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Manandhar A, Rimer IM, Soares Pereira T, Pichaco J, Rockwell FE, McAdam SAM. Dynamic soil hydraulic resistance regulates stomata. THE NEW PHYTOLOGIST 2024; 244:147-158. [PMID: 39096020 DOI: 10.1111/nph.20020] [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: 06/06/2024] [Accepted: 07/05/2024] [Indexed: 08/04/2024]
Abstract
The onset of stomatal closure reduces transpiration during drought. In seed plants, drought causes declines in plant water status which increases leaf endogenous abscisic acid (ABA) levels required for stomatal closure. There are multiple possible points of increased belowground resistance in the soil-plant atmospheric continuum that could decrease leaf water potential enough to trigger ABA production and the subsequent decreases in transpiration. We investigate the dynamic patterns of leaf ABA levels, plant hydraulic conductance and the point of failure in the soil-plant conductance in the highly embolism-resistant species Callitris tuberculata using continuous dendrometer measurements of leaf water potential during drought. We show that decreases in transpiration and ABA biosynthesis begin before any permanent decreases in predawn water potential, collapse in soil-plant hydraulic pathway and xylem embolism spread. We find that a dynamic but recoverable increases in hydraulic resistance in the soil in close proximity to the roots is the most likely driver of declines in midday leaf water potential needed for ABA biosynthesis and the onset of decreases in transpiration.
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Affiliation(s)
- Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Ian M Rimer
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Talitha Soares Pereira
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Javier Pichaco
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Ave Reina Mercedes 10, 41012, Seville, Spain
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
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2
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Harrison Day BL, Brodersen CR, Brodribb TJ. Weak link or strong foundation? Vulnerability of fine root networks and stems to xylem embolism. THE NEW PHYTOLOGIST 2024. [PMID: 39267263 DOI: 10.1111/nph.20115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 08/21/2024] [Indexed: 09/17/2024]
Abstract
Resolving the position of roots in the whole-plant hierarchy of drought-induced xylem embolism resistance is fundamental for predicting when species become isolated from soil water resources. Published research generally suggests that roots are the most vulnerable organ of the plant vascular system, although estimates vary significantly. However, our knowledge of root embolism excludes the fine roots (< 2 mm diameter) that form the bulk of total absorptive surface area of the root network for water and nutrient uptake. We measured fine root and stem xylem vulnerability in 10 vascular plant species from the major land plant clades (five angiosperms, three conifers, a fern and lycophyte), using standardised in situ methods (Optical Methods and MicroCT). Mean fine root embolism resistance across the network matched or exceeded stems in all study species. In six of these species (one fern, one lycophyte, three conifers and one angiosperm), fine roots were significantly more embolism resistant than stems. No clear relationship was found between root xylem conduit diameter and vulnerability. These results provide insight into the resistance of the plant hydraulic pathway at the site of water and nutrient uptake, and challenge the long-standing assumption that fine roots are more vulnerable than stems.
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Affiliation(s)
- Beatrice L Harrison Day
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
- School of the Environment, Yale University, New Haven, CT, 06520, USA
| | - Craig R Brodersen
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
- School of the Environment, Yale University, New Haven, CT, 06520, USA
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
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3
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Mekarni L, Cochard H, Lehmann MM, Turberg P, Grossiord C. In vivo X-ray microtomography locally affects stem radial growth with no immediate physiological impact. PLANT PHYSIOLOGY 2024; 196:153-163. [PMID: 38757896 DOI: 10.1093/plphys/kiae285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024]
Abstract
Microcomputed tomography (µCT) is a nondestructive X-ray imaging method used in plant physiology to visualize in situ plant tissues that enables assessments of embolized xylem vessels. Whereas evidence for X-ray-induced cellular damage has been reported, the impact on plant physiological processes such as carbon (C) uptake, transport, and use is unknown. Yet, these damages could be particularly relevant for studies that track embolism and C fluxes over time. We examined the physiological consequences of µCT scanning for xylem embolism over 3 mo by monitoring net photosynthesis (Anet), diameter growth, chlorophyll (Chl) concentration, and foliar nonstructural carbohydrate (NSC) content in 4 deciduous tree species: hedge maple (Acer campestre), ash (Fraxinus excelsior), European hornbeam (Carpinus betulus), and sessile oak (Quercus petraea). C transport from the canopy to the roots was also assessed through 13C labeling. Our results show that monthly X-ray application did not impact foliar Anet, Chl, NSC content, and C transport. Although X-ray effects did not vary between species, the most pronounced impact was observed in sessile oak, marked by stopped growth and stem deformations around the irradiated area. The absence of adverse impacts on plant physiology for all the tested treatments indicates that laboratory-based µCT systems can be used with different beam energy levels and doses without threatening the integrity of plant physiology within the range of tested parameters. However, the impacts of repetitive µCT on the stem radial growth at the irradiated zone leading to deformations in sessile oak might have lasting implications for studies tracking plant embolism in the longer-term.
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Affiliation(s)
- Laura Mekarni
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, CH-1015 Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Community Ecology Unit, 8903 Birmensdorf, Switzerland
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Marco M Lehmann
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Community Ecology Unit, 8903 Birmensdorf, Switzerland
| | - Pascal Turberg
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, CH-1015 Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Community Ecology Unit, 8903 Birmensdorf, Switzerland
| | - Charlotte Grossiord
- Plant Ecology Research Laboratory PERL, School of Architecture, Civil and Environmental Engineering, EPFL, CH-1015 Lausanne, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Community Ecology Unit, 8903 Birmensdorf, Switzerland
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4
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Haverroth EJ, Rimer IM, Oliveira LA, de Lima LGA, Cesarino I, Martins SCV, McAdam SAM, Cardoso AA. Gradients in embolism resistance within stems driven by secondary growth in herbs. PLANT, CELL & ENVIRONMENT 2024; 47:2986-2998. [PMID: 38644584 DOI: 10.1111/pce.14921] [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: 02/05/2024] [Revised: 03/22/2024] [Accepted: 04/08/2024] [Indexed: 04/23/2024]
Abstract
The stems of some herbaceous species can undergo basal secondary growth, leading to a continuum in the degree of woodiness along the stem. Whether the formation of secondary growth in the stem base results in differences in embolism resistance between the base and the upper portions of stems is unknown. We assessed the embolism resistance of leaves and the basal and upper portions of stems simultaneously within the same individuals of two divergent herbaceous species that undergo secondary growth in the mature stem bases. The species were Solanum lycopersicum (tomato) and Senecio minimus (fireweed). Basal stem in mature plants of both species displayed advanced secondary growth and greater resistance to embolism than the upper stem. This also resulted in significant vulnerability segmentation between the basal stem and the leaves in both species. Greater embolism resistance in the woodier stem base was found alongside decreases in the pith-to-xylem ratio, increases in the proportion of secondary xylem, and increases in lignin content. We show that there can be considerable variation in embolism resistance across the stem in herbs and that this variation is linked to the degree of secondary growth present. A gradient in embolism resistance across the stem in herbaceous plants could be an adaptation to ensure reproduction or basal resprouting during episodes of drought late in the lifecycle.
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Affiliation(s)
- Eduardo J Haverroth
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Ian M Rimer
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Leonardo A Oliveira
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Leydson G A de Lima
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
- Synthetic and Systems Biology Center, InovaUSP, Avenida Professor Lucio Martins Rodrigues, São Paulo, Brazil
| | - Igor Cesarino
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
- Synthetic and Systems Biology Center, InovaUSP, Avenida Professor Lucio Martins Rodrigues, São Paulo, Brazil
| | - Samuel C V Martins
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Amanda A Cardoso
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina, USA
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5
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Xu M, Li K, Xue Y, Wang F, Liu Z, Xiao T. Measurement of mass force field driving water refilling of cuttage. Sci Rep 2024; 14:8947. [PMID: 38637680 PMCID: PMC11026483 DOI: 10.1038/s41598-024-59716-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 04/15/2024] [Indexed: 04/20/2024] Open
Abstract
Cuttage is a common plant cultivation method, and the key to its survival is the restoration of water refilling, which remains unclear up to now. We report 3D dynamic imaging of water refilling of cuttage without resorting to any contrast agent. Hydrodynamics of the refilled water flow over time reveals the existence of a unit mass force field with a gradient along the refilling direction, which means that cutting plants also have a gradient force field to drive the recovery of water refilling, as predicted by Cohesion-Tension theory in normal plants. We found that force fields of different functional regions are isolated and independently distributed, which is conducive to ensure the safety of water transmission. At the same time, we also found that there is a so-called "inchworm effect" in the mass force field, which contributes to the force transfer inside the cutting through local force accumulation. Results of this paper demonstrate that the developed method for the measurement of mass force field in-vivo is applicable to help decipher the mechanism of plant water refilling.
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Affiliation(s)
- Mingwei Xu
- Research Center for Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ke Li
- Research Center for Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
| | - Yanling Xue
- Research Center for Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
| | - Feixiang Wang
- Research Center for Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China
| | - Zhixuan Liu
- Hunan Rice Research Institute, Hunan Academy of Agricultural Sciences, Changsha, 410125, China
| | - Tiqiao Xiao
- Research Center for Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201204, China.
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201800, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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6
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Roth-Nebelsick A, Konrad W. Modeling and Analyzing Xylem Vulnerability to Embolism as an Epidemic Process. Methods Mol Biol 2024; 2722:17-34. [PMID: 37897597 DOI: 10.1007/978-1-0716-3477-6_2] [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
Xylem vulnerability to embolism can be quantified by "vulnerability curves" (VC) that are obtained by subjecting wood samples to increasingly negative water potential and monitoring the progressive loss of hydraulic conductivity. VC are typically sigmoidal, and various approaches are used to fit the experimentally obtained VC data for extracting benchmark data of vulnerability to embolism. In addition to such empirical methods, mechanistic approaches to calculate embolism propagation are epidemic modeling and network theory. Both describe the transmission of "objects" (in this case, the transmission of gas) between interconnected elements. In network theory, a population of interconnected elements is described by graphs in which objects are represented by vertices or nodes and connections between these objections as edges linking the vertices. A graph showing a population of interconnected xylem conduits represents an "individual" wood sample that allows spatial tracking of embolism propagation. In contrast, in epidemic modeling, the transmission dynamics for a population that is subdivided into infection-relevant groups is calculated by an equation system. For this, embolized conduits are considered to be "infected," and the "infection" is the transmission of gas from embolized conduits to their still water-filled neighbors. Both approaches allow for a mechanistic simulation of embolism propagation.
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Affiliation(s)
| | - Wilfried Konrad
- Department of Geosciences, University of Tübingen, Tübingen, Germany.
- Institute of Botany, Technical University of Dresden, Dresden, Germany.
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7
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Tomasella M, Petruzzellis F, Natale S, Tromba G, Nardini A. Detecting and Quantifying Xylem Embolism by Synchrotron-Based X-Ray Micro-CT. Methods Mol Biol 2024; 2722:51-63. [PMID: 37897599 DOI: 10.1007/978-1-0716-3477-6_4] [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
The vulnerability to xylem embolism is a key trait underlying species-specific drought tolerance of plants, and hence is critical for screening climate-resilient crops and understanding vegetation responses to drought and heat waves. Yet, accurate determination of embolism in plant's xylem is challenging, because most traditional hydraulic techniques are destructive and prone to artefacts. Hence, direct and in vivo synchrotron-based X-ray micro-CT observation of xylem conduits has emerged as a key reference technique for accurate quantification of vulnerability to xylem embolism. Micro-CT is nowadays a fundamental tool for studies of plant hydraulic architecture, and this chapter describes the fundamentals of acquisition and processing of micro-CT images of plant xylem.
