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Anfodillo T, Olson ME. Stretched sapwood, ultra-widening permeability and ditching da Vinci: revising models of plant form and function. ANNALS OF BOTANY 2024; 134:19-42. [PMID: 38634673 PMCID: PMC11161570 DOI: 10.1093/aob/mcae054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 04/14/2024] [Indexed: 04/19/2024]
Abstract
BACKGROUND The mechanisms leading to dieback and death of trees under drought remain unclear. To gain an understanding of these mechanisms, addressing major empirical gaps regarding tree structure-function relations remains essential. SCOPE We give reasons to think that a central factor shaping plant form and function is selection simultaneously favouring constant leaf-specific conductance with height growth and isometric (1:1) scaling between leaf area and the volume of metabolically active sink tissues ('sapwood'). Sapwood volume-leaf area isometry implies that per-leaf area sapwood volumes become transversely narrower with height growth; we call this 'stretching'. Stretching means that selection must favour increases in permeability above and beyond that afforded by tip-to-base conduit widening ("ultra-widening permeability"), via fewer and wider vessels or tracheids with larger pits or larger margo openings. Leaf area-metabolically active sink tissue isometry would mean that it is unlikely that larger trees die during drought because of carbon starvation due to greater sink-source relationships as compared to shorter plants. Instead, an increase in permeability is most plausibly associated with greater risk of embolism, and this seems a more probable explanation of the preferential vulnerability of larger trees to climate change-induced drought. Other implications of selection favouring constant per-leaf area sapwood construction and maintenance costs are departure from the da Vinci rule expectation of similar sapwood areas across branching orders, and that extensive conduit furcation in the stem seems unlikely. CONCLUSIONS Because all these considerations impact the likelihood of vulnerability to hydraulic failure versus carbon starvation, both implicated as key suspects in forest mortality, we suggest that these predictions represent essential priorities for empirical testing.
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Affiliation(s)
- Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Legnaro (PD) 35020, Italy
| | - Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito sn de Ciudad Universitaria, Ciudad de México 04510, Mexico
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2
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Bartusch K, Blanco-Touriñán N, Rodriguez-Villalón A, Truernit E. Monitoring Xylem Transport in Arabidopsis thaliana Seedlings Using Fluorescent Dyes. Methods Mol Biol 2024; 2722:3-15. [PMID: 37897596 DOI: 10.1007/978-1-0716-3477-6_1] [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] [Indexed: 10/30/2023]
Abstract
Fluorescent dyes are often used to observe transport mechanisms in plant vascular tissues. However, it has been technically challenging to apply fluorescent dyes on roots to monitor xylem transport in vivo. Here, we present a fast, noninvasive, and high-throughput protocol to monitor xylem transport in seedlings. Using the fluorescent dyes 5(6)-carboxyfluorescein diacetate (CFDA) and Rhodamine WT, we were able to observe xylem transport on a cellular level in Arabidopsis thaliana roots. We describe how to apply these dyes on primary roots of young seedlings, how to monitor root-to-shoot xylem transport, and how to measure xylem transport velocity in roots. Moreover, we show that our protocol can also be applied to lateral roots and grafted seedlings to assess xylem (re)connection. Altogether, these techniques are useful for investigating xylem functionality in diverse experimental setups.
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Affiliation(s)
- Kai Bartusch
- Group of Phloem Development and Function, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland.
| | - Noel Blanco-Touriñán
- Group of Plant Vascular Development, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Antia Rodriguez-Villalón
- Group of Plant Vascular Development, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Elisabeth Truernit
- Group of Phloem Development and Function, Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland.
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3
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Konrad W, Neinhuis C, Roth-Nebelsick A. Straight roads into nowhere - obvious and not-so-obvious biological models for ferrophobic surfaces. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2022; 13:1345-1360. [PMID: 36474925 PMCID: PMC9679617 DOI: 10.3762/bjnano.13.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
There are currently efforts to improve strategies for biomimetic approaches, to identify pitfalls and to provide recommendations for a successful biomimetic work flow. In this contribution, a case study of a concrete biomimetic project is described that started with a posed technical problem for which seemingly obvious biological models exist. The technical problem was to devise a ferrophobic surface that prevents the contact between the copper surface of a tuyère (a water cooled aeration pipe within a blast furnace) and liquid iron. Therefore, biological external surfaces that strongly repel liquids appeared to be suitable, particularly the hair cover of the water fern Salvinia molesta and the surface of Collembola (an arthropod group). It turned out, however, that it was not feasible to realise the functional structures of both biological models for the tuyère problem. Instead, a seemingly not obvious biological model was identified, namely micropores within the cell walls of water-transporting conduits of plants that connect the conduits to a three-dimensional flow network. These specially shaped pores are assumed to be able to create stable air bodies, which support the refilling of embolised conduits. By adopting the shape of these micropores, a successful prototype for a ferrophobic copper surface repelling liquid iron could be devised. This case study illustrates that straight road maps from technical problems to obvious biological models are no guarantee for success, and that it is difficult to arrive at a formalised biomimetic working scheme. Rather, a broad understanding of biological function and its complexity is beneficial.
