1
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Kašpar J, Krůček M, Král K. The effects of solar radiation on daily and seasonal stem increment of canopy trees in European temperate old-growth forests. THE NEW PHYTOLOGIST 2024; 243:662-673. [PMID: 38769735 DOI: 10.1111/nph.19852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 05/05/2024] [Indexed: 05/22/2024]
Abstract
It is well established that solar irradiance greatly influences tree metabolism and growth through photosynthesis, but its effects acting through individual climate metrics have not yet been well quantified. Understanding these effects is crucial for assessing the impacts of climate change on forest ecosystems. To describe the effects of solar irradiance on tree growth, we installed 110 automatic dendrometers in two old-growth mountain forest reserves in Central Europe, performed detailed terrestrial and aerial laser scanning to obtain precise tree profiles, and used these to simulate the sum of solar irradiance received by each tree on a daily basis. Generalized linear mixed-effect models were applied to simulate the probability of growth and the growth intensity over seven growing seasons. Our results demonstrated various contrasting effects of solar irradiance on the growth of canopy trees. On the one hand, the highest daily growth rates corresponded with the highest solar irradiance potentials (i.e. the longest photoperiod). Intense solar irradiance significantly decreased tree growth, through an increase in the vapor pressure deficit. These effects were consistent for all species but had different magnitude. Tree growth is the most effective on long rainy/cloudy days with low solar irradiance.
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Affiliation(s)
- Jakub Kašpar
- Department of Forest Ecology, The Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Lidická 25-27, 602 00, Brno, Czech Republic
| | - Martin Krůček
- Department of Forest Ecology, The Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Lidická 25-27, 602 00, Brno, Czech Republic
| | - Kamil Král
- Department of Forest Ecology, The Silva Tarouca Research Institute for Landscape and Ornamental Gardening, Lidická 25-27, 602 00, Brno, Czech Republic
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2
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Sun W, Maseyk K, Lett C, Seibt U. Restricted internal diffusion weakens transpiration-photosynthesis coupling during heatwaves: Evidence from leaf carbonyl sulphide exchange. PLANT, CELL & ENVIRONMENT 2024; 47:1813-1833. [PMID: 38321806 DOI: 10.1111/pce.14840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 11/13/2023] [Accepted: 01/22/2024] [Indexed: 02/08/2024]
Abstract
Increasingly frequent and intense heatwaves threaten ecosystem health in a warming climate. However, plant responses to heatwaves are poorly understood. A key uncertainty concerns the intensification of transpiration when heatwaves suppress photosynthesis, known as transpiration-photosynthesis decoupling. Field observations of such decoupling are scarce, and the underlying physiological mechanisms remain elusive. Here, we use carbonyl sulphide (COS) as a leaf gas exchange tracer to examine potential mechanisms leading to transpiration-photosynthesis decoupling on a coast live oak in a southern California woodland in spring 2013. We found that heatwaves suppressed both photosynthesis and leaf COS uptake but increased transpiration or sustained it at non-heatwave levels throughout the day. Despite statistically significant decoupling between transpiration and photosynthesis, stomatal sensitivity to environmental factors did not change during heatwaves. Instead, midday photosynthesis during heatwaves was restricted by internal diffusion, as indicated by the lower internal conductance to COS. Thus, increased evaporative demand and nonstomatal limitation to photosynthesis act jointly to decouple transpiration from photosynthesis without altering stomatal sensitivity. Decoupling offered limited potential cooling benefits, questioning its effectiveness for leaf thermoregulation in xeric ecosystems. We suggest that adding COS to leaf and ecosystem flux measurements helps elucidate diverse physiological mechanisms underlying transpiration-photosynthesis decoupling.
