaret M Barbour
- Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Private Bag 4011, Narellan, NSW 2567, Australia
| | - Oliver Brendel
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France
| | - Hernán M Cabrera
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; Centro de Ecología Aplicada Ltda., Av. Suecia 3304, Ñuñoa, Santiago, Chile
| | - Marc Carriquí
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Antonio Díaz-Espejo
- Instituto de Recursos Naturales y Agrobiología, IRNAS-CSIC, Apartado 1052, 41080 Sevilla, Spain
| | - Cyril Douthe
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France; School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Erwin Dreyer
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France
| | - Juan P Ferrio
- Department of Crop and Forest Sciences, AGROTECNIO Center, Universitat de Lleida, Avda. Rovira Roure 191, 25198 Lleida, Spain
| | - Jorge Gago
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Alexander Gallé
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Jeroni Galmés
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Naomi Kodama
- Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba 305-8604, Japan
| | - Hipólito Medrano
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - José J Peguero-Pina
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Alicia Pou
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Miquel Ribas-Carbó
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Magdalena Tomás
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Tiina Tosens
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Charles R Warren
- School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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Kerhoulas LP, Kane JM. Sensitivity of ring growth and carbon allocation to climatic variation vary within ponderosa pine trees. TREE PHYSIOLOGY 2012; 32:14-23. [PMID: 22094578 DOI: 10.1093/treephys/tpr112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Most dendrochronological studies focus on cores sampled from standard positions (main stem, breast height), yet vertical gradients in hydraulic constraints and priorities for carbon allocation may contribute to different growth sensitivities with position. Using cores taken from five positions (coarse roots, breast height, base of live crown, mid-crown branch and treetop), we investigated how radial growth sensitivity to climate over the period of 1895-2008 varies by position within 36 large ponderosa pines (Pinus ponderosa Dougl.) in northern Arizona. The climate parameters investigated were Palmer Drought Severity Index, water year and monsoon precipitation, maximum annual temperature, minimum annual temperature and average annual temperature. For each study tree, we generated Pearson correlation coefficients between ring width indices from each position and six climate parameters. We also investigated whether the number of missing rings differed among positions and bole heights. We found that tree density did not significantly influence climatic sensitivity to any of the climate parameters investigated at any of the sample positions. Results from three types of analyses suggest that climatic sensitivity of tree growth varied with position height: (i) correlations of radial growth and climate variables consistently increased with height; (ii) model strength based on Akaike's information criterion increased with height, where treetop growth consistently had the highest sensitivity and coarse roots the lowest sensitivity to each climatic parameter; and (iii) the correlation between bole ring width indices decreased with distance between positions. We speculate that increased sensitivity to climate at higher positions is related to hydraulic limitation because higher positions experience greater xylem tensions due to gravitational effects that render these positions more sensitive to climatic stresses. The low sensitivity of root growth to all climatic variables measured suggests that tree carbon allocation to coarse roots is independent of annual climate variability. The greater number of missing rings in branches highlights the fact that canopy development is a low priority for carbon allocation during poor growing conditions.
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Affiliation(s)
- Lucy P Kerhoulas
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
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Miyata R, Kubo T, Nabeshima E, Kohyama TS. Common allometric response of open-grown leader shoots to tree height in co-occurring deciduous broadleaved trees. ANNALS OF BOTANY 2011; 108:1279-86. [PMID: 21914698 PMCID: PMC3197456 DOI: 10.1093/aob/mcr228] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 07/07/2011] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND AIMS Morphology of crown shoots changes with tree height. The height of forest trees is usually correlated with the light environment and this makes it difficult to separate the effects of tree size and of light conditions on the morphological plasticity of crown shoots. This paper addresses the tree-height dependence of shoot traits under full-light conditions where a tree crown is not shaded by other crowns. METHODS Focus is given to relationships between tree height and top-shoot traits, which include the shoot's leaf-blades and non-leafy mass, its total leaf-blade area and the length and basal diameter of the shoot's stem. We examine the allometric characteristics of open-grown current-year leader shoots at the tops of forest tree crowns up to 24 m high and quantify their responses to tree height in 13 co-occurring deciduous hardwood species in a cool-temperate forest in northern Japan. KEY RESULTS Dry mass allocated to leaf blades in a leader shoot increased with tree height in all 13 species. Specific leaf area decreased with tree height. Stem basal area was almost proportional to total leaf area in a leader shoot, where the proportionality constant did not depend on tree height, irrespective of species. Stem length for a given stem diameter decreased with tree height. CONCLUSIONS In the 13 species observed, height-dependent changes in allometry of leader shoots were convergent. This finding suggests that there is a common functional constraint in tree-height development. Under full-light conditions, leader shoots of tall trees naturally experience more severe water stress than those of short trees. We hypothesize that the height dependence of shoot allometry detected reflects an integrated response to height-associated water stress, which contributes to successful crown expansion and height gain.
