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Beckett HAA, Bryant C, Neeman T, Mencuccini M, Ball MC. Plasticity in branch water relations and stem hydraulic vulnerability enhances hydraulic safety in mangroves growing along a salinity gradient. PLANT, CELL & ENVIRONMENT 2024; 47:854-870. [PMID: 37975319 DOI: 10.1111/pce.14764] [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: 08/09/2023] [Revised: 10/05/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023]
Abstract
Coping with water stress depends on maintaining cellular function and hydraulic conductance. Yet measurements of vulnerability to drought and salinity do not often focus on capacitance in branch organs that buffer hydraulic function during water stress. The relationships between branch water relations, stem hydraulic vulnerability and stem anatomy were investigated in two co-occurring mangroves Aegiceras corniculatum and Rhizophora stylosa growing at low and high salinity. The dynamics of branch water release acted to conserve water content in the stem at the expense of the foliage during extended drying. Hydraulic redistribution from the foliage to the stem increased stem relative water content by up to 21%. The water potentials at which 12% and 50% loss of stem hydraulic conductivity occurred decreased by ~1.7 MPa in both species between low and high salinity sites. These coordinated tissue adjustments increased hydraulic safety despite declining turgor safety margins at higher salinity sites. Our results highlight the complex interplay of plasticity in organ-level water relations with hydraulic vulnerability in the maintenance of stem hydraulic function in mangroves distributed along salinity gradients. These results emphasise the importance of combining water relations and hydraulic vulnerability parameters to understand vulnerability to water stress across the whole plant.
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Affiliation(s)
- Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Callum Bryant
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Teresa Neeman
- Biological Data Science Institute, Australian National University, Canberra, Australia
| | - Maurizio Mencuccini
- Ecological and Forestry Applications Research Centre (CREAF), Barcelona, Bellaterra, Spain
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
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2
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Beckett HAA, Webb D, Turner M, Sheppard A, Ball MC. Bark water uptake through lenticels increases stem hydration and contributes to stem swelling. PLANT, CELL & ENVIRONMENT 2024; 47:72-90. [PMID: 37811590 DOI: 10.1111/pce.14733] [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: 03/09/2023] [Accepted: 09/26/2023] [Indexed: 10/10/2023]
Abstract
Foliar water uptake can recharge water storage tissue and enable greater hydration than through access to soil water alone; however, few studies have explored the role of the bark in facilitating water uptake. We investigated pathways and dynamics of bark water uptake (BWU) in stems of the mangrove Avicennia marina. We provide novel evidence that specific entry points control dynamics of water uptake through the outer bark surface. Furthermore, using a fluorescent symplastic tracer dye we provide the first evidence that lenticels on the outer bark surface facilitate BWU, thus increasing stem water content by up to 3.7%. X-ray micro-computed tomography showed that BWU was sufficient to cause measurable swelling of stem tissue layers increasing whole stem cross-sectional area by 0.83 mm2 or 2.8%, implicating it as a contributor to the diel patterns of water storage recharge that buffer xylem water potential and maintain hydration of living tissue.
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Affiliation(s)
- Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
| | - Daryl Webb
- Centre for Advanced Microscopy, Australian National University, Canberra, Australia
| | - Michael Turner
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, Australia
| | - Adrian Sheppard
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, Australia
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3
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Amada G, Yoshiko K, Kitayama K, Onoda Y. Roles of lower-side leaf trichomes in diffusion resistance and gas-exchange characteristics across environmental gradients in Metrosideros polymorpha. TREE PHYSIOLOGY 2023; 43:1400-1415. [PMID: 37098162 DOI: 10.1093/treephys/tpad053] [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: 11/20/2022] [Revised: 04/12/2023] [Accepted: 04/17/2023] [Indexed: 06/19/2023]
Abstract
Leaf trichomes on the lower leaf surface are common in many plant species, especially those grown under dry and/or low-temperature conditions; however, their adaptive significance remains unclear. Lower-side leaf trichomes can directly decrease gas fluxes through increased gas-diffusion resistance but can indirectly increase gas fluxes through increased leaf temperature owing to increased heat-diffusion resistance. We examined whether the combined direct and indirect effects of trichome resistance increase photosynthetic rates and water-use efficiency (WUE) using Metrosideros polymorpha Gaud., which varies widely in the masses of lower-side non-glandular leaf trichomes across various environments on the Hawaiian Islands. We employed both field surveys, including ecophysiological measurements at five elevation sites, and simulation analyses to predict the gas-exchange rates of leaves with various trichome-layer thicknesses across a wide range of environmental conditions. Field surveys showed that the trichome-layer thickness was the largest at the coldest and driest site and the thinnest at the wettest site. Field surveys, experimental manipulations and simulation analyses demonstrated that leaf trichomes significantly increased leaf temperature owing to the increased heat resistance. Simulation analyses showed that the effect of leaf trichomes on heat resistance was much larger than that on gas-flux resistance. Leaf trichomes can increase daily photosynthesis only in cold dry areas by increasing the leaf temperature. However, the increased leaf temperature with leaf trichomes resulted in a consistent decrease in the daily WUE at all elevation sites. The magnitudes of trichome effects on gas-exchange rates were associated with the temperature difference across the elevational gradient, the strong light intensity in Hawaii, the leaf-size variation and the conservative stomatal behavior of M. polymorpha as well as the trichome-layer thickness. In summary, the lower-side leaf trichomes in M. polymorpha can be beneficial for carbon assimilation in low-temperature environments but not for water conservation in most environments in terms of diffusion resistance.
