1
|
Males J, Baksh-Comeau Y, Jaggernauth D, Ballah S, Paltoo S, Griffiths H. Epiphytic CAM bromeliads indicate vulnerability of tropical forest communities to climate change. ANNALS OF BOTANY 2023; 132:699-715. [PMID: 37897046 PMCID: PMC10799987 DOI: 10.1093/aob/mcad152] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/14/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023]
Abstract
BACKGROUND AND SCOPE Vascular epiphytes have a variety of mechanisms to trap and retain water, including crassulacean acid metabolism (CAM). Niche segregation was investigated for epiphytic bromeliads on the tropical Caribbean island of Trinidad, where habitats range from lowland deciduous forests to high-rainfall montane tropical forests, ~1000 m in elevation. METHODS Four tank-impounding bromeliad epiphytes in the genus Aechmea (Ae. aquilega, Ae. fendleri, Ae. nudicaulis and Ae. dichlamydea) with CAM were mapped across their distinct geographical and elevational zonations in northern Trinidad and Tobago. Species distribution modelling was used to determine environmental limitations for each species. Anatomical and physiological measurements included leaf succulence traits, gas exchange and CAM activity; hydraulic conductance and vulnerability; stomatal sensitivity and quantum yield responses to nocturnal temperature and long-term water deficits. KEY RESULTS A total of 2876 field observations identified the transitions between the lowland Ae. aquilega and montane Ae. fendleri, occurring >500 m a.s.l. at the drier western end of the Northern Mountain Range and at progressively lower elevations towards the wetter, eastern region. Anatomical and physiological sensitivities of gas exchange, CAM activity and water use, and responses to elevated nocturnal temperatures and drought, were markedly different for Ae. fendleri compared with Ae. aquilega or the ubiquitous Ae. nudicaulis. CONCLUSIONS The species distribution model highlighted the susceptibility of Ae. fendleri to a changing climate. For each species, physiological and anatomical traits were tailored to environmental tolerances, consistent with specialist or generalist niche preferences. Using Intergovernmental Panel on Climate Change scenarios, we predict that rapid rainfall and temperature changes will lead to the loss of Ae. fendleri and associated lower (and upper) montane forest communities from Trinidad, seriously impacting both biodiversity and critical ecosystem functions here and in other tropical island habitats. Epiphytic bromeliads act as markers for threatened communities, and their physiological tolerances represent key indicators of climate change impacts.
Collapse
Affiliation(s)
- Jamie Males
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Yasmin Baksh-Comeau
- National Herbarium of Trinidad and Tobago, University of West Indies St Augustine Campus, Trinidad, Trinidad and Tobago
| | - Dan Jaggernauth
- National Herbarium of Trinidad and Tobago, University of West Indies St Augustine Campus, Trinidad, Trinidad and Tobago
| | - Shane Ballah
- National Herbarium of Trinidad and Tobago, University of West Indies St Augustine Campus, Trinidad, Trinidad and Tobago
| | - Shahada Paltoo
- National Herbarium of Trinidad and Tobago, University of West Indies St Augustine Campus, Trinidad, Trinidad and Tobago
| | - Howard Griffiths
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| |
Collapse
|
2
|
Pereira PN, Gaspar M, Smith JAC, Mercier H. Ammonium intensifies CAM photosynthesis and counteracts drought effects by increasing malate transport and antioxidant capacity in Guzmania monostachia. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1993-2003. [PMID: 29462338 PMCID: PMC6018993 DOI: 10.1093/jxb/ery054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 02/07/2018] [Indexed: 05/25/2023]
Abstract
Guzmania monostachia (Bromeliaceae) is a tropical epiphyte capable of up-regulating crassulacean acid metabolism (CAM) in its photosynthetic tissues in response to changing nutrient and water availability. Previous studies have shown that under drought there is a gradient of increasing CAM expression from the basal (youngest) to the apical (oldest) portion of the leaves, and additionally that nitrogen deficiency can further increase CAM intensity in the leaf apex of this bromeliad. The present study investigated the inter-relationships between nitrogen source (nitrate and/or ammonium) and water deficit in regulating CAM expression in G. monostachia leaves. The highest CAM activity was observed under ammonium nutrition in combination with water deficit. This was associated with enhanced activity of the key enzyme phosphoenolpyruvate carboxylase, elevated rates of ATP- and PPi-dependent proton transport at the vacuolar membrane in the presence of malate, and increased transcript levels of the vacuolar malate channel-encoding gene, ALMT. Water deficit was consistently associated with higher levels of total soluble sugars, which were maximal under ammonium nutrition, as were the activities of several antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase). Thus, ammonium nutrition, whilst associated with the highest degree of CAM induction in G. monostachia, also mitigates the effects of water deficit by osmotic adjustment and can limit oxidative damage in the leaves of this bromeliad under conditions that may be typical of its epiphytic habitat.
