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Sun Q. Structural variation and spatial polysaccharide profiling of intervessel pit membranes in grapevine. ANNALS OF BOTANY 2022; 130:595-609. [PMID: 35869610 PMCID: PMC9510951 DOI: 10.1093/aob/mcac096] [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: 05/17/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND AND AIMS Intervessel pit membranes (PMs) are important cell wall structures in the vessel system that may impact a plant's water transport and its susceptibility to vascular diseases. Functional roles of intervessel PMs largely depend on their structure and polysaccharide composition, which are the targets of this study. METHODS With grapevine used as a model plant, this study applied an immunogold-scanning electron microscopy technique to simultaneously analyse at high resolution intervessel PM structures and major pectic and hemicellulosic polysaccharides that make up intervessel PMs. KEY RESULTS Intervessel PMs in functional xylem showed significant structural variation, with about 90 % of them being structurally intact with smooth or relatively smooth surfaces and the remaining 10 % with progressively degraded structures. The results also elucidated details of the removal process of cell wall materials from the intervessel PM surface toward its depth during its natural degradation. Four groups of pectic and hemicellulosic polysaccharides were immunolocalized in intervessel PMs and differed in their spatial distribution and abundance. Weakly methyl-esterified homogalacturonans (WMe-HGs, detected by JIM5) were abundant in the surface layer, heavily methyl-esterified homogalacturonans (HMe-HGs, detected by JIM7) and xylans detected by CCRC-M140 were mostly found in deeper layers, and fucosylated xyloglucans (F-XyGs, detected by CCRC-M1) were more uniformly distributed at different depths of the intervessel PM. CONCLUSIONS Intervessel PMs displayed diverse structural variations in grapevine. They contained certain major groups of pectic and hemicellulosic polysaccharides with different spatial distributions and abundance. This information is crucial to reveal the polysaccharide profiling of the primary cell wall and to understand the roles of intervessel PMs in the regulation of water transport as well as in a plant's susceptibility to vascular diseases.
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Dória LC, Sonsin-Oliveira J, Rossi S, Marcati CR. Functional trade-offs in volume allocation to xylem cell types in 75 species from the Brazilian savanna Cerrado. ANNALS OF BOTANY 2022; 130:445-456. [PMID: 35863898 PMCID: PMC9486921 DOI: 10.1093/aob/mcac095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/20/2022] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Xylem is a crucial tissue for plant survival, performing the functions of water transport, mechanical support and storage. Functional trade-offs are a result of the different assemblages of xylem cell types within a certain wood volume. We assessed how the volume allocated to different xylem cell types can be associated with wood functional trade-offs (hydraulics, mechanical and storage) in species from the Cerrado, the Brazilian savanna. We also assessed the xylem anatomical characters linked to wood density across species. METHODS We analysed cross-sections of branches collected from 75 woody species belonging to 42 angiosperm families from the Cerrado. We estimated the wood volume fraction allocated to different cell types and performed measurements of vessel diameter and wood density. KEY RESULTS The largest volume of wood is allocated to fibres (0.47), followed by parenchyma (0.33) and vessels (0.20). Wood density is positively correlated to cell wall (fibre and vessel wall), and negatively to the fractions of fibre lumen and gelatinous fibres. We observed a trade-off between hydraulics (vessel diameter) and mechanics (cell wall fraction), and between mechanics and storage (parenchyma fraction). The expected positive functional relationships between hydraulics (vessel diameter) and water and carbohydrate storage (parenchyma and fibre lumen fractions) were not detected, though larger vessels are linked to a larger wood volume allocated to gelatinous fibres. CONCLUSIONS Woody species from the Cerrado show evidence of functional trade-offs between water transport, mechanical support and storage. Gelatinous fibres might be potentially linked to water storage and release by their positive relationship to increased vessel diameter, thus replacing the functional role of parenchyma and fibre lumen cells. Species can profit from the increased mechanical strength under tension provided by the presence of gelatinous fibres, avoiding expensive investments in high wood density.