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Affiliation(s)
- Martina Tomasella
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
| | | | - Sara Natale
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
| | | | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy.
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8
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Chu C, Momayyezi M, Stobbs JA, Soolanayakanahally RY, McElrone AJ, Knipfer T. Drought-induced fiber water release and xylem embolism susceptibility of intact balsam poplar saplings. PHYSIOLOGIA PLANTARUM 2023; 175:e14040. [PMID: 37882281 DOI: 10.1111/ppl.14040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/31/2023] [Accepted: 09/27/2023] [Indexed: 10/27/2023]
Abstract
Balsam poplar (Populus balsamifera L.) is a widespread tree species in North America with significant ecological and economic value. However, little is known about the susceptibility of saplings to drought-induced embolism and its link to water release from surrounding xylem fibers. Questions remain regarding localized mechanisms that contribute to the survival of saplings in vivo of this species under drought. Using X-ray micro-computed tomography on intact saplings of genotypes Gillam-5 and Carnduff-9, we found that functional vessels are embedded in a matrix of water-filled fibers under well-watered conditions in both genotypes. However, water-depleted fibers started to appear under moderate drought stress while vessels remained water-filled in both genotypes. Drought-induced xylem embolism susceptibility was comparable between genotypes, and a greater frequency of smaller diameter vessels in GIL-5 did not increase embolism resistance in this genotype. Despite having smaller vessels and a total vessel number that was comparable to CAR-9, stomatal conductance was generally higher in GIL-5 compared to CAR-9. In conclusion, our in vivo data on intact saplings indicate that differences in embolism susceptibility are negligible between GIL-5 and CAR-9, and that fiber water release should be considered as a mechanism that contributes to the maintenance of vessel functional status in saplings of balsam poplar experiencing their first drought event.
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Affiliation(s)
- Cheyenne Chu
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mina Momayyezi
- Department of Viticulture and Enology, University of California, Davis, California, USA
| | | | | | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, California, USA
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, California, USA
| | - Thorsten Knipfer
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
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9
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Gori A, Moura BB, Sillo F, Alderotti F, Pasquini D, Balestrini R, Ferrini F, Centritto M, Brunetti C. Unveiling resilience mechanisms of Quercus ilex seedlings to severe water stress: Changes in non-structural carbohydrates, xylem hydraulic functionality and wood anatomy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 878:163124. [PMID: 37001665 DOI: 10.1016/j.scitotenv.2023.163124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 05/13/2023]
Abstract
Over the last few decades, extensive dieback and mortality episodes of Quercus ilex L. have been documented after severe drought events in many Mediterranean forests. However, the underlying physiological, anatomical, and biochemical mechanisms remain poorly understood. We investigated the physiological and biochemical processes linked to embolism formation and non-structural carbohydrates (NSCs) dynamics in Q. ilex seedlings exposed to severe water stress and rewatering. Measurements of leaf gas exchange, water relations, non-structural carbohydrates, drought-related gene expression, and anatomical changes in wood parenchyma were assessed. Under water stress, the midday stem water potential dropped below - 4.5 MPa corresponding to a ~ 50 % loss of hydraulic conductivity. A 70 % reduction in stomatal conductance led to a strong depletion of wood NSCs. Starch consumption, resulting from the upregulation of the β-amylase gene BAM3, together with the downregulation of glucose (GPT1) and sucrose (SUC27) transport genes, suggests glucose utilization to sustain cellular metabolism in the wood parenchyma. After rewatering, the presence of residual xylem embolism led to an incomplete recovery of leaf gas exchanges. However, the partial restoration of photosynthesis allowed the accumulation of new starch reserves in the wood parenchyma and the production of new narrower vessels. In addition, changes in the cell wall composition of the wood parenchyma fibers were observed. Our findings indicate that thirty days of rewatering were sufficient to restore the NSCs reserves and growth rates of Q. ilex seedlings and that the carryover effects of water stress were primarily caused by hydraulic dysfunction.
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Affiliation(s)
- Antonella Gori
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy; National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy.
| | - Barbara Baesso Moura
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Fabiano Sillo
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Francesca Alderotti
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Dalila Pasquini
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy
| | - Raffaella Balestrini
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Francesco Ferrini
- University of Florence, Department of Agriculture, Food, Environment and Forestry (DAGRI), Sesto Fiorentino, Florence 50019, Italy; National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Mauro Centritto
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy
| | - Cecilia Brunetti
- National Research Council of Italy, Institute for Sustainable Plant Protection (IPSP), Sesto Fiorentino, Florence and Turin 50019 and 10135, Italy.
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10
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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: 3.0] [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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11
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Johnson KM, Brodribb TJ. Evidence for a trade-off between growth rate and xylem cavitation resistance in Callitris rhomboidea. TREE PHYSIOLOGY 2023:tpad037. [PMID: 36947141 DOI: 10.1093/treephys/tpad037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 03/14/2023] [Indexed: 06/18/2023]
Abstract
The ideal plant water transport system is one that features high efficiency and resistance to drought-induced damage (xylem cavitation), however species rarely possess both. This may be explained by trade-offs between traits, yet thus far, no proposed trade-off has offered a universal explanation for the lack water transport systems that are both highly drought-resistant and highly efficient. Here we find evidence for a new trade-off, between growth rate and resistance to xylem cavitation, in the canopies of a drought-resistant tree species (Callitris rhomboidea). Wide variation in cavitation resistance (P50) was found in distal branch tips (< 2 mm in diameter), converging to low variation in P50 in larger diameter stems (> 2 mm). We found a significant correlation between cavitation resistance and distal branchlet internode length across branch tips in C. rhomboidea canopies. Branchlets with long internodes (8 mm or longer) were significantly more vulnerable to drought-induced xylem cavitation than shorter internodes (4 mm or shorter). This suggests that varying growth rates, leading to differences in internode length, drive differences in cavitation resistance in C. rhomboidea trees. The only distinct anatomical difference found between internodes was the pith size, with the average pith to xylem area in long internodes, 5x greater than in short internodes. Understanding whether this trade-off exists within and between species will help us to uncover what drives and limits drought resistance across the world's flora.
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12
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Robinson JA, Rennie M, Clearwater M, Holland DJ, van den Berg AK, Watson M. Examination of embolisms in maple and birch saplings utilising microCT. Micron 2023; 168:103438. [PMID: 36889230 DOI: 10.1016/j.micron.2023.103438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
We demonstrate the application of synchrotron x-ray microtomography (microCT) to non-invasively examine the internal structure of a maple and birch sapling. We show that, through the use of standard image analysis techniques, embolised vessels can be extracted from reconstructed slices of the stem. By combining these thresholded images with connectivity analysis, we map out the embolisms within the sapling in three dimensions and evaluate the size distribution, showing that large embolisms over 0.005 mm3 in volume compose the majority of the saplings' total embolised volume. Finally we evaluate the radial distribution of embolisms, showing that in maple fewer embolisms are present towards the cambium, while birch has a more uniform distribution.
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Affiliation(s)
- James A Robinson
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand.
| | - Matt Rennie
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
| | - Mike Clearwater
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Daniel J Holland
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
| | - Abby K van den Berg
- Proctor Maple Research Center, University of Vermont, Underhill, VT, United States
| | - Matthew Watson
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
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13
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Pritzkow C, Brown MJM, Carins-Murphy MR, Bourbia I, Mitchell PJ, Brodersen C, Choat B, Brodribb TJ. Conduit position and connectivity affect the likelihood of xylem embolism during natural drought in evergreen woodland species. ANNALS OF BOTANY 2022; 130:431-444. [PMID: 35420657 PMCID: PMC9486930 DOI: 10.1093/aob/mcac053] [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: 12/20/2021] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Hydraulic failure is considered a main cause of drought-induced forest mortality. Yet, we have a limited understanding of how the varying intensities and long time scales of natural droughts induce and propagate embolism within the xylem. METHODS X-ray computed tomography (microCT) images were obtained from different aged branch xylem to study the number, size and spatial distribution of in situ embolized conduits among three dominant tree species growing in a woodland community. KEY RESULTS Among the three studied tree species, those with a higher xylem vulnerability to embolism (higher water potential at 50 % loss of hydraulic conductance; P50) were more embolized than species with lower P50. Within individual stems, the probability of embolism was independent of conduit diameter but associated with conduit position. Rather than the occurrence of random or radial embolism, we observed circumferential clustering of high and low embolism density, suggesting that embolism spreads preferentially among conduits of the same age. Older xylem also appeared more likely to accumulate embolisms than young xylem, but there was no pattern suggesting that branch tips were more vulnerable to cavitation than basal regions. CONCLUSIONS The spatial analysis of embolism occurrence in field-grown trees suggests that embolism under natural drought probably propagates by air spreading from embolized into neighbouring conduits in a circumferential pattern. This pattern offers the possibility to understand the temporal aspects of embolism occurrence by examining stem cross-sections.
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Affiliation(s)
- Carola Pritzkow
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | - Matilda J M Brown
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Ibrahim Bourbia
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT 06511, USA
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2750, Australia
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14
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Indore NS, Karunakaran C, Jayas DS. Synchrotron tomography applications in agriculture and food sciences research: a review. PLANT METHODS 2022; 18:101. [PMID: 35964094 PMCID: PMC9375343 DOI: 10.1186/s13007-022-00932-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/01/2022] [Indexed: 05/28/2023]
Abstract
Synchrotron imaging is widely used for research in many scientific disciplines. This article introduces the characteristics of synchrotron X-ray imaging and its applications in agriculture and food science research. The agriculture and food sector are a vast area that comprises of plants, seeds, animals, food and their products; soils with thriving microbial communities; and natural resources such as water, fertilizers, and organic matter. These entities have unique internal features, structures and compositions which differentiate them from each other in varieties, species, grades, and types. The use of a bright and tuneable monochromatic source of synchrotron imaging techniques enables researchers to study the internal features and compositions of plants, seeds, soil and food in a quick and non-destructive way to enhance their use, conservation and productivity. Synchrotron's different X-ray imaging techniques offer a wide domain of applications, which make them perfect to enhance the understanding of structures of raw and processed food products to promote food safety and security. Therefore, this paper summarizes the results of major experiments carried out with seeds, plants, soil, food and relevant areas of agricultural sciences with more emphasis on two synchrotron X-ray imaging techniques: absorption and phase-contrast imaging and computed tomography.
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Affiliation(s)
- Navnath S Indore
- Biosystem Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada
| | - Chithra Karunakaran
- Biosystem Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada
- Canadian Light Source Inc., Saskatoon, SK, S7N 2V3, Canada
| | - Digvir S Jayas
- Biosystem Engineering, University of Manitoba, Winnipeg, MB, R3T 5V6, Canada.