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Affiliation(s)
- Gaku Amada
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
- Institute of Arctic Climate and Environment Research, Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001, Japan
| | - Kosugi Yoshiko
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kanehiro Kitayama
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yusuke Onoda
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
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4
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Li C, Mo Y, Wang N, Xing L, Qu Y, Chen Y, Yuan Z, Ali A, Qi J, Fernández V, Wang Y, Kopittke PM. The overlooked functions of trichomes: Water absorption and metal detoxication. PLANT, CELL & ENVIRONMENT 2023; 46:669-687. [PMID: 36581782 DOI: 10.1111/pce.14530] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 12/20/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Trichomes are epidermal outgrowths on plant shoots. Their roles in protecting plants against herbivores and in the biosynthesis of specialized metabolites have long been recognized. Recently, studies are increasingly showing that trichomes also play important roles in water absorption and metal detoxication, with these roles having important implications for ecology, the environment, and agriculture. However, these two functions of trichomes have been largely overlooked and much remains unknown. In this review, we show that the trichomes of 37 plant species belonging to 14 plant families are involved in water absorption, while the trichomes of 33 species from 13 families are capable of sequestering metals within their trichomes. The ability of trichomes to absorb water results from their decreased hydrophobicity compared to the remainder of the leaf surface as well as the presence of special structures for collecting and absorbing water. In contrast, the metal detoxication function of trichomes results not only from the good connection of their basal cells to the underlying vascular tissues, but also from the presence of metal-chelating ligands and transporters within the trichomes themselves. Knowledge gaps and critical future research questions regarding these two trichome functions are highlighted. This review improves our understanding on trichomes.
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Affiliation(s)
- Cui Li
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Yingying Mo
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Nina Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Longyi Xing
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Yang Qu
- Baoji Academy of Agriculture Sciences, Baoji, China
| | - Yanlong Chen
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Zuoqiang Yuan
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Arshad Ali
- College of Life Sciences, Hebei University, Hebei, China
| | - Jiyan Qi
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Victoria Fernández
- School of Forest Engineering, Technical University of Madrid, Madrid, Spain
| | - Yuheng Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Peter M Kopittke
- School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Queensland, Australia
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5
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Fuenzalida TI, Blacker MJ, Turner M, Sheppard A, Ball MC. Foliar water uptake enables embolism removal in excised twigs of Avicennia marina. THE NEW PHYTOLOGIST 2023; 237:1136-1145. [PMID: 36372990 DOI: 10.1111/nph.18613] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
Embolism refilling is thought to require relaxation of xylem tension, and it is unclear whether and how tall trees or plants growing in arid or saline soils recover from embolism. We tested whether foliar water uptake could enable embolism refilling in dehydrated twigs of the grey mangrove (Avicennia marina). Four dehydrated twigs were imaged by laboratory-based micro-computed tomography before and after wetting leaves. Emboli were observed in dehydrated stems and leaves. Embolism decreased with increasing distance from the cut end of stems, suggesting that stem emboli were caused by cutting. A significant (P = 0.026) c. 80% reduction in the embolised area was observed in leaves between the start and the end of the experiment (29 ± 10 h after wetting). Embolus diameter was unaffected by wetting. Embolism refilling occurred slowly, in stems embolised by cutting and leaves embolised by cutting and/or dehydration. The lack of response of embolus diameter to wetting suggests that capillarity was not the main mechanism for refilling. Results show that excised twigs of A. marina are able to recover from embolism by absorption of atmospheric water and call for studies under natural conditions.
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Affiliation(s)
- Tomás I Fuenzalida
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - Matthew J Blacker
- Department of Quantum Science, Research School of Physics, Australian National University, Canberra, ACT, 2601, Australia
| | - Michael Turner
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, ACT, 2601, Australia
| | - Adrian Sheppard
- Department of Applied Mathematics, Research School of Physics, Australian National University, Canberra, ACT, 2601, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
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6
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Jiang (蒋国凤) GF, Li (李溯源) SY, Li (李艺蝉) YC, Roddy AB. Coordination of hydraulic thresholds across roots, stems, and leaves of two co-occurring mangrove species. PLANT PHYSIOLOGY 2022; 189:2159-2174. [PMID: 35640109 PMCID: PMC9342987 DOI: 10.1093/plphys/kiac240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 05/09/2022] [Indexed: 05/30/2023]
Abstract
Mangroves are frequently inundated with saline water and have evolved different anatomical and physiological mechanisms to filter and, in some species, excrete excess salt from the water they take up. Because salts impose osmotic stress, interspecific differences in salt tolerance and salt management strategy may influence physiological responses to drought throughout the entire plant hydraulic pathway, from roots to leaves. Here, we characterized embolism vulnerability simultaneously in leaves, stems, and roots of seedlings of two mangrove species (Avicennia marina and Bruguiera gymnorrhiza) along with turgor-loss points in roots and leaves and xylem anatomical traits. In both species, the water potentials causing 50% of total embolism were less negative in roots and leaves than they were in stems, but the water potentials causing incipient embolism (5%) were similar in roots, stems, and leaves. Stomatal closure in leaves and turgor loss in both leaves and roots occurred at water potentials only slightly less negative than the water potentials causing 5% of total embolism. Xylem anatomical traits were unrelated to vulnerability to embolism. Vulnerability segmentation may be important in limiting embolism spread into stems from more vulnerable roots and leaves. Interspecific differences in salt tolerance affected hydraulic traits from roots to leaves: the salt-secretor A. marina lost turgor at more negative water potentials and had more embolism-resistant xylem than the salt-excluder B. gymnorrhiza. Characterizing physiological thresholds of roots may help to explain recent mangrove mortality after drought and extended saltwater inundation.
