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Manzi OJL, Wittemann M, Dusenge ME, Habimana J, Manishimwe A, Mujawamariya M, Ntirugulirwa B, Zibera E, Tarvainen L, Nsabimana D, Wallin G, Uddling J. Canopy temperatures strongly overestimate leaf thermal safety margins of tropical trees. THE NEW PHYTOLOGIST 2024. [PMID: 39073111 DOI: 10.1111/nph.20013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 07/07/2024] [Indexed: 07/30/2024]
Abstract
Current estimates of temperature effects on plants mostly rely on air temperature, although it can significantly deviate from leaf temperature (Tleaf). To address this, some studies have used canopy temperature (Tcan). However, Tcan fails to capture the fine-scale variation in Tleaf among leaves and species in diverse canopies. We used infrared radiometers to study Tleaf and Tcan and how they deviate from air temperature (ΔTleaf and ΔTcan) in multispecies tropical tree plantations at three sites along an elevation and temperature gradient in Rwanda. Our results showed high Tleaf (up to c. 50°C) and ΔTleaf (on average 8-10°C and up to c. 20°C) of sun-exposed leaves during 10:00 h-15:00 h, being close to or exceeding photosynthetic heat tolerance thresholds. These values greatly exceeded simultaneously measured values of Tcan and ΔTcan, respectively, leading to strongly overestimated leaf thermal safety margins if basing those on Tcan data. Stomatal conductance and leaf size affected Tleaf and Tcan in line with their expected influences on leaf energy balance. Our findings highlight the importance of leaf traits for leaf thermoregulation and show that monitoring Tcan is not enough to capture the peak temperatures and heat stress experienced by individual leaves of different species in tropical forest canopies.
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Affiliation(s)
- Olivier Jean Leonce Manzi
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
- Integrated Polytechnic Regional College-Kitabi, Rwanda Polytechnic, PO Box 330, Huye, Rwanda
| | - Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
| | - Mirindi Eric Dusenge
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
- Department of Biology, Mount Allison University, Sackville, NB, E4L 1E4, Canada
| | - Jacques Habimana
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
| | - Aloysie Manishimwe
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Avenue de l'Armée, PO Box 3900, Kigali, Rwanda
| | - Myriam Mujawamariya
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Avenue de l'Armée, PO Box 3900, Kigali, Rwanda
| | - Bonaventure Ntirugulirwa
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
- Department of Biology, College of Science and Technology, University of Rwanda, Avenue de l'Armée, PO Box 3900, Kigali, Rwanda
- Rwanda Agriculture and Animal Resources Development Board, PO Box 5016, Kigali, Rwanda
- Rwanda Forestry Authority, PO Box 46, Muhanga, Rwanda
| | - Etienne Zibera
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
- School of Agriculture and Food Sciences, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, PO Box 210, Musanze, Rwanda
| | - Lasse Tarvainen
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
| | - Donat Nsabimana
- School of Forestry and Biodiversity Conservation, College of Agriculture, Animal Sciences and Veterinary Medicine, University of Rwanda, PO Box 210, Musanze, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, Gothenburg, SE-405 30, Sweden
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2
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Branch HA, Moxley DR, Angert AL. Regional differences in leaf evolution facilitate photosynthesis following severe drought. THE NEW PHYTOLOGIST 2024. [PMID: 39021265 DOI: 10.1111/nph.19963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/21/2024] [Indexed: 07/20/2024]
Abstract
Characterizing physiological and anatomical changes that underlie rapid evolution following climatic perturbation can broaden our understanding of how climate change is affecting biodiversity. It can also provide evidence of cryptic adaptation despite stasis at higher levels of biological organization. Here, we compared evolutionary changes in populations of Mimulus cardinalis from historically different climates in the north and south of the species' range following an exceptional drought. We grew seeds produced from predrought ancestral plants alongside peak-drought descendants in a common glasshouse and exposed them to wet and dry conditions. Before the drought, northern ancestral populations expressed traits contributing to drought escape, while southern ancestral populations expressed drought avoidance. Following the drought, both regions evolved to reduce water loss and maintain photosynthesis in dry treatments (drought avoidance), but via different anatomical alterations in stomata, trichomes, and palisade mesophyll. Additionally, southern populations lost the ability to take advantage of wet conditions. These results reveal rapid evolution towards drought avoidance at an anatomical level following an exceptional drought, but suggest that differences in the mechanisms between regions incur different trade-offs. This sheds light on the importance of characterizing underlying mechanisms for downstream life-history and macromorphological traits.