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15
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Miranda MT, Espinoza-Núñez E, Silva SF, Pereira L, Hayashi AH, Boscariol-Camargo RL, Carvalho SA, Machado EC, Ribeiro RV. Water stress signaling and hydraulic traits in three congeneric citrus species under water deficit. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 319:111255. [PMID: 35487664 DOI: 10.1016/j.plantsci.2022.111255] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 03/07/2022] [Accepted: 03/12/2022] [Indexed: 06/14/2023]
Abstract
Morpho-physiological strategies to deal with water deficit vary among citrus species and the chemical signaling through ABA and anatomical, hydraulic, and physiological traits were evaluated in saplings of Rangpur lime, Swingle citrumelo and Valencia sweet orange. Trunk and roots of Swingle citrumelo presented lower vessel diameter and higher vessel frequency as compared to the other species. However, relative water content at the turgor loss point (RWCTLP), the osmotic potential at full turgor (Ψ0), the osmotic potential at the turgor loss point (ΨTLP), bulk modulus of elasticity (ε) and the xylem water potential when hydraulic conductivity is reduced by 50% (Ψ50) and 88% (Ψ88) indicated similar hydraulic traits among citrus species, with Rangpur lime showing the highest hydraulic safety margin. Roots of Rangpur lime and Swingle citrumelo were more water conductive than ones of Valencia sweet orange, which was linked to higher stomatal conductance. Chemical signaling through ABA prevented shoot dehydration in Rangpur lime under water deficit, with this species showing a more conservative stomatal behavior, sensing, and responding rapidly to low soil moisture. Taken together, our results suggest that Rangpur lime - the drought tolerant species - has an improved control of leaf water status due to chemical signaling and effective stomatal regulation for reducing water loss as well as decreased root hydraulic conductivity for saving water resources under limiting conditions.
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Affiliation(s)
- Marcela T Miranda
- Agronomic Institute (IAC), Center R&D in Ecophysiology and Biophysics, Laboratory of Plant Physiology "Coaracy M. Franco", P.O. Box 28, Campinas 13012-970, SP, Brazil; University of Campinas (UNICAMP), Department of Plant Biology, Laboratory of Crop Physiology, P.O. Box 6109, Campinas 13083-970, SP, Brazil
| | - Erick Espinoza-Núñez
- Agronomic Institute (IAC), Center R&D in Ecophysiology and Biophysics, Laboratory of Plant Physiology "Coaracy M. Franco", P.O. Box 28, Campinas 13012-970, SP, Brazil; Universidad Nacional Agraria La Molina (UNALM), Department of Horticulture, La Molina, Lima, Peru
| | - Simone F Silva
- University of Campinas (UNICAMP), Department of Plant Biology, Laboratory of Crop Physiology, P.O. Box 6109, Campinas 13083-970, SP, Brazil
| | - Luciano Pereira
- University of Campinas (UNICAMP), Department of Plant Biology, Laboratory of Crop Physiology, P.O. Box 6109, Campinas 13083-970, SP, Brazil; Ulm University, Institute of Systematic Botany and Ecology, Ulm, Germany
| | - Adriana H Hayashi
- Instituto de Botânica, Núcleo de Pesquisa em Anatomia, São Paulo, SP, Brazil
| | | | - Sérgio A Carvalho
- Agronomic Institute (IAC), Center of Citriculture Sylvio Moreira, Cordeirópolis, SP, Brazil
| | - Eduardo C Machado
- Agronomic Institute (IAC), Center R&D in Ecophysiology and Biophysics, Laboratory of Plant Physiology "Coaracy M. Franco", P.O. Box 28, Campinas 13012-970, SP, Brazil
| | - Rafael V Ribeiro
- University of Campinas (UNICAMP), Department of Plant Biology, Laboratory of Crop Physiology, P.O. Box 6109, Campinas 13083-970, SP, Brazil.
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16
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Arend M, Link RM, Zahnd C, Hoch G, Schuldt B, Kahmen A. Lack of hydraulic recovery as a cause of post-drought foliage reduction and canopy decline in European beech. THE NEW PHYTOLOGIST 2022; 234:1195-1205. [PMID: 35238410 PMCID: PMC9310744 DOI: 10.1111/nph.18065] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/19/2022] [Indexed: 05/06/2023]
Abstract
European beech (Fagus sylvatica) was among the most affected tree species during the severe 2018 European drought. It not only suffered from instant physiological stress but also showed severe symptoms of defoliation and canopy decline in the following year. To explore the underlying mechanisms, we used the Swiss-Canopy-Crane II site and studied in branches of healthy and symptomatic trees the repair of hydraulic function and concentration of carbohydrates during the 2018 drought and in 2019. We found loss of hydraulic conductance in 2018, which did not recover in 2019 in trees that developed defoliation symptoms in the year after drought. Reduced branch foliation in symptomatic trees was associated with a gradual decline in wood starch concentration throughout summer 2019. Visualization of water transport in healthy and symptomatic branches in the year after the drought confirmed the close relationship between xylem functionality and supported branch leaf area. Our findings showed that embolized xylem does not regain function in the season following a drought and that sustained branch hydraulic dysfunction is counterbalanced by the reduction in supported leaf area. It suggests acclimation of leaf development after drought to mitigate disturbances in canopy hydraulic function.
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Affiliation(s)
- Matthias Arend
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Roman Mathias Link
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Cedric Zahnd
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Günter Hoch
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Bernhard Schuldt
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Ansgar Kahmen
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
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17
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Schreel JDM, Brodersen C, De Schryver T, Dierick M, Rubinstein A, Dewettinck K, Boone MN, Van Hoorebeke L, Steppe K. Foliar water uptake does not contribute to embolism repair in beech (Fagus sylvatica L.). ANNALS OF BOTANY 2022; 129:555-566. [PMID: 35141741 PMCID: PMC9007097 DOI: 10.1093/aob/mcac016] [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: 10/26/2021] [Accepted: 02/02/2022] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS Foliar water uptake has recently been suggested as a possible mechanism for the restoration of hydraulically dysfunctional xylem vessels. In this paper we used a combination of ecophysiological measurements, X-ray microcomputed tomography and cryo-scanning electron microscopy during a drought treatment to fully evaluate this hypothesis. KEY RESULTS Based on an assessment of these methods in beech (Fagus sylvatica L.) seedlings we were able to (1) confirm an increase in the amount of hydraulically redistributed water absorbed by leaves when the soil water potential decreased, and (2) locate this redistributed water in hydraulically active vessels in the stem. However, (3) no embolism repair was observed irrespective of the organ under investigation (i.e. stem, petiole or leaf) or the intensity of drought. CONCLUSIONS Our data provide evidence for a hydraulic pathway from the leaf surface to the stem xylem following a water potential gradient, but this pathway exists only in functional vessels and does not play a role in embolism repair for beech.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, FL, USA
- For correspondence. E-mail
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, USA
| | - Thomas De Schryver
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Manuel Dierick
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | | | - Koen Dewettinck
- Food Structure & Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Matthieu N Boone
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Luc Van Hoorebeke
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
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18
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Li X, Xi B, Wu X, Choat B, Feng J, Jiang M, Tissue D. Unlocking Drought-Induced Tree Mortality: Physiological Mechanisms to Modeling. FRONTIERS IN PLANT SCIENCE 2022; 13:835921. [PMID: 35444681 PMCID: PMC9015645 DOI: 10.3389/fpls.2022.835921] [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: 12/15/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Drought-related tree mortality has become a major concern worldwide due to its pronounced negative impacts on the functioning and sustainability of forest ecosystems. However, our ability to identify the species that are most vulnerable to drought, and to pinpoint the spatial and temporal patterns of mortality events, is still limited. Model is useful tools to capture the dynamics of vegetation at spatiotemporal scales, yet contemporary land surface models (LSMs) are often incapable of predicting the response of vegetation to environmental perturbations with sufficient accuracy, especially under stressful conditions such as drought. Significant progress has been made regarding the physiological mechanisms underpinning plant drought response in the past decade, and plant hydraulic dysfunction has emerged as a key determinant for tree death due to water shortage. The identification of pivotal physiological events and relevant plant traits may facilitate forecasting tree mortality through a mechanistic approach, with improved precision. In this review, we (1) summarize current understanding of physiological mechanisms leading to tree death, (2) describe the functionality of key hydraulic traits that are involved in the process of hydraulic dysfunction, and (3) outline their roles in improving the representation of hydraulic function in LSMs. We urge potential future research on detailed hydraulic processes under drought, pinpointing corresponding functional traits, as well as understanding traits variation across and within species, for a better representation of drought-induced tree mortality in models.
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Affiliation(s)
- Ximeng Li
- College of Life and Environmental Science, Minzu University of China, Beijing, China
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Benye Xi
- Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing, China
| | - Xiuchen Wu
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Jinchao Feng
- College of Life and Environmental Science, Minzu University of China, Beijing, China
| | - Mingkai Jiang
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - David Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Global Centre for Land-based Innovation, Western Sydney University, Richmond, NSW, Australia
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19
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Gauthey A, Peters JMR, Lòpez R, Carins-Murphy MR, Rodriguez-Dominguez CM, Tissue DT, Medlyn BE, Brodribb TJ, Choat B. Mechanisms of xylem hydraulic recovery after drought in Eucalyptus saligna. PLANT, CELL & ENVIRONMENT 2022; 45:1216-1228. [PMID: 35119114 DOI: 10.1111/pce.14265] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
The mechanisms by which woody plants recover xylem hydraulic capacity after drought stress are not well understood, particularly with regard to the role of embolism refilling. We evaluated the recovery of xylem hydraulic capacity in young Eucalyptus saligna plants exposed to cycles of drought stress and rewatering. Plants were exposed to moderate and severe drought stress treatments, with recovery monitored at time intervals from 24 h to 6 months after rewatering. The percentage loss of xylem vessels due to embolism (PLV) was quantified at each time point using microcomputed tomography with stem water potential (Ψx ) and canopy transpiration (Ec ) measured before scans. Plants exposed to severe drought stress suffered high levels of embolism (47.38% ± 10.97% PLV) and almost complete canopy loss. No evidence of embolism refilling was observed at 24 h, 1 week, or 3 weeks after rewatering despite rapid recovery in Ψx . Recovery of hydraulic capacity was achieved over a 6-month period by growth of new xylem tissue, with canopy leaf area and Ec recovering over the same period. These findings indicate that E. saligna recovers slowly from severe drought stress, with potential for embolism to persist in the xylem for many months after rainfall events.
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Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Environmental Sciences Division, Oak Ridge National Laboratory, Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Rosana Lòpez
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | | | - Celia M Rodriguez-Dominguez
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
- Laboratory of Plant Molecular Ecophysiology, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Sevilla, Spain
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
- Global Centre for Land Based Innovation, Western Syndey University, Richmond, New South Wales, Australia
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
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20
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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: 3] [Impact Index Per Article: 1.5] [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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21
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Guo L, Liu Y, Ran P, Wang G, Shan J, Li X, Liu C, Li J. A bioinspired bubble removal method in microchannels based on angiosperm xylem embolism repair. MICROSYSTEMS & NANOENGINEERING 2022; 8:34. [PMID: 35402001 PMCID: PMC8940964 DOI: 10.1038/s41378-022-00367-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/23/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
It is difficult to remove and eliminate bubbles in microchannels in many devices used in various biomedical fields, such as those needed for microfluidic immunoassays, point-of-care testing, and cell biology evaluations. Accumulated bubbles are associated with a number of negative outcomes, including a decrease in device sensitivity, inaccuracy of analysis results, and even functional failure. Xylem conduits of angiosperm have the ability to remove bubbles in obstructed conduits. Inspired by such an embolism repair mechanism, this paper proposes a bioinspired bubble removal method, which exhibits a prominent ability to dissolve bubbles continuously within a large range of flow rates (2 µL/min-850 µL/min) while retaining the stability and continuity of the flow without auxiliary equipment. Such a method also shows significant bubble removal stability in dealing with Newtonian liquids and non-Newtonian fluids, especially with high viscosity (6.76 Pa s) and low velocity (152 nL/min). Such advantages associated with the proposed bioinspired method reveal promising application prospects in macro/microfluidic fields ranging from 3D printing, implantable devices, virus detection, and biomedical fluid processing to microscale reactor operation and beyond.