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Affiliation(s)
| | - Su-Yuan Li (李溯源)
- Guangxi Key Laboratory of Forest Ecology and Conservation, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yi-Chan Li (李艺蝉)
- Guangxi Key Laboratory of Forest Ecology and Conservation, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning 530004, China
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7
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Rodriguez‐Dominguez CM, Forner A, Martorell S, Choat B, Lopez R, Peters JMR, Pfautsch S, Mayr S, Carins‐Murphy MR, McAdam SAM, Richardson F, Diaz‐Espejo A, Hernandez‐Santana V, Menezes‐Silva PE, Torres‐Ruiz JM, Batz TA, Sack L. Leaf water potential measurements using the pressure chamber: Synthetic testing of assumptions towards best practices for precision and accuracy. PLANT, CELL & ENVIRONMENT 2022; 45:2037-2061. [PMID: 35394651 PMCID: PMC9322401 DOI: 10.1111/pce.14330] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/21/2022] [Accepted: 03/26/2022] [Indexed: 05/24/2023]
Abstract
Leaf water potential (ψleaf ), typically measured using the pressure chamber, is the most important metric of plant water status, providing high theoretical value and information content for multiple applications in quantifying critical physiological processes including drought responses. Pressure chamber measurements of ψleaf (ψleafPC ) are most typical, yet, the practical complexity of the technique and of the underlying theory has led to ambiguous understanding of the conditions to optimize measurements. Consequently, specific techniques and precautions diversified across the global research community, raising questions of reliability and repeatability. Here, we surveyed specific methods of ψleafPC from multiple laboratories, and synthesized experiments testing common assumptions and practices in ψleafPC for diverse species: (i) the need for equilibration of previously transpiring leaves; (ii) leaf storage before measurement; (iii) the equilibration of ψleaf for leaves on bagged branches of a range of dehydration; (iv) the equilibration of ψleaf across the lamina for bagged leaves, and the accuracy of measuring leaves with artificially 'elongated petioles'; (v) the need in ψleaf measurements for bagging leaves and high humidity within the chamber; (vi) the need to avoid liquid water on leaf surfaces; (vii) the use of 'pulse' pressurization versus gradual pressurization; and (viii) variation among experimenters in ψleafPC determination. Based on our findings we provide a best practice protocol to maximise accuracy, and provide recommendations for ongoing species-specific tests of important assumptions in future studies.
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Affiliation(s)
- Celia M. Rodriguez‐Dominguez
- Protection of the Soil, Plant, Water SystemIrrigation and Crop Ecophysiology Group, IRNAS‐CSICSevillaSpain
- Plant BiotechnologyLaboratory of Plant Molecular Ecophysiology, IRNAS‐CSICSevillaSpain
| | - Alicia Forner
- Department of Biogeography and Global Change, International Global Change Laboratory (LINCGlobal), Museo Nacional de Ciencias NaturalesConsejo Superior de Investigaciones CientíficasMadridSpain
- Department of Ecology, Centro de Investigaciones sobre Desertificación, Consejo Superior de Investigaciones Científicas (CSIC)University of València and Generalitat ValencianaValenciaSpain
| | - Sebastia Martorell
- Departament de Biologia, Research Group on Plant Biology under Mediterranean ConditionsUniversitat de les Illes BalearsPalma de MallorcaSpain
| | - Brendan Choat
- Plants, Animals and Interactions, Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Rosana Lopez
- Departamento de Sistemas y Recursos NaturalesUniversidad Politécnica de MadridMadridSpain
| | - Jennifer M. R. Peters
- Division of Environmental Science, Oak Ridge National LaboratoryClimate Change Science InstituteOak RidgeTennesseeUSA
| | - Sebastian Pfautsch
- Geography, Tourism and Urban Planning, Urban Studies, School of Social Science and PsychologyWestern Sydney UniversityPenrithNew South WalesAustralia
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Madeline R. Carins‐Murphy
- Plant Sciences, Discipline of Biological Sciences, School of Natural SciencesUniversity of TasmaniaHobartAustralia
| | - Scott A. M. McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndianaUSA
| | - Freya Richardson
- Plant Sciences, Discipline of Biological Sciences, School of Natural SciencesUniversity of TasmaniaHobartAustralia
| | - Antonio Diaz‐Espejo
- Protection of the Soil, Plant, Water SystemIrrigation and Crop Ecophysiology Group, IRNAS‐CSICSevillaSpain
- Plant BiotechnologyLaboratory of Plant Molecular Ecophysiology, IRNAS‐CSICSevillaSpain
| | - Virginia Hernandez‐Santana
- Protection of the Soil, Plant, Water SystemIrrigation and Crop Ecophysiology Group, IRNAS‐CSICSevillaSpain
- Plant BiotechnologyLaboratory of Plant Molecular Ecophysiology, IRNAS‐CSICSevillaSpain
| | - Paulo E. Menezes‐Silva
- Laboratory of Integrative Physics and Physiology of Trees in a Fluctuating EnvironmentUniversité Clermont‐Auvergne, INRAE, PIAFClermont‐FerrandFrance
| | - Jose M. Torres‐Ruiz
- Laboratory of Integrative Physics and Physiology of Trees in a Fluctuating EnvironmentUniversité Clermont‐Auvergne, INRAE, PIAFClermont‐FerrandFrance
| | - Timothy A. Batz
- Department of Botany and Plant Pathology, Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndianaUSA
| | - Lawren Sack
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaLos AngelesCaliforniaUSA
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8
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Abstract
Foliar water uptake (FWU) is a mechanism that enables plants to acquire water from the atmosphere through their leaves. As mangroves live in a saline sediment water environment, the mechanism of FWU might be of vital importance to acquire freshwater and grow. The goal of this study was to assess the FWU capacity of six different mangrove species belonging to four genera using a series of submersion experiments in which the leaf mass increase was measured and expressed per unit leaf area. The foliar water uptake capacity differed between species with the highest and lowest average water uptake in Avicennia marina (Forssk.) Vierh. (1.52 ± 0.48 mg H2O cm−2) and Bruguiera gymnorhiza (L.) Lam. (0.13 ± 0.06 mg H2O cm−2), respectively. Salt-excreting species showed a higher FWU capacity than non-excreting species. Moreover, A. marina, a salt-excreting species, showed a distinct leaf anatomical trait, i.e., trichomes, which were not observed in the other species and might be involved in the water absorption process. The storage of leaves in moist Ziplock bags prior to measurement caused leaf water uptake to already occur during transport to the field station, which proportionately increased the leaf water potential (A. marina: −0.31 ± 0.13 MPa and B. gymnorhiza: −2.70 ± 0.27 MPa). This increase should be considered when performing best practice leaf water potential measurements but did not affect the quantification of FWU capacity because of the water potential gradient between a leaf and the surrounding water during submersion. Our results highlight the differences that exist in FWU capacity between species residing in the same area and growing under the same environmental conditions. This comparative study therefore enhances our understanding of mangrove species’ functioning.