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Affiliation(s)
- Haley A Branch
- Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Dylan R Moxley
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Amy L Angert
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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3
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Ning QR, Li Q, Zhang HP, Jin Y, Gong XW, Jiao RF, Bakpa EP, Zhao H, Liu H. Weak correlations among leaf thermal metrics, economic traits and damages under natural heatwaves. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:170022. [PMID: 38220006 DOI: 10.1016/j.scitotenv.2024.170022] [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: 11/13/2023] [Revised: 12/29/2023] [Accepted: 01/07/2024] [Indexed: 01/16/2024]
Abstract
The frequency and intensity of heatwaves are increasing around the world, causing severe damages to plants, but whether leaf thermal metrics is in line with leaf economic spectrum is still controversial. Here, we measured leaf damage ratio, leaf thermal metrics (tolerance and sensitivity) and economic traits of 131 woody species across five cities along the Yangtze River after a two-month natural extreme temperature event. We found that leaf thermal sensitivity but not thermal tolerance was correlated with leaf damage ratio, and the relationships between leaf thermal metrics and economic traits were weak, indicating that leaf thermal adaptation may be independent from leaf carbon construction. This study suggests a potential indicator for predicting plant survival under heatwaves, urging future research to explore more physiological traits to comprehensively understand plant heat responses and adaptations.
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Affiliation(s)
- Qiu-Rui Ning
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Qiang Li
- School of Tropical Medicine, Hainan Medical University, Haikou, China
| | - Hao-Ping Zhang
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Yi Jin
- Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China
| | - Xue-Wei Gong
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Rui-Fang Jiao
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Emily Patience Bakpa
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Han Zhao
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Hui Liu
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, State Key Laboratory of Plant Diversity and Specialty Crops, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; Key Laboratory of National Forestry and Grassland Administration on Plant Conservation and Utilization in Southern China, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
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4
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Mateus-Rodríguez JF, Lahive F, Hadley P, Daymond AJ. Effects of simulated climate change conditions of increased temperature and [CO2] on the early growth and physiology of the tropical tree crop, Theobroma cacao L. TREE PHYSIOLOGY 2023; 43:2050-2063. [PMID: 37758447 PMCID: PMC10714407 DOI: 10.1093/treephys/tpad116] [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: 08/09/2023] [Accepted: 09/18/2023] [Indexed: 10/03/2023]
Abstract
Despite multiple studies of the impact of climate change on temperate tree species, experiments on tropical and economically important tree crops, such as cacao (Theobroma cacao L.), are still limited. Here, we investigated the combined effects of increased temperature and atmospheric carbon dioxide concentration ([CO2]) on the growth, photosynthesis and development of juvenile plants of two contrasting cacao genotypes: SCA 6 and PA 107. The factorial growth chamber experiment combined two [CO2] treatments (410 and 700 p.p.m.) and three day/night temperature regimes (control: 31/22 °C, control + 2.5 °C: 33.5/24.5 °C and control + 5.0 °C: 36/27 °C) at a constant vapour pressure deficit (VPD) of 0.9 kPa. At elevated [CO2], the final dry weight and the total and individual leaf areas increased in both genotypes, while the duration for individual leaf expansion declined in PA 107. For both genotypes, elevated [CO2] also improved light-saturated net photosynthesis (Pn) and intrinsic water-use efficiency (iWUE), whereas leaf transpiration (E) and stomatal conductance (gs) decreased. Under a constant low VPD, increasing temperatures above 31/22 °C enhanced the rates of Pn, E and gs in both genotypes, suggesting that photosynthesis responds positively to higher temperatures than previously reported for cacao. However, dry weight and the total and individual leaf areas declined with increases in temperature, which was more evident in SCA 6 than PA 107, suggesting the latter genotype was more tolerant to elevated temperature. Our results suggest that the combined effect of elevated [CO2] and temperature is likely to improve the early growth of high temperature-tolerant genotypes, while elevated [CO2] appeared to ameliorate the negative effects of increased temperatures on growth parameters of more sensitive material. The evident genotypic variation observed in this study demonstrates the scope to select and breed cacao varieties capable of adapting to future climate change scenarios.