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Affiliation(s)
- Lihua Guo
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Yuanchang Liu
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE UK
| | - Penghui Ran
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Gang Wang
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Jie Shan
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Xudong Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Chong Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
| | - Jingmin Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China
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22
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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: 0] [Impact Index Per Article: 0] [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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23
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Johnson KM, Lucani C, Brodribb TJ. In vivo monitoring of drought-induced embolism in Callitris rhomboidea trees reveals wide variation in branchlet vulnerability and high resistance to tissue death. THE NEW PHYTOLOGIST 2022; 233:207-218. [PMID: 34625973 DOI: 10.1111/nph.17786] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Damage to the plant water transport system through xylem cavitation is known to be a driver of plant death in drought conditions. However, a lack of techniques to continuously monitor xylem embolism in whole plants in vivo has hampered our ability to investigate both how this damage propagates and the possible mechanistic link between xylem damage and tissue death. Using optical and fluorescence sensors, we monitored drought-induced xylem embolism accumulation and photosynthetic damage in vivo throughout the canopy of a drought-resistant conifer, Callitris rhomboidea, during drought treatments of c. 1 month duration. We show that drought-induced damage to the xylem can be monitored in vivo in whole trees during extended periods of water stress. Under these conditions, vulnerability of the xylem to cavitation varied widely among branchlets, with photosynthetic damage only recorded once > 90% of the xylem was cavitated. The variation in branchlet vulnerability has important implications for understanding how trees like C. rhomboidea survive drought, and the high resistance of branchlets to tissue damage points to runaway cavitation as a likely driver of tissue death in C. rhomboidea branch tips.
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Affiliation(s)
- Kate M Johnson
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Christopher Lucani
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Timothy J Brodribb
- Discipline of Biological Sciences, School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
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24
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Hájíčková M, Plichta R, Urban J, Volařík D, Gebauer R. Low resistance but high resilience to drought of flushing Norway spruce seedlings. TREE PHYSIOLOGY 2021; 41:1848-1860. [PMID: 33822237 DOI: 10.1093/treephys/tpab043] [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: 10/22/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Spring drought episodes are becoming more frequent and intensive in European temperate forests. To study tree resilience to spring drought, Norway spruce seedlings were exposed to three levels of drought stress (well-watered (W), moderately stressed (M) and severely stressed (S)) for 42 days and then fully irrigated for 14 days. Drought strongly reduced gas exchange parameters for both M and S seedlings. After 42 days, stomatal conductance was lower by 83 and 97% in M and S, respectively, than in W seedlings. Respiration prevailed over photosynthesis in S seedlings at the end of the drought period. Drought mostly reduced longitudinal growth, especially in shoots and needles. Xylem growth reduction was caused mainly by a lower number of newly produced tracheids, not by changes in their size. Norway spruce seedlings showed good resilience to spring drought, as the observed physiological parameters started to recover after rewatering and seedlings started to sprout and form new tracheids. In M seedlings, all physiological traits recovered to the level of W seedlings during the 14-day irrigation period but the recovery took longer in S seedlings. Shoots and needles did not regrow in length but leaf mass per area increased during the recovery phase. To conclude, Norway spruce seedlings showed good resilience to spring single-drought event, but time necessary to full recovery from stress could make seedlings more vulnerable to recurrent drought events.
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Affiliation(s)
- Martina Hájíčková
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Roman Plichta
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Josef Urban
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
- Siberian Federal University, Svobodnyy Ave, 82A, 660041 Krasnoyarsk, Krasnoyarsk Krai, Russia
| | - Daniel Volařík
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Roman Gebauer
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
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25
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Chen K, Zhang W, La T, Bastians PA, Guo T, Cao C. Microstructure investigation of plant architecture with X-ray microscopy. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 311:110986. [PMID: 34482923 DOI: 10.1016/j.plantsci.2021.110986] [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: 03/01/2021] [Revised: 06/22/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
In recent years, the plant morphology has been well studied by multiple approaches at cellular and subcellular levels. Two-dimensional (2D) microscopy techniques offer imaging of plant structures on a wide range of magnifications for researchers. However, subcellular imaging is still challenging in plant tissues like roots and seeds. Here we use a three-dimensional (3D) imaging technology based on the X-ray microscope (XRM) and analyze several plant tissues from different plant species. The XRM provides new insights into plant structures using non-destructive imaging at high-resolution and high contrast. We also utilized a workflow aiming to acquire accurate and high-quality images in the context of the whole specimen. Multiple plant samples including rice, tobacco, Arabidopsis and maize were used to display the differences of phenotypes. Our work indicates that the XRM is a powerful tool to investigate plant microstructure in high-resolution scale. Our work also provides evidence that evaluate and quantify tissue specific differences for a range of plant species. We also characterize novel plant tissue phenotypes by the XRM, such as seeds in Arabidopsis, and utilize them for novel observation measurement. Our work represents an evaluated spatial and temporal resolution solution on seed observation and screening.
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Affiliation(s)
- Ke Chen
- Rice Research Institute, Guangdong Academy of Agricultural Sciences/Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, 510640, Guangdong, China; King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering (BESE), 23955-6900, Thuwal, Saudi Arabia
| | - Wenting Zhang
- Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
| | - Ting La
- School of Biomedical Sciences and Pharmacy, The University of Newcastle, NSW, 2308, Australia
| | | | - Tao Guo
- National Key Laboratory of Plant Molecular Genetics, CAS Centre for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology & Ecology, Chinese Academic of Sciences, Shanghai, 200032, China.
| | - Chunjie Cao
- Carl Zeiss (Shanghai) Co., Ltd, Beijing, 100191, China.
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26
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Qin DW, Chen WJ, Zhong LX, Qin WM, Cao KF. Gas exchange and hydraulic function in seedlings of three basal angiosperm tree-species during water-withholding and re-watering. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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27
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Słupianek A, Dolzblasz A, Sokołowska K. Xylem Parenchyma-Role and Relevance in Wood Functioning in Trees. PLANTS (BASEL, SWITZERLAND) 2021; 10:1247. [PMID: 34205276 PMCID: PMC8235782 DOI: 10.3390/plants10061247] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem parenchyma cells, which constitute a significant functional fraction of the wood tissue, have been strongly neglected in studies on tree biology. Although there has recently been increased research interest in xylem parenchyma cells, the mechanisms that operate in these cells are poorly understood. Therefore, the present review focuses on selected roles of xylem parenchyma and its relevance in wood functioning. In addition, to elucidate the importance of xylem parenchyma, we have compiled evidence supporting the hypothesis on the significance of parenchyma cells in tree functioning and identified the key unaddressed questions in the field.
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Affiliation(s)
- Aleksandra Słupianek
- Department of Plant Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Kanonia 6/8, 50-328 Wrocław, Poland; (A.D.); (K.S.)
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28
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Wason J, Bouda M, Lee EF, McElrone AJ, Phillips RJ, Shackel KA, Matthews MA, Brodersen C. Xylem network connectivity and embolism spread in grapevine(Vitis vinifera L.). PLANT PHYSIOLOGY 2021; 186:373-387. [PMID: 33576825 PMCID: PMC8154096 DOI: 10.1093/plphys/kiab045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 01/17/2021] [Indexed: 05/20/2023]
Abstract
Xylem networks are vulnerable to the formation and spread of gas embolisms that reduce water transport. Embolisms spread through interconduit pits, but the three-dimensional (3D) complexity and scale of xylem networks means that the functional implications of intervessel connections are not well understood. Here, xylem networks of grapevine (Vitis vinifera L.) were reconstructed from 3D high-resolution X-ray micro-computed tomography (microCT) images. Xylem network performance was then modeled to simulate loss of hydraulic conductivity under increasingly negative xylem sap pressure simulating drought stress conditions. We also considered the sensitivity of xylem network performance to changes in key network parameters. We found that the mean pit area per intervessel connection was constant across 10 networks from three, 1.5-m stem segments, but short (0.5 cm) segments fail to capture complete network connectivity. Simulations showed that network organization imparted additional resistance to embolism spread beyond the air-seeding threshold of pit membranes. Xylem network vulnerability to embolism spread was most sensitive to variation in the number and location of vessels that were initially embolized and pit membrane vulnerability. Our results show that xylem network organization can increase stem resistance to embolism spread by 40% (0.66 MPa) and challenge the notion that a single embolism can spread rapidly throughout an entire xylem network.
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Affiliation(s)
- Jay Wason
- School of Forest Resources, University of Maine, Orono, Maine 04469
- School of the Environment, Yale University, New Haven, CT 06520
| | - Martin Bouda
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
| | - Eric F Lee
- Department of Engineering Sciences, Clackamas Community College, Oregon City, Oregon 97045
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California Davis, Davis, California
- Crops Pathology and Genetics Research Unit, USDA-ARS, Davis, California
| | - Ronald J Phillips
- Department of Chemical Engineering, University of California Davis, Davis, California
| | - Kenneth A Shackel
- Department of Plant Science, University of California Davis, Davis, California
| | - Mark A Matthews
- Department of Viticulture and Enology, University of California Davis, Davis, California
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT 06520
- Author for communication:
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29
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Guan X, Pereira L, McAdam SAM, Cao KF, Jansen S. No gas source, no problem: Proximity to pre-existing embolism and segmentation affect embolism spreading in angiosperm xylem by gas diffusion. PLANT, CELL & ENVIRONMENT 2021; 44:1329-1345. [PMID: 33529382 DOI: 10.1111/pce.14016] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/16/2021] [Accepted: 01/17/2021] [Indexed: 05/12/2023]
Abstract
Embolism spreading in dehydrating angiosperm xylem is driven by gas movement between embolized and sap-filled conduits. Here we examine how the proximity to pre-existing embolism and hydraulic segmentation affect embolism propagation. Based on the optical method, we compare xylem embolism resistance between detached leaves and leaves attached to branches, and between intact leaves and leaves with cut minor veins, for six species. Embolism resistance of detached leaves was significantly lower than that of leaves attached to stems, except for two species, with all vessels ending in their petioles. Cutting of minor veins showed limited embolism spreading in minor veins near the cuts prior to major veins. Moreover, despite strong agreement in the overall embolism resistance of detached leaves between the optical and pneumatic method, minor differences were observed during early stages of embolism formation. We conclude that embolism resistance may represent a relative trait due to an open-xylem artefact, with embolism spreading possibly affected by the proximity and connectivity to pre-existing embolism as a gas source, while hydraulic segmentation prevents such artefact. Since embolism formation may not rely on a certain pressure difference threshold between functional and embolized conduits, we speculate that embolism is facilitated by pressure-driven gas diffusion across pit membranes.
