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Smith-Martin CM, Johnson KM, Urquhart S, Carins-Murphy MR, Rodriguez-Dominguez CM, Lucani C, Corso D, Choat B, Gauthey A, Perez-Martinez LV, McAdam SAM, Werden LK, Brodribb TJ. Increasing air-filled vessels has little influence on vulnerability to drought-induced embolism in two species with long maximum xylem vessel length but low vessel connectivity. TREE PHYSIOLOGY 2025; 45:tpaf041. [PMID: 40188479 DOI: 10.1093/treephys/tpaf041] [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: 07/31/2024] [Revised: 02/18/2025] [Accepted: 03/19/2025] [Indexed: 04/08/2025]
Abstract
Perennial woody plants accumulate native xylem embolisms over time. However, whether this makes the water transport system more vulnerable to drought-induced dysfunction as the percentage of gas-filled vessels increases is unclear. We tested whether increasing the proportion of open (air-filled) vessels changes the overall embolism vulnerability in stems of angiosperm species with long maximum vessel lengths but relatively low vessel connectivity. Using optical vulnerability curves, we measured xylem vulnerability of 57 branches ranging in length from ~ 10 to over 300 cm, from two adult trees (Acacia mearnsii De Wild. and Eucalyptus globulus Labill.) known to have long maximum vessel length (>75 cm) but low vessel connectivity. The fraction of open vessels at different branch lengths was estimated by staining open vessels under suction and with X-ray micro-computed tomography (μCT). To relate this to native field conditions, the percentage of pre-existing native embolisms was measured with μCT on a different set of branches. Our results show that even when a large proportion (> 25%) of open (air-filled) vessels are present, the xylem-embolism thresholds (water potential at 12% (P12), 50% (P50) and 88% (P88) embolized xylem area) resemble those of branches with no open vessels. Scanning of native embolism with μCT revealed 10% (E. globulus) and 20% (A. mearnsii) native embolism under natural conditions. We conclude that even when approximately one-quarter of vessels are air-filled, there is no discernable effect on the overall xylem vulnerability of stem segments with long vessels and low vessel connectivity. Xylem vulnerability to embolism among all the branches measured from each of the two trees was relatively homogeneous with a ~10-20% variation. Our findings also suggest that the presence of pre-existing native embolisms, at the percentages observed in the field (<25%), would not increase vulnerability to xylem embolism in these species with largely isolated individual xylem vessels.
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Affiliation(s)
- Chris M Smith-Martin
- Department of Plant and Microbial Biology, University of Minnesota, 1475 Gortner Ave. St Paul, MN 55108, USA
| | - Kate M Johnson
- Ecological and Forestry Applications Research Centre (CREAF), Campus de Bellaterra, Cerdanyola del Vallès, 08193, Spain
| | - Shelley Urquhart
- School of Natural Sciences, University of Tasmania, Private Bag 55, Tas, Hobart 7001 Tasmania, Australia
| | - Madeline R Carins-Murphy
- School of Natural Sciences, University of Tasmania, Private Bag 55, Tas, Hobart 7001 Tasmania, Australia
| | - Celia M Rodriguez-Dominguez
- Plant Ecophysiology and Irrigation (ECOVER) Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes, 10, 41012 Sevilla, Spain
| | - Christopher Lucani
- School of Natural Sciences, University of Tasmania, Private Bag 55, Tas, Hobart 7001 Tasmania, Australia
| | - Déborah Corso
- School of Natural Sciences, University of Tasmania, Private Bag 55, Tas, Hobart 7001 Tasmania, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Bourke St, Richmond, NSW 2753, Australia
| | - Alice Gauthey
- The Birmingham Institute of Forest Research (BIFoR), University of Birmingham, Edgbaston Birmingham, B15 2TT, UK
| | | | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, 610 Purdue Mall, West Lafayette, IN 47907, USA
| | - Leland K Werden
- Institute of Integrative Biology, ETH Zürich (Swiss Federal Institute of Technology), Universitätstrasse 16, 8092 Zürich, Switzerland
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Private Bag 55, Tas, Hobart 7001 Tasmania, Australia
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2
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Stewart JJ, Allen BS, Polutchko SK, Ocheltree TW, Gleason SM. Xylem embolism refilling revealed in stems of a weedy grass. Proc Natl Acad Sci U S A 2025; 122:e2420618122. [PMID: 40112095 PMCID: PMC12002171 DOI: 10.1073/pnas.2420618122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2024] [Accepted: 02/25/2025] [Indexed: 03/22/2025] Open
Abstract
Plant hydraulic dysfunction by embolism formation can impair photosynthesis, growth, and reproduction and, in severe cases, lead to death. Embolism reversal, or "refilling," is a hypothesized adaptive process in which xylem functionality is rapidly and sustainably restored. This study investigated xylem embolism refilling during recovery from severe drought stress using entirely noninvasive measurements of the same plants. These results were considered in relation to functional traits to address long-standing gaps in understanding the consequences of severe drought stress. Leaf and stem xylem embolism as well as transpiration, photosynthesis, and stem water potential were characterized nondestructively on intact barnyard grass plants during an acute drought event. Plants were rewatered and returned to growth conditions for 10 d, during which time recovery of stem xylem embolism and transpiration were monitored. Leaf xylem embolism and declines in leaf gas exchange occurred mostly between -1.0 MPa and -2.0 MPa, whereas stem xylem embolism occurred mostly between -3.0 MPa and -4.0 MPa. In all measured plants, which included embolism levels up to 88%, stem xylem embolism reversed completely within 24 h after rewatering, and this refilling supported recovery of transpiration and growth after plants were returned to growth conditions. This study provides direct evidence of complete and functional stem xylem refilling. These results present a clear need to elucidate underlying mechanisms and the adaptive significance of this phenomenon as well as its prevalence in nature.
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Affiliation(s)
- Jared J. Stewart
- Water Management and Systems Research Unit, Agricultural Research Service, United States Department of Agriculture, Fort Collins, CO80526
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO80309
- Department of Forest and Rangeland Stewardship, Warner College of Natural Resources, Colorado State University, Fort Collins, CO80523
| | - Brendan S. Allen
- Water Management and Systems Research Unit, Agricultural Research Service, United States Department of Agriculture, Fort Collins, CO80526
- Department of Forest and Rangeland Stewardship, Warner College of Natural Resources, Colorado State University, Fort Collins, CO80523
| | - Stephanie K. Polutchko
- Water Management and Systems Research Unit, Agricultural Research Service, United States Department of Agriculture, Fort Collins, CO80526
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO80309
| | - Troy W. Ocheltree
- Water Management and Systems Research Unit, Agricultural Research Service, United States Department of Agriculture, Fort Collins, CO80526
- Department of Forest and Rangeland Stewardship, Warner College of Natural Resources, Colorado State University, Fort Collins, CO80523
| | - Sean M. Gleason
- Water Management and Systems Research Unit, Agricultural Research Service, United States Department of Agriculture, Fort Collins, CO80526
- Department of Forest and Rangeland Stewardship, Warner College of Natural Resources, Colorado State University, Fort Collins, CO80523
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3
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González‐Rebeles G, Alonso‐Arevalo MÁ, López E, Méndez‐Alonzo R. A low-cost protocol for the optical method of vulnerability curves to calculate P 50. APPLICATIONS IN PLANT SCIENCES 2025; 13:e70004. [PMID: 40308903 PMCID: PMC12038744 DOI: 10.1002/aps3.70004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2024] [Revised: 12/23/2024] [Accepted: 02/02/2025] [Indexed: 05/02/2025]
Abstract
Premise The quantification of plant drought resistance, particularly embolism formation, within and across species, is critical for ecosystem management and agriculture. We developed a cost-effective protocol to measure the water potential at which 50% of hydraulic conductivity (P 50) is lost in stems, using affordable and accessible materials in comparison to the traditional optical method. Methods and Results Our protocol uses inexpensive USB microscopes, which are secured along with the plants to a pegboard base to avoid movement. A Python program automatized the image acquisition. This method was applied to quantify P 50 in an exotic species (Nicotiana glauca) and native species (Rhus integrifolia) of the Mediterranean vegetation in Baja California, Mexico. Conclusions The intra- and interspecific patterns of variation in stem P 50 of N. glauca and R. integrifolia were obtained using the low-cost optical method with widely available and affordable materials that can be easily replicated for other species.
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Affiliation(s)
- Georgina González‐Rebeles
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de EnsenadaCarretera EnsenadaTijuana No. 3918, Zona Playitas, C.P. 22860EnsenadaBaja CaliforniaMexico
- Departamento del Hombre y su AmbienteUniversidad Autónoma Metropolitana–Unidad XochimilcoCalzada del Hueso 1100, Colonia Villa Quietud, Alcaldía Coyoacán, C.P. 04960Ciudad de MéxicoMexico
| | - Miguel Ángel Alonso‐Arevalo
- Departamento de Electrónica y Telecomunicaciones, Centro de Investigación Científica y de Educación Superior de EnsenadaCarretera EnsenadaTijuana No. 3918, Zona Playitas, C.P. 22860EnsenadaBaja CaliforniaMexico
| | - Eulogio López
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de EnsenadaCarretera EnsenadaTijuana No. 3918, Zona Playitas, C.P. 22860EnsenadaBaja CaliforniaMexico
| | - Rodrigo Méndez‐Alonzo
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de EnsenadaCarretera EnsenadaTijuana No. 3918, Zona Playitas, C.P. 22860EnsenadaBaja CaliforniaMexico
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Suissa JS, Niklas KJ, Tomescu AMF, Friedman WE. Ontogenetic correlates, not direct adaptation, explain the evolution of stelar morphology. THE NEW PHYTOLOGIST 2025; 245:465-479. [PMID: 39456128 DOI: 10.1111/nph.20185] [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: 05/24/2024] [Accepted: 08/23/2024] [Indexed: 10/28/2024]
Abstract
The primary vascular system of plants (the stele) has attracted interest from paleobotanists, developmental biologists, systematists, and physiologists for nearly two centuries. Ferns, with their diverse stelar morphology, deep evolutionary history, and prominent fossil record, have been a major focus in studies of the stele. To explain the diversity of stelar morphology, past adaptive hypotheses have invoked biomechanics, hydraulics, and drought tolerance as key selection pressures in the evolution of stelar complexity; but, these hypotheses often isolate the stele from a whole-plant developmental context, ignoring potential covariation between vascular patterning and shoot morphology. Furthermore, incongruence between expected patterns and observed data challenge adaptive hypotheses, precluding a comprehensive explanation of stelar evolution. While ontogeny has been previously recognized as a factor in stelar diversification, it has not been fully integrated into a comprehensive framework. Here we synthesize 150-years of research on stelar morphology, incorporating developmental, physiological, and phylogenetic data to present the ontogenetic hypothesis of stelar evolution. This hypothesis posits that stelar morphology is an integrated feature of whole-plant ontogeny, not a trait shaped by direct selection for adaptive patterns. This shift in perspective provides an updated framework for understanding the determinants of stelar morphology and focusses future efforts to ask more incisive questions about the evolution and function of primary vascular architecture.
