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Zotz G, Andrade JL, Einzmann HJR. CAM plants: their importance in epiphyte communities and prospects with global change. ANNALS OF BOTANY 2023; 132:685-698. [PMID: 36617243 PMCID: PMC10799991 DOI: 10.1093/aob/mcac158] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/08/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND AND SCOPE The epiphytic life form characterizes almost 10 % of all vascular plants. Defined by structural dependence throughout their life and their non-parasitic relationship with the host, the term epiphyte describes a heterogeneous and taxonomically diverse group of plants. This article reviews the importance of crassulacean acid metabolism (CAM) among epiphytes in current climatic conditions and explores the prospects under global change. RESULTS AND CONCLUSIONS We question the view of a disproportionate importance of CAM among epiphytes and its role as a 'key innovation' for epiphytism but do identify ecological conditions in which epiphytic existence seems to be contingent on the presence of this photosynthetic pathway. Possibly divergent responses of CAM and C3 epiphytes to future changes in climate and land use are discussed with the help of experimental evidence, current distributional patterns and the results of several long-term descriptive community studies. The results and their interpretation aim to stimulate a fruitful discussion on the role of CAM in epiphytes in current climatic conditions and in altered climatic conditions in the future.
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Affiliation(s)
- Gerhard Zotz
- Functional Ecology Group, Institute of Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Box 5634, D-26046 Oldenburg, Germany
- Smithsonian Tropical Research Institute, Box 0843-03092, Panama, Republic of Panama
| | - José Luis Andrade
- Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, Calle 43 No. 130, Chuburná de Hidalgo, Mérida, Yucatán, Mexico
| | - Helena J R Einzmann
- Functional Ecology Group, Institute of Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Box 5634, D-26046 Oldenburg, Germany
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Luján M, Leverett A, Winter K. Forty years of research into crassulacean acid metabolism in the genus Clusia: anatomy, ecophysiology and evolution. ANNALS OF BOTANY 2023; 132:739-752. [PMID: 36891814 PMCID: PMC10799992 DOI: 10.1093/aob/mcad039] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/21/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Clusia is the only genus containing dicotyledonous trees with a capacity to perform crassulacean acid metabolism (CAM). Since the discovery of CAM in Clusia 40 years ago, several studies have highlighted the extraordinary plasticity and diversity of life forms, morphology and photosynthetic physiology of this genus. In this review, we revisit aspects of CAM photosynthesis in Clusia and hypothesize about the timing, the environmental conditions and potential anatomical characteristics that led to the evolution of CAM in the group. We discuss the role of physiological plasticity in influencing species distribution and ecological amplitude in the group. We also explore patterns of allometry of leaf anatomical traits and their correlations with CAM activity. Finally, we identify opportunities for further research on CAM in Clusia, such as the role of elevated nocturnal accumulation of citric acid, and gene expression in C3-CAM intermediate phenotypes.
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Affiliation(s)
- Manuel Luján
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, UK
| | - Alistair Leverett
- School of Life Sciences, University of Essex, Colchester, Essex CO4 3SQ, UK
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancón, Republic of Panama
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3
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Paula Oliveira R, Zotz G, Wanek W, Franco AC. Leaf trait co‐variation and trade‐offs in gallery forest C
3
and CAM epiphytes. Biotropica 2021. [DOI: 10.1111/btp.12895] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Gerhard Zotz
- Department of Biology and Environmental Sciences University of Oldenburg Oldenburg Germany
| | - Wolfgang Wanek
- Department of Microbiology and Ecosystem Science University of Vienna Vienna Austria
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Huang J, Liu W, Li S, Song L, Lu H, Shi X, Chen X, Hu T, Liu S, Liu T. Ecological stoichiometry of the epiphyte community in a subtropical forest canopy. Ecol Evol 2019; 9:14394-14406. [PMID: 31938527 PMCID: PMC6953686 DOI: 10.1002/ece3.5875] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 10/31/2019] [Accepted: 11/04/2019] [Indexed: 11/06/2022] Open
Abstract
Epiphytes in tree canopies make a considerable contribution to the species diversity, aboveground biomass, and nutrient pools in forest ecosystems. However, the nutrient status of epiphytes and their possible adaptations to nutrient deficiencies in the forest canopy remain unclear. Therefore, we analyzed the stoichiometry of five macroelements (C, N, P, K, and Ca) in four taxonomic groups (lichens, bryophytes, ferns, and spermatophytes) to investigate this issue in a subtropical montane moist evergreen broad-leaved forest in Southwest China. We found that the interspecific variations in element concentrations and mass ratios were generally greater than the intraspecific variations. And there were significant stoichiometric differences among functional groups. Allometric relationships between N and P across the epiphyte community indicated that P might be in greater demand than N with an increase in nutrients. Although canopy nutrients were deficient, most epiphytes could still maintain high N and P concentrations and low N:P ratios. Moreover, ferns and spermatophytes allocated more limited nutrients to leaves than to stems and roots. To alleviate frequent drought stress in the forest canopy, vascular epiphytes maintained several times higher K concentrations in their leaves than in the tissues of lichens and bryophytes. Our results suggest that epiphytes may have evolved specific nutrient characteristics and adaptations, so that they can distribute in heterogeneous canopy habitats and maintain the stability of nutrient metabolism.