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Affiliation(s)
| | - Julia Sonsin-Oliveira
- Departamento de Biologia Vegetal, Programa de Pós-Graduação em Botânica, Instituto de Ciências Biológicas, Universidade de Brasilia (UnB), Brasília, DF, Brazil
| | - Sergio Rossi
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
| | - Carmen Regina Marcati
- Departamento de Ciência Florestal, Solos e Ambiente, Universidade Estadual Paulista (UNESP), Faculdade de Ciências Agronômicas, Avenida Universitária, Botucatu, SP, Brazil
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Li S, Li X, Wang J, Chen Z, Lu S, Wan X, Sun H, Wang L, Delzon S, Cochard H, Jiang X, Shu J, Zheng J, Yin Y. Hydraulic traits are coupled with plant anatomical traits under drought-rewatering cycles in Ginkgo biloba L. TREE PHYSIOLOGY 2022; 42:1216-1227. [PMID: 34962276 DOI: 10.1093/treephys/tpab174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Investigating the responses of plant anatomical traits of trees to drought-rewatering cycles helps us to understand their responses to climate change; however, such work has not been adequately reported. In this study, Ginkgo biloba L. saplings were subjected to moderate, severe, extreme and lethal drought conditions by withholding water according to the percentage loss of hydraulic conductivity (PLC) and rewatering on a regular basis. Samples of phloem, cambium and xylem were collected to quantify their cellular properties including cambium and phloem cell vitality, xylem growth ring width, pit aspiration rates and pit membrane thickness using light microscopy and transmission microscopy. The results showed that the mortality rate of G. biloba saplings reached 90% at approximately P88 (xylem water potential inducing 88% loss of hydraulic conductivity). The onset of cambium and phloem cell mortality might be in accordance with that of xylem embolism. Close negative correlations between xylem water potential and PLC and between xylem water potential and cambium and phloem mortality suggested that xylem hydraulic traits are coupled with anatomical traits under declining xylem water potential. Cambium and phloem cell vitality as well as xylem growth ring width decreased significantly with increasing drought conditions. However, xylem pit membrane thickness, cambial zone width and cambial cell geometry were not affected by the drought-rewatering cycles. The tracheid radial diameter, intertracheid cell wall thickness and tracheid density decreased significantly during both drought conditions and rewatering conditions. In addition to hydraulic traits, cambium and phloem cell vitality can be used as anatomical traits to evaluate the mortality of G. biloba under drought. Future work is proposed to observe the dynamics of pit aspiration rates under drought-rewatering cycles in situ to deepen our understanding of the essential role of bordered pits in the 'air-seeding' mechanism.
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Affiliation(s)
- Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
- Department of Environmental Science and Ecology, School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P.R. China
| | - Xin Li
- College of Forestry, Beijing Forestry University, Beijing 100083, P.R. China
| | - Jie Wang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Zhicheng Chen
- 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, P.R. China
| | - Sen Lu
- Department of Environmental Science and Ecology, School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, P.R. China
| | - Xianchong Wan
- 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, P.R. China
| | - Hongyan Sun
- Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
- Beijing Key Lab of Greening Plants Breeding, Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
| | - Li Wang
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, P.R. China
| | - Sylvain Delzon
- INRAE, BIOGECO, University of Bordeaux, 33615 Pessac, France
| | - Herve Cochard
- INRAE, PIAF, Université Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Xiaomei Jiang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
| | - Jianhua Shu
- Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
- Beijing Key Lab of Greening Plants Breeding, Beijing Institute of Landscape Architecture, Beijing 100102, P.R. China
| | - Jingming Zheng
- College of Forestry, Beijing Forestry University, Beijing 100083, P.R. China
| | - Yafang Yin
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P.R. China
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, P.R. China
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Sow MD, Le Gac AL, Fichot R, Lanciano S, Delaunay A, Le Jan I, Lesage-Descauses MC, Citerne S, Caius J, Brunaud V, Soubigou-Taconnat L, Cochard H, Segura V, Chaparro C, Grunau C, Daviaud C, Tost J, Brignolas F, Strauss SH, Mirouze M, Maury S. RNAi suppression of DNA methylation affects the drought stress response and genome integrity in transgenic poplar. THE NEW PHYTOLOGIST 2021; 232:80-97. [PMID: 34128549 DOI: 10.1111/nph.17555] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/08/2021] [Indexed: 05/27/2023]
Abstract
Trees are long-lived organisms that continuously adapt to their environments, a process in which epigenetic mechanisms are likely to play a key role. Via downregulation of the chromatin remodeler DECREASED IN DNA METHYLATION 1 (DDM1) in poplar (Populus tremula × Populus alba) RNAi lines, we examined how DNA methylation coordinates genomic and physiological responses to moderate water deficit. We compared the growth and drought response of two RNAi-ddm1 lines to wild-type (WT) trees under well-watered and water deficit/rewatering conditions, and analyzed their methylomes, transcriptomes, mobilomes and phytohormone contents in the shoot apical meristem. The RNAi-ddm1 lines were more tolerant to drought-induced cavitation but did not differ in height or stem diameter growth. About 5000 differentially methylated regions were consistently detected in both RNAi-ddm1 lines, colocalizing with 910 genes and 89 active transposable elements. Under water deficit conditions, 136 differentially expressed genes were found, including many involved in phytohormone pathways; changes in phytohormone concentrations were also detected. Finally, the combination of hypomethylation and drought led to the mobility of two transposable elements. Our findings suggest major roles for DNA methylation in regulation of genes involved in hormone-related stress responses, and the maintenance of genome integrity through repression of transposable elements.