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Affiliation(s)
- Wilfried Konrad
- Institute of Botany, Technical University Dresden, Zellescher Weg 20b, D-01217 Dresden, Germany
- Department of Geosciences, University of Tübingen, Schnarrenbergstr. 94–96, D-72076 Tübingen, Germany
| | - Christoph Neinhuis
- Institute of Botany, Technical University Dresden, Zellescher Weg 20b, D-01217 Dresden, Germany
| | - Anita Roth-Nebelsick
- State Museum of Natural History Stuttgart, Rosenstein 1, D-70191 Stuttgart, Germany
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4
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Feng X, Lu Y, Jiang M, Katul G, Manzoni S, Mrad A, Vico G. Instantaneous stomatal optimization results in suboptimal carbon gain due to legacy effects. PLANT, CELL & ENVIRONMENT 2022; 45:3189-3204. [PMID: 36030546 DOI: 10.1111/pce.14427] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Xue Feng
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yaojie Lu
- Department of Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Gabriel Katul
- Department of Civil and Environmental Engineering, Duke University, Durham, North Carolina, USA
| | - Stefano Manzoni
- Department of Physical Geography and Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
| | - Assaad Mrad
- Department of Civil and Environmental Engineering, University of California, Irvine, California, USA
- Department of Engineering, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Giulia Vico
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
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5
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Nakad M, Domec JC, Sevanto S, Katul G. Radial-axial transport coordination enhances sugar translocation in the phloem vasculature of plants. PLANT PHYSIOLOGY 2022; 189:2061-2071. [PMID: 35588257 PMCID: PMC9343002 DOI: 10.1093/plphys/kiac231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/27/2022] [Indexed: 05/21/2023]
Abstract
Understanding mass transport of photosynthates in the phloem of plants is necessary for predicting plant carbon allocation, productivity, and responses to water and thermal stress. Several hypotheses about optimization of phloem structure and function and limitations of phloem transport under drought have been proposed and tested with models and anatomical data. However, the true impact of radial water exchange of phloem conduits with their surroundings on mass transport of photosynthates has not been addressed. Here, the physics of the Munch mechanism of sugar transport is re-evaluated to include local variations in viscosity resulting from the radial water exchange in two dimensions (axial and radial) using transient flow simulations. Model results show an increase in radial water exchange due to a decrease in sap viscosity leading to increased sugar front speed and axial mass transport across a wide range of phloem conduit lengths. This increase is around 40% for active loaders (e.g. crops) and around 20% for passive loaders (e.g. trees). Thus, sugar transport operates more efficiently than predicted by previous models that ignore these two effects. A faster front speed leads to higher phloem resiliency under drought because more sugar can be transported with a smaller pressure gradient.
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Affiliation(s)
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, Gradignan 33175, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, USA
| | - Sanna Sevanto
- Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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6
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Johnson DM, Katul G, Domec J. Catastrophic hydraulic failure and tipping points in plants. PLANT, CELL & ENVIRONMENT 2022; 45:2231-2266. [PMID: 35394656 PMCID: PMC9544843 DOI: 10.1111/pce.14327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 06/12/2023]
Abstract
Water inside plants forms a continuous chain from water in soils to the water evaporating from leaf surfaces. Failures in this chain result in reduced transpiration and photosynthesis and are caused by soil drying and/or cavitation-induced xylem embolism. Xylem embolism and plant hydraulic failure share several analogies to 'catastrophe theory' in dynamical systems. These catastrophes are often represented in the physiological and ecological literature as tipping points when control variables exogenous (e.g., soil water potential) or endogenous (e.g., leaf water potential) to the plant are allowed to vary on time scales much longer than time scales associated with cavitation events. Here, plant hydraulics viewed from the perspective of catastrophes at multiple spatial scales is considered with attention to bubble expansion within a xylem conduit, organ-scale vulnerability to embolism, and whole-plant biomass as a proxy for transpiration and hydraulic function. The hydraulic safety-efficiency tradeoff, hydraulic segmentation and maximum plant transpiration are examined using this framework. Underlying mechanisms for hydraulic failure at fine scales such as pit membranes and cell-wall mechanics, intermediate scales such as xylem network properties and at larger scales such as soil-tree hydraulic pathways are discussed. Understudied areas in plant hydraulics are also flagged where progress is urgently needed.