Collapse
Affiliation(s)
- Paula Natália Pereira
- Department of Botany, Institute of Biosciences, University of São Paulo, CEP, São Paulo, SP, Brazil
| | - Marília Gaspar
- Department of Plant Physiology and Biochemistry, Institute of Botany, CEP, São Paulo, SP, Brazil
| | - J Andrew C Smith
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Helenice Mercier
- Department of Botany, Institute of Biosciences, University of São Paulo, CEP, São Paulo, SP, Brazil
| |
Collapse
|
3
|
|
4
|
North GB, Lynch FH, Maharaj FDR, Phillips CA, Woodside WT. Leaf hydraulic conductance for a tank bromeliad: axial and radial pathways for moving and conserving water. FRONTIERS IN PLANT SCIENCE 2013; 4:78. [PMID: 23596446 PMCID: PMC3622035 DOI: 10.3389/fpls.2013.00078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 03/19/2013] [Indexed: 05/22/2023]
Abstract
Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculature and other anatomical and morphological traits. Plants of the tank bromeliad Guzmania lingulata were investigated in a lowland tropical forest in Costa Rica and a shaded glasshouse in Los Angeles, CA, USA. Stomatal conductance to water vapor and leaf anatomical variables related to hydraulic conductance were measured for both groups. Tracheid diameters and numbers of vascular bundles (veins) were used with the Hagen-Poiseuille equation to calculate axial hydraulic conductance. Measurements of leaf hydraulic conductance using the evaporative flux method were also made for glasshouse plants. Values for axial conductance and leaf hydraulic conductance were used in a model based on leaky cable theory to estimate the conductance of the radial pathway from the vein to the leaf surface and to assess the relative contributions of both axial and radial pathways. In keeping with low stomatal conductance, low stomatal density, low vein density, and narrow tracheid diameters, leaf hydraulic conductance for G. lingulata was quite low in comparison with most other angiosperms. Using the predicted axial conductance in the leaky cable model, the radial resistance across the leaf mesophyll was predicted to predominate; lower, more realistic values of axial conductance resulted in predicted radial resistances that were closer to axial resistance in their impact on total leaf resistance. Tracer dyes suggested that water uptake through the tank region of the leaf was not limiting. Both dye movement and the leaky cable model indicated that the leaf blade of G. lingulata was structurally and hydraulically well-suited to conserve water.