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Affiliation(s)
- Mamadou D Sow
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Anne-Laure Le Gac
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Régis Fichot
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Sophie Lanciano
- IRD, UMR 232 DIADE, Université de Montpellier, Montpellier, 34090, France
- Laboratory of Plant Genome and Development, Université de Perpignan, Perpignan, 66860, France
| | - Alain Delaunay
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Isabelle Le Jan
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | | | - Sylvie Citerne
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, 78000, France
| | - Jose Caius
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Orsay, 91405, France
| | - Véronique Brunaud
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Orsay, 91405, France
| | - Ludivine Soubigou-Taconnat
- Institute of Plant Sciences Paris-Saclay (IPS2), Université Paris-Saclay, CNRS, INRAE, Université Evry, Orsay, 91405, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, 63000, France
| | - Vincent Segura
- BioForA, INRAE, ONF, UMR 0588, Orléans, 45075, France
- UMR AGAP Institut, Université Montpellier, CIRAD, INRAE, Institut Montpellier SupAgro, UMR 1334, Montpellier, F-34398, France
| | | | - Christoph Grunau
- UMR 5244, IHPE, Université de Perpignan, Perpignan, 66100, France
| | - Christian Daviaud
- Laboratory for Epigenetics and Environment Centre National de Recherche en Génomique Humaine, CEA- Institut de Biologie Francois Jacob, Université Paris-Saclay, Evry, 91057, France
| | - Jörg Tost
- Laboratory for Epigenetics and Environment Centre National de Recherche en Génomique Humaine, CEA- Institut de Biologie Francois Jacob, Université Paris-Saclay, Evry, 91057, France
| | - Franck Brignolas
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
| | - Steven H Strauss
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331-5752, USA
| | - Marie Mirouze
- IRD, UMR 232 DIADE, Université de Montpellier, Montpellier, 34090, France
- Laboratory of Plant Genome and Development, Université de Perpignan, Perpignan, 66860, France
| | - Stéphane Maury
- LBLGC, INRAE, Université d'Orléans, EA 1207 USC 1328, Orléans, 45067, France
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Kováč J, Lux A, Soukup M, Weidinger M, Gruber D, Lichtscheidl I, Vaculík M. A new insight on structural and some functional aspects of peri-endodermal thickenings, a specific layer in Noccaea caerulescens roots. ANNALS OF BOTANY 2020; 126:423-434. [PMID: 32296831 PMCID: PMC7424770 DOI: 10.1093/aob/mcaa069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND AIMS Cell walls of the peri-endodermis, a layer adjacent to the endodermis in alpine pennycress (Noccaea caerulescens) roots, form C-shaped peri-endodermal thickenings (PETs). Despite its specific position close to the endodermis, the assumed similarity of PETs to phi thickenings in many other species, and the fact that N. caerulescens is a well-studied heavy-metal-hyperaccumulating plant, the PET as a root trait is still not understood. METHODS Here, we characterized PET cell walls by histochemical techniques, Raman spectroscopy, immunolabelling and electron microscopy. Moreover, a role of PETs in solute transport was tested and compared with Arabidopsis thaliana plants, which do not form PETs in roots. KEY RESULTS Cell walls with PETs have a structured relief mainly composed of cellulose and lignin. Suberin, typical of endodermal cells, is missing but pectins are present on the inner surface of the PET. Penetrating dyes are not able to cross PETs either by the apoplasmic or the symplasmic pathway, and a significantly higher content of metals is found in root tissues outside of PETs than in innermost tissues. CONCLUSIONS Based on their development and chemical composition, PETs are different from the endodermis and closely resemble phi thickenings. Contrarily, the different structure and dye impermeability of PETs, not known in the case of phi thickenings, point to an additional barrier function which makes the peri-endodermis with PETs a unique and rare layer.