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Affiliation(s)
- Jun‐Biao Huang
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- University of Chinese Academy of SciencesBeijingChina
| | - Wen‐Yao Liu
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- Center of Plant EcologyCore Botanical GardensChinese Academy of SciencesXishuangbannaChina
| | - Su Li
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- Center of Plant EcologyCore Botanical GardensChinese Academy of SciencesXishuangbannaChina
| | - Liang Song
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- Center of Plant EcologyCore Botanical GardensChinese Academy of SciencesXishuangbannaChina
| | - Hua‐Zheng Lu
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- Center of Plant EcologyCore Botanical GardensChinese Academy of SciencesXishuangbannaChina
| | - Xian‐Meng Shi
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- University of Chinese Academy of SciencesBeijingChina
| | - Xi Chen
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- University of Chinese Academy of SciencesBeijingChina
| | - Tao Hu
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- University of Chinese Academy of SciencesBeijingChina
| | - Shuai Liu
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- University of Chinese Academy of SciencesBeijingChina
| | - Tao Liu
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaChina
- University of Chinese Academy of SciencesBeijingChina
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5
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Niechayev NA, Jones AM, Rosenthal DM, Davis SC. A model of environmental limitations on production of Agave americana L. grown as a biofuel crop in semi-arid regions. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6549-6559. [PMID: 30597061 PMCID: PMC6883261 DOI: 10.1093/jxb/ery383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 11/02/2018] [Indexed: 05/10/2023]
Abstract
Plants that use crassulacean acid metabolism (CAM) have the potential to meet growing agricultural resource demands using land that is considered unsuitable for many common crop species. Agave americana L., an obligate CAM plant, has potential as an advanced biofuel crop in water-limited regions, and has greater cold tolerance than other high-yielding CAM species, but physiological tolerances have not been completely resolved. We developed a model to estimate the growth responses of A. americana to water input, temperature, and photosynthetically active radiation (PAR). The photosynthetic response to PAR was determined experimentally by measuring the integrated leaf gas exchange over 24 h after acclimation to six light levels. Maximum CO2 fixation rates were observed at a PAR intensity of 1250 µmol photons m-2 s-1. Growth responses of A. americana to water and temperature were also determined, and a monthly environmental productivity index (EPI) was derived that can be used to predict biomass growth. The EPI was calculated as the product of water, temperature, and light indices estimated for conditions at a site in Maricopa (Arizona), and compared with measured biomass at the same site (where the first field trial of A. americana as a crop was completed). The monthly EPI summed over the lifetime of multi-year crops was highly correlated with the average measured biomass of healthy 2- and 3-year-old plants grown in the field. The resulting relationship between EPI and biomass provides a simple model for estimating the production of A. americana at a monthly time step according to light, temperature, and precipitation inputs, and is a useful tool for projecting the potential geographic range of this obligate CAM species in future climatic conditions.
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Affiliation(s)
- Nicholas A Niechayev
- Voinovich School of Leadership and Public Affairs, Ohio University, Athens, OH, USA
| | - Alexander M Jones
- Voinovich School of Leadership and Public Affairs, Ohio University, Athens, OH, USA
| | - David M Rosenthal
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, USA
| | - Sarah C Davis
- Voinovich School of Leadership and Public Affairs, Ohio University, Athens, OH, USA
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, USA
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Batke S, Holohan A, Hayden R, Fricke W, Porter AS, Evans-Fitz.Gerald CM. The Pressure Is On - Epiphyte Water-Relations Altered Under Elevated CO 2. FRONTIERS IN PLANT SCIENCE 2018; 9:1758. [PMID: 30538718 PMCID: PMC6277575 DOI: 10.3389/fpls.2018.01758] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/12/2018] [Indexed: 06/09/2023]
Abstract
Vascular epiphytes are a major biomass component of forests across the globe and they contribute to 9% of global vascular plant diversity. To improve our understanding of the whole-plant response of epiphytes to future climate change, we investigated for the first time both individual and combined effects of elevated CO2 (560 ppm) and light on the physiology and growth of two epiphyte species [Tillandsia brachycaulos (CAM) and Phlebodium aureum (C3)] grown for 272 days under controlled conditions. We found that under elevated CO2 the difference in water loss between the light (650 μmol m-2s-1) and shade (130 μmol m-2s-1) treatment was strongly reduced. Stomatal conductance (g s) decreased under elevated CO2, resulting in an approximate 40-45% reduction in water loss over a 24 h day/night period under high light and high CO2 conditions. Under lower light conditions water loss was reduced by approximately 20% for the CAM bromeliad under elevated CO2 and increased by approximately 126% for the C3 fern. Diurnal changes in leaf turgor and water loss rates correlated strong positively under ambient CO2 (400 ppm) and high light conditions. Future predicted increases in atmospheric CO2 are likely to alter plant water-relations in epiphytes, thus reducing the canopy cooling potential of epiphytes to future increases in temperature.