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Affiliation(s)
- Xinyi Guan
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Luciano Pereira
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
- Laboratory of Plant Physiology "Coaracy M. Franco", Center R&D in Ecophysiology and Biophysics, Agronomic Institute (IAC), Campinas, Brazil
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Scott A M McAdam
- Purdue Center for Plant Biology, Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana, USA
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilisation of Subtropical Agro-Bioresources, Guangxi University, Nanning, China
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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30
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Peltier DMP, Guo J, Nguyen P, Bangs M, Gear L, Wilson M, Jefferys S, Samuels-Crow K, Yocom LL, Liu Y, Fell MK, Auty D, Schwalm C, Anderegg WRL, Koch GW, Litvak ME, Ogle K. Temporal controls on crown nonstructural carbohydrates in southwestern US tree species. TREE PHYSIOLOGY 2021; 41:388-402. [PMID: 33147630 DOI: 10.1093/treephys/tpaa149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/29/2020] [Indexed: 06/11/2023]
Abstract
In trees, large uncertainties remain in how nonstructural carbohydrates (NSCs) respond to variation in water availability in natural, intact ecosystems. Variation in NSC pools reflects temporal fluctuations in supply and demand, as well as physiological coordination across tree organs in ways that differ across species and NSC fractions (e.g., soluble sugars vs starch). Using landscape-scale crown (leaves and twigs) NSC concentration measurements in three foundation tree species (Populus tremuloides, Pinus edulis, Juniperus osteosperma), we evaluated in situ, seasonal variation in NSC responses to moisture stress on three timescales: short-term (via predawn water potential), seasonal (via leaf δ13C) and annual (via current year's ring width index). Crown NSC responses to moisture stress appeared to depend on hydraulic strategy, where J. osteosperma appears to regulate osmotic potentials (via higher sugar concentrations), P. edulis NSC responses suggest respiratory depletion and P. tremuloides responses were consistent with direct sink limitations. We also show that overly simplistic models can mask seasonal and tissue variation in NSC responses, as well as strong interactions among moisture stress at different timescales. In general, our results suggest large seasonal variation in crown NSC concentrations reflecting the multiple cofunctions of NSCs in plant tissues, including storage, growth and osmotic regulation of hydraulically vulnerable leaves. We emphasize that crown NSC pool size cannot be viewed as a simple physiological metric of stress; in situ NSC dynamics are complex, varying temporally, across species, among NSC fractions and among tissue types.
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Affiliation(s)
- Drew M P Peltier
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Jessica Guo
- Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, USA
| | - Phiyen Nguyen
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Michael Bangs
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Linnea Gear
- Department of Chemistry and Biochemistry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Michelle Wilson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Stacy Jefferys
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Kimberly Samuels-Crow
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Larissa L Yocom
- Department of Wildland Resources and the Ecology Center, Utah State University, Logan, UT 84322, USA
| | - Yao Liu
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Michael K Fell
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - David Auty
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Christopher Schwalm
- Woods Hole Research Center, Falmouth, MA 02540, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - William R L Anderegg
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - George W Koch
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Marcy E Litvak
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Kiona Ogle
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
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31
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Koddenberg T, Greving I, Hagemann J, Flenner S, Krause A, Laipple D, Klein KC, Schmitt U, Schuster M, Wolf A, Seifert M, Ludwig V, Funk S, Militz H, Nopens M. Three-dimensional imaging of xylem at cell wall level through near field nano holotomography. Sci Rep 2021; 11:4574. [PMID: 33633184 PMCID: PMC7907381 DOI: 10.1038/s41598-021-83885-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 02/08/2021] [Indexed: 11/09/2022] Open
Abstract
Detailed imaging of the three-dimensionally complex architecture of xylary plants is important for studying biological and mechanical functions of woody plants. Apart from common two-dimensional microscopy, X-ray micro-computed tomography has been established as a three-dimensional (3D) imaging method for studying the hydraulic function of wooden plants. However, this X-ray imaging method can barely reach the resolution needed to see the minute structures (e.g. pit membrane). To complement the xylem structure with 3D views at the nanoscale level, X-ray near-field nano-holotomography (NFH) was applied to analyze the wood species Pinus sylvestris and Fagus sylvatica. The demanded small specimens required focused ion beam (FIB) application. The FIB milling, however, influenced the image quality through gallium implantation on the cell-wall surfaces. The measurements indicated that NFH is appropriate for imaging wood at nanometric resolution. With a 26 nm voxel pitch, the structure of the cell-wall surface in Pinus sylvestris could be visualized in genuine detail. In wood of Fagus sylvatica, the structure of a pit pair, including the pit membrane, between two neighboring fibrous cells could be traced tomographically.
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Affiliation(s)
- Tim Koddenberg
- Wood Biology and Wood Products, Faculty of Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 4, 37077, Göttingen, Germany
| | - Imke Greving
- Institute of Materials Physics, Helmholtz-Zentrum Geesthacht, Max Plank Straße1, 21502, Geesthacht, Germany
| | - Johannes Hagemann
- Deutsches Elektronen Synchrotron-DESY, Notkestrasse 85, 22607, Hamburg, Germany
| | - Silja Flenner
- Institute of Materials Physics, Helmholtz-Zentrum Geesthacht, Max Plank Straße1, 21502, Geesthacht, Germany
| | - Andreas Krause
- Thünen-Institute of Wood Research, Leuschnerstraße 91, Hamburg-Bergedorf, 21031, Hamburg, Germany
| | - Daniel Laipple
- Institute of Materials Physics, Helmholtz-Zentrum Geesthacht, Max Plank Straße1, 21502, Geesthacht, Germany
| | - Kim C Klein
- Wood Biology and Wood Products, Faculty of Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 4, 37077, Göttingen, Germany
| | - Uwe Schmitt
- Thünen-Institute of Wood Research, Leuschnerstraße 91, Hamburg-Bergedorf, 21031, Hamburg, Germany
| | - Max Schuster
- Erlangen Centre for Astroparticle Physics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erwin-Rommel-Strasse 1, 91058, Erlangen, Germany
| | - Andreas Wolf
- Erlangen Centre for Astroparticle Physics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erwin-Rommel-Strasse 1, 91058, Erlangen, Germany
| | - Maria Seifert
- Erlangen Centre for Astroparticle Physics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erwin-Rommel-Strasse 1, 91058, Erlangen, Germany
| | - Veronika Ludwig
- Erlangen Centre for Astroparticle Physics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erwin-Rommel-Strasse 1, 91058, Erlangen, Germany
| | - Stefan Funk
- Erlangen Centre for Astroparticle Physics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erwin-Rommel-Strasse 1, 91058, Erlangen, Germany
| | - Holger Militz
- Wood Biology and Wood Products, Faculty of Forest Sciences and Forest Ecology, University of Goettingen, Büsgenweg 4, 37077, Göttingen, Germany
| | - Martin Nopens
- Thünen-Institute of Wood Research, Leuschnerstraße 91, Hamburg-Bergedorf, 21031, Hamburg, Germany.
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32
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Drobnitch ST, Comas LH, Flynn N, Ibarra Caballero J, Barton RW, Wenz J, Person T, Bushey J, Jahn CE, Gleason SM. Drought-Induced Root Pressure in Sorghum bicolor. FRONTIERS IN PLANT SCIENCE 2021; 12:571072. [PMID: 33613594 PMCID: PMC7886691 DOI: 10.3389/fpls.2021.571072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 01/08/2021] [Indexed: 05/26/2023]
Abstract
Root pressure, also manifested as profusive sap flowing from cut stems, is a phenomenon in some species that has perplexed biologists for much of the last century. It is associated with increased crop production under drought, but its function and regulation remain largely unknown. In this study, we investigated the initiation, mechanisms, and possible adaptive function of root pressure in six genotypes of Sorghum bicolor during a drought experiment in the greenhouse. We observed that root pressure was induced in plants exposed to drought followed by re-watering but possibly inhibited by 100% re-watering in some genotypes. We found that root pressure in drought stressed and re-watered plants was associated with greater ratio of fine: coarse root length and shoot biomass production, indicating a possible role of root allocation in creating root pressure and adaptive benefit of root pressure for shoot biomass production. Using RNA-Seq, we identified gene transcripts that were up- and down-regulated in plants with root pressure expression, focusing on genes for aquaporins, membrane transporters, and ATPases that could regulate inter- and intra-cellular transport of water and ions to generate positive xylem pressure in root tissue.
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Affiliation(s)
- Sarah Tepler Drobnitch
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, United States
| | - Louise H. Comas
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Nora Flynn
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Jorge Ibarra Caballero
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, United States
| | - Ryan W. Barton
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Joshua Wenz
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Taylor Person
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, United States
| | - Julie Bushey
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Courtney E. Jahn
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, United States
| | - Sean M. Gleason
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
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33
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Gauthey A, Peters JMR, Carins-Murphy MR, Rodriguez-Dominguez CM, Li X, Delzon S, King A, López R, Medlyn BE, Tissue DT, Brodribb TJ, Choat B. Visual and hydraulic techniques produce similar estimates of cavitation resistance in woody species. THE NEW PHYTOLOGIST 2020; 228:884-897. [PMID: 32542732 DOI: 10.1111/nph.16746] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/02/2020] [Indexed: 05/24/2023]
Abstract
Hydraulic failure of the plant vascular system is a principal cause of forest die-off under drought. Accurate quantification of this process is essential to our understanding of the physiological mechanisms underpinning plant mortality. Imaging techniques increasingly are applied to estimate xylem cavitation resistance. These techniques allow for in situ measurement of embolism formation in real time, although the benefits and trade-offs associated with different techniques have not been evaluated in detail. Here we compare two imaging methods, microcomputed tomography (microCT) and optical vulnerability (OV), to standard hydraulic methods for measurement of cavitation resistance in seven woody species representing a diversity of major phylogenetic and xylem anatomical groups. Across the seven species, there was strong agreement between cavitation resistance values (P50 ) estimated from visualization techniques (microCT and OV) and between visual techniques and hydraulic techniques. The results indicate that visual techniques provide accurate estimates of cavitation resistance and the degree to which xylem hydraulic function is impacted by embolism. Results are discussed in the context of trade-offs associated with each technique and possible causes of discrepancy between estimates of cavitation resistance provided by visual and hydraulic techniques.