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Affiliation(s)
- Ján Kováč
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia and
| | - Alexander Lux
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Milan Soukup
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
| | - Marieluise Weidinger
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - Daniela Gruber
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - Irene Lichtscheidl
- Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Vienna, Austria
| | - Marek Vaculík
- Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Bratislava, Slovakia and
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Li S, Wang J, Yin Y, Li X, Deng L, Jiang X, Chen Z, Li Y. Investigating Effects of Bordered Pit Membrane Morphology and Properties on Plant Xylem Hydraulic Functions-A Case Study from 3D Reconstruction and Microflow Modelling of Pit Membranes in Angiosperm Xylem. PLANTS (BASEL, SWITZERLAND) 2020; 9:E231. [PMID: 32054100 PMCID: PMC7076482 DOI: 10.3390/plants9020231] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/18/2020] [Accepted: 02/08/2020] [Indexed: 01/12/2023]
Abstract
Pit membranes in between neighboring conduits of xylem play a crucial role in plant water transport. In this review, the morphological characteristics, chemical composition and mechanical properties of bordered pit membranes were summarized and linked with their functional roles in xylem hydraulics. The trade-off between xylem hydraulic efficiency and safety was closely related with morphology and properties of pit membranes, and xylem embolism resistance was also determined by the pit membrane morphology and properties. Besides, to further investigate the effects of bordered pit membranes morphology and properties on plant xylem hydraulic functions, here we modelled three-dimensional structure of bordered pit membranes by applying a deposition technique. Based on reconstructed 3D pit membrane structures, a virtual fibril network was generated to model the microflow pattern across inter-vessel pit membranes. Moreover, the mechanical behavior of intervessel pit membranes was estimated from a single microfibril's mechanical property. Pit membranes morphology varied among different angiosperm and gymnosperm species. Our modelling work suggested that larger pores of pit membranes do not necessarily contribute to major flow rate across pit membranes; instead, the obstructed degree of flow pathway across the pit membranes plays a more important role. Our work provides useful information for studying the mechanism of microfluid flow transport across pit membranes and also sheds light on investigating the response of pit membranes both at normal and stressed conditions, thus improving our understanding on functional roles of pit membranes in xylem hydraulic function. Further work could be done to study the morphological and mechanical response of bordered pit membranes under different dehydrated conditions, as well as the related microflow behavior, based on our constructed model.
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Affiliation(s)
- Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Jie Wang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Yafang Yin
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Xin Li
- College of Forestry, Beijing Forestry University, Beijing 100083, China;
| | - Liping Deng
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- International Center for Bamboo and Rattan, Beijing 100102, China
| | - Xiaomei Jiang
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China; (S.L.); (J.W.); (Y.Y.); (L.D.); (X.J.)
- Wood Collections (WOODPEDIA), Chinese Academy of Forestry, Beijing 100091, China
| | - Zhicheng Chen
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing 100083, China;
| | - Yujun Li
- School of Mechanical Engineering, Northwestern Polytechnical University, Xi’an 710072, China
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Moysset L, Llambrich E, Simón E. Calcium changes in Robinia pseudoacacia pulvinar motor cells during nyctinastic closure mediated by phytochromes. PROTOPLASMA 2019; 256:615-629. [PMID: 30382423 DOI: 10.1007/s00709-018-1323-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/15/2018] [Indexed: 06/08/2023]
Abstract
Potassium pyroantimonate precipitation, transmission electron microscopy, and X-ray microanalysis were used to investigate the subcellular localization of loosely bound calcium in Robinia pseudoacacia pulvinar motor cells during phytochrome-mediated nyctinastic closure. Calcium localization was carried out in pulvini collected in white light 2 h after the beginning of the photoperiod, immediately after a red light or a far-red light pulse applied 2 h after the beginning of the photoperiod and after 15 or 25 min of darkness respectively. Calcium antimonate precipitates were found in all the pulvinar tissues from the epidermis to the vascular bundle, independent of the light treatment. At subcellular level, precipitates were found mainly in the intercellular spaces, the inner surface of the plasma membrane, cytoplasm, colloidal vacuoles, and nuclei. Red light enhanced the nyctinastic closure of leaflets and caused an asymmetric distribution of cytosolic calcium precipitates between the extensor and flexor motor cells. Both the number and area of the cytosolic calcium precipitates drastically increased in the extensor cells compared to the flexor motor cells. Red light had a rapid and transient effect on the distribution of cytosolic calcium precipitates, which occurred during or at the end of the irradiation, before leaflet closure. By contrast, the distribution of cytosolic loosely bound calcium was similar between the extensor and flexor motor cells after irradiation with far-red light. Our results demonstrate that red light causes specific calcium mobilization in pulvinar motor cells and suggest the involvement of cytoplasmic Ca2+ as a second messenger for phytochrome during nyctinastic closure.
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Affiliation(s)
- Luisa Moysset
- Departament of Evolutive Biology, Ecology and Environmental Sciences, Section of Plant Physiology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Margalef Building, Floor 5, 08028, Barcelona, Spain.