Collapse
Affiliation(s)
| | - Frank H. Lynch
- Department of Mathematics, Occidental CollegeLos Angeles, CA, USA
| | | | | | | |
Collapse
|
5
|
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]
|
6
|
|
7
|
Zotz G, Winter K. Annual carbon balance and nitrogen-use efficiency in tropical C 3 and CAM epiphytes. THE NEW PHYTOLOGIST 1994; 126:481-492. [PMID: 33874470 DOI: 10.1111/j.1469-8137.1994.tb04245.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Over the course of 12 months, diel (24 h) measurements of gas exchange were performed on leaves of three epiphytic species growing in the crown of a kapok tree on Barro Colorado Island, Panama: a drought-deciduous orchid with the C2 , pathway (Catasetum viridiflavum Hook.), an evergreen C2 fern (Polypodium crassifolium L.), and an evergreen epiphyte with an intermediate C3 -C3 -CAM pathway of photosynthesis (Clusia uvitana Pitt.), The gas exchange characteristics of all three species; were strongly affected during the four-month dry season. Compared with the rainy season, mean daily carbon gain of Clusia uvitana was reduced by almost 40° paralleled bY a strong decrease in daytime CO2 uptake and an increase in CO2 uptake at night. The orchid, growing new leaves in the second half of the dry season, showed markedly decreased stomatal conductances and greatly reduced carbon gain. In the fern, daily carbon balance became negative during the dry season and chronic photoinhibition was indicated by reduced FV /FM ratios and a decreased photon-use efficiency of photosynthetic O2 evolution. Annual carbon gain was similar far the three species (about 10002 CO2 m-2 yr-1 ) as was long-term nitrogen-use efficiency (annual carbon gain/mean leaf nitrogen content, about 1·1 g CO2 mg N-1 yr-1 ). In the C3 CAM epiphyte, the long-term water use efficiency of net CO2 uptake was more than twice as high as in the two C3 epiphytes.
Collapse
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
| |
Collapse
|
8
|
Griffiths H, Smith JAC, Lüttge U, Popp M, Cram WJ, Diaz M, Lee HSJ, Medina E, SCHäfer C, Stimmel KH. Ecophysiology of xerophytic and halophytic vegetation of a coastal alluvial plain in northern Venezuela: IV. Tillandsia flexuosa Sw. and Schomburgkia humboldtiana Reichb., epiphytic CAM plants. THE NEW PHYTOLOGIST 1989; 111:273-282. [PMID: 33874247 DOI: 10.1111/j.1469-8137.1989.tb00691.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A comparison of the performance of two epiphytes with crassulacean acid metabolism (CAM) was made during the rainy season and dry season at the Ciénega el Ostional, Chichiriviche in northern Venezuela. The epiphytic bromeliad, Tillandsia flexuosa has water-retaining tanks and leaf trichomes, and propagates mainly vegetatively to produce large populations in the shrubby island vegetation. The epiphytic orchid, Schomburgkia humboldtiana formed smaller populations, and had large succulent leaves with uniform chlorenchyma and no distinct water-storage parenchyma, unlike T. flexuosa. Both epiphytes were myrmecophilous. Leaf succulence (kg m-2 ) declined by ∼ 10% in the dry season for both plants. Both epiphytes showed reduced CO2 uptake during Phase I (dark period) and (dawn-dusk) titratable acidity (ΔH+ ) in the dry season. Water-use efficiency (WUE) was higher for S. humboldtiana (16.0 × 10-3 mol CO2 per mol H2 O compared with 5.0 × 10 -3 for T. flexuosa) although WUE remained constant during rainy and dry season for each species. Sixty to seventy per cent of the dawn dusk titratable acidity was derived internally from respiratory CO2 (recycling) for both species, and in absolute terms, recycling decreased in the dry season, in contrast to the expected progression under drought stress. Recycling is an important facet of carbon balance for both species in both rainy and dry seasons. Leaf Na+ concentration was higher than values quoted for terrestrial salt stressed CAM plants. Fructose and glucose declined in leaf bases of T. flexuosa during the dark period, but not in the more distal regions of the leaf. S. humboldtiana showed a decrease in sucrose at night, and mannitol was also an important constituent of the leaves. Xylem sap tension maxima increased from 0.38 ± 0.09 MPa (rainy season) to only 0.55 ± 0.06 MPa (dry season) for T. flexuosa, these values being much lower than those found for terrestrial shrubs and herbs at the same site, the two epiphytes use CAM in conjunction with differing morphological adaptations to maintain growth throughout the year at the Ciénega el Ostional, but it would seem that T. flexuosa has better physiological characteristics for maintenance of carbon acquisition during the dry season.