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Affiliation(s)
- Jacob S Suissa
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA
- The Arnold Arboretum of Harvard University, Boston, MA, 02130, USA
| | - Karl J Niklas
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Alexandru M F Tomescu
- Department of Biological Sciences, California Polytechnic State University Humboldt, Arcata, CA, 95521, USA
| | - William E Friedman
- The Arnold Arboretum of Harvard University, Boston, MA, 02130, USA
- The Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
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5
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Silva LM, Pereira L, Kaack L, Guan X, Pfaff J, Trabi CL, Jansen S. The potential link between gas diffusion and embolism spread in angiosperm xylem: Evidence from flow-centrifuge experiments and modelling. PLANT, CELL & ENVIRONMENT 2024; 47:4977-4991. [PMID: 39119783 DOI: 10.1111/pce.15084] [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: 04/11/2024] [Revised: 06/19/2024] [Accepted: 07/27/2024] [Indexed: 08/10/2024]
Abstract
Understanding xylem embolism formation is challenging due to dynamic changes and multiphase interactions in conduits. Here, we hypothesise that embolism spread involves gas diffusion in xylem, and is affected by time. We measured hydraulic conductivity (Kh) in flow-centrifuge experiments over 1 h at a given pressure and temperature for stem samples of three angiosperm species. Temporal changes in Kh at 5, 22, and 35°C, and at various pressures were compared to modelled gas concentration changes in a recently embolised vessel in the centre of a centrifuge sample. Temporal changes in Kh were logarithmic and species-specific. Maximum relative increases of Kh between 6% and 40% happened at 22°C for low centrifugal speed (<3250 RPM), while maximum decreases between 41% and 61% occurred at higher speeds. These reductions in Kh were experimentally shown to be associated with a temporal increase of embolism at the centre of centrifuge samples, which was likely associated with gas concentration increases in recently embolized vessels. Although embolism is mostly pressure-driven, our experimental and modelled data indicate that time, conduit characteristics, and temperature are involved due to their potential role in gas diffusion. Gas diffusion, however, does not seem to cover the entire process of embolism spread.
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Affiliation(s)
| | | | - Lucian Kaack
- Institute of Botany, Ulm University, Ulm, Germany
- Botanical Garden of Ulm University, Hans-Krebs-Weg, Ulm, Germany
| | - Xinyi Guan
- Institute of Botany, Ulm University, Ulm, Germany
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Jonas Pfaff
- Institute of Botany, Ulm University, Ulm, Germany
| | - Christophe L Trabi
- Institute of Botany, Ulm University, Ulm, Germany
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Ulm, Germany
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6
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Rimer IM, McAdam SAM. Within-leaf variation in embolism resistance is not a rule for compound-leaved angiosperms. AMERICAN JOURNAL OF BOTANY 2024; 111:e16447. [PMID: 39686518 DOI: 10.1002/ajb2.16447] [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: 03/22/2024] [Revised: 09/23/2024] [Accepted: 09/25/2024] [Indexed: 12/18/2024]
Abstract
PREMISE Hydraulic segmentation, caused by the difference in embolism resistance across plant organs, provides a sacrificial layer of cheaper plant organs, like leaves, to protect more costly organs, such as stems, during drought. Within-leaf hydraulic segmentation has been observed in two compound-leaved tree species, with leaflets being more vulnerable than the rachis or petiole. Many herbaceous species have compound leaves, and some species have leaflets that are associated with pulvini at the base of the lamina, which could provide an anatomical means of preventing embolism from spreading within a leaf because of the higher number of vessel endings in the pulvinus. METHODS We used the optical vulnerability method to investigate whether differences in embolism resistance were observed across the leaf tissues of six herbaceous species and one deciduous tree species with compound leaves. Our species selection included both palmately and pinnately-compound leaved species, one of each with a pulvinus at the base of the leaflets. RESULTS We found considerable variation in embolism resistance across the species measured, but no evidence of variation in embolism resistance within the leaf. In two species with pulvini, we observed major embolism events crossing the pulvinus, spreading from the rachis or petiole into the lamina, and embolizing both tissues at the same water potential. CONCLUSIONS We conclude that within-leaf hydraulic segmentation, caused by variation in embolism resistance, is not a universal phenomenon to compound-leaved species and that the presence of a pulvinus does not provide a barrier to embolism spread in compound leaves.
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Affiliation(s)
- Ian M Rimer
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
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7
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Zhang F, Liu YW, Qin J, Jansen S, Zhu SD, Cao KF. Xylem embolism induced by freeze-thaw and drought are influenced by different anatomical traits in subtropical montane evergreen angiosperm trees. PHYSIOLOGIA PLANTARUM 2024; 176:e14567. [PMID: 39377145 DOI: 10.1111/ppl.14567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 08/29/2024] [Accepted: 09/16/2024] [Indexed: 10/09/2024]
Abstract
Subtropical evergreen broadleaved forests distributed in montane zones of southern China experience seasonal droughts and winter frost. Previously, studies have recognized that xylem anatomy is a determinant of its vulnerability to embolism caused by drought and freezing events. We hypothesized that there is a coordination of xylem resistance to freeze-thaw and drought-induced embolism for the subtropical montane evergreen broadleaved tree species because they are influenced by common xylem structural traits (e.g., vessel diameter). We examined the branch xylem anatomy, resistance to drought-induced embolism (P50), and the percent loss of branch hydraulic conductivity after a severe winter frost (PLCwinter) for 15 evergreen broadleaved tree species in a montane forest in South China. Our results showed that P50 of the studied species ranged from -2.81 to -5.13 MPa, which was not associated with most xylem anatomical properties except for the axial parenchyma-to-vessel connectivity. These tree species differed substantially in PLCwinter, ranging from 0% to 76.41%. PLCwinter was positively related to vessel diameter and negatively related to vessel density, vessel group index, and vessel-to-vessel connectivity, but no coordination with P50. This study suggests that hydraulic adaptation to frost is important to determine the distributional limit of subtropical montane evergreen woody angiosperms.
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Affiliation(s)
- Feng Zhang
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
| | - Yi-Wen Liu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
- Nanjing University, Nanjing, Jiangsu, China
| | - Jie Qin
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
- Tianjin University, Tianjin, Tianjin, China
| | | | - Shi-Dan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
| | - Kun-Fang Cao
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
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8
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Gerolamo CS, Pereira L, Costa FRC, Jansen S, Angyalossy V, Nogueira A. Lianas in tropical dry seasonal forests have a high hydraulic efficiency but not always a higher embolism resistance than lianas in rainforests. ANNALS OF BOTANY 2024; 134:337-350. [PMID: 38721801 PMCID: PMC11232521 DOI: 10.1093/aob/mcae077] [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: 12/19/2023] [Accepted: 05/07/2024] [Indexed: 07/10/2024]
Abstract
BACKGROUND AND AIMS Lianas have higher relative abundance and biomass in drier seasonal forests than in rainforests, but whether this difference is associated with their hydraulic strategies is unclear. Here, we investigate whether lianas of seasonally dry forests are safer and more efficient in water transport than rainforest lianas, explaining patterns of liana abundance. METHODS We measured hydraulic traits on five pairs of congeneric lianas of the tribe Bignonieae in two contrasting forest sites: the wet 'Dense Ombrophilous Forest' in Central Amazonia (~2 dry months) and the drier 'Semideciduous Seasonal Forest' in the inland Atlantic Forest (~6 dry months). We also gathered a broader database, including 197 trees and 58 liana species from different tropical forests, to compare hydraulic safety between habits and forest types. KEY RESULTS Bignonieae lianas from both forests had high and similar hydraulic efficiency but exhibited variability in resistance to embolism across forest types when phylogenetic relationships were taken into account. Three genera had higher hydraulic safety in the seasonal forest than in the rainforest, but species across both forests had similar positive hydraulic safety margins despite lower predawn water potential values of seasonal forest lianas. We did not find the safety-efficiency trade-off. Merging our results with previously published data revealed a high variability of resistance to embolism in both trees and lianas, independent of forest types. CONCLUSIONS The high hydraulic efficiency of lianas detected here probably favours their rapid growth across tropical forests, but differences in hydraulic safety highlight that some species are highly vulnerable and may rely on other mechanisms to cope with drought. Future research on the lethal dehydration threshold and the connection between hydraulic resistance strategies and liana abundance could offer further insights into tropical forest dynamics under climatic threats.
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Affiliation(s)
- Caian S Gerolamo
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil
| | - Luciano Pereira
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm D-89081, Germany
| | - Flavia R C Costa
- Instituto Nacional de Pesquisas da Amazônia – INPA, Manaus, AM, 69011-970, Brazil
| | - Steven Jansen
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm D-89081, Germany
| | - Veronica Angyalossy
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil
| | - Anselmo Nogueira
- Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC, São Bernardo do Campo, SP, 09606-070, Brazil
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Zhang Y, Pereira L, Kaack L, Liu J, Jansen S. Gold perfusion experiments support the multi-layered, mesoporous nature of intervessel pit membranes in angiosperm xylem. THE NEW PHYTOLOGIST 2024; 242:493-506. [PMID: 38404029 DOI: 10.1111/nph.19608] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Fluid transport across intervessel pit membranes of angiosperm xylem plays a major role in plant transpiration, with transport resistance largely depending on pore constriction sizes. Traditionally, fluid particles traversing pit membranes are assumed to cross a single instead of multiple pore constrictions. We tested a multi-layered pit membrane model in xylem of eight angiosperm species by estimating the size frequency of pore constrictions in relation to pit membrane thickness and compared modelled data with perfusion characteristics of nanoscale gold particles based on transmission electron microscopy. The size frequency of modelled pore constrictions showed similar patterns to the measured number of perfused particle sizes inside pit membranes, although frequency values measured were 10-50 times below modelled data. Small particles enter pit membranes most easily, especially when injected in thin pit membranes. The trapping of gold particles by pore constrictions becomes more likely with increasing pore constriction number and pit membrane thickness. While quantitative differences between modelled and experimental data are due to various practical limitations, their qualitative agreement supports a multi-layered pit membrane model with multiple pore constrictions. Pore constrictions between 5 and 50 nm are realistic, and confirm the mesoporous nature of pit membranes.