| | - Esther Llambrich
- Departament of Evolutive Biology, Ecology and Environmental Sciences, Section of Plant Physiology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Margalef Building, Floor 5, 08028, Barcelona, Spain
| | - Esther Simón
- Departament of Evolutive Biology, Ecology and Environmental Sciences, Section of Plant Physiology, Faculty of Biology, University of Barcelona, Av. Diagonal 643, Margalef Building, Floor 5, 08028, Barcelona, Spain
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8
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Jansen S, Klepsch M, Li S, Kotowska M, Schiele S, Zhang Y, Schenk H. Challenges in understanding air-seeding in angiosperm xylem. ACTA ACUST UNITED AC 2018. [DOI: 10.17660/actahortic.2018.1222.3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Allario T, Tixier A, Awad H, Lemaire C, Brunel N, Badel E, Barigah TS, Julien JL, Peyret P, Mellerowicz EJ, Cochard H, Herbette S. PtxtPME1 and homogalacturonans influence xylem hydraulic properties in poplar. PHYSIOLOGIA PLANTARUM 2018; 163:502-515. [PMID: 29412468 DOI: 10.1111/ppl.12702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/15/2018] [Accepted: 01/31/2018] [Indexed: 06/08/2023]
Abstract
While the xylem hydraulic properties, such as vulnerability to cavitation (VC), are of paramount importance in drought resistance, their genetic determinants remain unexplored. There is evidence that pectins and their methylation pattern are involved, but the detail of their involvement and the corresponding genes need to be clarified. We analyzed the hydraulic properties of the 35S::PME1 transgenic aspen that ectopically under- or over-express a xylem-abundant pectin methyl esterase, PtxtPME1. We also produced and analyzed 4CL1::PGII transgenic poplars expressing a fungal polygalacturonase, AnPGII, under the control of the Ptxa4CL1 promoter that is active in the developing xylem after xylem cell expansion. Both the 35S::PME1 under- and over-expressing aspen lines developed xylem with lower-specific hydraulic conductivity and lower VC, while the 4CL1::PGII plants developed xylem with a higher VC. These xylem hydraulic changes were associated with modifications in xylem structure or in intervessel pit structure that can result in changes in mechanical behavior of the pit membrane. This study shows that homogalacturonans and their methylation pattern influence xylem hydraulic properties, through its effect on xylem cell expansion and on intervessel pit properties and it show a role for PtxtPME1 in the xylem hydraulic properties.
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Affiliation(s)
- Thierry Allario
- UCA, INRA, PIAF, 63000, Clermont-Ferrand, France
- UCA, EA 4678 CIDAM, 63000, Clermont-Ferrand, France
| | - Aude Tixier
- UCA, INRA, PIAF, 63000, Clermont-Ferrand, France
| | - Hosam Awad
- Agriculture and Botany Department, Faculty of Agriculture, Menoufia University, Shebin El-Kom, Egypt
| | | | | | - Eric Badel
- UCA, INRA, PIAF, 63000, Clermont-Ferrand, France
| | | | | | | | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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Schenk HJ, Espino S, Rich-Cavazos SM, Jansen S. From the sap's perspective: The nature of vessel surfaces in angiosperm xylem. AMERICAN JOURNAL OF BOTANY 2018; 105:172-185. [PMID: 29578294 DOI: 10.1002/ajb2.1034] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 12/14/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Xylem sap in angiosperms moves under negative pressure in conduits and cell wall pores that are nanometers to micrometers in diameter, so sap is always very close to surfaces. Surfaces matter for water transport because hydrophobic ones favor nucleation of bubbles, and surface chemistry can have strong effects on flow. Vessel walls contain cellulose, hemicellulose, lignin, pectins, proteins, and possibly lipids, but what is the nature of the inner, lumen-facing surface that is in contact with sap? METHODS Vessel lumen surfaces of five angiosperms from different lineages were examined via transmission electron microscopy and confocal and fluorescence microscopy, using fluorophores and autofluorescence to detect cell wall components. Elemental composition was studied by energy-dispersive X-ray spectroscopy, and treatments with phospholipase C (PLC) were used to test for phospholipids. KEY RESULTS Vessel surfaces consisted mainly of lignin, with strong cellulose signals confined to pit membranes. Proteins were found mainly in inter-vessel pits and pectins only on outer rims of pit membranes and in vessel-parenchyma pits. Continuous layers of lipids were detected on most vessel surfaces and on most pit membranes and were shown by PLC treatment to consist at least partly of phospholipids. CONCLUSIONS Vessel surfaces appear to be wettable because lignin is not strongly hydrophobic and a coating with amphiphilic lipids would render any surface hydrophilic. New questions arise about these lipids and their possible origins from living xylem cells, especially about their effects on surface tension, surface bubble nucleation, and pit membrane function.