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Affiliation(s)
- Sven Batke
- Department of Biology, Edge Hill University, Ormskirk, United Kingdom
- School of Biology and Environmental Science, Earth Institute, University College Dublin, Dublin, Ireland
| | - Aidan Holohan
- School of Biology and Environmental Science, Earth Institute, University College Dublin, Dublin, Ireland
| | - Roisin Hayden
- School of Biology and Environmental Science, Earth Institute, University College Dublin, Dublin, Ireland
| | - Wieland Fricke
- School of Biology and Environmental Science, Earth Institute, University College Dublin, Dublin, Ireland
| | - Amanda Sara Porter
- School of Biology and Environmental Science, Earth Institute, University College Dublin, Dublin, Ireland
- Botany Department, Trinity College Dublin, Dublin, Ireland
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Zhang W, Hu H, Zhang SB. Divergent Adaptive Strategies by Two Co-occurring Epiphytic Orchids to Water Stress: Escape or Avoidance? FRONTIERS IN PLANT SCIENCE 2016; 7:588. [PMID: 27200059 PMCID: PMC4853394 DOI: 10.3389/fpls.2016.00588] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/18/2016] [Indexed: 05/21/2023]
Abstract
Due to the fluctuating water availability in the arboreal habitat, epiphytic plants are considered vulnerable to climate change and anthropogenic disturbances. Although co-occurring taxa have been observed divergent adaptive performances in response to drought, the underlying physiological and morphological mechanisms by which epiphyte species cope with water stress remain poorly understood. In the present study, two co-occurring epiphytic orchids with different phenologies were selected to investigate their drought-resistance performances. We compared their functional traits, and monitored their physiological performances in a 25-days of drought treatment. In contrast to the deciduous species Pleione albiflora, the evergreen species Coelogyne corymbosa had different root anatomical structures and higher values for saturated water content of pseudobulbs. Moreover, plants of C. corymbosa had thicker leaves and epidermis, denser veins and stomata, and higher values for leaf mass per unit area and the time required to dry saturated leaves to 70% relative water content. However, samples from that species had lower values for net photosynthetic rate (A n), stomatal length and chlorophyll content per unit dry mass. Nevertheless, due to greater capacity for water storage and conservation, C. corymbosa maintained higher A n, stomatal conductance (g s), and instantaneous water-use efficiency during severe drought period, and their values for leaf water potential were higher after the water stress treatment. By Day 10 after irrigation was restarted, only C. corymbosa plants recovered their values for A n and g s to levels close to those calculated prior to the imposition of water stress. Our results suggest that the different performance responding to drought and re-watering in two co-occurring epiphytic orchids is related to water-related traits and these two species have divergent adaptive mechanisms. Overall, C. corymbosa demonstrates drought avoidance by enhancing water uptake and storage, and by reducing water losses while P. albiflora employs a drought escape strategy by fixing more carbon during growing season and shedding leaves and roots at dry season, leaving a dormant pseudobulb to minimize transpiration. These findings may improve our understanding of the potential effects that climate change can have on the population dynamics of different epiphytic taxa.
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Affiliation(s)
- Wei Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
- University of Chinese Academy of SciencesBeijing, China
| | - Hong Hu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
| | - Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
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Holtum JAM, Winter K. Limited photosynthetic plasticity in the leaf-succulent CAM plant Agave angustifolia grown at different temperatures. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:843-849. [PMID: 32481038 DOI: 10.1071/fp13284] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 02/19/2014] [Indexed: 06/11/2023]
Abstract
In Agave angustifolia Haw., a leaf-succulent constitutive crassulacean acid metabolism (CAM) plant of tropical Panama, we tested whether nocturnal CO2 uptake and growth were reduced at night temperatures above 20°C. Unlike some CAM model species from habitats with pronounced day-night temperature variations, in A. angustifolia temperature affected little the relative contributions of CAM and C3 photosynthesis to growth. In plants grown under 12h light/dark regimes of 25/17, 30/22 and 35/27°C, biomass increased with temperature. Maintaining day temperature at 35°C and reducing night temperature from 27 to 17°C markedly lowered growth, a reduction partially reversed when roots were heated to 27°C. Across all treatments, whole-shoot δ13C values ranged between -14.6 and -13.2 ‰, indicating a stable proportion of CO2 was fixed at night, between 75 and 83%. Nocturnal acidification reflected growth, varying between 339 and 393μmol H+ g-1 fresh mass and 63-87μmol H+ cm-2. In outdoor open-top chambers, warming the air 3°C above ambient at night did not reduce biomass accumulation. The persistence of a high capacity for nocturnal CO2 fixation at the expense of a limited capacity for switching between C3 and CAM probably makes this Agave, and others like it, potential species for biomass production in seasonally-dry landscapes.