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Affiliation(s)
- Ya Zhang
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological Resources, College of Life Sciences, Anhui Normal University, Beijingzhong Road 2, Wuhu, 241000, China
| | - Luciano Pereira
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Lucian Kaack
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Jiabao Liu
- College of Ecology and Environment, Anhui Normal University, Beijingzhong Road 2, Wuhu, 241000, China
| | - Steven Jansen
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
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10
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Du T, Ling X, Huang J, Peng S, Xiong D. Photosynthesis of rice leaves with a parallel venation is highly tolerant to vein severing. PHYSIOLOGIA PLANTARUM 2024; 176:e14241. [PMID: 38454807 DOI: 10.1111/ppl.14241] [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: 08/01/2023] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/09/2024]
Abstract
Vein severing in plants caused by leaf damage is common in fields where crops are cultivated. It is hypothesized that leaves with complex reticulate venation can withstand hydraulic disturbances caused by vein severing, thereby preserving leaf carbon assimilation. However, limited research focuses on vein damage of leaves with parallel venation. We studied how vein-severing affected the photosynthetic traits of rice (Oryza sativa) leaves in seconds, minutes and days, under varying water-demand conditions and differing extents of water supply disruption. Rice leaves completely lost their photosynthetic capacity within 2.5 minutes after excision. Severing the midrib resulted in reduced light-saturated photosynthetic rate (A), stomatal conductance (gsw ) and transpiration rate (E) by 2.6, 6.8 and 5.9%, respectively, already after thirty minutes. We further investigated the photosynthetic trait responses to various extents of leaf width severing, while keeping the midrib functional. Surprisingly, A, gsw and E in the downstream area of the severed leaves largely remained stable, showing minimal variation across different leaf width severing ratios. These traits declined only slightly even under increased ambient light intensity and leaf-to-air vapor pressure deficit. This sustained photosynthesis post-severing is attributed to the efficient lateral water transport. Long-term leaf damage slightly but not significantly, impacted the downstream photosynthetic traits within five days post-severing. However, a more pronounced reduction in gas exchange during leaf senescence was observed nine days after severing. These findings suggested that rice leaves can tolerate hydraulic disturbances from vein severing and maintain functionality under various conditions, which is crucial for crop yield stability. However, long-term consequences require further investigation.
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Affiliation(s)
- Tingting Du
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xiaoxia Ling
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jianliang Huang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
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11
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Pereira L, Kaack L, Guan X, Silva LDM, Miranda MT, Pires GS, Ribeiro RV, Schenk HJ, Jansen S. Angiosperms follow a convex trade-off to optimize hydraulic safety and efficiency. THE NEW PHYTOLOGIST 2023; 240:1788-1801. [PMID: 37691289 DOI: 10.1111/nph.19253] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 08/11/2023] [Indexed: 09/12/2023]
Abstract
Intervessel pits are considered to function as valves that avoid embolism spreading and optimize efficient transport of xylem sap across neighbouring vessels. Hydraulic transport between vessels would therefore follow a safety-efficiency trade-off, which is directly related to the total intervessel pit area (Ap ), inversely related to the pit membrane thickness (TPM ) and driven by a pressure difference. To test this hypothesis, we modelled the relative transport rate of gas (ka ) and water (Q) at the intervessel pit level for 23 angiosperm species and correlated these parameters with the water potential at which 50% of embolism occurs (Ψ50 ). We also measured ka for 10 species using pneumatic measurements. The pressure difference across adjacent vessels and estimated values of ka and Q were related to Ψ50 , following a convex safety-efficiency trade-off based on modelled and experimental data. Minor changes in TPM and Ap exponentially affected the pressure difference and flow, respectively. Our results provide clear evidence that a xylem safety-efficiency trade-off is not linear, but convex due to flow across intervessel pit membranes, which represent mesoporous media within microporous conduits. Moreover, the convex nature of long-distance xylem transport may contribute to an adjustable fluid balance of plants, depending on environmental conditions.
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Affiliation(s)
- Luciano Pereira
- Institute of Botany, Ulm University, 89081, Ulm, Albert-Einstein-Allee 11, Germany
| | - Lucian Kaack
- Institute of Botany, Ulm University, 89081, Ulm, Albert-Einstein-Allee 11, Germany
- Botanical Garden of Ulm University, 89081, Ulm, Hans-Krebs-Weg, Germany
| | - Xinyi Guan
- Institute of Botany, Ulm University, 89081, Ulm, Albert-Einstein-Allee 11, Germany
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, 530004, Guangxi, Nanning, China
| | | | - Marcela T Miranda
- Laboratory of Plant Physiology 'Coaracy M. Franco', Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), PO Box 28, Campinas, 13012-970, SP, Brazil
| | - Gabriel S Pires
- Department of Plant Biology, Laboratory of Crop Physiology, Institute of Biology, University of Campinas (UNICAMP), 13083-970, SP, Campinas, PO Box 6109, Brazil
| | - Rafael V Ribeiro
- Department of Plant Biology, Laboratory of Crop Physiology, Institute of Biology, University of Campinas (UNICAMP), 13083-970, SP, Campinas, PO Box 6109, Brazil
| | - H Jochen Schenk
- Department of Biological Science, California State University Fullerton, 800 N. State College Blvd, Fullerton, 92831-3599, CA, USA
| | - Steven Jansen
- Institute of Botany, Ulm University, 89081, Ulm, Albert-Einstein-Allee 11, Germany
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12
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Paligi SS, Link RM, Isasa E, Bittencourt P, Cabral JS, Jansen S, Oliveira RS, Pereira L, Schuldt B. Assessing the agreement between the pneumatic and the flow-centrifuge method for estimating xylem safety in temperate diffuse-porous tree species. PLANT BIOLOGY (STUTTGART, GERMANY) 2023; 25:1171-1185. [PMID: 37703535 DOI: 10.1111/plb.13573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/06/2023] [Indexed: 09/15/2023]
Abstract
The increasing frequency of global change-type droughts has created a need for fast, accurate and widely applicable techniques for estimating xylem embolism resistance to improve forecasts of future forest changes. We used data from 12 diffuse-porous temperate tree species covering a wide range of xylem safety to compare the pneumatic and flow-centrifuge method, two rapid methods used for constructing xylem vulnerability curves. We evaluated the agreement between parameters estimated with both methods and the sensitivity of pneumatic measurements to the duration of air discharge (AD) measurements. There was close agreement between xylem water potentials at 50% air discharged (PAD), estimated with the Pneumatron, and 50% loss of hydraulic conductivity (PLC), estimated with the flow-centrifuge method (mean signed deviation: 0.12 MPa, Pearson correlation: 0.96 after 15 s of gas extraction). However, the relationship between the estimated slopes was more variable, resulting in lower agreement in the xylem water potential at 12% and 88% PAD/PLC. The agreement between the two methods was not affected by species-specific vessel length distributions. All pneumatic parameters were sensitive to AD time. Overall agreement was highest at relatively short AD times, with an optimum at 16 s. Our results highlight the value of the Pneumatron as an easy and reliable tool to estimate 50% embolism thresholds for a wide range of diffuse-porous temperate angiosperms. Further, our study provides a set of useful metrics for methodological comparisons of vulnerability curves in terms of systematic and random deviations, as well as overall agreement.
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Affiliation(s)
- S S Paligi
- Chair of Ecophysiology and Vegetation Ecology, Julius-von-Sachs Institute of Biological Sciences, University of Würzburg, Würzburg, Germany
| | - R M Link
- Chair of Ecophysiology and Vegetation Ecology, Julius-von-Sachs Institute of Biological Sciences, University of Würzburg, Würzburg, Germany
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technische Universität Dresden, Tharandt, Germany
| | - E Isasa
- Chair of Ecophysiology and Vegetation Ecology, Julius-von-Sachs Institute of Biological Sciences, University of Würzburg, Würzburg, Germany
| | - P Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - J S Cabral
- Ecosystem Modeling Group, Center for Computational and Theoretical Biology, University of Würzburg, Würzburg, Germany
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - S Jansen
- Institute of Botany, Ulm University, Ulm, Germany
| | - R S Oliveira
- Department of Plant Biology, Instituto de Biologia, University of Campinas, Campinas, SP, Brazil
| | - L Pereira
- Institute of Botany, Ulm University, Ulm, Germany
| | - B Schuldt
- Chair of Ecophysiology and Vegetation Ecology, Julius-von-Sachs Institute of Biological Sciences, University of Würzburg, Würzburg, Germany
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technische Universität Dresden, Tharandt, Germany
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13
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Petruzzellis F, Di Bonaventura A, Tordoni E, Tomasella M, Natale S, Trifilò P, Tromba G, Di Lillo F, D'Amico L, Bacaro G, Nardini A. The optical method based on gas injection overestimates leaf vulnerability to xylem embolism in three woody species. TREE PHYSIOLOGY 2023; 43:1784-1795. [PMID: 37427987 DOI: 10.1093/treephys/tpad088] [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: 02/21/2023] [Revised: 05/26/2023] [Accepted: 07/04/2023] [Indexed: 07/11/2023]
Abstract
Plant hydraulic traits related to leaf drought tolerance, like the water potential at turgor loss point (TLP) and the water potential inducing 50% loss of hydraulic conductance (P50), are extremely useful to predict the potential impacts of drought on plants. While novel techniques have allowed the inclusion of TLP in studies targeting a large group of species, fast and reliable protocols to measure leaf P50 are still lacking. Recently, the optical method coupled with the gas injection (GI) technique has been proposed as a possibility to speed up the P50 estimation. Here, we present a comparison of leaf optical vulnerability curves (OVcs) measured in three woody species, namely Acer campestre (Ac), Ostrya carpinifolia (Oc) and Populus nigra (Pn), based on bench dehydration (BD) or GI of detached branches. For Pn, we also compared optical data with direct micro-computed tomography (micro-CT) imaging in both intact saplings and cut shoots subjected to BD. Based on the BD procedure, Ac, Oc and Pn had P50 values of -2.87, -2.47 and -2.11 MPa, respectively, while the GI procedure overestimated the leaf vulnerability (-2.68, -2.04 and -1.54 MPa for Ac, Oc and Pn, respectively). The overestimation was higher for Oc and Pn than for Ac, likely reflecting the species-specific vessel lengths. According to micro-CT observations performed on Pn, the leaf midrib showed none or very few embolized conduits at -1.2 MPa, consistent with the OVcs obtained with the BD procedure but at odds with that derived on the basis of GI. Overall, our data suggest that coupling the optical method with GI might not be a reliable technique to quantify leaf hydraulic vulnerability since it could be affected by the 'open-vessel' artifact. Accurate detection of xylem embolism in the leaf vein network should be based on BD, preferably of intact up-rooted plants.