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Susana Espino
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Sarah M Rich-Cavazos
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
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11
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Morris H, Plavcová L, Gorai M, Klepsch MM, Kotowska M, Jochen Schenk H, Jansen S. Vessel-associated cells in angiosperm xylem: Highly specialized living cells at the symplast-apoplast boundary. AMERICAN JOURNAL OF BOTANY 2018; 105:151-160. [PMID: 29578292 DOI: 10.1002/ajb2.1030] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/13/2017] [Indexed: 05/13/2023]
Abstract
BACKGROUND Vessel-associated cells (VACs) are highly specialized, living parenchyma cells that are in direct contact with water-conducting, dead vessels. The contact may be sparse or in large tight groups of parenchyma that completely surrounds vessels. VACs differ from vessel distant parenchyma in physiology, anatomy, and function and have half-bordered pits at the vessel-parenchyma juncture. The distinct anatomy of VACs is related to the exchange of substances to and from the water-transport system, with the cells long thought to be involved in water transport in woody angiosperms, but where direct experimental evidence is lacking. SCOPE This review focuses on our current knowledge of VACs regarding anatomy and function, including hydraulic capacitance, storage of nonstructural carbohydrates, symplastic and apoplastic interactions, defense against pathogens and frost, osmoregulation, and the novel hypothesis of surfactant production. Based on microscopy, we visually represent how VACs vary in dimensions and general appearance between species, with special attention to the protoplast, amorphous layer, and the vessel-parenchyma pit membrane. CONCLUSIONS An understanding of the relationship between VACs and vessels is crucial to tackling questions related to how water is transported over long distances in xylem, as well as defense against pathogens. New avenues of research show how parenchyma-vessel contact is related to vessel diameter and a new hypothesis may explain how surfactants arising from VAC can allow water to travel under negative pressure. We also reinforce the message of connectivity between VAC and other cells between xylem and phloem.
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Affiliation(s)
- Hugh Morris
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Laboratory for Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Testing and Research, St. Gallen, Switzerland
| | - Lenka Plavcová
- University of Hradec Králové, Department of Biology, Faculty of Science, Rokitanského 62, 500 03, Hradec Králové, Czech Republic
| | - Mustapha Gorai
- University of Gabes, Higher Institute of Applied Biology of Medenine, Medenine, 4119, Tunisia
| | - Matthias M Klepsch
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Martyna Kotowska
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Macquarie University, Department of Biological Sciences, North Ryde, NSW, 2109, Australia
| | - H Jochen Schenk
- California State University Fullerton, Department of Biological Science, 800 N. State College Blvd., Fullerton, CA, 92831-3599, USA
| | - Steven Jansen
- Ulm University, Institute of Systematic Botany and Ecology, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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12
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Zhang Y, Klepsch M, Jansen S. Bordered pits in xylem of vesselless angiosperms and their possible misinterpretation as perforation plates. PLANT, CELL & ENVIRONMENT 2017; 40:2133-2146. [PMID: 28667823 DOI: 10.1111/pce.13014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
Vesselless wood represents a rare phenomenon within the angiosperms, characterizing Amborellaceae, Trochodendraceae and Winteraceae. Anatomical observations of bordered pits and their pit membranes based on light, scanning and transmission electron microscopy (SEM and TEM) are required to understand functional questions surrounding vesselless angiosperms and the potential occurrence of cryptic vessels. Interconduit pit membranes in 11 vesselless species showed a similar ultrastructure as mesophytic vessel-bearing angiosperms, with a mean thickness of 245 nm (± 53, SD; n = six species). Shrunken, damaged and aspirated pit membranes, which were 52% thinner than pit membranes in fresh samples (n = four species), occurred in all dried-and-rehydrated samples, and in fresh latewood of Tetracentron sinense and Trochodendron aralioides. SEM demonstrated that shrunken pit membranes showed artificially enlarged, > 100 nm wide pores. Moreover, perfusion experiments with stem segments of Drimys winteri showed that 20 and 50 nm colloidal gold particles only passed through 2 cm long dried-and-rehydrated segments, but not through similar sized fresh ones. These results indicate that pit membrane shrinkage is irreversible and associated with a considerable increase in pore size. Moreover, our findings suggest that pit membrane damage, which may occur in planta, could explain earlier records of vessels in vesselless angiosperms.
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Affiliation(s)
- Ya Zhang
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Matthias Klepsch
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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13
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Pouzoulet J, Scudiero E, Schiavon M, Rolshausen PE. Xylem Vessel Diameter Affects the Compartmentalization of the Vascular Pathogen Phaeomoniella chlamydospora in Grapevine. FRONTIERS IN PLANT SCIENCE 2017; 8:1442. [PMID: 28871268 PMCID: PMC5566965 DOI: 10.3389/fpls.2017.01442] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/03/2017] [Indexed: 05/23/2023]
Abstract
Fungal wilt diseases are a threat to global food safety. Previous studies in perennial crops showed that xylem vessel diameter affects disease susceptibility. We tested the hypothesis that xylem vessel diameter impacts occlusion processes and pathogen compartmentalization in Vitis vinifera L. We studied the interaction between four grape commercial cultivars with the vascular wilt pathogen Phaeomoniella chlamydospora. We used qPCR and wood necrotic lesion length to measure fungal colonization coupled with histological studies to assess differences in xylem morphology, pathogen compartmentalization, and fungal colonization strategy. We provided evidence that grape cultivar with wide xylem vessel diameter showed increased susceptibility to P. chlamydospora. The host response to pathogen included vessel occlusion with tyloses and gels, deposition of non-structural phenolic compounds and suberin in vessel walls and depletion of starch in parenchyma cells. Pathogen compartmentalization was less efficient in wide xylem vessels than in narrow diameter vessels. Large vessels displayed higher number of tyloses and gel pockets, which provided substrate for P. chlamydospora growth and routes to escape occluded vessels. We discuss in which capacity xylem vessel diameter is a key determinant of the compartmentalization process and in turn grape cultivar resistance to disease caused by P. chlamydospora.
