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Wittemann M, Mujawamariya M, Ntirugulirwa B, Uwizeye FK, Zibera E, Manzi OJL, Nsabimana D, Wallin G, Uddling J. Plasticity and implications of water-use traits in contrasting tropical tree species under climate change. PHYSIOLOGIA PLANTARUM 2024; 176:e14326. [PMID: 38708565 DOI: 10.1111/ppl.14326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 04/12/2024] [Indexed: 05/07/2024]
Abstract
Plants face a trade-off between hydraulic safety and growth, leading to a range of water-use strategies in different species. However, little is known about such strategies in tropical trees and whether different water-use traits can acclimate to warming. We studied five water-use traits in 20 tropical tree species grown at three different altitudes in Rwanda (RwandaTREE): stomatal conductance (gs), leaf minimum conductance (gmin), plant hydraulic conductance (Kplant), leaf osmotic potential (ψo) and net defoliation during drought. We also explored the links between these traits and growth and mortality data. Late successional (LS) species had low Kplant, gs and gmin and, thus, low water loss, while low ψo helped improve leaf water status during drought. Early successional (ES) species, on the contrary, used more water during both moist and dry conditions and exhibited pronounced drought defoliation. The ES strategy was associated with lower mortality and more pronounced growth enhancement at the warmer sites compared to LS species. While Kplant and gmin showed downward acclimation in warmer climates, ψo did not acclimate and gs measured at prevailing temperature did not change. Due to distinctly different water use strategies between successional groups, ES species may be better equipped for a warmer climate as long as defoliation can bridge drought periods.
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Affiliation(s)
- Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Myriam Mujawamariya
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
| | - Bonaventure Ntirugulirwa
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
- Rwanda Agriculture and Animal Resources Development Board (RAB), Kigali, Rwanda
- Rwanda Forestry Authority, Muhanga, Rwanda
| | - Felicien K Uwizeye
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Etienne Zibera
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Olivier Jean Leonce Manzi
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Integrated Polytechnic Regional College-Kitabi, Rwanda Polytechnic, Huye, Rwanda
| | - Donat Nsabimana
- School of Forestry and Biodiversity and Biological Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
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2
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Cox AJF, González-Caro S, Meir P, Hartley IP, Restrepo Z, Villegas JC, Sanchez A, Mercado LM. Variable thermal plasticity of leaf functional traits in Andean tropical montane forests. PLANT, CELL & ENVIRONMENT 2024; 47:731-750. [PMID: 38047584 DOI: 10.1111/pce.14778] [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: 06/14/2023] [Revised: 11/08/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
Tropical montane forests (TMFs) are biodiversity hotspots and provide vital ecosystem services, but they are disproportionately vulnerable to climate warming. In the Andes, cold-affiliated species from high elevations are being displaced at the hot end of their thermal distributions by warm-affiliated species migrating upwards from lower elevations, leading to compositional shifts. Leaf functional traits are strong indicators of plant performance and at the community level have been shown to vary along elevation gradients, reflecting plant adaptations to different environmental niches. However, the plastic response of such traits to relatively rapid temperature change in Andean TMF species remains unknown. We used three common garden plantations within a thermosequence in the Colombian Andes to investigate the warming and cooling responses of key leaf functional traits in eight cold- and warm-affiliated species with variable thermal niches. Cold-affiliated species shifted their foliar nutrient concentrations when exposed to warming, while all other traits did not significantly change; contrastingly, warm-affiliated species were able to adjust structural, nutrient and water-use efficiency traits from acquisitive to conservative strategies in response to cooling. Our findings suggest that cold-affiliated species will struggle to acclimate functional traits to warming, conferring warm-affiliated species a competitive advantage under climate change.