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Affiliation(s)
- Joseph A M Holtum
- Tropical Biology, James Cook University, Townsville, Qld 4811, Australia
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
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Winter K, Holtum JAM. Facultative crassulacean acid metabolism (CAM) plants: powerful tools for unravelling the functional elements of CAM photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3425-41. [PMID: 24642847 DOI: 10.1093/jxb/eru063] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Facultative crassulacean acid metabolism (CAM) describes the optional use of CAM photosynthesis, typically under conditions of drought stress, in plants that otherwise employ C3 or C4 photosynthesis. In its cleanest form, the upregulation of CAM is fully reversible upon removal of stress. Reversibility distinguishes facultative CAM from ontogenetically programmed unidirectional C3-to-CAM shifts inherent in constitutive CAM plants. Using mainly measurements of 24h CO2 exchange, defining features of facultative CAM are highlighted in five terrestrial species, Clusia pratensis, Calandrinia polyandra, Mesembryanthemum crystallinum, Portulaca oleracea and Talinum triangulare. For these, we provide detailed chronologies of the shifts between photosynthetic modes and comment on their usefulness as experimental systems. Photosynthetic flexibility is also reviewed in an aquatic CAM plant, Isoetes howellii. Through comparisons of C3 and CAM states in facultative CAM species, many fundamental biochemical principles of the CAM pathway have been uncovered. Facultative CAM species will be of even greater relevance now that new sequencing technologies facilitate the mapping of genomes and tracking of the expression patterns of multiple genes. These technologies and facultative CAM systems, when joined, are expected to contribute in a major way towards our goal of understanding the essence of CAM.
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Affiliation(s)
- Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
| | - Joseph A M Holtum
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia
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11
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Testo WL, Watkins JE. Influence of plant size on the ecophysiology of the epiphytic fern Asplenium auritum (Aspleniaceae) from Costa Rica. AMERICAN JOURNAL OF BOTANY 2012; 99:1840-1846. [PMID: 23132616 DOI: 10.3732/ajb.1200329] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY A central goal of plant ecophysiological studies is to generate patterns of physiological behavior that are applicable to a species, which can be complicated when plant size is considered. Studies indicate that plant size can influence numerous ecophysiological parameters, especially in vascular epiphytes. The few studies that have included ferns in their analyses suggest that plant size is less important in ferns than angiosperms. This study investigates this apparent disparity by examining the relationship between plant size and an array of ecophysiological parameters in the epiphytic fern Asplenium auritum, especially the role of plant size in determining responses to water stress. METHODS Plants were classified according to size and measured for a variety of functional traits, including maximum photosynthetic rate, stomatal conductance, water-use efficiency, stomatal density, chlorophyll content, chlorophyll a/b ratio, specific leaf area, whole plant drying rates, and desiccation tolerance. Results for all traits were compared across size classes to determine size-related differences. KEY RESULTS Plant size significantly influenced most traits examined, most notably photosynthetic rate, stomatal density, stomatal conductance, whole plant drying rates, and recovery from desiccation. We report the first evidence of size-mediated shifts in desiccation tolerance in plants: small individuals tolerated water loss, whereas larger individuals avoided desiccation. CONCLUSIONS Our findings indicate that size-mediated ecophysiological shifts are more important than previously thought in ferns, particularly in regard to water relations. Desiccation tolerance may allow young fern sporophytes to establish in stressful environments and is subsequently lost in older individuals.
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Affiliation(s)
- Weston L Testo
- Department of Biology, 13 Oak Drive, Colgate University, Hamilton, New York 13346, USA.
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Tsen EWJ, Holtum JAM. Crassulacean acid metabolism (CAM) in an epiphytic ant-plant, Myrmecodia beccarii Hook.f. (Rubiaceae). PHOTOSYNTHESIS RESEARCH 2012; 113:311-320. [PMID: 22442054 DOI: 10.1007/s11120-012-9732-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Accepted: 02/27/2012] [Indexed: 05/31/2023]
Abstract
This study demonstrates unequivocally the presence of crassulacean acid metabolism (CAM) in a species of the Rubiaceae, the fourth largest angiosperm plant family. The tropical Australian endemic epiphytic ant-plant, Myrmecodia beccarii Hook.f., exhibits net CO(2) uptake in the dark and a concomitant accumulation of titratable acidity in plants in the field and in cultivation. Plants growing near Cardwell, in a north Queensland coastal seasonally dry forest of Melaleuca viridiflora Sol. ex Gaertn., accumulated ~50 % of their 24 h carbon gain in the dark during the warm wet season. During the transition from the wet season to the dry season, 24 h carbon gain was reduced whilst the proportion of carbon accumulated during the dark increased. By mid dry season many plants exhibited zero net carbon uptake over 24 h, but CO(2) uptake in the dark was observed in some plants following localised rainfall. In a shade-house experiment, droughted plants in which CO(2) uptake in the light was absent and dark CO(2) uptake was reduced, were able to return to relatively high rates of CO(2) uptake in the light and dark within 12 h of rewatering.