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Affiliation(s)
- Jérôme Pouzoulet
- Department of Botany and Plant Sciences, University of California, Riverside, RiversideCA, United States
| | - Elia Scudiero
- United States Salinity Laboratory, United States Department of Agriculture–Agricultural Research Service, RiversideCA, United States
| | - Marco Schiavon
- Department of Botany and Plant Sciences, University of California, Riverside, RiversideCA, United States
| | - Philippe E. Rolshausen
- Department of Botany and Plant Sciences, University of California, Riverside, RiversideCA, United States
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14
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Venturas MD, Sperry JS, Hacke UG. Plant xylem hydraulics: What we understand, current research, and future challenges. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:356-389. [PMID: 28296168 DOI: 10.1111/jipb.12534] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/09/2017] [Indexed: 05/22/2023]
Abstract
Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connection with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality.
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Affiliation(s)
- Martin D Venturas
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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15
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Hacke UG, Spicer R, Schreiber SG, Plavcová L. An ecophysiological and developmental perspective on variation in vessel diameter. PLANT, CELL & ENVIRONMENT 2017; 40:831-845. [PMID: 27304704 DOI: 10.1111/pce.12777] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 05/05/2023]
Abstract
Variation in xylem vessel diameter is one of the most important parameters when evaluating plant water relations. This review provides a synthesis of the ecophysiological implications of variation in lumen diameter together with a summary of our current understanding of vessel development and its endogenous regulation. We analyzed inter-specific variation of the mean hydraulic vessel diameter (Dv ) across biomes, intra-specific variation of Dv under natural and controlled conditions, and intra-plant variation. We found that the Dv measured in young branches tends to stay below 30 µm in regions experiencing winter frost, whereas it is highly variable in the tropical rainforest. Within a plant, the widest vessels are often found in the trunk and in large roots; smaller diameters have been reported for leaves and small lateral roots. Dv varies in response to environmental factors and is not only a function of plant size. Despite the wealth of data on vessel diameter variation, the regulation of diameter is poorly understood. Polar auxin transport through the vascular cambium is a key regulator linking foliar and xylem development. Limited evidence suggests that auxin transport is also a determinant of vessel diameter. The role of auxin in cell expansion and in establishing longitudinal continuity during secondary growth deserve further study.
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Affiliation(s)
- Uwe G Hacke
- University of Alberta, Department of Renewable Resources, Edmonton, AB T6G 2E3, Canada
| | - Rachel Spicer
- Connecticut College, Department of Botany, New London, CT 06320, USA
| | - Stefan G Schreiber
- University of Alberta, Department of Renewable Resources, Edmonton, AB T6G 2E3, Canada
| | - Lenka Plavcová
- University of Hradec Králové, Department of Biology, Rokitanského 62, Hradec Králové, 500 03, Czech Republic
- Charles University, Department of Experimental Plant Biology, Viničná 5, Prague, 128 44, Czech Republic
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16
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Sun Q, Sun Y, Juzenas K. Immunogold scanning electron microscopy can reveal the polysaccharide architecture of xylem cell walls. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:2231-2244. [PMID: 28398585 PMCID: PMC5447876 DOI: 10.1093/jxb/erx103] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Immunofluorescence microscopy (IFM) and immunogold transmission electron microscopy (TEM) are the two main techniques commonly used to detect polysaccharides in plant cell walls. Both are important in localizing cell wall polysaccharides, but both have major limitations, such as low resolution in IFM and restricted sample size for immunogold TEM. In this study, we have developed a robust technique that combines immunocytochemistry with scanning electron microscopy (SEM) to study cell wall polysaccharide architecture in xylem cells at high resolution over large areas of sample. Using multiple cell wall monoclonal antibodies (mAbs), this immunogold SEM technique reliably localized groups of hemicellulosic and pectic polysaccharides in the cell walls of five different xylem structures (vessel elements, fibers, axial and ray parenchyma cells, and tyloses). This demonstrates its important advantages over the other two methods for studying cell wall polysaccharide composition and distribution in these structures. In addition, it can show the three-dimensional distribution of a polysaccharide group in the vessel lateral wall and the polysaccharide components in the cell wall of developing tyloses. This technique, therefore, should be valuable for understanding the cell wall polysaccharide composition, architecture and functions of diverse cell types.