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Affiliation(s)
- Francesco Petruzzellis
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Azzurra Di Bonaventura
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Viale delle Scienze 206, Udine 33100, Italy
| | - Enrico Tordoni
- Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, Tartu 50409, Estonia
| | - Martina Tomasella
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Sara Natale
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
- Department of Biology, University of Padova, Via U. Bassi 58/B, Padova 35121, Italy
| | - Patrizia Trifilò
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, Messina 98166, Italy
| | - Giuliana Tromba
- Elettra Sincrotrone Trieste, Area Science Park, Basovizza, Trieste 34149, Italy
| | - Francesca Di Lillo
- Elettra Sincrotrone Trieste, Area Science Park, Basovizza, Trieste 34149, Italy
| | - Lorenzo D'Amico
- Elettra Sincrotrone Trieste, Area Science Park, Basovizza, Trieste 34149, Italy
- Department of Physics, University of Trieste, Via A. Valerio 2, Trieste 34127, Italy
| | - Giovanni Bacaro
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Andrea Nardini
- Department of Life Sciences, University of Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
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14
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Feng F, Wagner Y, Klein T, Hochberg U. Xylem resistance to cavitation increases during summer in Pinus halepensis. PLANT, CELL & ENVIRONMENT 2023; 46:1849-1859. [PMID: 36793149 DOI: 10.1111/pce.14573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 05/04/2023]
Abstract
Cavitation resistance has often been viewed as a relatively static trait, especially for stems of forest trees. Meanwhile, other hydraulic traits, such as turgor loss point (Ψtlp ) and xylem anatomy, change during the season. In this study, we hypothesized that cavitation resistance is also dynamic, changing in coordination with Ψtlp . We began with a comparison of optical vulnerability (OV), microcomputed tomography (µCT) and cavitron methods. All three methods significantly differed in the slope of the curve,Ψ12 and Ψ88 , but not in Ψ50 (xylem pressures that cause 12%, 88%, 50% cavitation, respectively). Thus, we followed the seasonal dynamics (across 2 years) of Ψ50 in Pinus halepensis under Mediterranean climate using the OV method. We found that Ψ50 is a plastic trait with a reduction of approximately 1 MPa from the end of the wet season to the end of the dry season, in coordination with the dynamics of the midday xylem water potential (Ψmidday ) and the Ψtlp . The observed plasticity enabled the trees to maintain a stable positive hydraulic safety margin and avoid cavitation during the long dry season. Seasonal plasticity is vital for understanding the actual risk of cavitation to plants and for modeling species' ability to tolerate harsh environments.
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Affiliation(s)
- Feng Feng
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Yael Wagner
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tamir Klein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Uri Hochberg
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
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15
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Tavares JV, Oliveira RS, Mencuccini M, Signori-Müller C, Pereira L, Diniz FC, Gilpin M, Marca Zevallos MJ, Salas Yupayccana CA, Acosta M, Pérez Mullisaca FM, Barros FDV, Bittencourt P, Jancoski H, Scalon MC, Marimon BS, Oliveras Menor I, Marimon BH, Fancourt M, Chambers-Ostler A, Esquivel-Muelbert A, Rowland L, Meir P, Lola da Costa AC, Nina A, Sanchez JMB, Tintaya JS, Chino RSC, Baca J, Fernandes L, Cumapa ERM, Santos JAR, Teixeira R, Tello L, Ugarteche MTM, Cuellar GA, Martinez F, Araujo-Murakami A, Almeida E, da Cruz WJA, Del Aguila Pasquel J, Aragāo L, Baker TR, de Camargo PB, Brienen R, Castro W, Ribeiro SC, Coelho de Souza F, Cosio EG, Davila Cardozo N, da Costa Silva R, Disney M, Espejo JS, Feldpausch TR, Ferreira L, Giacomin L, Higuchi N, Hirota M, Honorio E, Huaraca Huasco W, Lewis S, Flores Llampazo G, Malhi Y, Monteagudo Mendoza A, Morandi P, Chama Moscoso V, Muscarella R, Penha D, Rocha MC, Rodrigues G, Ruschel AR, Salinas N, Schlickmann M, Silveira M, Talbot J, Vásquez R, Vedovato L, Vieira SA, Phillips OL, Gloor E, Galbraith DR. Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests. Nature 2023; 617:111-117. [PMID: 37100901 PMCID: PMC10156596 DOI: 10.1038/s41586-023-05971-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 03/17/2023] [Indexed: 04/28/2023]
Abstract
Tropical forests face increasing climate risk1,2, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, [Formula: see text]50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk3-5, little is known about how these vary across Earth's largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters [Formula: see text]50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both [Formula: see text]50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth-mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon6,7, with strong implications for the Amazon carbon sink.
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Affiliation(s)
- Julia Valentim Tavares
- School of Geography, University of Leeds, Leeds, UK.
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
| | | | - Caroline Signori-Müller
- School of Geography, University of Leeds, Leeds, UK
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Department of Plant Biology, Institute of Biology, Programa de Pós Graduação em Biologia Vegetal, University of Campinas, Campinas, Brazil
| | - Luciano Pereira
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | | | | | | | | | - Martin Acosta
- Programa de Pós-Graduação em Ecologia e Manejo de Recursos Naturais, Universidade Federal do Acre, Rio Branco, Brazil
| | | | - Fernanda de V Barros
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
- Department of Plant Biology, Institute of Biology, Programa de Pós Graduação em Ecologia, University of Campinas, Campinas, Brazil
| | - Paulo Bittencourt
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Halina Jancoski
- Departamento de Ciências Biológicas, Universidade do Estado de Mato Grosso (UNEMAT), Nova Xavantina, Brazil
| | - Marina Corrêa Scalon
- Departamento de Ciências Biológicas, Universidade do Estado de Mato Grosso (UNEMAT), Nova Xavantina, Brazil
- Programa de Pós-Graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba, Brazil
| | - Beatriz S Marimon
- Departamento de Ciências Biológicas, Universidade do Estado de Mato Grosso (UNEMAT), Nova Xavantina, Brazil
| | - Imma Oliveras Menor
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
- AMAP (Botanique et Modélisation de l'Architecture des Plantes et des Végétations), CIRAD, CNRS, INRA, IRD, Université de Montpellier, Montpellier, France
| | - Ben Hur Marimon
- Departamento de Ciências Biológicas, Universidade do Estado de Mato Grosso (UNEMAT), Nova Xavantina, Brazil
| | - Max Fancourt
- School of Geography, University of Leeds, Leeds, UK
| | | | - Adriane Esquivel-Muelbert
- School of Geography, University of Birmingham, Birmingham, UK
- Birmingham Institute of Forest Research (BIFoR), Birmingham, UK
| | - Lucy Rowland
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Patrick Meir
- School of Geosciences, University of Edinburgh, Edinburgh, UK
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | | | - Alex Nina
- Pontificia Universidad Católica del Perú, Lima, Peru
| | | | - Jose S Tintaya
- Universidad Nacional de San Antonio Abad del Cusco, Cusco, Peru
| | | | - Jean Baca
- Universidad Nacional de la Amazonia Peruana, Iquitos, Peru
| | | | - Edwin R M Cumapa
- Instituto de Geociências, Faculdade de Meteorologia, Universidade Federal do Pará, Belém, Brazil
| | | | - Renata Teixeira
- Universidad Nacional de San Antonio Abad del Cusco, Cusco, Peru
| | - Ligia Tello
- Universidad Nacional de la Amazonia Peruana, Iquitos, Peru
| | - Maira T M Ugarteche
- Museo de Historia Natural Noel Kempff Mercado, Santa Cruz de la Sierra, Bolivia
- Universidad Autonoma Gabriel Rene Moreno, Santa Cruz, Bolivia
| | - Gina A Cuellar
- Museo de Historia Natural Noel Kempff Mercado, Santa Cruz de la Sierra, Bolivia
- Universidad Autonoma Gabriel Rene Moreno, Santa Cruz, Bolivia
| | - Franklin Martinez
- Museo de Historia Natural Noel Kempff Mercado, Santa Cruz de la Sierra, Bolivia
- Universidad Autonoma Gabriel Rene Moreno, Santa Cruz, Bolivia
| | - Alejandro Araujo-Murakami
- Museo de Historia Natural Noel Kempff Mercado, Santa Cruz de la Sierra, Bolivia
- Universidad Autonoma Gabriel Rene Moreno, Santa Cruz, Bolivia
| | - Everton Almeida
- Instituto de Biodiversidade e Florestas, Universidade Federal do Oeste do Pará, Santarém, Brazil
| | | | - Jhon Del Aguila Pasquel
- Universidad Nacional de la Amazonia Peruana (UNAP), Iquitos, Peru
- Instituto de Investigaciones de la Amazonia Peruana, Iquitos, Peru
| | - Luís Aragāo
- National Institute for Space Research (INPE), São José dos Campos-SP, Brazil
| | | | | | - Roel Brienen
- School of Geography, University of Leeds, Leeds, UK
| | - Wendeson Castro
- Laboratório de Botânica e Ecologia Vegetal, Universidade Federal do Acre, Rio Branco, Brazil
- SOS Amazônia, Programa Governança e Proteção da Paisagem Verde na Amazônia, Rio Branco-AC, Brazil
| | | | | | - Eric G Cosio
- Sección Química, Pontificia Universidad Católica del Perú, Lima, Peru
| | | | - Richarlly da Costa Silva
- Programa de Pós-Graduação em Ecologia e Manejo de Recursos Naturais, Universidade Federal do Acre, Rio Branco, Brazil
- Instituto Federal de Educação, Ciência e Tecnologia do Acre, Campus Baixada do Sol, Rio Branco, Brazil
| | - Mathias Disney
- Department of Geography, University College London, London, UK
| | - Javier Silva Espejo
- Universidad Nacional de San Antonio Abad del Cusco, Cusco, Peru
- Departamento de Biología, Universidad de La Serena, La Serena, Chile
| | - Ted R Feldpausch
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | - Leandro Giacomin
- Departamento de Sistemática e Ecologia, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Niro Higuchi
- Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | - Marina Hirota
- Department of Plant Biology, Institute of Biology, University of Campinas, Campinas, Brazil
- Department of Physics, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Euridice Honorio
- Instituto de Investigaciones de la Amazonia Peruana, Iquitos, Peru
| | - Walter Huaraca Huasco
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Simon Lewis
- School of Geography, University of Leeds, Leeds, UK
- Department of Geography, University College London, London, UK
| | - Gerardo Flores Llampazo
- Instituto de Investigaciones de la Amazonia Peruana, Iquitos, Peru
- Universidad Nacional Jorge Basadre de Grohmann (UNJBG), Tacna, Peru
| | - Yadvinder Malhi
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Abel Monteagudo Mendoza
- Universidad Nacional de San Antonio Abad del Cusco, Cusco, Peru