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Affiliation(s)
- Wu Sun
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California, USA
| | - Kadmiel Maseyk
- School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, UK
| | - Céline Lett
- Department of Environmental Research and Innovation, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
| | - Ulli Seibt
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California, USA
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3
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Fletcher C, Ripple WJ, Newsome T, Barnard P, Beamer K, Behl A, Bowen J, Cooney M, Crist E, Field C, Hiser K, Karl DM, King DA, Mann ME, McGregor DP, Mora C, Oreskes N, Wilson M. Earth at risk: An urgent call to end the age of destruction and forge a just and sustainable future. PNAS NEXUS 2024; 3:pgae106. [PMID: 38566756 PMCID: PMC10986754 DOI: 10.1093/pnasnexus/pgae106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Human development has ushered in an era of converging crises: climate change, ecological destruction, disease, pollution, and socioeconomic inequality. This review synthesizes the breadth of these interwoven emergencies and underscores the urgent need for comprehensive, integrated action. Propelled by imperialism, extractive capitalism, and a surging population, we are speeding past Earth's material limits, destroying critical ecosystems, and triggering irreversible changes in biophysical systems that underpin the Holocene climatic stability which fostered human civilization. The consequences of these actions are disproportionately borne by vulnerable populations, further entrenching global inequities. Marine and terrestrial biomes face critical tipping points, while escalating challenges to food and water access foreshadow a bleak outlook for global security. Against this backdrop of Earth at risk, we call for a global response centered on urgent decarbonization, fostering reciprocity with nature, and implementing regenerative practices in natural resource management. We call for the elimination of detrimental subsidies, promotion of equitable human development, and transformative financial support for lower income nations. A critical paradigm shift must occur that replaces exploitative, wealth-oriented capitalism with an economic model that prioritizes sustainability, resilience, and justice. We advocate a global cultural shift that elevates kinship with nature and communal well-being, underpinned by the recognition of Earth's finite resources and the interconnectedness of its inhabitants. The imperative is clear: to navigate away from this precipice, we must collectively harness political will, economic resources, and societal values to steer toward a future where human progress does not come at the cost of ecological integrity and social equity.
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Affiliation(s)
- Charles Fletcher
- School of Ocean and Earth Science and Technology, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - William J Ripple
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - Thomas Newsome
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
| | - Phoebe Barnard
- Center for Environmental Politics and School of Interdisciplinary Arts and Sciences, University of Washington, Seattle, WA 98195, USA
- African Climate and Development Initiative and FitzPatrick Institute, University of Cape Town, Cape Town 7700, South Africa
| | - Kamanamaikalani Beamer
- Hui ‘Āina Momona Program, Richardson School of Law, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
- Hawai‘inuiākea School of Hawaiian Knowledge, Kamakakūokalani Center for Hawaiian Studies, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - Aishwarya Behl
- School of Ocean and Earth Science and Technology, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - Jay Bowen
- Institute of American Indian Arts, Santa Fe, NM 87508, USA
- Upper Skagit Tribe, Sedro Woolley, WA 98284, USA
| | - Michael Cooney
- School of Ocean and Earth Science and Technology, Hawai‘i Natural Energy Institute, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - Eileen Crist
- Department of Science Technology and Society, Virginia Tech, Blacksburg, VA 24060, USA
| | - Christopher Field
- Doerr School for Sustainability, Stanford Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA
| | - Krista Hiser
- Department of Languages, Linguistics, and Literature, Kapi‘olani Community College, Honolulu, HI 96816, USA
- Global Council for Science and the Environment, Washington, DC 20006, USA
| | - David M Karl
- Department of Oceanography, School of Ocean and Earth Science and Technology, Honolulu, HI 96822, USA
- Daniel K. Inouye Center for Microbial Oceanography, Research and Education, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - David A King