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Affiliation(s)
- Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Madeline R Carins-Murphy
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia
| | - Celia M Rodriguez-Dominguez
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes, 10, Sevilla, 41012, Spain
| | - Ximeng Li
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Sylvain Delzon
- UMR BIOGECO, INRA, Univ Bordeaux, Talence, 33450, France
| | - Andrew King
- L'Orme de Merisiers, Synchrotron SOLEIL, 91190 Saint-Aubin-BP48, Gif-sur-Yvette Cedex, France
| | - Rosana López
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
- PIAF, INRA, University of Clermont-Auvergne, 63100, Clermont-Ferrand, France
| | - Belinda E Medlyn
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas, 7001, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
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Peters JMR, Gauthey A, Lopez R, Carins-Murphy MR, Brodribb TJ, Choat B. Non-invasive imaging reveals convergence in root and stem vulnerability to cavitation across five tree species. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6623-6637. [PMID: 32822502 PMCID: PMC7586747 DOI: 10.1093/jxb/eraa381] [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: 12/05/2019] [Accepted: 08/18/2020] [Indexed: 05/08/2023]
Abstract
Root vulnerability to cavitation is challenging to measure and under-represented in current datasets. This gap limits the precision of models used to predict plant responses to drought because roots comprise the critical interface between plant and soil. In this study, we measured vulnerability to drought-induced cavitation in woody roots and stems of five tree species (Acacia aneura, Cedrus deodara, Eucalyptus crebra, Eucalytus saligna, and Quercus palustris) with a wide range of xylem anatomies. X-ray microtomography was used to visualize the accumulation of xylem embolism in stems and roots of intact plants that were naturally dehydrated to varying levels of water stress. Vulnerability to cavitation, defined as the water potential causing a 50% loss of hydraulic function (P50), varied broadly among the species (-4.51 MPa to -11.93 MPa in stems and -3.13 MPa to -9.64 MPa in roots). The P50 of roots and stems was significantly related across species, with species that had more vulnerable stems also having more vulnerable roots. While there was strong convergence in root and stem vulnerability to cavitation, the P50 of roots was significantly higher than the P50 of stems in three species. However, the difference in root and stem vulnerability for these species was small; between 1% and 31% of stem P50. Thus, while some differences existed between organs, roots were not dramatically more vulnerable to embolism than stems, and the differences observed were less than those reported in previous studies. Further study is required to evaluate the vulnerability across root orders and to extend these conclusions to a greater number of species and xylem functional types.
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Affiliation(s)
- Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Oak Ridge National Laboratory, Climate Change Science Institute & Environmental Science Division, Oak Ridge, TN, USA
| | - Alice Gauthey
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Rosana Lopez
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- Departamento de Sistemas y Recursos Naturales. Universidad Politécnica de Madrid, Ciudad Universitaria, Madrid, Spain
| | | | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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Gebauer R, Plichta R, Urban J, Volařík D, Hájíčková M. The resistance and resilience of European beech seedlings to drought stress during the period of leaf development. TREE PHYSIOLOGY 2020; 40:1147-1164. [PMID: 32470134 DOI: 10.1093/treephys/tpaa066] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/27/2020] [Indexed: 05/26/2023]
Abstract
Spring drought is becoming a frequently occurring stress factor in temperate forests. However, the understanding of tree resistance and resilience to the spring drought remains insufficient. In this study, European beech (Fagus sylvatica L.) seedlings at the early stage of leaf development were moderately and severely drought stressed for 1 month and then subjected to a 2-week recovery period after rewatering. The study aimed to disentangle the complex relationships between leaf gas exchange, vascular anatomy, tree morphology and patterns of biomass allocation. Stomatal conductance decreased by 80 and 85% upon moderate and severe drought stress, respectively, which brought about a decline in net photosynthesis. However, drought did not affect the indices of slow chlorophyll fluorescence, indicating no permanent damage to the light part of the photosynthetic apparatus. Stem hydraulic conductivity decreased by more than 92% at both drought levels. Consequently, the cambial activity of stressed seedlings declined, which led to lower stem biomass, reduced tree ring width and a lower number of vessels in the current tree ring, these latter also with smaller dimensions. In contrast, the petiole structure was not affected, but at the cost of reduced leaf biomass. Root biomass was reduced only by severe drought. After rewatering, the recovery of gas exchange and regrowth of the current tree ring were observed, all delayed by several days and by lower magnitudes in severely stressed seedlings. The reduced stem hydraulic conductivity inhibited the recovery of gas exchange, but xylem function started to recover by regrowth and refilling of embolized vessels. Despite the damage to conductive xylem, no mortality occurred. These results suggest the low resistance but high resilience of European beech to spring drought. Nevertheless, beech resilience could be weakened if the period between drought events is short, as the recovery of severely stressed seedlings took longer than 14 days.
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Affiliation(s)
- Roman Gebauer
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Roman Plichta
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Josef Urban
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
- Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk, Russia
| | - Daniel Volařík
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Martina Hájíčková
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
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Miller ML, Roddy AB, Brodersen CR, McElrone AJ, Johnson DM. Anatomical and hydraulic responses to desiccation in emergent conifer seedlings. AMERICAN JOURNAL OF BOTANY 2020; 107:1177-1188. [PMID: 32754914 DOI: 10.1002/ajb2.1517] [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: 12/30/2019] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
PREMISE The young seedling life stage is critical for reforestation after disturbance and for species migration under climate change, yet little is known regarding their basic hydraulic function or vulnerability to drought. Here, we sought to characterize responses to desiccation including hydraulic vulnerability, xylem anatomical traits, and impacts on other stem tissues that contribute to hydraulic functioning. METHODS Larix occidentalis, Pseudotsuga menziesii, and Pinus ponderosa (all ≤6 weeks old) were imaged using x-ray computed microtomography during desiccation to assess seedling biomechanical responses with concurrently measured hydraulic conductivity (ks ) and water potential (Ψ) to assess vulnerability to xylem embolism formation and other tissue damage. RESULTS In non-stressed samples for all species, pith and cortical cells appeared circular and well hydrated, but they started to empty and deform with decreasing Ψ which resulted in cell tearing and eventual collapse. Despite the severity of this structural damage, the vascular cambium remained well hydrated even under the most severe drought. There were significant differences among species in vulnerability to xylem embolism formation, with 78% xylem embolism in L. occidentalis by Ψ of -2.1 MPa, but only 47.7% and 62.1% in P. ponderosa and P. menziesii at -4.27 and -6.73 MPa, respectively. CONCLUSIONS Larix occidentalis seedlings appeared to be more susceptible to secondary xylem embolism compared to the other two species, but all three maintained hydration of the vascular cambium under severe stress, which could facilitate hydraulic recovery by regrowth of xylem when stress is relieved.
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Affiliation(s)
- Megan L Miller
- Department of Forest, Rangeland, and Fire Sciences, University of Idaho, 875 Perimeter Drive MS 1133, Moscow, ID, 83844, USA
| | - Adam B Roddy
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, CA, 95616, USA
- USDA-ARS, Davis, CA, 95616, USA
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA
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Chen Z, Zhu S, Zhang Y, Luan J, Li S, Sun P, Wan X, Liu S. Tradeoff between storage capacity and embolism resistance in the xylem of temperate broadleaf tree species. TREE PHYSIOLOGY 2020; 40:1029-1042. [PMID: 32310276 DOI: 10.1093/treephys/tpaa046] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Xylem traits are critical plant functional traits associated with water transport, mechanical support, and carbohydrate and water storage. Studies on the xylem hydraulic efficiency-safety tradeoff are numerous; however, the storage function of xylem parenchyma is rarely considered. The effects of a substantial number of xylem traits on water transport, embolism resistance, mechanical support, storage capacity and nonstructural carbohydrate (NSC) content were investigated in 19 temperate broadleaf species planted in an arid limestone habitat in northern China. There was no xylem hydraulic efficiency-safety tradeoff in the 19 broadleaf species. The total parenchyma fraction was negatively correlated with the fiber fraction. Embolism resistance was positively correlated with indicators of xylem mechanical strength such as vessel wall reinforcement, vessel wall thickness and fiber wall thickness, and was negatively related to the axial parenchyma fraction, especially the paratracheal parenchyma fraction. The paratracheal parenchyma fraction was positively correlated with the ratio of the paratracheal parenchyma fraction to the vessel fraction. In addition, the xylem NSC concentration was positively related to the total parenchyma fraction and axial parenchyma fraction. There was a storage capacity-embolism resistance tradeoff in the xylem of 19 broadleaf species in arid limestone habitats. We speculate that the temperate broadleaf species may show a spectrum of xylem hydraulic strategies, from the embolism resistance strategy related to a more negative P50 (the water potential corresponding to 50% loss of xylem conductivity) to the embolization repair strategy based on more paratracheal parenchyma.
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Affiliation(s)
- Zhicheng Chen
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yongtao Zhang
- Mountain Tai Forest Ecosystem Research Station of National Forestry and Grassland Administration, Forestry College of Shandong Agricultural University, Taian 271018, China
| | - Junwei Luan
- Key Laboratory of Bamboo and Rattan Science and Technology, Institute for Resources and Environment, International Centre for Bamboo and Rattan, National Forestry and Grassland Administration, Beijing 100102, China
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
| | - Pengsen Sun
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Xianchong Wan
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
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Mayr S, Schmid P, Beikircher B, Feng F, Badel E. Die hard: timberline conifers survive annual winter embolism. THE NEW PHYTOLOGIST 2020; 226:13-20. [PMID: 31677276 PMCID: PMC7065000 DOI: 10.1111/nph.16304] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/27/2019] [Indexed: 05/02/2023]
Abstract
During winter, timberline trees are exposed to drought and frost, factors known to induce embolism. Studies indicated that conifers cope with winter embolism by xylem refilling. We analysed the loss of hydraulic conductivity (LC) in Picea abies branch xylem over 10 years, and correlated winter embolism to climate parameters. LC was investigated by direct X-ray micro-computer tomography (micro-CT) observations and potential cavitation fatigue by Cavitron measurements. Trees showed up to 100% winter embolism, whereby LC was highest, when climate variables indicated frost drought and likely freeze-thaw stress further increased LC. During summer, LC never exceeded 16%, due to hydraulic recovery. Micro-CT revealed homogenous embolism during winter and that recovery was based on xylem refilling. Summer samples exhibited lower LC in outermost compared to older tree rings, although no cavitation fatigue was detected. Long-term data and micro-CT observations demonstrate that timberline trees can survive annual cycles of pronounced winter-embolism followed by xylem refilling. Only a small portion of the xylem conductivity cannot be restored during the first year, while remaining conduits are refilled without fatigue during consecutive years. We identify important research topics to better understand the complex induction and repair of embolism at the timberline and its relevance to general plant hydraulics.
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Affiliation(s)
- Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwartestr. 156020InnsbruckAustria
| | - Peter Schmid
- Department of BotanyUniversity of InnsbruckSternwartestr. 156020InnsbruckAustria
| | - Barbara Beikircher
- Department of BotanyUniversity of InnsbruckSternwartestr. 156020InnsbruckAustria
| | - Feng Feng
- College of ForestryNorthwest A&F University3 Taicheng RdYangling712100ShaanxiChina
| | - Eric Badel
- INRA, PIAFUniversité Clermont AuvergneF‐63000Clermont–FerrandFrance
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DeSoto L, Cailleret M, Sterck F, Jansen S, Kramer K, Robert EMR, Aakala T, Amoroso MM, Bigler C, Camarero JJ, Čufar K, Gea-Izquierdo G, Gillner S, Haavik LJ, Hereş AM, Kane JM, Kharuk VI, Kitzberger T, Klein T, Levanič T, Linares JC, Mäkinen H, Oberhuber W, Papadopoulos A, Rohner B, Sangüesa-Barreda G, Stojanovic DB, Suárez ML, Villalba R, Martínez-Vilalta J. Low growth resilience to drought is related to future mortality risk in trees. Nat Commun 2020; 11:545. [PMID: 31992718 PMCID: PMC6987235 DOI: 10.1038/s41467-020-14300-5] [Citation(s) in RCA: 125] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 12/05/2019] [Indexed: 11/23/2022] Open
Abstract
Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions may be crucial to long-term survival. We assessed how growth resilience to severe droughts, including its components resistance and recovery, is related to the ability to survive future droughts by using a tree-ring database of surviving and now-dead trees from 118 sites (22 species, >3,500 trees). We found that, across the variety of regions and species sampled, trees that died during water shortages were less resilient to previous non-lethal droughts, relative to coexisting surviving trees of the same species. In angiosperms, drought-related mortality risk is associated with lower resistance (low capacity to reduce impact of the initial drought), while it is related to reduced recovery (low capacity to attain pre-drought growth rates) in gymnosperms. The different resilience strategies in these two taxonomic groups open new avenues to improve our understanding and prediction of drought-induced mortality.