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9
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Preisler Y, Hölttä T, Grünzweig JM, Oz I, Tatarinov F, Ruehr NK, Rotenberg E, Yakir D. The importance of tree internal water storage under drought conditions. TREE PHYSIOLOGY 2022; 42:771-783. [PMID: 34726242 DOI: 10.1093/treephys/tpab144] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
Global warming and drying trends, as well as the increase in frequency and intensity of droughts, may have unprecedented impacts on various forest ecosystems. We assessed the role of internal water storage (WS) in drought resistance of mature pine trees in the semi-arid Yatir Forest. Transpiration (T), soil moisture and sap flow (SF) were measured continuously, accompanied by periodical measurements of leaf and branch water potential (Ψleaf) and water content (WC). The data were used to parameterize a tree hydraulics model to examine the impact of WS capacitance on the tree water relations. The results of the continuous measurements showed a 5-h time lag between T and SF in the dry season, which peaked in the early morning and early afternoon, respectively. A good fit between model results and observations was only obtained when the empirically estimated WS capacitance was included in the model. Without WS during the dry season, Ψleaf would drop below a threshold known to cause hydraulic failure and cessation of gas exchange in the studied tree species. Our results indicate that tree WS capacitance is a key drought resistance trait that could enhance tree survival in a drying climate, contributing up to 45% of the total daily transpiration during the dry season.
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Affiliation(s)
- Yakir Preisler
- Earth and Planetary Science, Weizmann Institute of Science, 234 Herzl St. Rehovot, Rehovot 7610001, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Herzl Street POB 12, Rehovot 7610001, Israel
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 3 Yliopistonkatu st, 0001 Helsinki, Finland
| | - José M Grünzweig
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Herzl Street POB 12, Rehovot 7610001, Israel
| | - Itay Oz
- Earth and Planetary Science, Weizmann Institute of Science, 234 Herzl St. Rehovot, Rehovot 7610001, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Herzl Street POB 12, Rehovot 7610001, Israel
| | - Fedor Tatarinov
- Earth and Planetary Science, Weizmann Institute of Science, 234 Herzl St. Rehovot, Rehovot 7610001, Israel
| | - Nadine K Ruehr
- Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research-Atmospheric Environmental Research (IMK-IFU), Garmisch-Partenkirchen 82467, Germany
| | - Eyal Rotenberg
- Earth and Planetary Science, Weizmann Institute of Science, 234 Herzl St. Rehovot, Rehovot 7610001, Israel
| | - Dan Yakir
- Earth and Planetary Science, Weizmann Institute of Science, 234 Herzl St. Rehovot, Rehovot 7610001, Israel
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10
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Boanares D, Bueno A, de Souza AX, Kozovits AR, Sousa HC, Pimenta LPS, Isaias RMDS, França MGC. Cuticular wax composition contributes to different strategies of foliar water uptake in six plant species from foggy rupestrian grassland in tropical mountains. PHYTOCHEMISTRY 2021; 190:112894. [PMID: 34364088 DOI: 10.1016/j.phytochem.2021.112894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/21/2021] [Accepted: 07/31/2021] [Indexed: 06/13/2023]
Abstract
The cuticle is the outermost region of the epidermal cell wall of plant aerial organs. The cuticle acts as a two-way lipid barrier for water diffusion; therefore, it plays a vital role in foliar water uptake (FWU). We hypothesised that the chemical composition of the cuticular waxes influences the FWU strategy that plants adopt in a foggy tropical ecosystem. We analysed the leaf cuticular waxes of six plant species known by their different FWU strategies, in both qualitative and quantitative approaches, to test this hypothesis. We also investigated the fine structure of the plant cuticle by scanning electron microscopy. Neither the total wax loads nor the amounts of single wax compound classes correlated to the FWU. In contrast, the qualitative chemical composition of the cuticular waxes was related to the water absorption speed but not to the maximum water absorbed. The presence of wax crystals might interfere with the FWU. Our findings suggest that a complex three-dimensional network of the cuticular compounds contributes to different strategies of FWU in six plant species from foggy tropical mountaintops.
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Affiliation(s)
- Daniela Boanares
- Departamento de Botânica, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
| | - Amauri Bueno
- University of Würzburg, Julius-von-Sachs Institute of Biological Sciences, Chair of Botany II - Ecophysiology and Vegetation Ecology, Würzburg, Germany.
| | - Aline Xavier de Souza
- University of Würzburg, Julius-von-Sachs Institute of Biological Sciences, Chair of Botany II - Ecophysiology and Vegetation Ecology, Würzburg, Germany
| | | | - Hildeberto Caldas Sousa
- Departamento de Biodiversidade, Evolução e Meio Ambiente, Universidade Federal de Ouro Preto, Minas Gerais, Brazil
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11
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Bryant C, Fuenzalida TI, Zavafer A, Nguyen HT, Brothers N, Harris RJ, Beckett HAA, Holmlund HI, Binks O, Ball MC. Foliar water uptake via cork warts in mangroves of the Sonneratia genus. PLANT, CELL & ENVIRONMENT 2021; 44:2925-2937. [PMID: 34118083 DOI: 10.1111/pce.14129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
Foliar water uptake (FWU) occurs in plants of diverse ecosystems; however, the diversity of pathways and their associated FWU kinetics remain poorly resolved. We characterized a novel FWU pathway in two mangrove species of the Sonneratia genus, S. alba and S. caseolaris. Further, we assessed the influence of leaf wetting duration, wet-dry seasonality and leaf dehydration on leaf conductance to surface water (Ksurf ). The symplastic tracer dye, disodium fluorescein, revealed living cells subtending and encircling leaf epidermal structures known as cork warts as a pathway of FWU entry into the leaf. Rehydration kinetics experiments revealed a novel mode of FWU, with slow and steady rates of water uptake persistent over a duration of 12 hr. Ksurf increased with longer durations of leaf wetting and was greater in leaves with more negative water potentials at the initiation of leaf wetting. Ksurf declined by 68% between wet and dry seasons. Our results suggest that FWU via cork warts in Sonneratia sp. may be rate limited and under active regulation. We conclude that FWU pathways in halophytes may require ion exclusion to avoid uptake of salt when inundated, paralleling the capacity of halophyte roots for ion selectivity during water acquisition.