- Department of Chemistry, University of Cambridge, Cambridge CB2 1DQ, UK
| | - Michael E Mann
- Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Davianna P McGregor
- Department of Ethnic Studies, Center for Oral History, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - Camilo Mora
- Department of Geography and Environment, University of Hawai‘i at Mānoa, Honolulu, HI 96822, USA
| | - Naomi Oreskes
- Department of the History of Science, Harvard University, Cambridge, MA 02138, USA
| | - Michael Wilson
- Associate Justice, Hawaii Supreme Court (retired), Honolulu, HI 96813, USA
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4
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Griffani DS, Rognon P, Farquhar GD. The role of thermodiffusion in transpiration. THE NEW PHYTOLOGIST 2024. [PMID: 38453691 DOI: 10.1111/nph.19642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/28/2024] [Indexed: 03/09/2024]
Abstract
Plant leaf temperatures can differ from ambient air temperatures. A temperature gradient in a gas mixture gives rise to a phenomenon known as thermodiffusion, which operates in addition to ordinary diffusion. Whilst transpiration is generally understood to be driven solely by the ordinary diffusion of water vapour along a concentration gradient, we consider the implications of thermodiffusion for transpiration. We develop a new modelling framework that introduces the effects of thermodiffusion on the transpiration rate, E. By applying this framework, we quantify the proportion of E attributable to thermodiffusion for a set of physiological and environmental conditions, varied over a wide range. Thermodiffusion is found to be most significant (in some cases > 30% of E) when a leaf-to-air temperature difference coincides with a relatively small water vapour concentration difference across the boundary layer; a boundary layer conductance that is large as compared to the stomatal conductance; or a relatively low transpiration rate. Thermodiffusion also alters the conditions required for the onset of reverse transpiration, and the rate at which this water vapour uptake occurs.
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Affiliation(s)
- Danielle S Griffani
- Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW, 2480, Australia
| | - Pierre Rognon
- School of Civil Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
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5
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Herrera CM. Refrigerated flowers in the torrid Mediterranean summer. Ecology 2024; 105:e4268. [PMID: 38350709 DOI: 10.1002/ecy.4268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/30/2023] [Accepted: 01/19/2024] [Indexed: 02/15/2024]
Affiliation(s)
- Carlos M Herrera
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
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6
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Kullberg AT, Coombs L, Soria Ahuanari RD, Fortier RP, Feeley KJ. Leaf thermal safety margins decline at hotter temperatures in a natural warming 'experiment' in the Amazon. THE NEW PHYTOLOGIST 2024; 241:1447-1463. [PMID: 37984063 DOI: 10.1111/nph.19413] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/28/2023] [Indexed: 11/22/2023]
Abstract
The threat of rising global temperatures may be especially pronounced for low-latitude, lowland plant species that have evolved under stable climatic conditions. However, little is known about how these species may acclimate to elevated temperatures. Here, we leveraged a strong, steep thermal gradient along a natural geothermal river to assess the ability of woody plants in the Amazon to acclimate to elevated air temperatures. We measured leaf traits in six common tropical woody species along the thermal gradient to investigate whether individuals of these species: acclimate their thermoregulatory traits to maintain stable leaf temperatures despite higher ambient temperatures; acclimate their photosynthetic thermal tolerances to withstand hotter leaf temperatures; and whether acclimation is sufficient to maintain stable leaf thermal safety margins (TSMs) across different growth temperatures. Individuals of three species acclimated their thermoregulatory traits, and three species increased their thermal tolerances with growth temperature. However, acclimation was generally insufficient to maintain constant TSMs. Notwithstanding, leaf health was generally consistent across growth temperatures. Acclimation in woody Amazonian plants is generally too weak to maintain TSMs at high growth temperatures, supporting previous findings that Amazonian plants will be increasingly vulnerable to thermal stress as temperatures rise.