- Jardín Botánico de Missouri, Oxapampa, Peru
| | - Paulo Morandi
- Departamento de Ciências Biológicas, Universidade do Estado de Mato Grosso (UNEMAT), Nova Xavantina, Brazil
| | - Victor Chama Moscoso
- Universidad Nacional de San Antonio Abad del Cusco, Cusco, Peru
- Jardín Botánico de Missouri, Oxapampa, Peru
| | - Robert Muscarella
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Deliane Penha
- Programa de Pós-Graduação em Biodiversidade, Universidade Federal do Oeste do Pará, Santarém, Brazil
| | - Mayda Cecília Rocha
- Instituto de Ciências e Tecnologia das Águas, Universidade Federal do Oeste do Pará, Santarém, Brazil
| | - Gleicy Rodrigues
- Programa de Pós-Graduação em Botânica, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
| | | | - Norma Salinas
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
- Sección Química, Pontificia Universidad Católica del Perú, Lima, Peru
| | - Monique Schlickmann
- Programa de Pós-Graduação em Biodiversidade, Universidade Federal do Oeste do Pará, Santarém, Brazil
| | - Marcos Silveira
- Museu Universitário, Centro de Ciências Biológicas e da Natureza, Universidade Federal do Acre, Rio Branco, Brazil
| | - Joey Talbot
- Institute for Transport Studies, University of Leeds, Leeds, UK
| | | | - Laura Vedovato
- College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Simone Aparecida Vieira
- Núcleo de Estudos e Pesquisas Ambientais, Universidade Estadual de Campinas, Campinas, Brazil
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16
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Isasa E, Link RM, Jansen S, Tezeh FR, Kaack L, Sarmento Cabral J, Schuldt B. Addressing controversies in the xylem embolism resistance-vessel diameter relationship. THE NEW PHYTOLOGIST 2023; 238:283-296. [PMID: 36636783 DOI: 10.1111/nph.18731] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Although xylem embolism is a key process during drought-induced tree mortality, its relationship to wood anatomy remains debated. While the functional link between bordered pits and embolism resistance is known, there is no direct, mechanistic explanation for the traditional assumption that wider vessels are more vulnerable than narrow ones. We used data from 20 temperate broad-leaved tree species to study the inter- and intraspecific relationship of water potential at 50% loss of conductivity (P50 ) with hydraulically weighted vessel diameter (Dh ) and tested its link to pit membrane thickness (TPM ) and specific conductivity (Ks ) on species level. Embolism-resistant species had thick pit membranes and narrow vessels. While Dh was weakly associated with TPM , the P50 -Dh relationship remained highly significant after accounting for TPM . The interspecific pattern between P50 and Dh was mirrored by a link between P50 and Ks , but there was no evidence for an intraspecific relationship. Our results provide robust evidence for an interspecific P50 -Dh relationship across our species. As a potential cause for the inconsistencies in published P50 -Dh relationships, our analysis suggests differences in the range of trait values covered, and the level of data aggregation (species, tree or sample level) studied.
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Affiliation(s)
- Emilie Isasa
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
| | - Roman Mathias Link
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Pienner Str. 7, 01737, Tharandt, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Fon Robinson Tezeh
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Juliano Sarmento Cabral
- Ecosystem Modeling Group, Center for Computational and Theoretical Biology, University of Würzburg, Klara-Oppenheimer-Weg 32, 97074, Würzburg, Germany
- Biodiversity Modelling and Environmental Change, School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Bernhard Schuldt
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute of Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, 97082, Würzburg, Germany
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Pienner Str. 7, 01737, Tharandt, Germany
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17
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Tonet V, Carins-Murphy M, Deans R, Brodribb TJ. Deadly acceleration in dehydration of Eucalyptus viminalis leaves coincides with high-order vein cavitation. PLANT PHYSIOLOGY 2023; 191:1648-1661. [PMID: 36690460 PMCID: PMC10022613 DOI: 10.1093/plphys/kiad016] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/08/2022] [Accepted: 12/17/2022] [Indexed: 05/17/2023]
Abstract
Xylem cavitation during drought is proposed as a major driver of canopy collapse, but the mechanistic link between hydraulic failure and leaf damage in trees is still uncertain. Here, we used the tree species manna gum (Eucalyptus viminalis) to explore the connection between xylem dysfunction and lethal desiccation in leaves. Cavitation damage to leaf xylem could theoretically trigger lethal desiccation of tissues by severing water supply under scenarios such as runaway xylem cavitation, or the local failure of terminal parts of the leaf vein network. To investigate the role of xylem failure in leaf death, we compared the timing of damage to the photosynthetic machinery (Fv/Fm decline) with changes in plant hydration and xylem cavitation during imposed water stress. The water potential at which Fv/Fm was observed to decline corresponded to the water potential marking a transition from slow to very rapid tissue dehydration. Both events also occurred simultaneously with the initiation of cavitation in leaf high-order veins (HOV, veins from the third order above) and the analytically derived point of leaf runaway hydraulic failure. The close synchrony between xylem dysfunction and the photosynthetic damage strongly points to water supply disruption as the trigger for desiccation of leaves in this hardy evergreen tree. These results indicate that runaway cavitation, possibly triggered by HOV network failure, is the tipping agent determining the vulnerability of E. viminalis leaves to damage during drought and suggest that HOV cavitation and runaway hydraulic failure may play a general role in determining canopy damage in plants.
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Affiliation(s)
- Vanessa Tonet
- School of Biological Sciences, University of Tasmania, Sandy Bay, Tasmania 7001, Australia
| | - Madeline Carins-Murphy
- School of Biological Sciences, University of Tasmania, Sandy Bay, Tasmania 7001, Australia
| | - Ross Deans
- ARC Centre of Excellence in Translational Photosynthesis, Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
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18
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Avila RT, Kane CN, Batz TA, Trabi C, Damatta FM, Jansen S, McAdam SAM. The relative area of vessels in xylem correlates with stem embolism resistance within and between genera. TREE PHYSIOLOGY 2023; 43:75-87. [PMID: 36070431 DOI: 10.1093/treephys/tpac110] [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: 05/24/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
The resistance of xylem conduits to embolism is a major factor defining drought tolerance and can set the distributional limits of species across rainfall gradients. Recent work suggests that the proximity of vessels to neighbors increases the vulnerability of a conduit. We therefore investigated whether the relative vessel area of xylem correlates with intra- and inter-generic variation in xylem embolism resistance in species pairs or triplets from the genera Acer, Cinnamomum, Ilex, Quercus and Persea, adapted to environments differing in aridity. We used the optical vulnerability method to assess embolism resistance in stems and conducted anatomical measurements on the xylem in which embolism resistance was quantified. Vessel lumen fraction (VLF) correlated with xylem embolism resistance across and within genera. A low VLF likely increases the resistance to gas movement between conduits, by diffusion or advection, whereas a high VLF enhances gas transport thorough increased conduit-to-conduit connectivity and reduced distances between conduits and therefore the likelihood of embolism propagation. We suggest that the rate of gas movement due to local pressure differences and xylem network connectivity is a central driver of embolism propagation in angiosperm vessels.
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Affiliation(s)
- Rodrigo T Avila
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Cade N Kane
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Timothy A Batz
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
| | - Christophe Trabi
- Faculty of Natural Sciences, Institute of Systematic Botany and Ecology, Ulm University, Ulm, Baden-Württemberg 89081, Germany
| | - Fábio M Damatta
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - Steven Jansen
- Faculty of Natural Sciences, Institute of Systematic Botany and Ecology, Ulm University, Ulm, Baden-Württemberg 89081, Germany
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
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19
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Yang D, Pereira L, Peng G, Ribeiro RV, Kaack L, Jansen S, Tyree MT. A unit pipe pneumatic model to simulate gas kinetics during measurements of embolism in excised angiosperm xylem. TREE PHYSIOLOGY 2023; 43:88-101. [PMID: 36049079 DOI: 10.1093/treephys/tpac105] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
The pneumatic method has been introduced to quantify embolism resistance in plant xylem of various organs by applying a partial vacuum to cut-open xylem. Despite the similarity in vulnerability curves between the pneumatic and other methods, a modeling approach is needed to investigate if changes in xylem embolism during dehydration can be accurately quantified based on gas diffusion kinetics. Therefore, a unit pipe pneumatic (UPPn) model was developed to estimate gas extraction from intact conduits, which were axially interconnected by inter-conduit pit membranes to cut-open conduits. The physical laws used included Fick's law for diffusion, Henry's law for gas concentration partitioning between liquid and gas phases at equilibrium and the ideal gas law. The UPPn model showed that 91% of the extracted gas came from the first five series of embolized, intact conduits and only 9% from the aqueous phase after 15 s of simulation. Considering alternative gas sources, embolism resistance measured with a pneumatron device was systematically overestimated by 2-17%, which corresponded to a typical measuring error of 0.11 MPa for P50 (the water potential equivalent to 50% of the maximum amount of gas extracted). It is concluded that pneumatic vulnerability curves directly measure embolism of intact conduits due to the fast movement of gas across interconduit pit membranes, while gas extraction from sap and diffusion across hydrated cell walls is about 100 times slower. We expect that the UPPn model will also contribute to the understanding of embolism propagation based on temporal gas dynamics.