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Affiliation(s)
- Callum Bryant
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Tomas I Fuenzalida
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Alonso Zavafer
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Hoa T Nguyen
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
- Vietnam National University of Agriculture, Trau Quy, Gia Lam, Ha Noi, Vietnam
| | - Nigel Brothers
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Rosalie J Harris
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Holly A A Beckett
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Helen I Holmlund
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
- Pepperdine University, Natural Science Division, Malibu, CA, 90263, USA
| | - Oliver Binks
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
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12
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Coopman RE, Nguyen HT, Mencuccini M, Oliveira RS, Sack L, Lovelock CE, Ball MC. Harvesting water from unsaturated atmospheres: deliquescence of salt secreted onto leaf surfaces drives reverse sap flow in a dominant arid climate mangrove, Avicennia marina. THE NEW PHYTOLOGIST 2021; 231:1401-1414. [PMID: 33983649 DOI: 10.1111/nph.17461] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
The mangrove Avicennia marina adjusts internal salt concentrations by foliar salt secretion. Deliquescence of accumulated salt causes leaf wetting that may provide a water source for salt-secreting plants in arid coastal wetlands where high nocturnal humidity can usually support deliquescence whereas rainfall events are rare. We tested the hypotheses that salt deliquescence on leaf surfaces can drive top-down rehydration, and that such absorption of moisture from unsaturated atmospheres makes a functional contribution to dry season shoot water balances. Sap flow and water relations were monitored to assess the uptake of atmospheric water by branches during shoot wetting events under natural and manipulated microclimatic conditions. Reverse sap flow rates increased with increasing relative humidity from 70% to 89%, consistent with function of salt deliquescence in harvesting moisture from unsaturated atmospheres. Top-down rehydration elevated branch water potentials above those possible from root water uptake, subsidising transpiration rates and reducing branch vulnerability to hydraulic failure in the subsequent photoperiod. Absorption of atmospheric moisture harvested through deliquescence of salt on leaf surfaces enhances water balances of Avicennia marina growing in hypersaline wetlands under arid climatic conditions. Top-down rehydration from these frequent, low intensity wetting events contributes to prevention of carbon starvation and hydraulic failure during drought.
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Affiliation(s)
- Rafael E Coopman
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
- Ecophysiology Laboratory for Forest Conservation, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Campus Isla Teja, Casilla 567, Valdivia, Chile
| | - Hoa T Nguyen
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
- Department of Botany, Faculty of Agronomy, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Hanoi, 131000, Vietnam
| | - Maurizio Mencuccini
- CREAF, Universidad Autonoma de Barcelona, Cerdanyola del Valles 08193, Barcelona, Spain
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, CP6109, Brazil
| | - Lawren Sack
- Department of Ecology and Evolution, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Catherine E Lovelock
- School of Biological Sciences, The University of Queensland, St Lucia, Qld, 4072, Australia
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
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13
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Foliar water uptake in arid ecosystems: seasonal variability and ecophysiological consequences. Oecologia 2020; 193:337-348. [PMID: 32474806 DOI: 10.1007/s00442-020-04673-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 05/19/2020] [Indexed: 10/24/2022]
Abstract
Foliar water uptake (FWU) has been reported for different species across several ecosystems types. However, little attention has been given to arid ecosystems, where FWU during dew formation or small rain events could ameliorate water deficits. FWU and their effects on leaf water potential (ΨLeaf) were evaluated in grasses and shrubs exploring different soil water sources in a Patagonian steppe. Also, seasonal variability in FWU and the role of cell wall elasticity in determining the effects on ΨLeaf were assessed. Eleven small rain events (< 8 mm) and 45 days with dew formation were recorded during the study period. All species exhibited FWU after experimental wetting. There was a large variability in FWU across species, from 0.04 mmol m-2 s-1 in species with deep roots to 0.75 mmol m-2 s-1 in species with shallow roots. Species-specific mean FWU rates were positively correlated with mean transpiration rates. The increase in ΨLeaf after leaf wetting varied between 0.65 MPa and 1.67 MPa across species and seasons. The effects of FWU on ΨLeaf were inversely correlated with cell wall elasticity. FWU integrated over both seasons varied between 28 mol m-2 in species with deep roots to 361 mol m-2 in species with shallow roots. Taking into account the percentage of coverage of each species, accumulated FWU represented 1.6% of the total annual transpiration of grasses and shrubs in this ecosystem. Despite this low FWU integrated over time compared to transpiration, wetting leaves surfaces can help to avoid larger water deficit during the dry season.
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14
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Binks O, Coughlin I, Mencuccini M, Meir P. Equivalence of foliar water uptake and stomatal conductance? PLANT, CELL & ENVIRONMENT 2020; 43:524-528. [PMID: 31677188 DOI: 10.1111/pce.13663] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/29/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Affiliation(s)
- Oliver Binks
- Research School of Biology, The Australian National University, Canberra, 2601, Australian Capital Territory, Australia
| | - Ingrid Coughlin
- Research School of Biology, The Australian National University, Canberra, 2601, Australian Capital Territory, Australia
| | | | - Patrick Meir
- Research School of Biology, The Australian National University, Canberra, 2601, Australian Capital Territory, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
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15
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Fuenzalida TI, Bryant CJ, Ovington LI, Yoon HJ, Oliveira RS, Sack L, Ball MC. Shoot surface water uptake enables leaf hydraulic recovery in Avicennia marina. THE NEW PHYTOLOGIST 2019; 224:1504-1511. [PMID: 31419324 DOI: 10.1111/nph.16126] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/11/2019] [Indexed: 05/08/2023]
Abstract
The significance of shoot surface water uptake (SSWU) has been debated, and it would depend on the range of conditions under which it occurs. We hypothesized that the decline of leaf hydraulic conductance (Kleaf ) in response to dehydration may be recovered through SSWU, and that the hydraulic conductance to SSWU (Ksurf ) declines with dehydration. We quantified effects of leaf dehydration on Ksurf and effects of SSWU on recovery of Kleaf in dehydrated leaves of Avicennia marina. SSWU led to overnight recovery of Kleaf , with recovery retracing the same path as loss of Kleaf in response to dehydration. SSWU declined with dehydration. By contrast, Ksurf declined with rehydration time but not with dehydration. Our results showed a role of SSWU in the recovery of leaf hydraulic conductance and revealed that SSWU is sensitive to leaf hydration status. The prevalence of SSWU in vegetation suggests an important role for atmospheric water sources in maintenance of leaf hydraulic function, with implications for plant responses to changing environments.