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Affiliation(s)
- Edward W J Tsen
- Tropical Biology, James Cook University, Townsville, QLD, 4811, Australia
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13
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Zotz G, Asshoff R. Growth in epiphytic bromeliads: response to the relative supply of phosphorus and nitrogen. PLANT BIOLOGY (STUTTGART, GERMANY) 2010; 12:108-13. [PMID: 20653893 DOI: 10.1111/j.1438-8677.2009.00216.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Insufficient nitrogen (N) and phosphorus (P) frequently limit primary production. Although most nutrient studies on vascular epiphytes have focused on N uptake, circumstantial evidence suggests that P rather than N is the most limiting element for growth in this plant group. We directly tested this by subjecting a total of 162 small individuals of three bromeliad species (Guzmania monostachia, Tillandsia elongata, Werauhia sanguinolenta) to three N and three P levels using a full-factorial experimental design, and determined relative growth rates (RGR) and nutrient acquisition over a period of 11 weeks. Both N and P supply had a significant effect on RGR, but only tissue P concentrations were correlated with growth. Uptake rates of N and P, in contrast, were not correlated with RGR. Increased nutrient supply led to an up to sevenfold increase in tissue P concentration compared to natural conditions, while concentrations of N hardly changed or even decreased. All treatment combinations, even at the lowest experimental P supply, led to decreased N:P ratios. We conclude that P is at least as limiting as N for vegetative function under natural conditions in these epiphytic bromeliads. This conclusion is in line with the general notion of the prevalence of P limitation for the functioning of terrestrial vegetation in the tropics.
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Affiliation(s)
- G Zotz
- Universität Oldenburg, Institut für Biologie und Umweltwissenschaften, AG Funktionelle Okologie, Oldenburg, Germany.
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Habitat, CO2 uptake and growth for the CAM epiphytic cactus Epiphyllum phyllanthus in a Panamanian tropical forest. JOURNAL OF TROPICAL ECOLOGY 2009. [DOI: 10.1017/s0266467400009469] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
ABSTRACTIn the tropical forest of Barro Colorado Island, habitat characteristics, diel acidity changes, CO2 uptake and growth were investigated for the epiphytic cactus Epiphyllum phyllanthus (L.) Haw. It occurred most frequently in tree cavities with its roots in canopy soil and was especially abundant on two tree species: Platypodium elegans J. Vogel and Tabebuia guayacan (Seem.) Hemsl. Its maximum net CO2 uptake rates were low under natural conditions (1.4 μmol m−1) but were comparable to those of other CAM and C3 epiphytes under wet conditions in a screenhouse. Under both natural conditions and in the screenhouse, partial shade enhanced growth and CAM activity. When plants grew under a photosynthetic photon flux of c. 4 mol m−2 d−1, their nocturnal acidity increase and total net CO2 uptake were twice as much as for plants growing at lower (an average of 2.4 mol m−2 d−1) and higher (7.7 mol m−2 d−1) photosynthetic photon fluxes. Stem elongation was 27% greater at the intermediate photosynthetic photon flux. Seedlings of E. phyllanthus survived three months of drought and responded rapidly to rewetting, recovering fully within three days. Transpiration rates and nocturnal acidity increases also recovered to the values of well-watered plants a few days after rewetting, indicating that this species can take advantage of episodic rainfall during the dry season.
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Lüttge U. Photosynthetic flexibility and ecophysiological plasticity: questions and lessons from Clusia, the only CAM tree, in the neotropics. THE NEW PHYTOLOGIST 2006; 171:7-25. [PMID: 16771979 DOI: 10.1111/j.1469-8137.2006.01755.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The discovery of crassulacean acid metabolism (CAM) in the trees of Clusia: arrival in the limelight of international research 8 II. Phylogeny 8 III. Photosynthetic physiotypes 10 IV. Metabolic flexibility: organic acid variations 12 V. The environmental control of photosynthetic flexibility 13 VI. Phenotypic plasticity: physiotypes and morphotypes 16 VII. Ecological amplitude and habitat impact 16 VIII. Conclusions and outlook 21 Acknowledgements 22 References 22 Summary It is the aim of this review to present a monographic survey of the neotropical genus Clusia on scaling levels from molecular phylogeny, metabolism, photosynthesis and autecological environmental responses to ecological amplitude and synecological habitat impact. Clusia is the only dicotyledonous genus with real trees performing crassulacean acid metabolism (CAM). By way of introduction, a brief historical reminiscence describes the discovery of CAM in Clusia and the consequent increase in interest in studying this particular genus of tropical shrubs and trees. The molecular phylogeny of CAM in the genus is compared with that in Kalanchoë and the Bromeliaceae. At the level of metabolism and photosynthesis, the great plasticity of expression of photosynthetic physiotypes, i.e. (i) C(3) photosynthesis, (ii) CAM including CAM idling, (iii) CAM cycling and (iv) C(3)/CAM-intermediate behaviour, as well as metabolic flexibility in Clusia is illustrated. At the level of autecology, the factors water, irradiance and temperature, which control photosynthetic flexibility, are assessed. The phenotypic plasticity of physiotypes and morphotypes is described. At the level of synecology, the ecological amplitude of Clusia in the tropics and the relations to habitat are surveyed.