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Affiliation(s)
- Julián Fernando Mateus-Rodríguez
- Centro de Investigación Palmira, Corporación Colombiana de Investigación Agropecuaria – AGROSAVIA, Intersección Carrera 36A con Calle 23, Palmira, Valle del Cauca, Postcode 753533, Colombia
| | - Fiona Lahive
- School of Agriculture, Policy and Development, University of Reading, Earley Gate, Reading RG6 6EU, UK
| | - Paul Hadley
- School of Agriculture, Policy and Development, University of Reading, Earley Gate, Reading RG6 6EU, UK
| | - Andrew J Daymond
- School of Agriculture, Policy and Development, University of Reading, Earley Gate, Reading RG6 6EU, UK
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5
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Kullberg AT, Feeley KJ. Limited acclimation of leaf traits and leaf temperatures in a subtropical urban heat island. TREE PHYSIOLOGY 2022; 42:2266-2281. [PMID: 35708568 DOI: 10.1093/treephys/tpac066] [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: 12/20/2021] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
The consequences of rising temperatures for trees will vary between species based on their abilities to acclimate their leaf thermoregulatory traits and photosynthetic thermal tolerances. We tested the hypotheses that adult trees in warmer growing conditions (i) acclimate their thermoregulatory traits to regulate leaf temperatures, (ii) acclimate their thermal tolerances such that tolerances are positively correlated with leaf temperature and (iii) that species with broader thermal niche breadths have greater acclimatory abilities. To test these hypotheses, we measured leaf traits and thermal tolerances of seven focal tree species across steep thermal gradients in Miami's urban heat island. We found that some functional traits varied significantly across air temperatures within species. For example, leaf thickness increased with maximum air temperature in three species, and leaf mass per area and leaf reflectance both increased with air temperature in one species. Only one species was marginally more homeothermic than expected by chance due to acclimation of its thermoregulatory traits, but this acclimation was insufficient to offset elevated air temperatures. Thermal tolerances acclimated to higher maximum air temperatures in two species. As a result of limited acclimation, leaf thermal safety margins (TSMs) were narrower for trees in hotter areas. We found some support for our hypothesis that species with broader thermal niches are better at acclimating to maintain more stable TSMs across the temperature gradients. These findings suggest that trees have limited abilities to acclimate to high temperatures and that thermal niche specialists may be at a heightened risk of thermal stress as global temperatures continue to rise.
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Affiliation(s)
- Alyssa T Kullberg
- 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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6
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Li X, Wen Y, Chen X, Qie Y, Cao KF, Wee AKS. Correlations between photosynthetic heat tolerance and leaf anatomy and climatic niche in Asian mangrove trees. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:960-966. [PMID: 35962602 DOI: 10.1111/plb.13460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
Photosynthetic heat tolerance (PHT ) is a key predictor of plant response to climate change. Mangroves are an ecologically and economically important coastal plant community comprised of trees growing at their physiological limits. Mangroves are currently impacted by global warming, yet the PHT of mangrove trees is poorly understood. In this study, we provide the first assessment of PHT in 13 Asian mangrove species, based on the critical temperature that causes the initial damage (TCrit ) and the temperature that causes 50% damage (T50 ) to photosystem II. We tested the hypotheses that the PHT in mangroves is: (i) correlated with climatic niche and leaf traits, and (ii) higher than in plants from other tropical ecosystems. Our results demonstrated correlations between PHT and multiple key climate variables, the palisade to spongy mesophyll ratio and the leaf area. The two most heat-sensitive species were Kandelia obovata and Avicennia marina. Our study also revealed that mangrove trees show high heat tolerance compared to plants from other tropical ecosystems. The high PHT of mangroves thus demonstrated a conservative evolutionary strategy in heat tolerance, and highlights the need for integrative and comparative studies on thermoregulatory traits and climatic niche in order to understand the physiological response of mangrove trees to climate change-driven heatwaves and rising global temperatures.
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Affiliation(s)
- X Li
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - Y Wen
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - X Chen
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - Y Qie
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - K-F Cao
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - A K S Wee
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
- School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Jalan Broga, Semenyih, Malaysia
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7
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Warming Responses of Leaf Morphology Are Highly Variable among Tropical Tree Species. FORESTS 2022. [DOI: 10.3390/f13020219] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Leaf morphological traits vary along climate gradients, but it is currently unclear to what extent this results from acclimation rather than adaptation. Knowing so is important for predicting the functioning of long-lived organisms, such as trees, in a rapidly changing climate. We investigated the leaf morphological warming responses of 18 tropical tree species with early (ES) abd late (LS) successional strategies, planted at three sites along an elevation gradient from 2400 m a.s.l. (15.2 °C mean temperature) to 1300 m a.s.l. (20.6 °C mean temperature) in Rwanda. Leaf size expressed as leaf area (LA) and leaf mass per area (LMA) decreased, while leaf width-to-length ratio (W/L) increased with warming, but only for one third to half of the species. While LA decreased in ES species, but mostly not in LS species, changes in LMA and leaf W/L were common in both successional groups. ES species had lower LMA and higher LA and leaf W/L compared to LS species. Values of LMA and LA of juvenile trees in this study were mostly similar to corresponding data on four mature tree species in another elevation-gradient study in Rwanda, indicating that our results are applicable also to mature forest trees. We conclude that leaf morphological responses to warming differ greatly between both successional groups and individual species, with potential consequences for species competitiveness and community composition in a warmer climate.