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Affiliation(s)
- Tomás I Fuenzalida
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - Callum J Bryant
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - Leuwin I Ovington
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - Hwan-Jin Yoon
- Statistical Consulting Unit, The Australian National University, Acton, ACT, 2601, Australia
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas - UNICAMP, Campinas, São Paulo, CP 6109, Brazil
| | - Lawren Sack
- Department of Ecology and Evolution, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Marilyn C Ball
- Plant Science Division, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
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16
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Vilas MP, Adams MP, Ball MC, Meynecke JO, Santini NS, Swales A, Lovelock CE. Night and day: Shrinking and swelling of stems of diverse mangrove species growing along environmental gradients. PLoS One 2019; 14:e0221950. [PMID: 31479477 PMCID: PMC6719867 DOI: 10.1371/journal.pone.0221950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 08/19/2019] [Indexed: 12/22/2022] Open
Abstract
Tree stems swell and shrink daily, which is thought to reflect changes in the volume of water within stem tissues. We observed these daily patterns using automatic dendrometer bands in a diverse group of mangrove species over five mangrove forests across Australia and New Caledonia. We found that mangrove stems swelled during the day and shrank at night. Maximum swelling was highly correlated with daily maxima in air temperature. Variation in soil salinity and levels of tidal inundation did not influence the timing of stem swelling over all species. Medium-term increases in stem circumference were highly sensitive to rainfall. We defoliated trees to assess the role of foliar transpiration in stem swelling and shrinking. Defoliated trees showed maintenance of the pattern of daytime swelling, indicating that processes other than canopy transpiration influence the temporary stem diameter increments, which could include thermal swelling of stems. More research is required to understand the processes contributing to stem shrinking and swelling. Automatic Dendrometer Bands could provide a useful tool for monitoring the response of mangroves to extreme climatic events as they provide high-frequency, long-term, and large-scale information on tree water status.
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Affiliation(s)
- Maria P. Vilas
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, Australia
- CSIRO Agriculture and Food, Biosciences Precinct, St Lucia, QLD, Australia
| | - Matthew P. Adams
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD, Australia
- School of Earth and Environmental Sciences, The University of Queensland, St Lucia, QLD, Australia
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Marilyn C. Ball
- Research School of Biology, Australian National University College of Science, Australian National University, Canberra ACT, Australia
| | - Jan-Olaf Meynecke
- Griffith Centre for Coastal Management, Griffith University, Gold Coast, QLD, Australia
| | - Nadia S. Santini
- Cátedra Consejo Nacional de Ciencia y Tecnología, Crédito Constructor, Benito Juárez, Ciudad de México, México
- Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México
| | - Andrew Swales
- National Institute of Water and Atmospheric Research, Hamilton, New Zealand
| | - Catherine E. Lovelock
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
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17
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Schreel JDM, Van de Wal BAE, Hervé-Fernandez P, Boeckx P, Steppe K. Hydraulic redistribution of foliar absorbed water causes turgor-driven growth in mangrove seedlings. PLANT, CELL & ENVIRONMENT 2019; 42:2437-2447. [PMID: 30953380 DOI: 10.1111/pce.13556] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 03/25/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
Although foliar water uptake (FWU) has been shown in mature Avicennia marina trees, the importance for its seedlings remains largely unknown. A series of experiments were therefore performed using artificial rainfall events in a greenhouse environment to assess the ecological implications of FWU in A. marina seedlings. One-hour artificial rainfall events resulted in an increased leaf water potential, a reversed sap flow, and a rapid diameter increment signifying a turgor-driven growth of up to 30.1 ± 5.4 μm. Furthermore, the application of an artificial rainfall event with deuterated water showed that the amount of water absorbed by the leaves and transported to the stem was directly and univocally correlated to the observed growth spurts. The observations in this process-based study show that FWU is an important water acquisition mechanism under certain circumstances and might be of ecological importance for the establishment of A. marina seedlings. Distribution of mangrove trees might hence be more significantly disturbed by climate change-driven changes in rainfall patterns than previously assumed.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Bart A E Van de Wal
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Pedro Hervé-Fernandez
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
- Isotope Bioscience Laboratory (ISOFYS), Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Pascal Boeckx
- Isotope Bioscience Laboratory (ISOFYS), Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, 9000, Belgium
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18
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Binks O, Mencuccini M, Rowland L, da Costa ACL, de Carvalho CJR, Bittencourt P, Eller C, Teodoro GS, Carvalho EJM, Soza A, Ferreira L, Vasconcelos SS, Oliveira R, Meir P. Foliar water uptake in Amazonian trees: Evidence and consequences. GLOBAL CHANGE BIOLOGY 2019; 25:2678-2690. [PMID: 31012521 DOI: 10.1111/gcb.14666] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 04/05/2019] [Accepted: 04/12/2019] [Indexed: 06/09/2023]
Abstract
The absorption of atmospheric water directly into leaves enables plants to alleviate the water stress caused by low soil moisture, hydraulic resistance in the xylem and the effect of gravity on the water column, while enabling plants to scavenge small inputs of water from leaf-wetting events. By increasing the availability of water, and supplying it from the top of the canopy (in a direction facilitated by gravity), foliar uptake (FU) may be a significant process in determining how forests interact with climate, and could alter our interpretation of current metrics for hydraulic stress and sensitivity. FU has not been reported for lowland tropical rainforests; we test whether FU occurs in six common Amazonian tree genera in lowland Amazônia, and make a first estimation of its contribution to canopy-atmosphere water exchange. We demonstrate that FU occurs in all six genera and that dew-derived water may therefore be used to "pay" for some morning transpiration in the dry season. Using meteorological and canopy wetness data, coupled with empirically derived estimates of leaf conductance to FU (kfu ), we estimate that the contribution by FU to annual transpiration at this site has a median value of 8.2% (103 mm/year) and an interquartile range of 3.4%-15.3%, with the biggest sources of uncertainty being kfu and the proportion of time the canopy is wet. Our results indicate that FU is likely to be a common strategy and may have significant implications for the Amazon carbon budget. The process of foliar water uptake may also have a profound impact on the drought tolerance of individual Amazonian trees and tree species, and on the cycling of water and carbon, regionally and globally.