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Affiliation(s)
- Dongmei Yang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Luciano Pereira
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, P.O. Box 6109, University of Campinas (UNICAMP), Campinas 13083-970, Brazil
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11 Ulm D-89081, Germany
| | - Guoquan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Rafael V Ribeiro
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, P.O. Box 6109, University of Campinas (UNICAMP), Campinas 13083-970, Brazil
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11 Ulm D-89081, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11 Ulm D-89081, Germany
| | - Melvin T Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
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20
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Chen YJ, Maenpuen P, Zhang JL, Zhang YJ. Remaining uncertainties in the Pneumatic method. THE NEW PHYTOLOGIST 2023; 237:384-391. [PMID: 36537302 DOI: 10.1111/nph.18530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 10/01/2022] [Indexed: 06/17/2023]
Affiliation(s)
- Ya-Jun Chen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- Yuanjiang Savanna Ecosystem Research Station, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Yuanjiang, Yunnan, 653300, China
| | - Phisamai Maenpuen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiao-Lin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA
- Climate Change Institute, University of Maine, Orono, ME, 04469, USA
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21
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Brum M, Pereira L, Ribeiro RV, Jansen S, Bittencourt PRL, Oliveira RS, Saleska SR. Reconciling discrepancies in measurements of vulnerability to xylem embolism with the pneumatic method: A comment on Chen et al. (2021) 'Quantifying vulnerability to embolism in tropical trees and lianas using five methods: can discrepancies be explained by xylem structural traits?': A comment on Chen et al. (2021) 'Quantifying vulnerability to embolism in tropical trees and lianas using five methods: can discrepancies be explained by xylem structural traits?'. THE NEW PHYTOLOGIST 2023; 237:374-383. [PMID: 36537303 DOI: 10.1111/nph.18531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/11/2022] [Indexed: 05/12/2023]
Affiliation(s)
- Mauro Brum
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721-0088, USA
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Rafael Vasconcelos Ribeiro
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Paulo R L Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
| | - Rafael S Oliveira
- Department of Plant Biology, Institute of Biology, UNICAMP, PO Box 6109, 13083-970, Campinas, SP, Brazil
| | - Scott R Saleska
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721-0088, USA
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22
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Lens F, Gleason SM, Bortolami G, Brodersen C, Delzon S, Jansen S. Functional xylem characteristics associated with drought-induced embolism in angiosperms. THE NEW PHYTOLOGIST 2022; 236:2019-2036. [PMID: 36039697 DOI: 10.1111/nph.18447] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Hydraulic failure resulting from drought-induced embolism in the xylem of plants is a key determinant of reduced productivity and mortality. Methods to assess this vulnerability are difficult to achieve at scale, leading to alternative metrics and correlations with more easily measured traits. These efforts have led to the longstanding and pervasive assumed mechanistic link between vessel diameter and vulnerability in angiosperms. However, there are at least two problems with this assumption that requires critical re-evaluation: (1) our current understanding of drought-induced embolism does not provide a mechanistic explanation why increased vessel width should lead to greater vulnerability, and (2) the most recent advancements in nanoscale embolism processes suggest that vessel diameter is not a direct driver. Here, we review data from physiological and comparative wood anatomy studies, highlighting the potential anatomical and physicochemical drivers of embolism formation and spread. We then put forward key knowledge gaps, emphasising what is known, unknown and speculation. A meaningful evaluation of the diameter-vulnerability link will require a better mechanistic understanding of the biophysical processes at the nanoscale level that determine embolism formation and spread, which will in turn lead to more accurate predictions of how water transport in plants is affected by drought.
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Affiliation(s)
- Frederic Lens
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
- Leiden University, Institute of Biology Leiden, Plant Sciences, Sylviusweg 72, 2333 BE, Leiden, the Netherlands
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
| | - Giovanni Bortolami
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, 06511, USA
| | - Sylvain Delzon
- University of Bordeaux, INRAE, BIOGECO, 33615, Pessac, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
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23
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Guan X, Werner J, Cao KF, Pereira L, Kaack L, McAdam SAM, Jansen S. Stem and leaf xylem of angiosperm trees experiences minimal embolism in temperate forests during two consecutive summers with moderate drought. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:1208-1223. [PMID: 34990084 DOI: 10.1111/plb.13384] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Drought events may increase the likelihood that the plant water transport system becomes interrupted by embolism. Yet our knowledge about the temporal frequency of xylem embolism in the field is frequently lacking, as it requires detailed, long-term measurements. We measured xylem embolism resistance and midday xylem water potentials during the consecutive summers of 2019 and 2020 to estimate maximum levels of embolism in leaf and stem xylem of ten temperate angiosperm tree species. We also studied vessel and pit membrane characteristics based on light and electron microscopy to corroborate potential differences in embolism resistance between leaves and stems. Apart from A. pseudoplatanus and Q. petraea, eight species experienced minimum xylem water potentials that were close to or below those required to initiate embolism. Water potentials corresponding to ca. 12% loss of hydraulic conductivity (PLC) could occur in six species, while considerable levels of embolism around 50% PLC were limited to B. pendula and C. avellana. There was a general agreement in embolism resistance between stems and leaves, with leaves being equally or more resistant than stems. Also, xylem embolism resistance was significantly correlated to intervessel pit membrane thickness (TPM ) for stems, but not to vessel diameter and total intervessel pit membrane surface area of a vessel. Our data indicate that low amounts of embolism occur in most species during moderate summer drought, and that considerable levels of embolism are uncommon. Moreover, our experimental and TPM data show that leaf xylem is generally no more vulnerable than stem xylem.
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Affiliation(s)
- X Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - J Werner
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - K-F Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, Guangxi, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, China
| | - L Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - L Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - S A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - S Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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24
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Peng G, Geng H, Li Y, Ren Z, Peng J, Cao L, Pereira L, Tyree MT, Yang D. The theory behind vessel length determination using gas flow rates and comparison between two pneumatic methods based on seven woody species. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5612-5624. [PMID: 35552690 DOI: 10.1093/jxb/erac206] [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: 12/10/2021] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
In plants, xylem vessel length is important for long-distance water transport; however, the currently used methods for vessel length measurement are inconvenient and time-consuming. The recently developed semi-automated Pneumatron is a device based on the pneumatic theory that is similar to the air-injection method, and can rapidly estimate vessel length. Mean vessel length was compared between the Pneumatron and the air-injection method in seven woody species with a wide range of vessel lengths (2.3-78.7 cm). The results were consistent between the two methods, regardless of whether the same or different samples were used. The theory underlying the gas flow in vessels was improved and expanded, and compared to that underlying the water flow in order to better understand the pneumatic processes within a stem sample. Moreover, a new and simple equation for gas flow in vessels was derived based on the molar gas flow (mol s-1) rather than volume flow, because the former remains constant with distance throughout the stem axis. We strongly recommend using the Pneumatron in future studies owing to its low cost, convenience, rapidity, and simple operation. However, a number of potential issues need to be considered to avoid artifacts during measurements.
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Affiliation(s)
- Guoquan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Hongru Geng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Yaxin Li
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Zhiyang Ren
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Juan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Lei Cao
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Melvin T Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| | - Dongmei Yang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
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25
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Sorek Y, Greenstein S, Hochberg U. Seasonal adjustment of leaf embolism resistance and its importance for hydraulic safety in deciduous trees. PHYSIOLOGIA PLANTARUM 2022; 174:e13785. [PMID: 36151946 PMCID: PMC9828144 DOI: 10.1111/ppl.13785] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/27/2022] [Accepted: 09/15/2022] [Indexed: 05/20/2023]
Abstract
Embolism resistance is often viewed as seasonally stable. Here we examined the seasonality in the leaf xylem vulnerability curve (VC) and turgor loss point (ΨTLP ) of nine deciduous species that originated from Mediterranean, temperate, tropical, or sub-tropical habitats and were growing on the Volcani campus, Israel. All four Mediterranean/temperate species exhibited a shift of their VC to lower xylem pressures (Ψx ) along the dry season, in addition to two of the five tropical/sub-tropical species. In three of the species that exhibited VC seasonality, it was critical for avoiding embolism in the leaf. In total, seven out of the nine species avoided embolism. The seasonal VC adjustment was over two times higher as compared with the seasonal adjustment of ΨTLP , resulting in improved hydraulic safety as the season progressed. The results suggest that seasonality in the leaf xylem vulnerability is common in species that originate from Mediterranean or temperate habitats that have large seasonal environmental changes. This seasonality is advantageous because it enables a gradual seasonal reduction in the Ψx without increasing the danger of embolism. The results also highlight that measuring the minimal Ψx and the VC at different times can lead to erroneous estimations of the hydraulic safety margins. Changing the current hydraulic dogma into a seasonal dynamic in the vulnerability of the xylem itself should enable physiologists to understand plants' responses to their environment better.
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Affiliation(s)
- Yonatan Sorek
- Institute of Soil, Water and Environmental Science, Volcani CenterAgricultural Research OrganizationRishon LeZionIsrael
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and EnvironmentThe Hebrew University of JerusalemRehovotIsrael
| | - Smadar Greenstein
- Institute of Soil, Water and Environmental Science, Volcani CenterAgricultural Research OrganizationRishon LeZionIsrael
| | - Uri Hochberg
- Institute of Soil, Water and Environmental Science, Volcani CenterAgricultural Research OrganizationRishon LeZionIsrael
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26
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Bittencourt PRDL, Bartholomew DC, Banin LF, Bin Suis MAF, Nilus R, Burslem DFRP, Rowland L. Divergence of hydraulic traits among tropical forest trees across topographic and vertical environment gradients in Borneo. THE NEW PHYTOLOGIST 2022; 235:2183-2198. [PMID: 35633119 PMCID: PMC9545514 DOI: 10.1111/nph.18280] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 05/23/2022] [Indexed: 06/13/2023]
Abstract
Fine-scale topographic-edaphic gradients are common in tropical forests and drive species spatial turnover and marked changes in forest structure and function. We evaluate how hydraulic traits of tropical tree species relate to vertical and horizontal spatial niche specialization along such a gradient. Along a topographic-edaphic gradient with uniform climate in Borneo, we measured six key hydraulic traits in 156 individuals of differing heights in 13 species of Dipterocarpaceae. We investigated how hydraulic traits relate to habitat, tree height and their interaction on this gradient. Embolism resistance increased in trees on sandy soils but did not vary with tree height. By contrast, water transport capacity increased on sandier soils and with increasing tree height. Habitat and height only interact for hydraulic efficiency, with slope for height changing from positive to negative from the clay-rich to the sandier soil. Habitat type influenced trait-trait relationships for all traits except wood density. Our data reveal that variation in the hydraulic traits of dipterocarps is driven by a combination of topographic-edaphic conditions, tree height and taxonomic identity. Our work indicates that hydraulic traits play a significant role in shaping forest structure across topographic-edaphic and vertical gradients and may contribute to niche specialization among dipterocarp species.