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Affiliation(s)
- Lucía DeSoto
- Estación Experimental de Zonas Áridas, Spanish National Research Council (EEZA-CSIC), Almería, Spain.
- Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal.
| | - Maxime Cailleret
- INRAE, Université Aix-Marseille, UMR Recover, Aix-en-Provence, France
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
| | - Koen Kramer
- Forest Ecology and Forest Management Group, Wageningen University, Wageningen, The Netherlands
- Land Life Company, Amsterdam, Netherlands
| | - Elisabeth M R Robert
- CREAF, Bellaterrra (Cerdanyola del Vallès), Catalonia, Spain
- Ecology and Biodiversity, Vrije Universiteit Brussel, Brussels, Belgium
- Laboratory of Wood Biology and Xylarium, Royal Museum for Central Africa (RMCA), Tervuren, Belgium
| | - Tuomas Aakala
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Mariano M Amoroso
- Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural (IRNAD), Universidad Nacional de Río Negro, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Río Negro, Argentina
| | - Christof Bigler
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - J Julio Camarero
- Instituto Pirenaico de Ecología, Spanish National Research Council (IPE-CSIC), Zaragoza, Spain
| | - Katarina Čufar
- Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Guillermo Gea-Izquierdo
- Centro de Investigación Forestal (CIFOR), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Sten Gillner
- Institute of Forest Botany and Forest Zoology, TU Dresden, Dresden, Germany
| | | | - Ana-Maria Hereş
- Department of Forest Sciences, Transilvania University of Brasov, Brasov, Romania
- BC3 - Basque Centre for Climate Change, Leioa, Spain
| | - Jeffrey M Kane
- Department of Forestry and Wildland Resources, Humboldt State University, Arcata, CA, USA
| | - Vyacheslav I Kharuk
- Sukachev Institute of Forest, Siberian Division of the Russian Academy of Sciences (RAS), Krasnoyarsk, Russia
- Siberian Federal University, Krasnoyarsk, Russia
| | - Thomas Kitzberger
- Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBOMA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bariloche, Argentina
- Department of Ecology, Universidad Nacional del Comahue, Río Negro, Argentina
| | - Tamir Klein
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tom Levanič
- Department of Yield and Silviculture, Slovenian Forestry Institute, Ljubljana, Slovenia
| | - Juan C Linares
- Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Seville, Spain
| | - Harri Mäkinen
- Natural Resources Institute Finland (Luke), Espoo, Finland
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | | | - Brigitte Rohner
- Forest Ecology, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Birmensdorf, Switzerland
| | | | - Dejan B Stojanovic
- Institute of Lowland Forestry and Environment, University of Novi Sad, Novi Sad, Serbia
| | - Maria Laura Suárez
- Grupo Ecología Forestal, CONICET - INTA, EEA Bariloche, Bariloche, Argentina
| | - Ricardo Villalba
- Instituto Argentino de Nivología Glaciología y Ciencias Ambientales (IANIGLA-CONICET), Mendoza, Argentina
| | - Jordi Martínez-Vilalta
- CREAF, Bellaterrra (Cerdanyola del Vallès), Catalonia, Spain
- Universitat Autònoma de Barcelona, Bellaterrra (Cerdanyola del Vallès), Catalonia, Spain
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Creek D, Lamarque LJ, Torres-Ruiz JM, Parise C, Burlett R, Tissue DT, Delzon S. Xylem embolism in leaves does not occur with open stomata: evidence from direct observations using the optical visualization technique. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1151-1159. [PMID: 31641746 DOI: 10.1093/jxb/erz474] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Drought represents a major abiotic constraint to plant growth and survival. On the one hand, plants keep stomata open for efficient carbon assimilation while, on the other hand, they close them to prevent permanent hydraulic impairment from xylem embolism. The order of occurrence of these two processes (stomatal closure and the onset of leaf embolism) during plant dehydration has remained controversial, largely due to methodological limitations. However, the newly developed optical visualization method now allows concurrent monitoring of stomatal behaviour and leaf embolism formation in intact plants. We used this new approach directly by dehydrating intact saplings of three contrasting tree species and indirectly by conducting a literature survey across a greater range of plant taxa. Our results indicate that increasing water stress generates the onset of leaf embolism consistently after stomatal closure, and that the lag time between these processes (i.e. the safety margin) rises with increasing embolism resistance. This suggests that during water stress, embolism-mediated declines in leaf hydraulic conductivity are unlikely to act as a signal for stomatal down-regulation. Instead, these species converge towards a strategy of closing stomata early to prevent water loss and delay catastrophic xylem dysfunction.
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Affiliation(s)
- Danielle Creek
- Université Clermont-Auvergne, INRA, PIAF, Clermont-Ferrand, France
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | | | | | | | - Regis Burlett
- BIOGECO, INRA, Université de Bordeaux, Pessac, France
| | - David T Tissue
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
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Tomasella M, Petrussa E, Petruzzellis F, Nardini A, Casolo V. The Possible Role of Non-Structural Carbohydrates in the Regulation of Tree Hydraulics. Int J Mol Sci 2019; 21:E144. [PMID: 31878253 PMCID: PMC6981889 DOI: 10.3390/ijms21010144] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/13/2019] [Accepted: 12/22/2019] [Indexed: 12/29/2022] Open
Abstract
The xylem is a complex system that includes a network of dead conduits ensuring long-distance water transport in plants. Under ongoing climate changes, xylem embolism is a major and recurrent cause of drought-induced tree mortality. Non-structural carbohydrates (NSC) play key roles in plant responses to drought and frost stress, and several studies putatively suggest their involvement in the regulation of xylem water transport. However, a clear picture on the roles of NSCs in plant hydraulics has not been drawn to date. We summarize the current knowledge on the involvement of NSCs during embolism formation and subsequent hydraulic recovery. Under drought, sugars are generally accumulated in xylem parenchyma and in xylem sap. At drought-relief, xylem functionality is putatively restored in an osmotically driven process involving wood parenchyma, xylem sap and phloem compartments. By analyzing the published data on stem hydraulics and NSC contents under drought/frost stress and subsequent stress relief, we found that embolism build-up positively correlated to stem NSC depletion, and that the magnitude of post-stress hydraulic recovery positively correlated to consumption of soluble sugars. These findings suggest a close relationship between hydraulics and carbohydrate dynamics. We call for more experiments on hydraulic and NSC dynamics in controlled and field conditions.
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Affiliation(s)
- Martina Tomasella
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Elisa Petrussa
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 91, 33100 Udine, Italy; (E.P.); (V.C.)
| | - Francesco Petruzzellis
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Andrea Nardini
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Valentino Casolo
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 91, 33100 Udine, Italy; (E.P.); (V.C.)
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McDowell NG, Brodribb TJ, Nardini A. Hydraulics in the 21 st century. THE NEW PHYTOLOGIST 2019; 224:537-542. [PMID: 31545889 DOI: 10.1111/nph.16151] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
| | - Timothy J Brodribb
- School of Biological Science, University of Tasmania, Hobart, TAS, Australia
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Trieste, Italy
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Wason JW, Brodersen CR, Huggett BA. The functional implications of tracheary connections across growth rings in four northern hardwood trees. ANNALS OF BOTANY 2019; 124:297-306. [PMID: 31330537 PMCID: PMC6758585 DOI: 10.1093/aob/mcz076] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/02/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS Deciduous angiosperm trees transport xylem sap through trunks and branches in vessels within annual growth rings. Utilizing previous growth rings for sap transport could increase vessel network size and redundancy but may expose new xylem to residual air embolisms in the network. Despite the important role of vessel networks in sap transport and drought resistance, our understanding of cross-ring connections within and between species is limited. METHODS We studied cross-ring connections in four temperate deciduous trees using dye staining and X-ray microcomputed tomography (microCT) to detect xylem connectivity across growth rings and quantify their impact on hydraulic conductivity. KEY RESULTS Acer rubrum and Fraxinus americana had cross-ring connections visible in microCT but only A. rubrum used previous growth rings for axial sap flow. Fagus grandifolia and Quercus rubra, however, did not have cross-ring connections. Accounting for the number of growth rings that function for axial transport improved hydraulic conductivity estimates. CONCLUSIONS These data suggest that the presence of cross-ring connections may help explain aspects of whole-tree xylem sap transport and should be considered for plant hydraulics measurements in these species and others with similar anatomy.
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Affiliation(s)
- Jay W Wason
- School of Forest Resources, University of Maine, Orono, ME, USA
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
- For correspondence. E-mail
| | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
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Hammond WM, Yu K, Wilson LA, Will RE, Anderegg WRL, Adams HD. Dead or dying? Quantifying the point of no return from hydraulic failure in drought-induced tree mortality. THE NEW PHYTOLOGIST 2019; 223:1834-1843. [PMID: 31087656 PMCID: PMC6771894 DOI: 10.1111/nph.15922] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 05/05/2019] [Indexed: 05/18/2023]
Abstract
Determining physiological mechanisms and thresholds for climate-driven tree die-off could help improve global predictions of future terrestrial carbon sinks. We directly tested for the lethal threshold in hydraulic failure - an inability to move water due to drought-induced xylem embolism - in a pine sapling experiment. In a glasshouse experiment, we exposed loblolly pine (Pinus taeda) saplings (n = 83) to drought-induced water stress ranging from mild to lethal. Before rewatering to relieve drought stress, we measured native hydraulic conductivity and foliar color change. We monitored all measured individuals for survival or mortality. We found a lethal threshold at 80% loss of hydraulic conductivity - a point of hydraulic failure beyond which it is more likely trees will die, than survive, and describe mortality risk across all levels of water stress. Foliar color changes lagged behind hydraulic failure - best predicting when trees had been dead for some time, rather than when they were dying. Our direct measurement of native conductivity, while monitoring the same individuals for survival or mortality, quantifies a continuous probability of mortality risk from hydraulic failure. Predicting tree die-off events and understanding the mechanism involved requires knowledge not only of when trees are dead, but when they begin dying - having passed the point of no return.