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Affiliation(s)
- Rie Miyata
- Graduate School of Environmental Science, Hokkaido University, Kita-ku, Sapporo, 060-0810, Japan.
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31
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Han Q. Height-related decreases in mesophyll conductance, leaf photosynthesis and compensating adjustments associated with leaf nitrogen concentrations in Pinus densiflora. TREE PHYSIOLOGY 2011; 31:976-984. [PMID: 21467050 DOI: 10.1093/treephys/tpr016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydraulic limitations associated with increasing tree height result in reduced foliar stomatal conductance (g(s)) and light-saturated photosynthesis (A(max)). However, it is unclear whether the decline in A(max) is attributable to height-related modifications in foliar nitrogen concentration (N), to mesophyll conductance (g(m)) or to biochemical capacity for photosynthesis (maximum rate of carboxylation, V(cmax)). Simultaneous measurements of gas exchange and chlorophyll fluorescence were made to determine g(m) and V(cmax) in four height classes of Pinus densiflora Sieb. & Zucc. trees. As the average height of growing trees increased from 3.1 to 13.7 m, g(m) decreased from 0.250 to 0.107 mol m(-2) s(-1), and the CO(2) concentration from the intercellular space (C(i)) to the site of carboxylation (C(c)) decreased by an average of 74 µmol mol(-1). Furthermore, V(cmax) estimated from C(c) increased from 68.4 to 112.0 µmol m(-2) s(-1) with the increase in height, but did not change when it was calculated based on C(i). In contrast, A(max) decreased from 14.17 to 10.73 µmol m(-2) s(-1). Leaf dry mass per unit area (LMA) increased significantly with tree height as well as N on both a dry mass and an area basis. All of these parameters were significantly correlated with tree height. In addition, g(m) was closely correlated with LMA and g(s), indicating that increased diffusive resistance for CO(2) may be the inevitable consequence of morphological adaptation. Foliar N per unit area was positively correlated with V(cmax) based on C(c) but negatively with A(max), suggesting that enhancement of photosynthetic capacity is achieved by allocating more N to foliage in order to minimize the declines in A(max). Increases in the N cost associated with carbon gain because of the limited water available to taller trees lead to a trade-off between water use efficiency and photosynthetic nitrogen use efficiency. In conclusion, the height-related decrease in photosynthetic performance appears to result mainly from diffusive resistances rather than biochemical limitations.
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Affiliation(s)
- Qingmin Han
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Ibaraki 305-8687, Japan.