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Affiliation(s)
- Alyssa T Kullberg
- Department of Biology, University of Miami, Coral Gables, FL, 33146, USA
| | - Lauren Coombs
- Hussman Institute of Human Genomics, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Roy D Soria Ahuanari
- Herbario Regional de Ucayali IVITA, Pucallpa (HRUIP), Universidad Nacional Mayor de San Marcos, Pucallpa, 25001, Peru
| | - Riley P Fortier
- Department of Biology, University of Miami, Coral Gables, FL, 33146, USA
| | - Kenneth J Feeley
- Department of Biology, University of Miami, Coral Gables, FL, 33146, USA
- Fairchild Tropical Botanic Garden, Coral Gables, FL, 33156, USA
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7
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Zhu L, Scafaro AP, Vierling E, Ball MC, Posch BC, Stock F, Atkin OK. Heat tolerance of a tropical-subtropical rainforest tree species Polyscias elegans: time-dependent dynamic responses of physiological thermostability and biochemistry. THE NEW PHYTOLOGIST 2024; 241:715-731. [PMID: 37932881 DOI: 10.1111/nph.19356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 10/01/2023] [Indexed: 11/08/2023]
Abstract
Heat stress interrupts physiological thermostability and triggers biochemical responses that are essential for plant survival. However, there is limited knowledge on the speed plants adjust to heat in hours and days, and which adjustments are crucial. Tropical-subtropical rainforest tree species (Polyscias elegans) were heated at 40°C for 5 d, before returning to 25°C for 13 d of recovery. Leaf heat tolerance was quantified using the temperature at which minimal chl a fluorescence sharply rose (Tcrit ). Tcrit , metabolites, heat shock protein (HSP) abundance and membrane lipid fatty acid (FA) composition were quantified. Tcrit increased by 4°C (48-52°C) within 2 h of 40°C exposure, along with rapid accumulation of metabolites and HSPs. By contrast, it took > 2 d for FA composition to change. At least 2 d were required for Tcrit , HSP90, HSP70 and FAs to return to prestress levels. The results highlight the multi-faceted response of P. elegans to heat stress, and how this response varies over the scale of hours to days, culminating in an increased level of photosynthetic heat tolerance. These responses are important for survival of plants when confronted with heat waves amidst ongoing global climate change.
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Affiliation(s)
- Lingling Zhu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, 159 Longpan Road, Nanjing, 210037, China
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
| | - Andrew P Scafaro
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Marilyn C Ball
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
| | - Bradley C Posch
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
- Department of Research, Conservation, and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - Frederike Stock
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
- Australian Plant Phenomics Facility, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
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8
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Lamour J, Souza DC, Gimenez BO, Higuchi N, Chave J, Chambers J, Rogers A. Wood-density has no effect on stomatal control of leaf-level water use efficiency in an Amazonian forest. PLANT, CELL & ENVIRONMENT 2023; 46:3806-3821. [PMID: 37635450 DOI: 10.1111/pce.14704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/20/2023] [Accepted: 08/16/2023] [Indexed: 08/29/2023]
Abstract
Forest disturbances increase the proportion of fast-growing tree species compared to slow-growing ones. To understand their relative capacity for carbon uptake and their vulnerability to climate change, and to represent those differences in Earth system models, it is necessary to characterise the physiological differences in their leaf-level control of water use efficiency and carbon assimilation. We used wood density as a proxy for the fast-slow growth spectrum and tested the assumption that trees with a low wood density (LWD) have a lower water-use efficiency than trees with a high wood density (HWD). We selected 5 LWD tree species and 5 HWD tree species growing in the same location in an Amazonian tropical forest and measured in situ steady-state gas exchange on top-of-canopy leaves with parallel sampling and measurement of leaf mass area and leaf nitrogen content. We found that LWD species invested more nitrogen in photosynthetic capacity than HWD species, had higher photosynthetic rates and higher stomatal conductance. However, contrary to expectations, we showed that the stomatal control of the balance between transpiration and carbon assimilation was similar in LWD and HWD species and that they had the same dark respiration rates.