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Affiliation(s)
| | - David C. Bartholomew
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QEUK
- Department of Ecology and Environmental ScienceUmeå University90736UmeåSweden
| | | | | | - Reuben Nilus
- Sabah Forestry DepartmentForest Research CentrePO Box 1407Sandakan90715SabahMalaysia
| | | | - Lucy Rowland
- College of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QEUK
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27
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Levionnois S, Kaack L, Heuret P, Abel N, Ziegler C, Coste S, Stahl C, Jansen S. Pit characters determine drought-induced embolism resistance of leaf xylem across 18 Neotropical tree species. PLANT PHYSIOLOGY 2022; 190:371-386. [PMID: 35567500 PMCID: PMC9434246 DOI: 10.1093/plphys/kiac223] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/19/2022] [Indexed: 05/16/2023]
Abstract
Embolism spreading in xylem is an important component of plant drought resistance. Since embolism resistance has been shown to be mechanistically linked to pit membrane characters in stem xylem, we speculate that similar mechanisms account for leaf xylem. We conducted transmission electron microscopy to investigate pit membrane characters in leaf xylem across 18 Neotropical tree species. We also conducted gold perfusion and polar lipid detection experiments on three species covering the full range of leaf embolism resistance. We then related these observations to previously published data on embolism resistance of leaf xylem. We also incorporated previously published data on stem embolism resistance and stem xylem pit membranes to investigate the link between vulnerability segmentation (i.e. difference in embolism resistance) and leaf-stem anatomical variation. Maximum pit membrane thickness (Tpm,max) and the pit membrane thickness-to-diameter ratio (Tpm,max/Dpm) were predictive of leaf embolism resistance, especially when vestured pits were taken into account. Variation in Tpm,max/Dpm was the only trait predictive of vulnerability segmentation between leaves and stems. Gold particles of 5- and 10-nm infiltrated pit membranes in three species, while the entry of 50-nm particles was blocked. Moreover, polar lipids were associated with inner conduit walls and pits. Our results suggest that mechanisms related to embolism spreading are determined by Tpm, pore constrictions (i.e. the narrowest bottlenecks along pore pathways), and lipid surfactants, which are largely similar between leaf and stem xylem and between temperate and tropical trees. However, our mechanistic understanding of embolism propagation and the functional relevance of Tpm,max/Dpm remains elusive.
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Affiliation(s)
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Ulm D-89081, Germany
| | | | - Nina Abel
- Institute of Systematic Botany and Ecology, Ulm University, Ulm D-89081, Germany
| | - Camille Ziegler
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
- Université de Lorraine, AgroParisTech, INRAE, UMR SILVA, Nancy 54000, France
| | - Sabrina Coste
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
| | - Clément Stahl
- UMR EcoFoG, AgroParisTech, CIRAD, CNRS, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
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28
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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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29
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Cardoso AA, Kane CN, Rimer IM, McAdam SAM. Seeing is believing: what visualising bubbles in the xylem has revealed about plant hydraulic function. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:759-772. [PMID: 35718950 DOI: 10.1071/fp21326] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/29/2022] [Indexed: 06/15/2023]
Abstract
Maintaining water transport in the xylem is critical for vascular plants to grow and survive. The drought-induced accumulation of embolism, when gas enters xylem conduits, causes declines in hydraulic conductance (K ) and is ultimately lethal. Several methods can be used to estimate the degree of embolism in xylem, from measuring K in tissues to directly visualising embolism in conduits. One method allowing a direct quantification of embolised xylem area is the optical vulnerability (OV) technique. This method has been used across different organs and has a high spatial and temporal resolution. Here, we review studies using the OV technique, discuss the main advantages and disadvantages of this method, and summarise key advances arising from its use. Vulnerability curves generated by the OV method are regularly comparable to other methods, including the centrifuge and X-ray microtomography. A major advantage of the OV technique over other methods is that it can be simultaneously used to determine in situ embolism formation in leaves, stems and roots, in species spanning the phylogeny of land plants. The OV method has been used to experimentally investigate the spreading of embolism through xylem networks, associate embolism with downstream tissue death, and observe embolism formation in the field.
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Affiliation(s)
- Amanda A Cardoso
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Cade N Kane
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Ian M Rimer
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
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30
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Tulik M, Wojtan R, Jura-Morawiec J. Theoretical considerations regarding the functional anatomical traits of primary and secondary xylem in dragon tree trunk using the example of Dracaena draco. PLANTA 2022; 256:52. [PMID: 35906444 PMCID: PMC9338164 DOI: 10.1007/s00425-022-03966-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
In Dracaena draco trunks, the primary and secondary xylem conduits co-function. Both are resistant to embolism; however, secondary conduits are mainly involved in mechanical support. Monocotyledonous dragon trees (Dracaena spp., Asparagaceae) possess in their trunks both primary and secondary xylem elements, organized into vascular bundles, that for dozens of years co-function and enable the plant to transport water efficiently as well as provide mechanical support. Here, based on the modified Hagen-Poiseuille's formula, we examined the functional anatomical xylem traits of the trunk in two young D. draco individuals to compare their function in both primary and secondary growth. We provided analyses of the: (i) conduits surface sculpture and their cell walls thickness, (ii) conduit diameter and frequency, (iii) hydraulically weighted diameter, (iv) theoretical hydraulic conductivity, (v) area-weighted mean conduit diameter, as well as (vi) vulnerability index. The conduits in primary growth, located in the central part of the trunk, were loosely arranged, had thinner cell walls, larger mean hydraulically weighted diameter, and significantly larger value of the theoretical hydraulic conductivity than conduits in secondary growth, which form a rigid cylinder near the trunk surface. Based on the vulnerability index, both primary and secondary conduits are resistant to embolism. Taking into account the distribution within a trunk, the secondary growth conduits seems to be mainly involved in mechanical support as they are twisted, form structures similar to sailing ropes and have thick cell walls, and a peripheral localization. D. draco has been adapted to an environment with water deficit by distinctive, spatial separation of the xylem elements fulfilling supportive and conductive functions.
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Affiliation(s)
- Mirela Tulik
- Department of Forest Botany, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Rafał Wojtan
- Department of Dendrometry and Forest Productivity, Warsaw University of Life Sciences, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Joanna Jura-Morawiec
- Polish Academy of Sciences Botanical Garden - CBDC in Powsin, Prawdziwka 2, 02-973 Warsaw, Poland
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31
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Song J, Trueba S, Yin XH, Cao KF, Brodribb TJ, Hao GY. Hydraulic vulnerability segmentation in compound-leaved trees: Evidence from an embolism visualization technique. PLANT PHYSIOLOGY 2022; 189:204-214. [PMID: 35099552 PMCID: PMC9070814 DOI: 10.1093/plphys/kiac034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/27/2021] [Indexed: 05/11/2023]
Abstract
The hydraulic vulnerability segmentation (HVS) hypothesis implies the existence of differences in embolism resistance between plant organs along the xylem pathway and has been suggested as an adaptation allowing the differential preservation of more resource-rich tissues during drought stress. Compound leaves in trees are considered a low-cost means of increasing leaf area and may thus be expected to show evidence of strong HVS, given the tendency of compound-leaved tree species to shed their leaf units during drought. However, the existence and role of HVS in compound-leaved tree species during drought remain uncertain. We used an optical visualization technique to estimate embolism occurrence in stems, petioles, and leaflets of shoots in two compound-leaved tree species, Manchurian ash (Fraxinus mandshurica) and Manchurian walnut (Juglans mandshurica). We found higher (less negative) water potentials corresponding to 50% loss of conductivity (P50) in leaflets and petioles than in stems in both species. Overall, we observed a consistent pattern of stem > petiole > leaflet in terms of xylem resistance to embolism and hydraulic safety margins (i.e. the difference between mid-day water potential and P50). The coordinated variation in embolism vulnerability between organs suggests that during drought conditions, trees benefit from early embolism and subsequent shedding of more expendable organs such as leaflets and petioles, as this provides a degree of protection to the integrity of the hydraulic system of the more carbon costly stems. Our results highlight the importance of HVS as an adaptive mechanism of compound-leaved trees to withstand drought stress.
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Affiliation(s)
- Jia Song
- CAS Key Laboratory of Forest Ecology and Management & Key Laboratory of Terrestrial Ecosystem Carbon Neutrality Liaoning Province, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China
- School of Environmental and Geographical Science, Shanghai Normal University, Shanghai 200234, China
- Yangtze River Delta National Observatory of Wetland Ecosystem, Shanghai Normal University, Shanghai 200234, China
| | - Santiago Trueba
- University of Bordeaux, INRAE, BIOGECO, 33615 Pessac, France
| | - Xiao-Han Yin
- CAS Key Laboratory of Forest Ecology and Management & Key Laboratory of Terrestrial Ecosystem Carbon Neutrality Liaoning Province, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, and College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
| | - Timothy J Brodribb
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia
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32
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Avila RT, Guan X, Kane CN, Cardoso AA, Batz TA, DaMatta FM, Jansen S, McAdam SAM. Xylem embolism spread is largely prevented by interconduit pit membranes until the majority of conduits are gas-filled. PLANT, CELL & ENVIRONMENT 2022; 45:1204-1215. [PMID: 34984700 DOI: 10.1111/pce.14253] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 11/29/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Xylem embolism resistance varies across species influencing drought tolerance, yet little is known about the determinants of the embolism resistance of an individual conduit. Here we conducted an experiment using the optical vulnerability method to test whether individual conduits have a specific water potential threshold for embolism formation and whether pre-existing embolism in neighbouring conduits alters this threshold. Observations were made on a diverse sample of angiosperm and conifer species through a cycle of dehydration, rehydration and subsequent dehydration to death. Upon rehydration after the formation of embolism, no refilling was observed. When little pre-existing embolism was present, xylem conduits had a conserved, individual embolism-resistance threshold that varied across the population of conduits. The consequence of a variable conduit-specific embolism threshold is that a small degree of pre-existing embolism in the xylem results in apparently more resistant xylem in subsequent dehydrations, particularly in angiosperms with vessels. While our results suggest that pit membranes separating xylem conduits are critical for maintaining a conserved individual conduit threshold for embolism when little pre-existing embolism is present, as the percentage of embolized conduits increases, gas movement, local pressure differences and connectivity between conduits increasingly contribute to embolism spread.