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Affiliation(s)
- Oliver Binks
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | | | - Lucy Rowland
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | | | - Paulo Bittencourt
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Cleiton Eller
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | | | - Azul Soza
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | | | | | - Rafael Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | - Patrick Meir
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- School of Geosciences, University of Edinburgh, Edinburgh, UK
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19
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Martinez-Vilalta J, Anderegg WRL, Sapes G, Sala A. Greater focus on water pools may improve our ability to understand and anticipate drought-induced mortality in plants. THE NEW PHYTOLOGIST 2019; 223:22-32. [PMID: 30560995 DOI: 10.1111/nph.15644] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/06/2018] [Indexed: 05/23/2023]
Abstract
Drought-induced tree mortality has major impacts on ecosystem carbon and water cycles, and is expected to increase in forests across the globe with climate change. A large body of research in the past decade has advanced our understanding of plant water and carbon relations under drought. However, despite intense research, we still lack generalizable, cross-scale indicators of mortality risk. In this Viewpoint, we propose that a more explicit consideration of water pools could improve our ability to monitor and anticipate mortality risk. Specifically, we focus on the relative water content (RWC), a classic metric in plant water relations, as a potential indicator of mortality risk that is physiologically relevant and integrates different aspects related to hydraulics, stomatal responses and carbon economy under drought. Measures of plant water content are likely to have a strong mechanistic link with mortality and to be integrative, threshold-prone and relatively easy to measure and monitor at large spatial scales, and may complement current mortality metrics based on water potential, loss of hydraulic conductivity and nonstructural carbohydrates. We discuss some of the potential advantages and limitations of these metrics to improve our capacity to monitor and predict drought-induced tree mortality.
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Affiliation(s)
- Jordi Martinez-Vilalta
- CREAF, Cerdanyola del Valles, 08193, Barcelona, Spain
- Universitat Autònoma de Barcelona, Cerdanyola del Valles, 08193, Barcelona, Spain
| | | | - Gerard Sapes
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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20
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Fu X, Meinzer FC, Woodruff DR, Liu YY, Smith DD, McCulloh KA, Howard AR. Coordination and trade-offs between leaf and stem hydraulic traits and stomatal regulation along a spectrum of isohydry to anisohydry. PLANT, CELL & ENVIRONMENT 2019; 42:2245-2258. [PMID: 30820970 DOI: 10.1111/pce.13543] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/22/2019] [Accepted: 02/24/2019] [Indexed: 06/09/2023]
Abstract
The degree of plant iso/anisohydry, a widely used framework for classifying species-specific hydraulic strategies, integrates multiple components of the whole-plant hydraulic pathway. However, little is known about how it associates with coordination of functional and structural traits within and across different organs. We examined stem and leaf hydraulic capacitance and conductivity/conductance, stem xylem anatomical features, stomatal regulation of daily minimum leaf and stem water potential (Ψ), and the kinetics of stomatal responses to vapour pressure deficit (VPD) in six diverse woody species differing markedly in their degree of iso/anisohydry. At the stem level, more anisohydric species had higher wood density and lower native capacitance and conductivity. Like stems, leaves of more anisohydric species had lower hydraulic conductance; however, unlike stems, their leaves had higher native capacitance at their daily minimum values of leaf Ψ. Moreover, rates of VPD-induced stomatal closure were related to intrinsic rather than native leaf capacitance and were not associated with species' degree of iso/anisohydry. Our results suggest a trade-off between hydraulic storage and efficiency in the leaf, but a coordination between hydraulic storage and efficiency in the stem along a spectrum of plant iso/anisohydry.
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Affiliation(s)
- Xiaoli Fu
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
- Zhongke-Ji'an Institute for Eco-Environmental Sciences, Ji'an, China
| | | | - David R Woodruff
- USDA Forest Service, Pacific Northwest Research Station, Corvallis, Oregon
| | - Yan-Yan Liu
- Key Laboratory of Environment Change and Resources Use in Beibu Gulf, Ministry of Education, Guangxi Teachers Education University, Nanning, China
| | - Duncan D Smith
- Department of Botany, University of Wisconsin, Madison, Wisconsin
| | | | - Ava R Howard
- Department of Biology, Western Oregon University, Monmouth, Oregon
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21
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Hilty J, Pook C, Leuzinger S. Water relations determine short time leaf growth patterns in the mangrove Avicennia marina (Forssk.) Vierh. PLANT, CELL & ENVIRONMENT 2019; 42:527-535. [PMID: 30171613 DOI: 10.1111/pce.13435] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/13/2018] [Accepted: 08/15/2018] [Indexed: 06/08/2023]
Abstract
High-resolution leaf growth is rarely studied despite its importance as a metric for plant performance and resource use efficiency. This is in part due to methodological challenges. Here, we present a method for in situ leaf growth measurements in a natural environment. We measured instantaneous leaf growth on a mature Avicennia marina subsp. australasica tree over several weeks. We measured leaf expansion by taking time-lapse images and analysing them using marker tracking software. A custom-made instrument was designed to enable long-term field studies. We detected a distinct diel growth pattern with leaf area shrinkage in the morning and leaf expansion in the afternoon and at night. On average, the observed daily shrinkage was 37% of the net growth. Most of the net growth occurred at night. Diel leaf area shrinkage and recovery continued after growth cessation. The amount of daily growth was negatively correlated with shrinkage, and instantaneous leaf growth and shrinkage were correlated with changes in leaf turgor. We conclude that, at least in this tree species, instantaneous leaf growth patterns are very strongly linked to, and most likely driven by, leaf water relations, suggesting decoupling of short-term growth patterns from carbon assimilation.