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Affiliation(s)
- Ulrich Lüttge
- Institute of Botany, Technical University of Darmstadt, Darmstadt, Germany.
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Winter K, Aranda J, Holtum JAM. Carbon isotope composition and water-use efficiency in plants with crassulacean acid metabolism. FUNCTIONAL PLANT BIOLOGY : FPB 2005; 32:381-388. [PMID: 32689140 DOI: 10.1071/fp04123] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2004] [Accepted: 11/17/2004] [Indexed: 06/11/2023]
Abstract
The relationship between water-use efficiency, measured as the transpiration ratio (g H2O transpired g-1 above- plus below-ground dry mass accumulated), and 13C / 12C ratio (expressed as δ13C value) of bulk biomass carbon was compared in 15 plant species growing under tropical conditions at two field sites in the Republic of Panama. The species included five constitutive crassulacean acid metabolism (CAM) species [Aloe vera (L.) Webb & Berth., Ananas comosus (L.) Merr., Euphorbia tirucalli L., Kalanchoë daigremontiana Hamet et Perr., Kalanchoë pinnata (Lam.) Pers.], two species of tropical C3 trees (Tectona grandis Linn. f. and Swietenia macrophylla King), one C4 species (Zea mays L.), and seven arborescent species of the neotropical genus Clusia, of which two exhibited pronounced CAM. The transpiration ratios of the C3 and CAM species, which ranged between 496 g H2O g-1 dry mass in the C3-CAM species Clusia pratensis Seeman to 54 g H2O g-1 dry mass in the constitutive CAM species Aloe vera, correlated strongly with δ13C values and nocturnal CO2 gain suggesting that δ13C value can be used to estimate both water-use efficiency and the proportion of CO2 gained by CAM species during the light and the dark integrated over the lifetime of the tissues.
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Affiliation(s)
- Klaus Winter
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Ancón, Republic of Panama
| | - Jorge Aranda
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Ancón, Republic of Panama
| | - Joseph A M Holtum
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Ancón, Republic of Panama
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Cardelus CL, Chazdon RL. Inner-crown Microenvironments of Two Emergent Tree Species in a Lowland Wet Forest1. Biotropica 2005. [DOI: 10.1111/j.1744-7429.2005.00032.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Graham EA, Andrade JL. Drought tolerance associated with vertical stratification of two co-occurring epiphytic bromeliads in a tropical dry forest. AMERICAN JOURNAL OF BOTANY 2004; 91:699-706. [PMID: 21653425 DOI: 10.3732/ajb.91.5.699] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Vertical stratification of epiphytes generally has not been reported for dry forests. For two epiphytic Crassulacean acid metabolism bromeliads that segregate vertically, it was hypothesized that different potentials for photoprotection or shade tolerance rather than drought tolerance is responsible for the observed stratification. The light environment, capacity for photoprotection, germination response to light quality, and responses to light and drought were thus examined for Tillandsia brachycaulos and T. elongata. Vertical and light-environment distributions differed for the two species but photoprotection and photodamage did not where they occurred at similar field locations; T. brachycaulos had a higher pigment acclimation to light. Tillandsia brachycaulos had higher acid accumulation under low light as opposed to T. elongata, which responded similarly to all but the highest light treatment. Tillandsia brachycaulos maintained positive total daily net CO(2) uptake through 30 d of drought; T. elongata had a total daily net CO(2) loss after 7 d of drought. The vertical stratification was most likely the result of the sensitivity to drought of T. elongata rather than differences in photoprotection or shade tolerance between the two species. Tillandsia elongata occurs in more exposed locations, which may be advantageous for rainfall interception and dew formation.