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Tarvainen L, Wittemann M, Mujawamariya M, Manishimwe A, Zibera E, Ntirugulirwa B, Ract C, Manzi OJL, Andersson MX, Spetea C, Nsabimana D, Wallin G, Uddling J. Handling the heat - photosynthetic thermal stress in tropical trees. THE NEW PHYTOLOGIST 2022; 233:236-250. [PMID: 34655491 DOI: 10.1111/nph.17809] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/09/2021] [Indexed: 06/13/2023]
Abstract
Warming climate increases the risk for harmful leaf temperatures in terrestrial plants, causing heat stress and loss of productivity. The heat sensitivity may be particularly high in equatorial tropical tree species adapted to a thermally stable climate. Thermal thresholds of the photosynthetic system of sun-exposed leaves were investigated in three tropical montane tree species native to Rwanda with different growth and water use strategies (Harungana montana, Syzygium guineense and Entandrophragma exselsum). Measurements of chlorophyll fluorescence, leaf gas exchange, morphology, chemistry and temperature were made at three common gardens along an elevation/temperature gradient. Heat tolerance acclimated to maximum leaf temperature (Tleaf ) across the species. At the warmest sites, the thermal threshold for normal function of photosystem II was exceeded in the species with the highest Tleaf despite their higher heat tolerance. This was not the case in the species with the highest transpiration rates and lowest Tleaf . The results point to two differently effective strategies for managing thermal stress: tolerance through physiological adjustment of leaf osmolality and thylakoid membrane lipid composition, or avoidance through morphological adaptation and transpiratory cooling. More severe photosynthetic heat stress in low-transpiring montane climax species may result in a competitive disadvantage compared to high-transpiring pioneer species with more efficient leaf cooling.
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Affiliation(s)
- Lasse Tarvainen
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Maria Wittemann
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Myriam Mujawamariya
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Aloysie Manishimwe
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Etienne Zibera
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Bonaventure Ntirugulirwa
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
- Rwanda Agriculture and Animal Development Board, PO Box 5016, Kigali, Rwanda
| | - Claire Ract
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Olivier J L Manzi
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
- Department of Biology, University of Rwanda, University Avenue, PO Box 117, Huye, Rwanda
| | - Mats X Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Donat Nsabimana
- School of Forestry and Biodiversity and Biological Sciences, University of Rwanda, Busogo, Rwanda
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
| | - Johan Uddling
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Gothenburg, SE-405 30, Sweden
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Slot M, Cala D, Aranda J, Virgo A, Michaletz ST, Winter K. Leaf heat tolerance of 147 tropical forest species varies with elevation and leaf functional traits, but not with phylogeny. PLANT, CELL & ENVIRONMENT 2021; 44:2414-2427. [PMID: 33817813 DOI: 10.1111/pce.14060] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
Exceeding thermal thresholds causes irreversible damage and ultimately loss of leaves. The lowland tropics are among the warmest forested biomes, but little is known about heat tolerance of tropical forest plants. We surveyed leaf heat tolerance of sun-exposed leaves from 147 tropical lowland and pre-montane forest species by determining the temperatures at which potential photosystem II efficiency based on chlorophyll a fluorescence started to decrease (TCrit ) and had decreased by 50% (T50 ). TCrit averaged 46.7°C (5th-95th percentile: 43.5°C-49.7°C) and T50 averaged 49.9°C (47.8°C-52.5°C). Heat tolerance partially adjusted to site temperature; TCrit and T50 decreased with elevation by 0.40°C and 0.26°C per 100 m, respectively, while mean annual temperature decreased by 0.63°C per 100 m. The phylogenetic signal in heat tolerance was weak, suggesting that heat tolerance is more strongly controlled by environment than by evolutionary legacies. TCrit increased with the estimated thermal time constant of the leaves, indicating that species with thermally buffered leaves maintain higher heat tolerance. Among lowland species, T50 increased with leaf mass per area, suggesting that in species with structurally more costly leaves the risk of leaf loss during hot spells is reduced. These results provide insight in variation in heat tolerance at local and regional scales.
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Affiliation(s)
- Martijn Slot
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Daniela Cala
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
- Paul H. O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana, USA
| | - Jorge Aranda
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Aurelio Virgo
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Sean T Michaletz
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Klaus Winter
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
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10
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Tserej O, Feeley KJ. Variation in leaf temperatures of tropical and subtropical trees are related to leaf thermoregulatory traits and not geographic distributions. Biotropica 2021. [DOI: 10.1111/btp.12919] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Olga Tserej
- Biology Department University of Miami Coral Gables FL USA
- Fairchild Tropical Botanic Garden Coral Gables FL USA
| | - Kenneth J. Feeley
- Biology Department University of Miami Coral Gables FL USA
- Fairchild Tropical Botanic Garden Coral Gables FL USA
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