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Affiliation(s)
- Jonas Hilty
- Institute for Applied Ecology New Zealand, School of Science, Auckland University of Technology, Auckland, New Zealand
| | - Chris Pook
- Institute for Applied Ecology New Zealand, School of Science, Auckland University of Technology, Auckland, New Zealand
| | - Sebastian Leuzinger
- Institute for Applied Ecology New Zealand, School of Science, Auckland University of Technology, Auckland, New Zealand
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22
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Berry ZC, Emery NC, Gotsch SG, Goldsmith GR. Foliar water uptake: Processes, pathways, and integration into plant water budgets. PLANT, CELL & ENVIRONMENT 2019; 42:410-423. [PMID: 30194766 DOI: 10.1111/pce.13439] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 08/27/2018] [Accepted: 08/28/2018] [Indexed: 05/04/2023]
Abstract
Nearly all plant families, represented across most major biomes, absorb water directly through their leaves. This phenomenon is commonly referred to as foliar water uptake. Recent studies have suggested that foliar water uptake provides a significant water subsidy that can influence both plant water and carbon balance across multiple spatial and temporal scales. Despite this, our mechanistic understanding of when, where, how, and to what end water is absorbed through leaf surfaces remains limited. We first review the evidence for the biophysical conditions necessary for foliar water uptake to occur, focusing on the plant and atmospheric water potentials necessary to create a gradient for water flow. We then consider the different pathways for uptake, as well as the potential fates of the water once inside the leaf. Given that one fate of water from foliar uptake is to increase leaf water potentials and contribute to the demands of transpiration, we also provide a quantitative synthesis of observed rates of change in leaf water potential and total fluxes of water into the leaf. Finally, we identify critical research themes that should be addressed to effectively incorporate foliar water uptake into traditional frameworks of plant water movement.
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Affiliation(s)
- Z Carter Berry
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
| | - Nathan C Emery
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Sybil G Gotsch
- Department of Biology, Franklin and Marshall College, Lancaster, Pennsylvania, USA
| | - Gregory R Goldsmith
- Schmid College of Science and Technology, Chapman University, Orange, California, USA
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23
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Steppe K, Vandegehuchte MW, Van de Wal BAE, Hoste P, Guyot A, Lovelock CE, Lockington DA. Direct uptake of canopy rainwater causes turgor-driven growth spurts in the mangrove Avicennia marina. TREE PHYSIOLOGY 2018; 38:979-991. [PMID: 29562244 DOI: 10.1093/treephys/tpy024] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Mangrove forests depend on a dense structure of sufficiently large trees to fulfil their essential functions as providers of food and wood for animals and people, CO2 sinks and protection from storms. Growth of these forests is known to be dependent on the salinity of soil water, but the influence of foliar uptake of rainwater as a freshwater source, additional to soil water, has hardly been investigated. Under field conditions in Australia, stem diameter variation, sap flow and stem water potential of the grey mangrove (Avicennia marina (Forssk.) Vierh.) were simultaneously measured during alternating dry and rainy periods. We found that sap flow in A. marina was reversed, from canopy to roots, during and shortly after rainfall events. Simultaneously, stem diameters rapidly increased with growth rates up to 70 μm h-1, which is about 25-75 times the normal growth rate reported in temperate trees. A mechanistic tree model was applied to provide evidence that A. marina trees take up water through their leaves, and that this water contributes to turgor-driven stem growth. Our results indicate that direct uptake of freshwater by the canopy during rainfall supports mangrove tree growth and serve as a call to consider this water uptake pathway if we aspire to correctly assess influences of changing rainfall patterns on mangrove tree growth.
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Affiliation(s)
- Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Maurits W Vandegehuchte
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Bart A E Van de Wal
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Pieter Hoste
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent, Belgium
| | - Adrien Guyot
- National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia
- School of Civil Engineering, The University of Queensland, St. Lucia, Queensland, Australia
- Department of Civil Engineering, Monash University, Clayton, Victoria, Australia
| | - Catherine E Lovelock
- National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia
- School of Biological Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - David A Lockington
- National Centre for Groundwater Research and Training, Flinders University, Adelaide, South Australia, Australia
- School of Civil Engineering, The University of Queensland, St. Lucia, Queensland, Australia
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Fernández V, Bahamonde HA, Javier Peguero-Pina J, Gil-Pelegrín E, Sancho-Knapik D, Gil L, Goldbach HE, Eichert T. Physico-chemical properties of plant cuticles and their functional and ecological significance. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5293-5306. [PMID: 28992247 DOI: 10.1093/jxb/erx302] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/03/2017] [Indexed: 05/19/2023]
Abstract
Most aerial plant surfaces are covered with a lipid-rich cuticle, which is a barrier for the bidirectional transport of substances between the plant and the surrounding environment. This review article provides an overview of the significance of the leaf cuticle as a barrier for the deposition and absorption of water and electrolytes. After providing insights into the physico-chemical properties of plant surfaces, the mechanisms of foliar absorption are revised with special emphasis on solutes. Due to the limited information and relative importance of the leaf cuticle of herbaceous and deciduous cultivated plants, an overview of the studies developed with Alpine conifers and treeline species is provided. The significance of foliar water uptake as a phenomenon of ecophysiological relevance in many areas of the world is also highlighted. Given the observed variability in structure and composition among, for example, plant species and organs, it is concluded that it is currently not possible to establish general permeability and wettability models that are valid for predicting liquid-surface interactions and the subsequent transport of water and electrolytes across plant surfaces.
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Affiliation(s)
- Victoria Fernández
- Forest Genetics and Ecophysiology Research Group, School of Forest Engineering, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - Hector A Bahamonde
- Instituto Nacional de Tecnología Agropecuaria (INTA), cc 332, 9400 Río Gallegos, Santa Cruz, Argentina
| | - José Javier Peguero-Pina
- Unidad de Recursos Forestales, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, 50059 Zaragoza, Spain
| | - Eustaquio Gil-Pelegrín
- Unidad de Recursos Forestales, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, 50059 Zaragoza, Spain
| | - Domingo Sancho-Knapik
- Unidad de Recursos Forestales, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, 50059 Zaragoza, Spain
| | - Luis Gil
- Forest Genetics and Ecophysiology Research Group, School of Forest Engineering, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - Heiner E Goldbach
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, 53115 Bonn, Germany
| | - Thomas Eichert
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, 53115 Bonn, Germany
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