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Affiliation(s)
- Julien Lamour
- Department of Environmental & Climate Sciences, Brookhaven National Laboratory, Upton, New York, USA
- Evolution and Biological Diversity (EDB), CNRS/IRD/UPS, Toulouse, France
| | - Daisy C Souza
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
| | - Bruno O Gimenez
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
- Department of Geography, University of California, Berkeley, California, USA
| | - Niro Higuchi
- National Institute of Amazonian Research (INPA), Forest Management Laboratory (LMF), Manaus, Amazonas, Brazil
| | - Jérôme Chave
- Evolution and Biological Diversity (EDB), CNRS/IRD/UPS, Toulouse, France
| | - Jeffrey Chambers
- Department of Geography, University of California, Berkeley, California, USA
| | - Alistair Rogers
- Department of Environmental & Climate Sciences, Brookhaven National Laboratory, Upton, New York, USA
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9
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Moran ME, Aparecido LMT, Koepke DF, Cooper HF, Doughty CE, Gehring CA, Throop HL, Whitham TG, Allan GJ, Hultine KR. Limits of thermal and hydrological tolerance in a foundation tree species (Populus fremontii) in the desert southwestern United States. THE NEW PHYTOLOGIST 2023; 240:2298-2311. [PMID: 37680030 DOI: 10.1111/nph.19247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/05/2023] [Indexed: 09/09/2023]
Abstract
Populus fremontii is among the most dominant, and ecologically important riparian tree species in the western United States and can thrive in hyper-arid riparian corridors. Yet, P. fremontii forests have rapidly declined over the last decade, particularly in places where temperatures sometimes exceed 50°C. We evaluated high temperature tolerance of leaf metabolism, leaf thermoregulation, and leaf hydraulic function in eight P. fremontii populations spanning a 5.3°C mean annual temperature gradient in a well-watered common garden, and at source locations throughout the lower Colorado River Basin. Two major results emerged. First, despite having an exceptionally high Tcrit (the temperature at which Photosystem II is disrupted) relative to other tree taxa, recent heat waves exceeded Tcrit , requiring evaporative leaf cooling to maintain leaf-to-air thermal safety margins. Second, in midsummer, genotypes from the warmest locations maintained lower midday leaf temperatures, a higher midday stomatal conductance, and maintained turgor pressure at lower water potentials than genotypes from more temperate locations. Taken together, results suggest that under well-watered conditions, P. fremontii can regulate leaf temperature below Tcrit along the warm edge of its distribution. Nevertheless, reduced Colorado River flows threaten to lower water tables below levels needed for evaporative cooling during episodic heat waves.
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Affiliation(s)
- Madeline E Moran
- School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Luiza M T Aparecido
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Dan F Koepke
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - Hillary F Cooper
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Christopher E Doughty
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Catherine A Gehring
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Heather L Throop
- School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Thomas G Whitham
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Gerard J Allan
- Department of Biological Sciences and Center for Adaptable Western Landscapes, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
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10
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Javadian M, Scott RL, Biederman JA, Zhang F, Fisher JB, Reed SC, Potts DL, Villarreal ML, Feldman AF, Smith WK. Thermography captures the differential sensitivity of dryland functional types to changes in rainfall event timing and magnitude. THE NEW PHYTOLOGIST 2023; 240:114-126. [PMID: 37434275 DOI: 10.1111/nph.19127] [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: 05/11/2023] [Accepted: 06/21/2023] [Indexed: 07/13/2023]
Abstract
Drylands of the southwestern United States are rapidly warming, and rainfall is becoming less frequent and more intense, with major yet poorly understood implications for ecosystem structure and function. Thermography-based estimates of plant temperature can be integrated with air temperature to infer changes in plant physiology and response to climate change. However, very few studies have evaluated plant temperature dynamics at high spatiotemporal resolution in rainfall pulse-driven dryland ecosystems. We address this gap by incorporating high-frequency thermal imaging into a field-based precipitation manipulation experiment in a semi-arid grassland to investigate the impacts of rainfall temporal repackaging. All other factors held constant, we found that fewer/larger precipitation events led to cooler plant temperatures (1.4°C) compared to that of many/smaller precipitation events. Perennials, in particular, were 2.5°C cooler than annuals under the fewest/largest treatment. We show these patterns were driven by: increased and consistent soil moisture availability in the deeper soil layers in the fewest/largest treatment; and deeper roots of perennials providing access to deeper plant available water. Our findings highlight the potential for high spatiotemporal resolution thermography to quantify the differential sensitivity of plant functional groups to soil water availability. Detecting these sensitivities is vital to understanding the ecohydrological implications of hydroclimate change.