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Affiliation(s)
- Andrew J F Cox
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Sebastián González-Caro
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, UK
- Division of Plant Sciences, Research, The Australian National University, Canberra, Australia
| | - Iain P Hartley
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
| | - Zorayda Restrepo
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
- Grupo de Servicios Ecositémicos y Cambio Climático, Corporación, Medellín, Colombia
| | - Juan C Villegas
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
| | - Adriana Sanchez
- Programa de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Lina M Mercado
- Department of Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, UK
- UK Centre for Ecology & Hydrology, Crowmarsh-Gifford, Wallingford, UK
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3
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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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Feeley KJ, Bernal-Escobar M, Fortier R, Kullberg AT. Tropical Trees Will Need to Acclimate to Rising Temperatures-But Can They? PLANTS (BASEL, SWITZERLAND) 2023; 12:3142. [PMID: 37687387 PMCID: PMC10490527 DOI: 10.3390/plants12173142] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023]
Abstract
For tropical forests to survive anthropogenic global warming, trees will need to avoid rising temperatures through range shifts and "species migrations" or tolerate the newly emerging conditions through adaptation and/or acclimation. In this literature review, we synthesize the available knowledge to show that although many tropical tree species are shifting their distributions to higher, cooler elevations, the rates of these migrations are too slow to offset ongoing changes in temperatures, especially in lowland tropical rainforests where thermal gradients are shallow or nonexistent. We also show that the rapidity and severity of global warming make it unlikely that tropical tree species can adapt (with some possible exceptions). We argue that the best hope for tropical tree species to avoid becoming "committed to extinction" is individual-level acclimation. Although several new methods are being used to test for acclimation, we unfortunately still do not know if tropical tree species can acclimate, how acclimation abilities vary between species, or what factors may prevent or facilitate acclimation. Until all of these questions are answered, our ability to predict the fate of tropical species and tropical forests-and the many services that they provide to humanity-remains critically impaired.
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Affiliation(s)
- Kenneth J. Feeley
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA; (M.B.-E.); (R.F.); (A.T.K.)
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Dusenge ME, Warren JM, Reich PB, Ward EJ, Murphy BK, Stefanski A, Bermudez R, Cruz M, McLennan DA, King AW, Montgomery RA, Hanson PJ, Way DA. Boreal conifers maintain carbon uptake with warming despite failure to track optimal temperatures. Nat Commun 2023; 14:4667. [PMID: 37537190 PMCID: PMC10400668 DOI: 10.1038/s41467-023-40248-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 07/13/2023] [Indexed: 08/05/2023] Open
Abstract
Warming shifts the thermal optimum of net photosynthesis (ToptA) to higher temperatures. However, our knowledge of this shift is mainly derived from seedlings grown in greenhouses under ambient atmospheric carbon dioxide (CO2) conditions. It is unclear whether shifts in ToptA of field-grown trees will keep pace with the temperatures predicted for the 21st century under elevated atmospheric CO2 concentrations. Here, using a whole-ecosystem warming controlled experiment under either ambient or elevated CO2 levels, we show that ToptA of mature boreal conifers increased with warming. However, shifts in ToptA did not keep pace with warming as ToptA only increased by 0.26-0.35 °C per 1 °C of warming. Net photosynthetic rates estimated at the mean growth temperature increased with warming in elevated CO2 spruce, while remaining constant in ambient CO2 spruce and in both ambient CO2 and elevated CO2 tamarack with warming. Although shifts in ToptA of these two species are insufficient to keep pace with warming, these boreal conifers can thermally acclimate photosynthesis to maintain carbon uptake in future air temperatures.
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Affiliation(s)
- Mirindi Eric Dusenge
- Department of Biology, Mount Allison University, Sackville, NB, E4L 1E4, Canada.
- Western Centre for Climate Change, Sustainable Livelihoods and Health, Department of Geography and Environment, The University of Western Ontario, London, ON, N6G 2V4, Canada.
- Department of Biology, The University of Western Ontario, London, ON, N6A 3K7, Canada.
| | - Jeffrey M Warren
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, Saint Paul, MN, 55108, USA
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW, 2753, Australia
- Institute for Global Change Biology, and School for the Environment and Sustainability, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Eric J Ward
- US Geological Survey, Wetland and Aquatic Research Center, Lafayette, LA, USA
| | - Bridget K Murphy
- Department of Biology, The University of Western Ontario, London, ON, N6A 3K7, Canada
- Department of Biology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Graduate Program in Cell and Systems Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada
| | - Artur Stefanski
- Department of Forest Resources, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Raimundo Bermudez
- Department of Forest Resources, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Marisol Cruz
- Departamento de Ciencias Biologicas, Universidad de Los Andes, Bogota, Colombia
| | - David A McLennan
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Anthony W King
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Rebecca A Montgomery
- Department of Forest Resources, University of Minnesota, Saint Paul, MN, 55108, USA
| | - Paul J Hanson
- Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Danielle A Way
- Department of Biology, The University of Western Ontario, London, ON, N6A 3K7, Canada.
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia.
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA.
- Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973, USA.