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Affiliation(s)
- Eric A Graham
- Centro de Investigación Científica de Yucatán, Calle 43 No. 130, Col. Chuburná de Hidalgo, C.P. 97200, Yucatán, México
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Zotz G, Hietz P. The physiological ecology of vascular epiphytes: current knowledge, open questions. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:2067-2078. [PMID: 11604445 DOI: 10.1093/jexbot/52.364.2067] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The current knowledge of the physiological ecology of vascular epiphytes is reviewed here with an emphasis on the most recent literature. It is argued that by far the most relevant abiotic constraint for growth and vegetative function of vascular epiphytes is water shortage, while other factors such as nutrient availability or irradiation, are generally of inferior importance. However, it is shown that the present understanding of epiphyte biology is still highly biased, both taxonomically and ecologically, and it is concluded that any generalizations are still preliminary. Future studies should include a much wider range of taxa and growing sites within the canopy to reach a better understanding how abiotic factors are limiting epiphyte growth and survival which, in turn, should affect epiphyte community composition. Finally, a more integrative approach to epiphyte biology is encouraged: physiological investigations should be balanced by studies of other possible constraints, for example, substrate instability, dispersal limitation, competition or herbivory.
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Affiliation(s)
- G Zotz
- Lehrstuhl für Botanik II der Universität Würzburg, Julius-von-Sachs-Platz 3, D-97082 Würzburg, Germany.
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Zotz G, Ziegler H. The occurrence of crassulacean acid metabolism among vascular epiphytes from Central Panama. THE NEW PHYTOLOGIST 1997; 137:223-229. [PMID: 33863189 DOI: 10.1046/j.1469-8137.1997.00800.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The occurrence of crassulacean acid metabolism (CAM) among the epiphyte flora of the lowland forest on Barro Colorado Island (BCJ), Panama, was investigated. A total of 116 species was included, i.e. about 2/3 of the known epiphyte taxa. As judged from the carbon isotope ratios and the absence of Kranz anatomy, indications of CAM were found in 29 species of three families, Orchidaceae (20), Bromeliaceae (7), and Cactaceae (2). We estimate that about 25% of the epiphyte flora of BCI are CAM plants. CAM was most prevalent in exposed sites, but even in the understorey two epiphyte species engage in CAM.
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Affiliation(s)
- G Zotz
- Julius-von-Sachs-Institut fur Biowissenschaften mit Botanischem Garten der Unversität Würzburg, Lehrstuhl für Botanik II, Mittlerer Dallenbergweg 64, D-97082 Würzburg, Germany
| | - H Ziegler
- Institut für Botanik und Mikrobiologie der Technischen Universität München, Lehrstuhl für Botanik, Arcisstr. 21, D-80290 München, Germany
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Andrade JL, Nobel PS. Microhabitats and Water Relations of Epiphytic Cacti and Ferns in a Lowland Neotropical Forest1. Biotropica 1997. [DOI: 10.1111/j.1744-7429.1997.tb00427.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mulkey SS, Kitajima K, Wright S. Plant physiological ecology of tropical forest canopies. Trends Ecol Evol 1996; 11:408-12. [DOI: 10.1016/0169-5347(96)10043-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Is crassulacean acid metabolism activity in sympatric species of hemi-epiphytic stranglers such as Clusia related to carbon cycling as a photoprotective process? Oecologia 1996; 106:28-38. [DOI: 10.1007/bf00334404] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/1995] [Accepted: 10/16/1995] [Indexed: 10/24/2022]
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Zotz G, Tyree MT. Water stress in the epiphytic orchid, Dimerandra emarginata (G. Meyer) Hoehne. Oecologia 1996; 107:151-159. [PMID: 28307300 DOI: 10.1007/bf00327898] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/1995] [Accepted: 02/01/1996] [Indexed: 10/26/2022]
Abstract
The epiphytic orchid, Dimerandra emarginata, occurs in habitats characterized by high light intensities and very variable water supply. Long-term observations of the water status indicate that this species experienced at least moderate water stress over most of the year. Well-watered, it showed high rates of net CO2 uptake (A, 7 μmol m-2 s-1), high transpiration rates (E, 1.4 mmol m-2 s-1), and little nocturnal acidification. Drought induced crassulacean acid metabolism activity and resulted in a strong decline of both A and E. The same conditions also led to chronic photoinhibition as indicated by a predawn ratio of variable to maximum fluorescence (Fv/Fm) of 0.6 after 9 days of drought. Diurnal changes in fluorescence characteristics were much more pronounced. Midday ratios of dark adapted Fv/Fm were as low as 0.35, but recovered in the afternoon and were probably mostly due to non-photochemical quenching of photosynthesis. Measured water losses of leaves and stems were compared to plant water content (PWC). In large plants, about 32% of PWC was transpired on a single day under well-watered conditions. Model calculations indicate that transpiration per unit leaf area should be strongly dependent upon plant size in this species. Comparisons of calculated daily water loss, PWC and the length of drought periods suggest that D. emarginata can only survive a dry season by drawing on the water reserves of older stems and by an efficient uptake of the occasional rain.