Collapse
Affiliation(s)
- H Griffiths
- Department of Biology, The University, Newcastle upon Tyne, NE1 7RU, UK
| | - J A C Smith
- Department of Botany, University of Edinburgh, Edinburgh, EH9 3JH, UK
- Institut für Botanik, Technische Hochschule Darmstadt, D-6100 Darmstadt, FRG
| | - U Lüttge
- Institut für Botanik, Technische Hochschule Darmstadt, D-6100 Darmstadt, FRG
| | - M Popp
- Institut für Pflanzenphysiologie der Universität, A-1091 Wien, Austria
- Institut für Angewandte Botanik, Westfälische Wilhelms-Universität D-4400 Münister, FRG
| | - W J Cram
- Department of Biology, The University, Newcastle upon Tyne, NE1 7RU, UK
| | - M Diaz
- Centra de Investigaciones en Ecologia y Zonas Aridas, Universidad Nacional Experimental Francisco de Miranda, Cora, Venezuela
| | - H S J Lee
- Department of Biology, The University, Newcastle upon Tyne, NE1 7RU, UK
- Institut für Botanik, Technische Hochschule Darmstadt, D-6100 Darmstadt, FRG
| | - E Medina
- Centro de Ecologia y Ciencias Ambientales, Instituto Venezolano de Investigaciones Cientificas, Caracas 1020-A, Venezuela
| | - C SCHäfer
- Institut für Botanik, Technische Hochschule Darmstadt, D-6100 Darmstadt, FRG
| | - K-H Stimmel
- Institut für Botanik, Technische Hochschule Darmstadt, D-6100 Darmstadt, FRG
| |
Collapse
|
9
|
|
10
|
Carbon Dioxide Concentrating Mechanisms and the Evolution of CAM in Vascular Epiphytes. ECOLOGICAL STUDIES 1989. [DOI: 10.1007/978-3-642-74465-5_3] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
11
|
Earnshaw MJ, Winter K, Ziegler H, Stichler W, Cruttwell NEG, Kerenga K, Cribb PJ, Wood J, Croft JR, Carver KA, Gunn TC. Altitudinal changes in the incidence of crassulacean acid metabolism in vascular epiphytes and related life forms in Papua New Guinea. Oecologia 1987; 73:566-572. [DOI: 10.1007/bf00379417] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/1987] [Indexed: 10/26/2022]
|
12
|
Martin CE, Adams WW. Crassulacean acid metabolism, CO2-recycling, and tissue desiccation in the Mexican epiphyte Tillandsia schiedeana Steud (Bromeliaceae). PHOTOSYNTHESIS RESEARCH 1987; 11:237-244. [PMID: 24435539 DOI: 10.1007/bf00055063] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/1986] [Revised: 06/09/1986] [Accepted: 06/24/1986] [Indexed: 06/03/2023]
Abstract
After 23 days without water in a greenhouse, rates of nocturnal CO2 uptake in Tillandsia schiedeana decreased substantially and maximum rates occurred later in the dark period eventually coinciding with the onset of illumination. Nocturnal CO2 uptake accounted for less than half the total nighttime increase in acidity measured in well-watered plants. With increased tissue desiccation, only 11-12% of measured acid accumulation was attributable to atmospheric CO2 uptake. Plants desiccated for 30 days regained initial levels of nocturnal acid accumulation and CO2 uptake after rehydration for 10h. These results stress the importance of CO2 recycling via CAM in this epiphytic bromeliad, especially during droughts.
Collapse
Affiliation(s)
- C E Martin
- Department of Botany, University of Kansas, 66045, Lawrence, Kansas, USA
| | | |
Collapse
|