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Affiliation(s)
- Daniel M. Johnson
- Warnell School of Forestry and Natural ResourcesUniversity of GeorgiaAthensGeorgiaUSA
| | - Gabriel Katul
- Department of Civil and Environmental EngineeringDuke UniversityDurhamNorth CarolinaUSA
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
| | - Jean‐Christophe Domec
- Nicholas School of the EnvironmentDuke UniversityDurhamNorth CarolinaUSA
- Department of ForestryBordeaux Sciences Agro, UMR INRAE‐ISPA 1391GradignanFrance
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7
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van den Herik B, ten Tusscher K. Undirected Sucrose Efflux Mitigation by the FT-Like SP6A Preferentially Enhances Tuber Resource Partitioning. FRONTIERS IN PLANT SCIENCE 2022; 13:817909. [PMID: 35615135 PMCID: PMC9125184 DOI: 10.3389/fpls.2022.817909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/18/2022] [Indexed: 06/15/2023]
Abstract
The yield of harvestable plant organs depends on overall photosynthetic output and the subsequent distribution of the produced assimilates from source leaves across different sink organs. In this study, we aimed to obtain, using a two-sink transport model, mechanistic understanding of how the interplay between sink and pathway properties together determines sink resource partitioning. As a working example, we analyzed the partitioning of resources within potato plants, investigating the determinants of tuber sink yield. Our results indicated that, contrary to earlier studies, with a spatially explicit biophysically detailed model, transport pathway properties significantly affect sink resource partitioning within the physiologically relevant domain. Additionally, we uncovered that xylem flow, through its hydraulic coupling to the phloem, and sucrose efflux along the phloem, also significantly affected resource partitioning. For tubers, it is the cumulative disadvantage compared to sink leaves (distance, xylem flow, and sucrose efflux) that enable an undirected SP6A-mediated reduction of sucrose efflux to preferentially benefit tuber resource partitioning. Combined with the SP6A-mediated sink strength increase, undirected SP6A introduction significantly enhances tuber resource partitioning.
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8
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Treydte K, Lehmann MM, Wyczesany T, Pfautsch S. Radial and axial water movement in adult trees recorded by stable isotope tracing. TREE PHYSIOLOGY 2021; 41:2248-2261. [PMID: 34100071 DOI: 10.1093/treephys/tpab080] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/31/2021] [Indexed: 06/12/2023]
Abstract
The capacity of trees to release water from storage compartments into the transpiration stream can mitigate damage to hydraulic functioning. However, the location of these 'transient' water sources and also the pathways of water movement other than vertical through tree stems still remain poorly understood. We conducted an experiment on two tree species in a common garden in eastern Australia that naturally grow in regions of high (Eucalyptus tereticornis, 'Red Gum') and low (Eucalyptus sideroxylon, 'Ironbark') annual precipitation rates. Deuterium-enriched water (1350% label strength) was directly introduced into the transpiration stream of three trees per species for four consecutive days. Subsequently, the trees were felled, woody tissue samples were collected from different heights and azimuthal positions of the stems, and stable isotope ratios were determined on the water extracted from all samples. The presence/absence of the tracer along the radial and vertical stem axes in combination with xylem hydraulic properties inferred from sapflow, leaf and stem water potentials, wood moisture contents and anatomical sapwood characteristics elucidated species-specific patterns of short-term stem water storage and movement. The distribution of water isotopes at natural abundance among woody tissues indicated systematic differences with highest values of sapwood water and lower values in inner bark and heartwood. Presence of tracer in water of the inner bark highlighted the importance of this tissue as capacitor. Although injected at the northern side of stems, tracer was also discovered at the southern side, providing empirical evidence for circumferential flow in sapwood, particularly of Ironbark. Greater vertical water transport in Red Gum compared with more radial and circumferential water transport in Ironbark were associated with species-specific sapwood anatomy. Our study highlights the value of combining information from stable isotope tracers and wood anatomy to investigate patterns of water transport and storage of tall trees in situ.