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6
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Cox AJF, Hartley IP, Meir P, Sitch S, Dusenge ME, Restrepo Z, González-Caro S, Villegas JC, Uddling J, Mercado LM. Acclimation of photosynthetic capacity and foliar respiration in Andean tree species to temperature change. THE NEW PHYTOLOGIST 2023; 238:2329-2344. [PMID: 36987979 DOI: 10.1111/nph.18900] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/13/2023] [Indexed: 05/19/2023]
Abstract
Climate warming is causing compositional changes in Andean tropical montane forests (TMFs). These shifts are hypothesised to result from differential responses to warming of cold- and warm-affiliated species, with the former experiencing mortality and the latter migrating upslope. The thermal acclimation potential of Andean TMFs remains unknown. Along a 2000 m Andean altitudinal gradient, we planted individuals of cold- and warm-affiliated species (under common soil and irrigation), exposing them to the hot and cold extremes of their thermal niches, respectively. We measured the response of net photosynthesis (Anet ), photosynthetic capacity and leaf dark respiration (Rdark ) to warming/cooling, 5 months after planting. In all species, Anet and photosynthetic capacity at 25°C were highest when growing at growth temperatures (Tg ) closest to their thermal means, declining with warming and cooling in cold-affiliated and warm-affiliated species, respectively. When expressed at Tg , photosynthetic capacity and Rdark remained unchanged in cold-affiliated species, but the latter decreased in warm-affiliated counterparts. Rdark at 25°C increased with temperature in all species, but remained unchanged when expressed at Tg . Both species groups acclimated to temperature, but only warm-affiliated species decreased Rdark to photosynthetic capacity ratio at Tg as temperature increased. This could confer them a competitive advantage under future warming.
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Affiliation(s)
- Andrew J F Cox
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
| | - Iain P Hartley
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, EH9 3JN, UK
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Stephen Sitch
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
| | - Mirindi Eric Dusenge
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, The University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Zorayda Restrepo
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
- UK Centre for Ecology and Hydrology, Crowmarsh-Gifford, Wallingford, OX10 8BB, UK
| | - Sebastian González-Caro
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
- UK Centre for Ecology and Hydrology, Crowmarsh-Gifford, Wallingford, OX10 8BB, UK
| | - Juan Camilo Villegas
- Grupo de Investigación en Ecología Aplicada, Universidad de Antioquia, Medellín, Colombia
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Lina M Mercado
- Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter, EX4 4RKJ, UK
- UK Centre for Ecology and Hydrology, Crowmarsh-Gifford, Wallingford, OX10 8BB, UK
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Spiers JA, Oatham MP, Rostant LV, Farrell AD. Determining the ecophysiological limits of a narrow niche tropical conifer tree (Podocarpus trinitensis). TREE PHYSIOLOGY 2023; 43:781-793. [PMID: 36585840 DOI: 10.1093/treephys/tpac151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 12/06/2022] [Accepted: 12/23/2022] [Indexed: 05/13/2023]
Abstract
Many tropical species live close to their thermal limits within a narrow niche. Here, we investigate the ecophysiological limits of the tropical tree Podocarpus trinitensis, which is endemic to Trinidad and Tobago where most populations exist as isolated stands on hilltops. Five wild stands from a range of elevations were compared in the field with measurements of leaf temperature, canopy cover, stomatal conductance (gs), chlorophyll content and several chlorophyll fluorescence parameters. A parallel greenhouse experiment was used to acclimate seedlings to 'CONTROL' and 'HEAT' treatments (with mid-day air temperatures of 34.5 and 37 °C respectively), after which the above parameters were measured along with photosynthetic light and temperature response curves, leaf morphology and in vitro Fv/Fm thermostability. There was a positive association between improved physiological performance and elevation. In the high elevation sites, leaf temperatures were significantly lower while most of the physiological parameters were higher (gs, chlorophyll content, ɸ PSII, ETRmax and Isat90). In the greenhouse, HEAT and CONTROL plants were similar for most parameters, except leaf temperature (which was coupled with air temperature) and leaf mass per unit area (which was higher in HEAT plants). Temperature response curves showed an optimum temperature for photosynthesis of 30 ± 0.5 °C (TOpt) and in vitro Fv/Fm indicated a critical temperature of 47.4 ± 0.38 °C for HEAT and 48.2 ± 0.24 °C for CONTROL (T50), with no indication of heat acclimation. Podocarpus trinitensis was found to be shade tolerant. In the field, seedlings established under a close canopy (>95% canopy cover) and had a low light saturation point (LCP). In the greenhouse, where more light was available, seedlings retained a low light compensation point, light saturation point (LSP) and maximum photosynthetic rate (Amax). The results suggest that P. trinitensis is moderately heat tolerant with the higher elevation sites being more habitable, but stands are also able to survive near sea level under a closed canopy. The narrow niche, along with the 30 ± 0.5 °C optimum temperature for photosynthesis and the lack of thermal plasticity in critical temperature, suggests that P. trinitensis has little room to acclimate to temperatures higher than those currently experienced.