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32
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Ubierna N, Marshall JD. Estimation of canopy average mesophyll conductance using δ(13) C of phloem contents. PLANT, CELL & ENVIRONMENT 2011; 34:1521-1535. [PMID: 21554329 DOI: 10.1111/j.1365-3040.2011.02350.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Conductance to CO(2) inside leaves, known as mesophyll conductance (g(m)), imposes large limitations on photosynthesis. Because g(m) is difficult to quantify, it is often neglected in calculations of (13)C photosynthetic discrimination. The 'soluble sugar method' estimates g(m) via differences between observed photosynthetic discrimination, calculated from the δ(13)C of soluble sugars, and discrimination when g(m) is infinite. We expand upon this approach and calculate a photosynthesis-weighted average for canopy mesophyll conductance ((c) g(m)) using δ(13)C of stem phloem contents. We measured gas exchange at three canopy positions and collected stem phloem contents in mature trees of three conifer species (Pseudotsuga menziesii, Thuja plicata and Larix occidentalis). We generated species-specific and seasonally variable estimates of (c)g(m) . We found that (c)g(m) was significantly different among species (0.41, 0.22 and 0.09 mol m(-2) s(-1) for Larix, Pseudotsuga and Thuja, respectively), but was similar throughout the season. Ignoring respiratory and photorespiratory fractionations ((c)Δ(ef)) resulted in ≈30% underestimation of (c)g(m) in Larix and Pseudotsuga, but was innocuous in Thuja. Substantial errors (~1-4‰) in photosynthetic discrimination calculations were introduced by neglecting (c)g(m) and (c)Δ(ef) . Our method is easy to apply and cost-effective, captures species variation and would have captured seasonal variation had it existed. The method provides an average canopy value, which makes it suitable for parameterization of canopy-scale models of photosynthesis, even in tall trees.
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Affiliation(s)
- Nerea Ubierna
- Department of Forest Resources, University of Idaho, Moscow, ID 83844-1133, USA.
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Ambrose AR, Sillett SC, Koch GW, Van Pelt R, Antoine ME, Dawson TE. Effects of height on treetop transpiration and stomatal conductance in coast redwood (Sequoia sempervirens). TREE PHYSIOLOGY 2010; 30:1260-1272. [PMID: 20631010 DOI: 10.1093/treephys/tpq064] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Treetops become increasingly constrained by gravity-induced water stress as they approach maximum height. Here we examine the effects of height on seasonal and diurnal sap flow dynamics at the tops of 12 unsuppressed Sequoia sempervirens (D. Don) Endl. (coast redwood) trees 68-113 m tall during one growing season. Average treetop sap velocity (V(S)), transpiration per unit leaf area (E(L)) and stomatal conductance per unit leaf area (G(S)) significantly decreased with increasing height. These differences in sap flow were associated with an unexpected decrease in treetop sapwood area-to-leaf area ratios (A(S):A(L)) in the tallest trees. Both E(L) and G(S) declined as soil moisture decreased and vapor pressure deficit (D) increased throughout the growing season with a greater decline in shorter trees. Under high soil moisture and light conditions, reference G(S) (G(Sref); G(S) at D = 1 kPa) and sensitivity of G(S) to D (-δ; dG(S)/dlnD) significantly decreased with increasing height. The close relationship we observed between G(Sref) and -δ is consistent with the role of stomata in regulating E(L) and leaf water potential (Ψ(L)). Our results confirm that increasing tree height reduces gas exchange of treetop foliage and thereby contributes to lower carbon assimilation and height growth rates as S. sempervirens approaches maximum height.
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Affiliation(s)
- Anthony R Ambrose
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
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Drake JE, Raetz LM, Davis SC, DeLucia EH. Hydraulic limitation not declining nitrogen availability causes the age-related photosynthetic decline in loblolly pine (Pinus taeda L.). PLANT, CELL & ENVIRONMENT 2010; 33:1756-66. [PMID: 20545880 DOI: 10.1111/j.1365-3040.2010.02180.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Declining net primary production (NPP) with forest age is often attributed to a corresponding decline in gross primary production (GPP). We tested two hypotheses explaining the decline of GPP in ageing stands (14-115 years old) of Pinus taeda L.: (1) increasing N limitation limits photosynthetic capacity and thus decreases GPP with increasing age; and (2) hydraulic limitations increasingly induce stomatal closure, reducing GPP with increasing age. We tested these hypotheses using measurements of foliar nitrogen, photosynthesis, sap-flow and dendroclimatological techniques. Hypothesis (1) was not supported; foliar N retranslocation did not increase and declines were not observed in foliar N, leaf area per tree or photosynthetic capacity. Hypothesis (2) was supported; declines were observed in light-saturated photosynthesis, leaf- and canopy-level stomatal conductance, concentration of CO(2) inside leaf air-spaces (corroborated by an increase in wood δ(13) C) and specific leaf area (SLA), while stomatal limitation and the ratio of sapwood area (SA) to leaf area increased. The sensitivity of radial growth to inter-annual variation in temperature and drought decreased with age, suggesting that tree water use becomes increasingly conservative with age. We conclude that hydraulic limitation increasingly limits the photosynthetic rates of ageing loblolly pine trees, possibly explaining the observed reduction of NPP.