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Affiliation(s)
- Gerhard Zotz
- Department of Botany, University of Vermont, 05405, Burlington, VT, USA.,Smithsonian Tropical Research Institute, Apdo. 2072, Balboa, Republic of Panama
| | - Melvin T Tyree
- Department of Botany, University of Vermont, 05405, Burlington, VT, USA.,Smithsonian Tropical Research Institute, Apdo. 2072, Balboa, Republic of Panama.,Forest Service, U S Department of Agriculture, 705 Spear Street, 05405, Burlington, VT, USA
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Seasonal Changes in Daytime Versus Nighttime CO2 Fixation of Clusia uvitana In Situ. CRASSULACEAN ACID METABOLISM 1996. [DOI: 10.1007/978-3-642-79060-7_21] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Zotz G, Tyree MT, Cochard H. Hydraulic architecture, water relations and vulnerability to cavitation of Clusia uvitana Pittier: a C 3 -CAM tropical hemiepiphyte. THE NEW PHYTOLOGIST 1994; 127:287-295. [PMID: 33874511 DOI: 10.1111/j.1469-8137.1994.tb04279.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Clusia uvitana Pittíer (Clusiacea) is a tropical hemiepiphyte that has been shown to display a high plasticity in the expression of CAM in response to the environment. When water is available CO2 is taken up mostly during the- day. This study of the water relations and hydraulic architecture has revealed that leaf water potentials, £ ranged from 0-7 to -0.9 MPa and changed very little with time or water availability. The absolute hydraulic conductivity of stem segments (K,) and the specific conductivity (K1 ) were comparable to many other temperate and tropical species, but the leaf specificity conductivity (K1 ) was 1/3 to 1/30 that of many other species. So stems supported high leaf areas per unit of hydraulic conductivity. C uvitana was very vulnerable to cavitation, reaching 50 % loss of hydraulic conductivity at stem £=1.3 MPa. The species survives in spite of low K1 and high xylem vulnerability, because the CAM physiology insures low transpiration rates and high ability to evade dehydration.
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Affiliation(s)
- Gerhard Zotz
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Republic of Panama
| | - Melvin T Tyree
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Republic of Panama
- U.S. Deportment of Agriculture, Forest Service, 705 Spear Street, Burlington, Vermont, USA 05402
| | - Hervé Cochard
- INRA, Lahoratoire d'Ecophysiologie Forestière, 54280 Champenoux (Nancy), France
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Zotz G, Winter K. A one-year study on carbon, water and nutrient relationships in a tropical C 3 -CAM hemi-epiphyte, Clusia uvitana Pittier. THE NEW PHYTOLOGIST 1994; 127:45-60. [PMID: 33874396 DOI: 10.1111/j.1469-8137.1994.tb04258.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Diel (24 h) courses of CO2 and water-vapour exchange of leaves of hemi-epiphytic plants of Clusia uvitana Pittier (Clusiaceae) were measured under natural tropical conditions in the semi-evergreen moist forest of Barro Colorado Island, Panama, from January 1991 until January 1992. Plants were studied at two sites, in the crown of a 47-m tall tree (Ceiba pentandra) and on the shore of Lake Gatun, at a height of about 2-4 m. The following results were obtained: (1) Diel carbon gain was mainly a function of photosynthetic photon fluence rate (PPFR) on individual days. PPFR also strongly affected CAM activity. A leafless period of the host tree Ceiba pentandra resulted in higher incident PPFRs and slightly lower nighttime temperatures in the canopy of C uvitana; this led to increases in both daytime and nighttime CO2 fixation. (2) In fully mature sun leaves from the two sites, nocturnal net uptake of atmospheric CO2 occurred on almost all of the 71 days measured and nocturnal carbon gain was enhanced during the dry season. (3) In C. uvitana at the Lake site, 24-h carbon gain during the wet and dry season was similar to C. uvitana at the Ceiba site during the leafless period of the host tree. Overall CAM activity was lower at the Lake site. (4) Recycling of respiratory CO2 was a major route for nocturnal acid synthesis. Nocturnal net uptake of atmospheric CO2 was closely correlated with changes in titratable acidity, but accounted for only about 30% of the nocturnal increase in organic acids. (5) Mature shade leaves performed CAM only during the dry season, whereas in the wet season they showed atmospheric CO2 uptake exclusively in the light. (6) Independent of exposure or season, leaves less than about 12 wk old showed a C3 pattern of diel gas exchange and the level of titratable acidity was high day and night. (7) The annual carbon budget of outer canopy leaves of C uvitana in the Ceiba site was 1780 g CO2 m-2 a-1 and the average long-term water-use efficiency was 23 × 10-3 g CO2 g-1 H2 O. (8) Vegetative growth was strongly seasonal. Branch length increment and leaf area development was much higher in the wet season. Mineral element contents in these evergreen plants showed no age-related changes, but a significant proportion of elements was retrieved before abscission.
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Affiliation(s)
- Gerhard Zotz
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Republic of Panama
| | - Klaus Winter
- Smithsonian Tropical Research Institute, P.O. Box 2072, Balboa, Republic of Panama
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