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Affiliation(s)
- William M. Hammond
- Plant Biology, Ecology and EvolutionOklahoma State UniversityStillwaterOK74078USA
| | - Kailiang Yu
- School of Biological SciencesUniversity of UtahSalt Lake CityUT84112USA
| | - Luke A. Wilson
- Plant Biology, Ecology and EvolutionOklahoma State UniversityStillwaterOK74078USA
- Department of Natural Resource Ecology and ManagementOklahoma State UniversityStillwaterOK74078USA
| | - Rodney E. Will
- Department of Natural Resource Ecology and ManagementOklahoma State UniversityStillwaterOK74078USA
| | | | - Henry D. Adams
- Plant Biology, Ecology and EvolutionOklahoma State UniversityStillwaterOK74078USA
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45
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Ruehr NK, Grote R, Mayr S, Arneth A. Beyond the extreme: recovery of carbon and water relations in woody plants following heat and drought stress. TREE PHYSIOLOGY 2019; 39:1285-1299. [PMID: 30924906 PMCID: PMC6703153 DOI: 10.1093/treephys/tpz032] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 01/08/2019] [Accepted: 03/13/2019] [Indexed: 05/19/2023]
Abstract
Plant responses to drought and heat stress have been extensively studied, whereas post-stress recovery, which is fundamental to understanding stress resilience, has received much less attention. Here, we present a conceptual stress-recovery framework with respect to hydraulic and metabolic functioning in woody plants. We further synthesize results from controlled experimental studies following heat or drought events and highlight underlying mechanisms that drive post-stress recovery. We find that the pace of recovery differs among physiological processes. Leaf water potential and abscisic acid concentration typically recover within few days upon rewetting, while leaf gas exchange-related variables lag behind. Under increased drought severity as indicated by a loss in xylem hydraulic conductance, the time for stomatal conductance recovery increases markedly. Following heat stress release, a similar delay in leaf gas exchange recovery has been observed, but the reasons are most likely a slow reversal of photosynthetic impairment and other temperature-related leaf damages, which typically manifest at temperatures above 40 °C. Based thereon, we suggest that recovery of gas exchange is fast following mild stress, while recovery is slow and reliant on the efficiency of repair and regrowth when stress results in functional impairment and damage to critical plant processes. We further propose that increasing stress severity, particular after critical stress levels have been reached, increases the carbon cost involved in reestablishing functionality. This concept can guide future experimental research and provides a base for modeling post-stress recovery of carbon and water relations in trees.
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Affiliation(s)
- Nadine K Ruehr
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research—Atmospheric Environmental Research (KIT/IMK-IFU), Garmisch-Partenkirchen, Germany
| | - Rüdiger Grote
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research—Atmospheric Environmental Research (KIT/IMK-IFU), Garmisch-Partenkirchen, Germany
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Almut Arneth
- Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research—Atmospheric Environmental Research (KIT/IMK-IFU), Garmisch-Partenkirchen, Germany
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46
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Noninvasive Investigation of Phloem Structure by 3D Synchrotron X-Ray Microtomography. Methods Mol Biol 2019. [PMID: 31197785 DOI: 10.1007/978-1-4939-9562-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
X-ray microtomography (μCT) is a three-dimensional imaging technique, which has, over the past decade, established itself as a go-to method for nondestructive visualization of plant tissue with submicrometer resolution. μCT is closely related to medical computed tomography, in that a measurement consists of acquiring a series of radiographs from different directions around the sample. Especially with synchrotron X-ray sources, these radiographs exhibit significant phase contrast. This greatly enhances soft tissue contrast, making it well suited for plant imaging. Tomographic reconstruction techniques are then employed to convert the stack of radiographs into a 3D volumetric image. Compared with the laboratory X-ray tube-based systems, synchrotron tomography beamlines also offer high throughput, with tens of samples scanned over the course of a typical 24-h beam time.Synchrotrons are typically operated as user facilities, with a staff member assisting users in aligning the beamline and all instrumentation-related matters. From the user's point of view, success of a synchrotron μCT experiment is often dependent on secure sample mounting, choice of appropriate beam parameters, and post-processing the data, i.e., extracting scientifically meaningful results from the 3D image. In this chapter, we review the issues to consider in preparation of a μCT experiment from the point of view of a phloem researcher, emphasizing those aspects which are directly under the user's control rather than technical specifics, which vary from one beamline to another.
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Brodersen CR, Roddy AB, Wason JW, McElrone AJ. Functional Status of Xylem Through Time. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:407-433. [PMID: 30822114 DOI: 10.1146/annurev-arplant-050718-100455] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Water transport in vascular plants represents a critical component of terrestrial water cycles and supplies the water needed for the exchange of CO2 in the atmosphere for photosynthesis. Yet, many fundamental principles of water transport are difficult to assess given the scale and location of plant xylem. Here we review the mechanistic principles that underpin long-distance water transport in vascular plants, with a focus on woody species. We also discuss the recent development of noninvasive tools to study the functional status of xylem networks in planta. Limitations of current methods to detect drought-induced xylem blockages (e.g., embolisms) and quantify corresponding declines in sap flow, and the coordination of hydraulic dysfunction with other physiological processes are assessed. Future avenues of research focused on cross-validation of plant hydraulics methods are discussed, as well as a proposed fundamental shift in the theory and methodology used to characterize and measure plant water use.
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Affiliation(s)
- Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511, USA;
| | - Adam B Roddy
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511, USA;
| | - Jay W Wason
- School of Forest Resources, University of Maine, Orono, Maine 04469, USA
| | - Andrew J McElrone
- US Department of Agriculture, Agricultural Research Service, Davis, California 95616, USA
- Department of Viticulture and Enology, University of California, Davis, California 95616, USA
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Knipfer T, Reyes C, Earles JM, Berry ZC, Johnson DM, Brodersen CR, McElrone AJ. Spatiotemporal Coupling of Vessel Cavitation and Discharge of Stored Xylem Water in a Tree Sapling. PLANT PHYSIOLOGY 2019; 179:1658-1668. [PMID: 30718351 PMCID: PMC6446773 DOI: 10.1104/pp.18.01303] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/25/2019] [Indexed: 05/06/2023]
Abstract
Water discharge from stem internal storage compartments is thought to minimize the risk of vessel cavitation. Based on this concept, one would expect that water storage compartments involved in the buffering of xylem tensions empty before the onset of vessel cavitation under drought stress, and potentially refill after soil saturation. However, scant in vivo data exist that elucidate this localized spatiotemporal coupling. In this study on intact saplings of American chestnut (Castanea dentata), x-ray computed microtomography (microCT) showed that the xylem matrix surrounding vessels releases stored water and becomes air-filled either concurrent to or after vessel cavitation under progressive drought stress. Among annual growth rings, the xylem matrix of the current year remained largely water-filled even under severe drought stress. In comparison, microtomography images collected on excised stems showed that applied pressures of much greater than 0 MPa were required to induce water release from the xylem matrix. Viability staining highlighted that water release from the xylem matrix was associated primarily with emptying of dead fibers. Refilling of the xylem matrix and vessels was detected in intact saplings when the canopy was bagged and stem water potential was close to 0 MPa, and in leafless saplings over the winter period. In conclusion, this study indicates that the bulk of water stored in the xylem matrix is released after the onset of vessel cavitation, and suggests that capillary water contributes to overall stem water storage under drought but is not used primarily for the prevention of drought-induced vessel cavitation in this species.
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Affiliation(s)
- Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, California 95616
| | - Clarissa Reyes
- Department of Viticulture and Enology, University of California, Davis, California 95616
| | - J Mason Earles
- Department of Viticulture and Enology, University of California, Davis, California 95616
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511
| | - Z Carter Berry
- Schmid College of Science and Technology, Chapman University, Orange, California 92866
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602
| | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, California 95616
- U.S. Department of Agriculture-Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, California 95618
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49
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Losso A, Bär A, Dämon B, Dullin C, Ganthaler A, Petruzzellis F, Savi T, Tromba G, Nardini A, Mayr S, Beikircher B. Insights from in vivo micro-CT analysis: testing the hydraulic vulnerability segmentation in Acer pseudoplatanus and Fagus sylvatica seedlings. THE NEW PHYTOLOGIST 2019; 221:1831-1842. [PMID: 30347122 PMCID: PMC6492020 DOI: 10.1111/nph.15549] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/14/2018] [Indexed: 05/23/2023]
Abstract
The seedling stage is the most susceptible one during a tree's life. Water relations may be crucial for seedlings due to their small roots, limited water buffers and the effects of drought on water transport. Despite obvious relevance, studies on seedling xylem hydraulics are scarce as respective methodical approaches are limited. Micro-CT scans of intact Acer pseudoplatanus and Fagus sylvatica seedlings dehydrated to different water potentials (Ψ) allowed the simultaneous observation of gas-filled versus water-filled conduits and the calculation of percentage loss of conductivity (PLC) in stems, roots and leaves (petioles or main veins). Additionally, anatomical analyses were performed and stem PLC measured with hydraulic techniques. In A. pseudoplatanus, petioles showed a higher Ψ at 50% PLC (Ψ50 -1.13MPa) than stems (-2.51 MPa) and roots (-1.78 MPa). The main leaf veins of F. sylvatica had similar Ψ50 values (-2.26 MPa) to stems (-2.74 MPa) and roots (-2.75 MPa). In both species, no difference between root and stems was observed. Hydraulic measurements on stems closely matched the micro-CT based PLC calculations. Micro-CT analyses indicated a species-specific hydraulic architecture. Vulnerability segmentation, enabling a disconnection of the hydraulic pathway upon drought, was observed in A. pseudoplatanus but not in the especially shade-tolerant F. sylvatica. Hydraulic patterns could partly be related to xylem anatomical traits.
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Affiliation(s)
- Adriano Losso
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Andreas Bär
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Birgit Dämon
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Christian Dullin
- Institute for Diagnostic and Interventional RadiologyUniversity Medical Center GoettingenRobert‐Koch‐Straße 40Göttingen37075Germany
- Max‐Plank‐Institute for Experimental MedicineHermann‐Rein‐Straße 3Göttingen37075Germany
- Elettra‐Sincrotrone TriesteArea Science ParkTriesteBasovizza34149Italy
| | - Andrea Ganthaler
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Francesco Petruzzellis
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Tadeja Savi
- Department of Crop SciencesDivision of Viticulture and PomologyUniversity of Natural Resources and Life Sciences ViennaKonrad Lorenzstrasse 24TullnA‐3430Austria
| | - Giuliana Tromba
- Elettra‐Sincrotrone TriesteArea Science ParkTriesteBasovizza34149Italy
| | - Andrea Nardini
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Barbara Beikircher
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
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50
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Choat B, Nolf M, Lopez R, Peters JMR, Carins-Murphy MR, Creek D, Brodribb TJ. Non-invasive imaging shows no evidence of embolism repair after drought in tree species of two genera. TREE PHYSIOLOGY 2019; 39:113-121. [PMID: 30137594 DOI: 10.1093/treephys/tpy093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/29/2018] [Indexed: 06/08/2023]
Abstract
Drought stress can result in significant impairment of the plant hydraulic system via blockage of xylem conduits by gas emboli. Recovery after drought stress is an essential component of plant survival but is still a poorly understood process. In this study, we examined the capacity of woody species from two genera (Eucalyptus and Quercus) to refill embolized xylem vessels during a cycle of drought and recovery. Observations were made on intact plants of Eucalyptus calmudulensis, E. grandis, E. saligna and Quercus palustris using X-ray microtomography. We found no evidence of an effective xylem refilling mechanism in any of the plant species. Despite rehydration and recovery of plant water potential to near pre-drought levels, embolized vessels were not refilled up to 72 h after rewatering. In E. saligna, water droplets accumulated in previously air-filled vessels for a very small percentage of vessels. However, no instances of complete refilling that would restore embolized vessels to hydraulic function were observed. Our observations suggest that rapid refilling of embolized vessels after drought may not be a wide spread mechanism in woody plants and that embolism formed during drought represents long term cost to the plant hydraulic system.
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Affiliation(s)
- Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Markus Nolf
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Rosana Lopez
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- PIAF, Institut National dela Recherche Agronomique, UCA, Clermont-Ferrand, France
| | - Jennifer M R Peters
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | | | - Danielle Creek
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | - Timothy J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
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