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Affiliation(s)
- Mostafa Javadian
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - Russell L Scott
- Southwest Watershed Research Center, USDA Agricultural Research Service, Tucson, AZ, 85719, USA
| | - Joel A Biederman
- Southwest Watershed Research Center, USDA Agricultural Research Service, Tucson, AZ, 85719, USA
| | - Fangyue Zhang
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
- Southwest Watershed Research Center, USDA Agricultural Research Service, Tucson, AZ, 85719, USA
| | - Joshua B Fisher
- Schmid College of Science and Technology, Chapman University, Orange, CA, 92866, USA
| | - Sasha C Reed
- Southwest Biological Science Center, US Geological Survey, Moab, UT, 84532, USA
| | - Daniel L Potts
- Biology Department, SUNY Buffalo State, Buffalo, NY, 14222, USA
| | - Miguel L Villarreal
- Western Geographic Science Center, US Geological Survey, Moffett Field, CA, 94035, USA
| | - Andrew F Feldman
- Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
- NASA Postdoctoral Program, NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - William K Smith
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
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11
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Gauthey A, Bachofen C, Deluigi J, Didion-Gency M, D'Odorico P, Gisler J, Mas E, Schaub M, Schuler P, Still CJ, Tunas A, Grossiord C. Absence of canopy temperature variation despite stomatal adjustment in Pinus sylvestris under multidecadal soil moisture manipulation. THE NEW PHYTOLOGIST 2023; 240:127-137. [PMID: 37483100 DOI: 10.1111/nph.19136] [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: 04/20/2023] [Accepted: 06/23/2023] [Indexed: 07/25/2023]
Abstract
Global warming and droughts push forests closer to their thermal limits, altering tree carbon uptake and growth. To prevent critical overheating, trees can adjust their thermotolerance (Tcrit ), temperature and photosynthetic optima (Topt and Aopt ), and canopy temperature (Tcan ) to stay below damaging thresholds. However, we lack an understanding of how soil droughts affect photosynthetic thermal plasticity and Tcan regulation. In this study, we measured the effect of soil moisture on the seasonal and diurnal dynamics of net photosynthesis (A), stomatal conductance (gs ), and Tcan , as well as the thermal plasticity of photosynthesis (Tcrit , Topt , and Aopt ), over the course of 1 yr using a long-term irrigation experiment in a drought-prone Pinus sylvestris forest in Switzerland. Irrigation resulted in higher needle-level A, gs , Topt , and Aopt compared with naturally drought-exposed trees. No daily or seasonal differences in Tcan were observed between treatments. Trees operated below their thermal thresholds (Tcrit ), independently of soil moisture content. Despite strong Tcan and Tair coupling, we provide evidence that drought reduces trees' temperature optimum due to a substantial reduction of gs during warm and dry periods of the year. These findings provide important insights regarding the effects of soil drought on the thermal tolerance of P. sylvestris.
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Affiliation(s)
- Alice Gauthey
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Christoph Bachofen
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Janisse Deluigi
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Margaux Didion-Gency
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Petra D'Odorico
- Land Change Science Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Jonas Gisler
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Eugénie Mas
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Marcus Schaub
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Philipp Schuler
- Forest Dynamics Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, 97331, OR, USA
| | - Alex Tunas
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, Lausanne, CH-1015, Switzerland
- Community Ecology Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, CH-8903, Switzerland
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12
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Crous KY, Cheesman AW, Middleby K, Rogers EIE, Wujeska-Klause A, Bouet AYM, Ellsworth DS, Liddell MJ, Cernusak LA, Barton CVM. Similar patterns of leaf temperatures and thermal acclimation to warming in temperate and tropical tree canopies. TREE PHYSIOLOGY 2023; 43:1383-1399. [PMID: 37099805 PMCID: PMC10423462 DOI: 10.1093/treephys/tpad054] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 03/22/2023] [Accepted: 04/17/2023] [Indexed: 06/19/2023]
Abstract
As the global climate warms, a key question is how increased leaf temperatures will affect tree physiology and the coupling between leaf and air temperatures in forests. To explore the impact of increasing temperatures on plant performance in open air, we warmed leaves in the canopy of two mature evergreen forests, a temperate Eucalyptus woodland and a tropical rainforest. The leaf heaters consistently maintained leaves at a target of 4 °C above ambient leaf temperatures. Ambient leaf temperatures (Tleaf) were mostly coupled to air temperatures (Tair), but at times, leaves could be 8-10 °C warmer than ambient air temperatures, especially in full sun. At both sites, Tleaf was warmer at higher air temperatures (Tair > 25 °C), but was cooler at lower Tair, contrary to the 'leaf homeothermy hypothesis'. Warmed leaves showed significantly lower stomatal conductance (-0.05 mol m-2 s-1 or -43% across species) and net photosynthesis (-3.91 μmol m-2 s-1 or -39%), with similar rates in leaf respiration rates at a common temperature (no acclimation). Increased canopy leaf temperatures due to future warming could reduce carbon assimilation via reduced photosynthesis in these forests, potentially weakening the land carbon sink in tropical and temperate forests.