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Affiliation(s)
- J E Drake
- Program of Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana-Champaign, IL 61802, USA
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Oldham AR, Sillett SC, Tomescu AMF, Koch GW. The hydrostatic gradient, not light availability, drives height-related variation in Sequoia sempervirens (Cupressaceae) leaf anatomy. AMERICAN JOURNAL OF BOTANY 2010; 97:1087-1097. [PMID: 21616861 DOI: 10.3732/ajb.0900214] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PREMISE OF THE STUDY Leaves at the tops of most trees are smaller, thicker, and in many other ways different from leaves on the lowermost branches. This height-related variation in leaf structure has been explained as acclimation to differing light environments and, alternatively, as a consequence of hydrostatic, gravitational constraints on turgor pressure that reduce leaf expansion. • METHODS To separate hydrostatic effects from those of light availability, we used anatomical analysis of height-paired samples from the inner and outer tree crowns of tall redwoods (Sequoia sempervirens). • KEY RESULTS Height above the ground correlates much more strongly with leaf anatomy than does light availability. Leaf length, width, and mesophyll porosity all decrease linearly with height and help explain increases in leaf-mass-to-area ratio and decreases in both photosynthetic capacity and internal gas-phase conductance with increasing height. Two functional traits-leaf thickness and transfusion tissue-also increase with height and may improve water-stress tolerance. Transfusion tissue area increases enough that whole-leaf vascular volume does not change significantly with height in most trees. Transfusion tracheids become deformed with height, suggesting they may collapse under water stress and act as a hydraulic buffer that improves leaf water status and reduces the likelihood of xylem dysfunction. • CONCLUSIONS That such variation in leaf structure may be caused more by gravity than by light calls into question use of the terms "sun" and "shade" to describe leaves at the tops and bottoms of tall tree crowns.
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Affiliation(s)
- Alana R Oldham
- Department of Biological Sciences, Humboldt State University, Arcata, California 95521 USA
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36
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Niklas KJ, Cobb ED. Ontogenetic changes in the numbers of short- vs. long-shoots account for decreasing specific leaf area in Acer rubrum (Aceraceae) as trees increase in size. AMERICAN JOURNAL OF BOTANY 2010; 97:27-37. [PMID: 21622364 DOI: 10.3732/ajb.0900249] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Specific leaf area (SLA) is reported to decrease with increasing plant size among dicot tree species despite a strong positive correlation between SLA and relative growth rate. This diminishing returns in SLA may result from changes in the relative numbers of different shoot types bearing leaves with different SLAs as trees increase in overall size. This ontogenetic shift hypothesis was examined for 15 Acer rubrum trees differing in basal stem diameter (0.01 m ≤ D ≤ 0.62 m). Detailed analyses of the largest tree showed that short-shoots produced leaves with significantly smaller SLA than the leaves produced by long-shoots regardless of the location of shoots within the canopy. A combination of random effect and split-plot (main-effect) ANOVA models showed that >94% of the variance observed for SLA was attributable to shoot type rather than to the location of leaves in the canopy. Further, with increasing trunk diameter, the number of short-shoots increased rapidly relative to the number of long-shoots. Although the leaves of short-shoots gain disproportionately more surface area per unit mass investment compared to the leaves produced by long-shoots, our data show that ontogenetic shifts occurring at the shoot and whole plant level account for size-dependent decreases in total canopy SLA.
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Affiliation(s)
- Karl J Niklas
- Department of Plant Biology, Cornell University, Ithaca, New York 14853 USA
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