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Affiliation(s)
- Rodrigo T Avila
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Xinyi Guan
- Institute of Systematic Botany and Ecology, Faculty of Natural Sciences, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Cade N Kane
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Amanda A Cardoso
- Instituto de Ciências da Natureza, Universidade Federal de Alfenas, Alfenas, Brazil
| | - Timothy A Batz
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
| | - Fábio M DaMatta
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Faculty of Natural Sciences, Ulm University, Ulm, Baden-Württemberg, Germany
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, Indiana, USA
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Jansen S, Bittencourt P, Pereira L, Schenk HJ, Kunert N. A crucial phase in plants - it's a gas, gas, gas! THE NEW PHYTOLOGIST 2022; 233:1556-1559. [PMID: 35048375 DOI: 10.1111/nph.17875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Affiliation(s)
- Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Paulo Bittencourt
- College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - H Jochen Schenk
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
| | - Norbert Kunert
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Gregor-Mendel-Straße 33, 1180, Vienna, Austria
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34
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Song Y, Poorter L, Horsting A, Delzon S, Sterck F. Pit and tracheid anatomy explain hydraulic safety but not hydraulic efficiency of 28 conifer species. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1033-1048. [PMID: 34626106 PMCID: PMC8793876 DOI: 10.1093/jxb/erab449] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/07/2021] [Indexed: 05/16/2023]
Abstract
Conifers face increased drought mortality risks because of drought-induced embolism in their vascular system. Variation in embolism resistance may result from species differences in pit structure and function, as pits control the air seeding between water-transporting conduits. This study quantifies variation in embolism resistance and hydraulic conductivity for 28 conifer species grown in a 50-year-old common garden experiment and assesses the underlying mechanisms. Conifer species with a small pit aperture, high pit aperture resistance, and large valve effect were more resistant to embolism, as they all may reduce air seeding. Surprisingly, hydraulic conductivity was only negatively correlated with tracheid cell wall thickness. Embolism resistance and its underlying pit traits related to pit size and sealing were more strongly phylogenetically controlled than hydraulic conductivity and anatomical tracheid traits. Conifers differed in hydraulic safety and hydraulic efficiency, but there was no trade-off between safety and efficiency because they are driven by different xylem anatomical traits that are under different phylogenetic control.
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Affiliation(s)
- Yanjun Song
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Lourens Poorter
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Angelina Horsting
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
| | - Sylvain Delzon
- University of Bordeaux, INRA, UMR BIOGECO, 33450 Talence, France
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University and Research, PO Box 47, 6700 AA, Wageningen, The Netherlands
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35
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Ganthaler A, Bär A, Dämon B, Losso A, Nardini A, Dullin C, Tromba G, von Arx G, Mayr S. Alpine dwarf shrubs show high proportions of nonfunctional xylem: Visualization and quantification of species-specific patterns. PLANT, CELL & ENVIRONMENT 2022; 45:55-68. [PMID: 34783044 DOI: 10.1111/pce.14226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/15/2021] [Accepted: 07/15/2021] [Indexed: 06/13/2023]
Abstract
Xylem conductive capacity is a key determinant of plant hydraulic function and intimately linked to photosynthesis and productivity, but can be impeded by temporary or permanent conduit dysfunctions. Here we show that persistent xylem dysfunctions in unstressed plants are frequent in Alpine dwarf shrubs and occur in various but species-specific cross-sectional patterns. Combined synchrotron micro-computed tomography (micro-CT) imaging, xylem staining, and flow measurements in saturated samples of six widespread Ericaceae species evidence a high proportion (19%-50%) of hydraulically nonfunctional xylem areas in the absence of drought stress, with regular distribution of dysfunctions between or within growth rings. Dysfunctions were only partly reversible and reduced the specific hydraulic conductivity to 1.38 to 3.57 ×10-4 m2 s-1 MPa-1 . Decommission of inner growth rings was clearly related to stem age and a higher vulnerability to cavitation of older rings, while the high proportion of nonfunctional conduits in each annual ring needs further investigations. The lower the xylem fraction contributing to the transport function, the higher was the hydraulic efficiency of conducting xylem areas. Improved understanding of the functional lifespan of xylem elements and the prevalence and nature of dysfunctions is critical to correctly assess structure-function relationships and whole-plant hydraulic strategies.
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Affiliation(s)
- Andrea Ganthaler
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Andreas Bär
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Birgit Dämon
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
| | - Christian Dullin
- Elettra-Sincrotrone Trieste, Basovizza, Italy
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany
- Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
- Diagnostic and Interventional Radiology, University Hospital, Heidelberg, Germany
| | | | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
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36
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Suissa JS, Friedman WE. From cells to stems: the effects of primary vascular construction on drought-induced embolism in fern rhizomes. THE NEW PHYTOLOGIST 2021; 232:2238-2253. [PMID: 34273190 DOI: 10.1111/nph.17629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
While a considerable amount of data exists on the link between xylem construction and hydraulic function, few studies have focused on resistance to drought-induced embolism of primary vasculature in herbaceous plants. Ferns rely entirely on primary xylem and display a remarkable diversity of vascular construction in their rhizomes, making them an ideal group in which to examine hydraulic structure-function relationships. New optical methods allowed us to measure vulnerability to embolism in rhizomes, which are notoriously difficult to work with. We investigated five fern species based on their diverse xylem traits at the cellular, histological, and architectural levels. To link below- and above-ground hydraulics, we then measured leaf-stem vulnerability segmentation. Overall, rhizome vulnerability to embolism was correlated most strongly with cellular but not histological or architectural traits. Interestingly, at P6-12 , species with increased architectural dissection were actually more vulnerable to embolism, suggesting different hydraulic dynamics at low compared to high percent embolism. Importantly, leaves fully embolize before stems reach P88 , suggesting strong vulnerability segmentation. This is the first study to explore the functional implications of primary vascular construction in fern rhizomes and leaf-stem vulnerability segmentation. Strong segmentation suggests that leaves protect perennial rhizomes against severe drought stress and hydraulically induced mortality.
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Affiliation(s)
- Jacob S Suissa
- The Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- The Arnold Arboretum of Harvard University, Boston, MA, 02131, USA
| | - William E Friedman
- The Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- The Arnold Arboretum of Harvard University, Boston, MA, 02131, USA
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37
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Trabi CL, Pereira L, Guan X, Miranda MT, Bittencourt PRL, Oliveira RS, Ribeiro RV, Jansen S. A User Manual to Measure Gas Diffusion Kinetics in Plants: Pneumatron Construction, Operation, and Data Analysis. FRONTIERS IN PLANT SCIENCE 2021; 12:633595. [PMID: 34163496 PMCID: PMC8216216 DOI: 10.3389/fpls.2021.633595] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/12/2021] [Indexed: 05/17/2023]
Abstract
The Pneumatron device measures gas diffusion kinetics in the xylem of plants. The device provides an easy, low-cost, and powerful tool for research on plant water relations and gas exchange. Here, we describe in detail how to construct and operate this device to estimate embolism resistance of angiosperm xylem, and how to analyse pneumatic data. Simple and more elaborated ways of constructing a Pneumatron are shown, either using wires, a breadboard, or a printed circuit board. The instrument is based on an open-source hardware and software system, which allows users to operate it in an automated or semi-automated way. A step-by-step manual and a troubleshooting section are provided. An excel spreadsheet and an R-script are also presented for fast and easy data analysis. This manual aims at helping users to avoid common mistakes, such as unstable measurements of the minimum and maximum amount of gas discharged from xylem tissue, which has major consequences for estimating embolism resistance. Major advantages of the Pneumatron device include its automated and accurate measurements of gas diffusion rates, including highly precise measurements of the gas volume in intact, embolised conduits. It is currently unclear if the method can also be applied to woody monocots, gymnosperm species that possess torus-margo pit membranes, or to herbaceous species.
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Affiliation(s)
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
- Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Xinyi Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Marcela T. Miranda
- Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
| | | | - Rafael S. Oliveira
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael V. Ribeiro
- Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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38
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Kaack L, Weber M, Isasa E, Karimi Z, Li S, Pereira L, Trabi CL, Zhang Y, Schenk HJ, Schuldt B, Schmidt V, Jansen S. Pore constrictions in intervessel pit membranes provide a mechanistic explanation for xylem embolism resistance in angiosperms. THE NEW PHYTOLOGIST 2021; 230:1829-1843. [PMID: 33595117 DOI: 10.1111/nph.17282] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/09/2021] [Indexed: 05/27/2023]
Abstract
Embolism spreading in angiosperm xylem occurs via mesoporous pit membranes between vessels. Here, we investigate how the size of pore constrictions in pit membranes is related to pit membrane thickness and embolism resistance. Pit membranes were modelled as multiple layers to investigate how pit membrane thickness and the number of intervessel pits per vessel determine pore constriction sizes, the probability of encountering large pores, and embolism resistance. These estimations were complemented by measurements of pit membrane thickness, embolism resistance, and number of intervessel pits per vessel in stem xylem (n = 31, 31 and 20 species, respectively). The modelled constriction sizes in pit membranes decreased with increasing membrane thickness, explaining the measured relationship between pit membrane thickness and embolism resistance. The number of pits per vessel affected constriction size and embolism resistance much less than pit membrane thickness. Moreover, a strong relationship between modelled and measured embolism resistance was observed. Pore constrictions provide a mechanistic explanation for why pit membrane thickness determines embolism resistance, which suggests that hydraulic safety can be uncoupled from hydraulic efficiency. Although embolism spreading remains puzzling and encompasses more than pore constriction sizes, angiosperms are unlikely to have leaky pit membranes, which enables tensile transport of water.
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Affiliation(s)
- Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Matthias Weber
- Institute of Stochastics, Ulm University, Helmholtzstraße 18, Ulm, D-89069, Germany
| | - Emilie Isasa
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute for Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, Würzburg, D-97082, Germany
| | - Zohreh Karimi
- Department of Biology, Faculty of Sciences, Golestan University, Shahid Beheshti St., Gorgan, 15759-49138, Iran
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Christophe L Trabi
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Ya Zhang
- College of Life Sciences, Anhui Normal University, Beijingdong Road 1, Wuhu, 241000, China
| | - H Jochen Schenk
- Department of Biological Science, California State University Fullerton, Fullerton, CA, 92834-6850, USA
| | - Bernhard Schuldt
- Ecophysiology and Vegetation Ecology, Julius-von-Sachs-Institute for Biological Sciences, University of Würzburg, Julius-von-Sachs-Platz 3, Würzburg, D-97082, Germany
| | - Volker Schmidt
- Institute of Stochastics, Ulm University, Helmholtzstraße 18, Ulm, D-89069, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
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