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Affiliation(s)
- Joshua A Spiers
- Department of Life Sciences, University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Michael P Oatham
- Department of Life Sciences, University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Luke V Rostant
- Department of Life Sciences, University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
| | - Aidan D Farrell
- Department of Life Sciences, University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
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8
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Mujawamariya M, Wittemann M, Dusenge ME, Manishimwe A, Ntirugulirwa B, Zibera E, Nsabimana D, Wallin G, Uddling J. Contrasting warming responses of photosynthesis in early- and late-successional tropical trees. TREE PHYSIOLOGY 2023:tpad035. [PMID: 36971469 DOI: 10.1093/treephys/tpad035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/01/2023] [Indexed: 06/18/2023]
Abstract
The productivity and climate feedbacks of tropical forests depend on tree physiological responses to warmer and, over large areas, seasonally drier conditions. However, knowledge regarding such responses is limited due to data scarcity. We studied the impact of growth temperature on net photosynthesis (An), maximum rates of Rubisco carboxylation at 25°C (Vcmax25), stomatal conductance (gs) and the slope parameter of the stomatal conductance-photosynthesis model (g1), in ten early- (ES) and eight late-successional (LS) tropical tree species grown at three sites along an elevation gradient in Rwanda, differing by 6.8°C in daytime ambient air temperature. The effect of seasonal drought on An was also investigated. We found that warm climate decreased wet-season An in LS species, but not in ES species. Values of Vcmax25 were lower at the warmest site across both successional groups, and An and Vcmax25 were higher in ES compared to LS species. Stomatal conductance exhibited no significant site differences and g1 was similar across both sites and successional groups. Drought strongly reduced An at warmer sites but not at the coolest montane site and this response was similar in both ES and LS species. Our results suggest that warming has negative effects on leaf-level photosynthesis in LS species, while both LS and ES species suffer photosynthesis declines in a warmer climate with more pronounced droughts. The contrasting responses of An between successional groups may lead to shifts in species' competitive balance in a warmer world, to the disadvantage of LS trees.
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Affiliation(s)
- Myriam Mujawamariya
- Department of Biology, College of Science and Technology, University of Rwanda, Avenue de l'Armée, Kigali P.O.Box 3900, Rwanda
- Center of Excellence in Biodiversity Conservation and Natural Resources Management, College of Science and Technology, University of Rwanda, Avenue de l'Armée, Kigali P.O.Box 3900, Rwanda
- Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Gothenburg, Sweden
| | - Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Gothenburg, Sweden
| | - Mirindi Eric Dusenge
- Western Center for Climate Change, Sustainable Livelihoods and Health, Department of Geography, The University of Western Ontario, London, Ontario, Canada
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, United Kingdom
| | - Aloysie Manishimwe
- Department of Biology, College of Science and Technology, University of Rwanda, Avenue de l'Armée, Kigali P.O.Box 3900, Rwanda
- Center of Excellence in Biodiversity Conservation and Natural Resources Management, College of Science and Technology, University of Rwanda, Avenue de l'Armée, Kigali P.O.Box 3900, Rwanda
- Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Gothenburg, Sweden
| | - Bonaventure Ntirugulirwa
- Department of Biology, College of Science and Technology, University of Rwanda, Avenue de l'Armée, Kigali P.O.Box 3900, Rwanda
- Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Gothenburg, Sweden
- Rwanda Forestry Authority, Muhanga P.O. Box 46, Rwanda
| | - Etienne Zibera
- School of Forestry and Biodiversity, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze P.O. Box 210, Rwanda
| | - Donat Nsabimana
- Center of Excellence in Biodiversity Conservation and Natural Resources Management, College of Science and Technology, University of Rwanda, Avenue de l'Armée, Kigali P.O.Box 3900, Rwanda
- School of Forestry and Biodiversity, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, Musanze P.O. Box 210, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Gothenburg, Sweden
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, OX1 3QY, United Kingdom
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, P.O. Box 461, SE-405 30 Gothenburg, Sweden
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