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Affiliation(s)
- Kerstin Treydte
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Marco M Lehmann
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Tomasz Wyczesany
- Plant Functional Biology and Climate Change Cluster, University of Technology, Sydney, NSW 2007, Australia
| | - Sebastian Pfautsch
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, NSW 2751, Australia
- Urban Studies, School of Social Sciences, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
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9
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Mrad A, Johnson DM, Love DM, Domec JC. The roles of conduit redundancy and connectivity in xylem hydraulic functions. THE NEW PHYTOLOGIST 2021; 231:996-1007. [PMID: 33908055 DOI: 10.1111/nph.17429] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Wood anatomical traits shape a xylem segment's hydraulic efficiency and resistance to embolism spread due to declining water potential. It has been known for decades that variations in conduit connectivity play a role in altering xylem hydraulics. However, evaluating the precise effect of conduit connectivity has been elusive. The objective here is to establish an analytical linkage between conduit connectivity and grouping and tissue-scale hydraulics. It is hypothesized that an increase in conduit connectivity brings improved resistance to embolism spread due to increased hydraulic pathway redundancy. However, an increase in conduit connectivity could also reduce resistance due to increased speed of embolism spread with respect to pressure. We elaborate on this trade-off using graph theory, percolation theory and computational modeling of xylem. The results are validated using anatomical measurements of Acer branch xylem. Considering only species with vessels, increases in connectivity improve resistance to embolism spread without negatively affecting hydraulic conductivity. The often measured grouping index fails to capture the totality of the effect of conduit connectivity on xylem hydraulics. Variations in xylem network characteristics, such as conduit connectivity, might explain why hypothesized trends among woody species, such as the 'safety-efficiency' trade-off hypothesis, are weaker than expected.
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Affiliation(s)
- Assaad Mrad
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Department of Civil and Environmental Engineering, University of California, Irvine, CA, 92697, USA
- Department of Engineering, Wake Forest University, Winston-Salem, NC, 27101, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - David M Love
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
| | - Jean-Christophe Domec
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, Gradignan Cedex, 33175, France
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10
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Ray DM, Savage JA. Seasonal changes in temperate woody plant phloem anatomy and physiology: implications for long-distance transport. AOB PLANTS 2021; 13:plab028. [PMID: 34234934 PMCID: PMC8255074 DOI: 10.1093/aobpla/plab028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 05/21/2021] [Indexed: 06/13/2023]
Abstract
Seasonal changes in climate are accompanied by shifts in carbon allocation and phenological changes in woody angiosperms, the timing of which can have broad implications for species distributions, interactions and ecosystem processes. During critical transitions from autumn to winter and winter to spring, physiological and anatomical changes within the phloem could impose a physical limit on the ability of woody angiosperms to transport carbon and signals. There is a paucity of the literature that addresses tree (floral or foliar) phenology, seasonal phloem anatomy and seasonal phloem physiology together, so our knowledge of how carbon transport could fluctuate seasonally, especially in temperate climates is limited. We review phloem phenology focussing on how sieve element anatomy and phloem sap flow could affect carbon availability throughout the year with a focus on winter. To investigate whether flow is possible in the winter, we construct a simple model of phloem sap flow and investigate how changes to the sap concentration, pressure gradient and sieve plate pores could influence flow during the winter. Our model suggests that phloem transport in some species could occur year-round, even in winter, but current methods for measuring all the parameters surrounding phloem sap flow make it difficult to test this hypothesis. We highlight outstanding questions that remain about phloem functionality in the winter and emphasize the need for new methods to address gaps in our knowledge about phloem function.
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Affiliation(s)
- Dustin M Ray
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
| | - Jessica A Savage
- Department of Biology, University of Minnesota Duluth, Duluth, MN 55811, USA
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11
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Abstract
Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.
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12
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Cao Y, Ma C, Chen H, Zhang J, White JC, Chen G, Xing B. Xylem-based long-distance transport and phloem remobilization of copper in Salix integra Thunb. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122428. [PMID: 32208308 DOI: 10.1016/j.jhazmat.2020.122428] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 02/12/2020] [Accepted: 02/28/2020] [Indexed: 06/10/2023]
Abstract
Due to high biomass and an ability to accumulate metals, fast-growing tree species are good candidates for phytoremediation. However, little is known about the long-distance transport of heavy metals in woody plants. The present work focused on the xylem transport and phloem remobilization of copper (Cu) in Salix integra Thunb. Seedlings with 45 d preculture were grown in nutrient solutions added with 0.32 and 10 μM CuSO4 for 5 d. Micro X-ray fluorescence imaging showed the high Cu intensity in xylem tissues of both stem and root cross sections, confirming that the xylem played a vital role in Cu transport from roots to shoots. Cu was presented in both xylem sap and phloem exudate, which demonstrates the long-distance transport of Cu via both vascular tissues. Additionally, the 65Cu spiked mature leaf exported approximately 78 % 65Cu to newly emerged shoots, and approximately 22 % downward to the new roots, confirming the bidirectional transport of Cu via phloem. To our knowledge, this is the first report to characterize Cu vascular transport and remobilization in fast-growing woody plants, and the findings provide valuable mechanistic understanding for the phytoremediation of Cu-contaminated soils.