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Affiliation(s)
- K Y Crous
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - A W Cheesman
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - K Middleby
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - E I E Rogers
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - A Wujeska-Klause
- Urban Studies, School of Social Science, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - A Y M Bouet
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - D S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
| | - M J Liddell
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - L A Cernusak
- Centre for Tropical Environmental and Sustainability Science (TESS) and College of Science and Engineering, James Cook University, Cairns, Queensland 4878, Australia
| | - C V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales 2751, Australia
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13
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Scafaro AP, Posch BC, Evans JR, Farquhar GD, Atkin OK. Rubisco deactivation and chloroplast electron transport rates co-limit photosynthesis above optimal leaf temperature in terrestrial plants. Nat Commun 2023; 14:2820. [PMID: 37198175 DOI: 10.1038/s41467-023-38496-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/03/2023] [Indexed: 05/19/2023] Open
Abstract
Net photosynthetic CO2 assimilation rate (An) decreases at leaf temperatures above a relatively mild optimum (Topt) in most higher plants. This decline is often attributed to reduced CO2 conductance, increased CO2 loss from photorespiration and respiration, reduced chloroplast electron transport rate (J), or deactivation of Ribulose-1,5-bisphosphate Carboxylase Oxygenase (Rubisco). However, it is unclear which of these factors can best predict species independent declines in An at high temperature. We show that independent of species, and on a global scale, the observed decline in An with rising temperatures can be effectively accounted for by Rubisco deactivation and declines in J. Our finding that An declines with Rubisco deactivation and J supports a coordinated down-regulation of Rubisco and chloroplast electron transport rates to heat stress. We provide a model that, in the absence of CO2 supply limitations, can predict the response of photosynthesis to short-term increases in leaf temperature.
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Affiliation(s)
- Andrew P Scafaro
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia.
- Centre for Entrepreneurial Agri-Technology, Gould Building, Australian National University, Canberra, 2601, Australia.
| | - Bradley C Posch
- Department of Research, Collections and Conservation, Desert Botanical Garden, Phoenix, AZ, USA
| | - John R Evans
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Graham D Farquhar
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Owen K Atkin
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Centre for Entrepreneurial Agri-Technology, Gould Building, Australian National University, Canberra, 2601, Australia
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14
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Guo Z, Still CJ, Lee CKF, Ryu Y, Blonder B, Wang J, Bonebrake TC, Hughes A, Li Y, Yeung HCH, Zhang K, Law YK, Lin Z, Wu J. Does plant ecosystem thermoregulation occur? An extratropical assessment at different spatial and temporal scales. THE NEW PHYTOLOGIST 2023; 238:1004-1018. [PMID: 36495263 DOI: 10.1111/nph.18632] [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: 08/09/2022] [Accepted: 11/11/2022] [Indexed: 06/17/2023]
Abstract
To what degree plant ecosystems thermoregulate their canopy temperature (Tc ) is critical to assess ecosystems' metabolisms and resilience with climate change, but remains controversial, with opinions from no to moderate thermoregulation capability. With global datasets of Tc , air temperature (Ta ), and other environmental and biotic variables from FLUXNET and satellites, we tested the 'limited homeothermy' hypothesis (indicated by Tc & Ta regression slope < 1 or Tc < Ta around midday) across global extratropics, including temporal and spatial dimensions. Across daily to weekly and monthly timescales, over 80% of sites/ecosystems have slopes ≥1 or Tc > Ta around midday, rejecting the above hypothesis. For those sites unsupporting the hypothesis, their Tc -Ta difference (ΔT) exhibits considerable seasonality that shows negative, partial correlations with leaf area index, implying a certain degree of thermoregulation capability. Spatially, site-mean ΔT exhibits larger variations than the slope indicator, suggesting ΔT is a more sensitive indicator for detecting thermoregulatory differences across biomes. Furthermore, this large spatial-wide ΔT variation (0-6°C) is primarily explained by environmental variables (38%) and secondarily by biotic factors (15%). These results demonstrate diverse thermoregulation patterns across global extratropics, with most ecosystems negating the 'limited homeothermy' hypothesis, but their thermoregulation still occurs, implying that slope < 1 or Tc < Ta are not necessary conditions for plant thermoregulation.
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Affiliation(s)
- Zhengfei Guo
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Christopher J Still
- Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
| | - Calvin K F Lee
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Youngryel Ryu
- Department of Landscape Architecture and Rural Systems Engineering, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul, South Korea
| | - Benjamin Blonder
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, 94720, USA
| | - Jing Wang
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Timothy C Bonebrake
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
| | - Alice Hughes
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
| | - Yan Li
- State Key Laboratory of Earth Surface Processes and Resources Ecology, Beijing Normal University, Beijing, 100875, China
| | - Henry C H Yeung
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Kun Zhang
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Department of Mathematics, The University of Hong Kong, Hong Kong, China
| | - Ying Ki Law
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Ziyu Lin
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Jin Wu
- School for Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
- Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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15
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Drake JE. A data-intensive documentation of plant ecosystem thermoregulation across spatial and temporal scales. THE NEW PHYTOLOGIST 2023; 238:921-923. [PMID: 36920400 DOI: 10.1111/nph.18819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Affiliation(s)
- John E Drake
- Department of Sustainable Resources Management, State University of New York College of Environmental Science and Forestry (SUNY-ESF), 1 Forestry Drive, Syracuse, NY, 13210, USA
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16
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Still CJ, Sibley A, DePinte D, Busby PE, Harrington CA, Schulze M, Shaw DR, Woodruff D, Rupp DE, Daly C, Hammond WM, Page GFM. Causes of widespread foliar damage from the June 2021 Pacific Northwest Heat Dome: more heat than drought. TREE PHYSIOLOGY 2023; 43:203-209. [PMID: 36611006 DOI: 10.1093/treephys/tpac143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Affiliation(s)
- C J Still
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - A Sibley
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - D DePinte
- US Department of Agriculture, Forest Service, Pacific Northwest Region, State & Private Forestry, Forest Health Protection, Redmond, OR 97756, USA
| | - P E Busby
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - C A Harrington
- US Department of Agriculture, Forest Service, Pacific Northwest Research Station, Olympia, WA 98512, USA
| | - M Schulze
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
| | - D R Shaw
- Department of Forest Engineering, Resources, and Management, Oregon State University, Corvallis, OR 97331, USA
| | - D Woodruff
- US Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331, USA
| | - D E Rupp
- Oregon Climate Change Research Institute, College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - C Daly
- PRISM Climate Group, Northwest Alliance for Computational Science and Engineering, Oregon State University, Corvallis, OR 97331, USA
| | - W M Hammond
- Agronomy Department, University of Florida, Institute of Food and Agricultural Sciences, Gainesville, FL 32611, USA
| | - G F M Page
- Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, Locked Bag 104, Bentley Delivery Centre, Bentley, Western Australia 6983, Australia
- CSIRO Land and Water, Private Bag 5, Wembley, Western Australia 6913, Australia
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