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Affiliation(s)
- Yini Cao
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, Zhejiang, 311400, China
| | - Chuanxin Ma
- Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, CT, 06504, United States
| | - Hongjun Chen
- Hunan Commodities Quality Supervision and Inspection Institute, Changsha, 410007, China
| | - Jianfeng Zhang
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, Zhejiang, 311400, China
| | - Jason C White
- Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, CT, 06504, United States
| | - Guangcai Chen
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, Zhejiang, 311400, China.
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, 01003, United States
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13
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Du W, Pan ZY, Hussain SB, Han ZX, Peng SA, Liu YZ. Foliar Supplied Boron Can Be Transported to Roots as a Boron-Sucrose Complex via Phloem in Citrus Trees. FRONTIERS IN PLANT SCIENCE 2020; 11:250. [PMID: 32211005 PMCID: PMC7076173 DOI: 10.3389/fpls.2020.00250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/18/2020] [Indexed: 05/07/2023]
Abstract
Although foliar boron (B) fertilization is regarded as an efficient way to remedy B deficiency, the mechanisms of foliar B transport from leaves to roots are still unclear. In this study, performed with 1-year-old "Newhall" navel orange (Citrus sinensis) grafted on trifoliate orange (Poncirus trifoliata) plants, we analyzed the B concentration in leaves and roots, B-sucrose complex in the phloem sap after foliar application of 10B, girdling, and/or shading treatments. Results indicated that 10B concentration was significantly increased in roots after foliar 10B treatment. On the other hand, both girdling the scion stem and shading over the plants with a black plastic net significantly reduced the B and 10B concentration in roots. LC-MS analysis revealed that foliar 10B-treated plants had higher concentration of sucrose and some sugar alcohols in the phloem sap as compared to foliar water-treated plants. Combining with the analysis in the artificial mixture of B and sucrose, a higher peak intensity of the 10B-sucrose complex was found in the phloem sap of foliar 10B-treated plants compared to the control plants. Taken together, it is concluded that foliar B can be long distance transported from leaves to roots via phloem, at least by forming a B-sucrose complex in citrus plants.
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Affiliation(s)
- Wei Du
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Zhi-Yong Pan
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Syed Bilal Hussain
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Zhong-Xing Han
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Shu-Ang Peng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
| | - Yong-Zhong Liu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, China
- College of Horticulture & Forestry Sciences, Huazhong Agricultural University, Wuhan, China
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14
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Park J, Go T, Ryu J, Lee SJ. Air spreading through wetted cellulose membranes: Implications for the safety function of hydraulic valves in plants. Phys Rev E 2019; 100:032409. [PMID: 31640020 DOI: 10.1103/physreve.100.032409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Indexed: 06/10/2023]
Abstract
Plants transport water against the risk of cavitation inside xylem vessels, called "embolism." As one of their hydraulic strategies, pit membranes composed of cellulose fibers have been known as safety valves that prevent the spreading of embolism towards adjacent xylem vessels. However, detailed observation of embolism spreading through a pit membrane is still lacking. Here, we hypothesized that the pit membranes normally remain to be wetted in xylem vessels and noticed in particular the hydraulic role of water film on air spreading that has been overlooked previously. For the hydrodynamic study of the embolism spreading through a wetted pit membrane, we investigated the penetration and spreading dynamics of air plugs through the wetted cellulose membrane in a channel flow. Air spreading exhibits two types of dynamics: continuous and discrete spreading. We elucidated the correlation of dynamic characteristics of air flow and pressure variations according to membrane thickness. Our study speculates that the thickness of pit membranes affects the behaviors of water film captured by cellulose fibers, and it is a crucial criterion for the reversible gating of further spreading of embolism throughout xylem networks.
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Affiliation(s)
- JooYoung Park
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| | - Taesik Go
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| | - Jeongeun Ryu
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
| | - Sang Joon Lee
- Department of Mechanical Engineering, Pohang University of Science and Technology, San 31, Hyoja-dong, Pohang 37673, South Korea
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