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Affiliation(s)
- Qiang Sun
- Department of Biology, University of Wisconsin, Stevens Point, WI 54481, USA
| | - Yuliang Sun
- School of Medicine, Boston University, Boston, MA 02118, USA
| | - Kevin Juzenas
- Department of Biology, University of Wisconsin, Stevens Point, WI 54481, USA
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17
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Morris H, Brodersen C, Schwarze FWMR, Jansen S. The Parenchyma of Secondary Xylem and Its Critical Role in Tree Defense against Fungal Decay in Relation to the CODIT Model. FRONTIERS IN PLANT SCIENCE 2016; 7:1665. [PMID: 27881986 PMCID: PMC5101214 DOI: 10.3389/fpls.2016.01665] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 10/24/2016] [Indexed: 05/22/2023]
Abstract
This review examines the roles that ray and axial parenchyma (RAP) plays against fungal pathogens in the secondary xylem of wood within the context of the CODIT model (Compartmentalization of Decay in Trees), a defense concept first conceived in the early 1970s by Alex Shigo. This model, simplistic in its design, shows how a large woody perennial is highly compartmented. Anatomical divisions in place at the time of infection or damage, (physical defense) alongside the 'active' response by the RAP during and after wounding work together in forming boundaries that function to restrict air or decay spread. The living parenchyma cells play a critical role in all of the four walls (differing anatomical constructs) that the model comprises. To understand how living cells in each of the walls of CODIT cooperate, we must have a clear vision of their complex interconnectivity from a three-dimensional perspective, along with knowledge of the huge variation in ray parenchyma (RP) and axial parenchyma (AP) abundance and patterns. Crucial patterns for defense encompass the symplastic continuum between both RP and AP and the dead tissues, with the latter including the vessel elements, libriform fibers, and imperforate tracheary elements (i.e., vasicentric and vascular tracheids). Also, the heartwood, a chemically altered antimicrobial non-living substance that forms the core of many trees, provides an integral part of the defense system. In the heartwood, dead RAP can play an important role in defense, depending on the genetic constitution of the species. Considering the array of functions that RAP are associated with, from capacitance, through to storage, and long-distance water transport, deciding how their role in defense fits into this suite of functions is a challenge for plant scientists, and likely depends on a range of factors. Here, we explore the important role of RAP in defense against fungal pathogens and the trade-offs involved from a viewpoint for structure-function relations, while also examining how fungi can breach the defense system using an array of enzymes in conjunction with the physically intrusive hyphae.
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Affiliation(s)
- Hugh Morris
- Institute of Systematic Botany and Ecology, Ulm UniversityUlm, Germany
| | - Craig Brodersen
- School of Forestry and Environmental Studies, Yale University, New HavenCT, USA
| | - Francis W. M. R. Schwarze
- Laboratory for Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Testing and ResearchSt. Gallen, Switzerland
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm UniversityUlm, Germany
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18
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Klepsch MM, Schmitt M, Paul Knox J, Jansen S. The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity. AOB PLANTS 2016; 8:plw052. [PMID: 27354661 PMCID: PMC4975070 DOI: 10.1093/aobpla/plw052] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/10/2016] [Indexed: 05/03/2023]
Abstract
Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e. the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell-wall matrix polymers such as heteroxylans or arabinogalactan-proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18 % (± 9) to 32 % (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13)-related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel-related characteristics. Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect.
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Affiliation(s)
- Matthias M Klepsch
- Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
| | - Marco Schmitt
- Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
| | - J Paul Knox
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Steven Jansen
- Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany
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19
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Hocking B, Tyerman SD, Burton RA, Gilliham M. Fruit Calcium: Transport and Physiology. FRONTIERS IN PLANT SCIENCE 2016; 7:569. [PMID: 27200042 PMCID: PMC4850500 DOI: 10.3389/fpls.2016.00569] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/13/2016] [Indexed: 05/18/2023]
Abstract
Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium-regulated signaling pathways that control ripening would assist in addressing calcium deficiency disorders and improving fruit pathogen resistance.
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Affiliation(s)
- Bradleigh Hocking
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
- ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Stephen D. Tyerman
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Rachel A. Burton
- ARC Centre of Excellence in Plant Cell Walls, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
| | - Matthew Gilliham
- Plant Transport and Signaling Laboratory, ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen OsmondSA, Australia
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20
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Huang D, Wang C, Yuan J, Cao J, Lan H. Differentiation of the seed coat and composition of the mucilage of Lepidium perfoliatum L.: a desert annual with typical myxospermy. Acta Biochim Biophys Sin (Shanghai) 2015; 47:775-87. [PMID: 26341978 DOI: 10.1093/abbs/gmv078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 05/21/2015] [Indexed: 11/12/2022] Open
Abstract
Myxospermy is an important feature in seeds of many plant species grown in desert region. Fertilization can initiate differentiation of the seed coat epidermis into a specialized cell type with mucilage production. In the present study, comprehensive analyses were performed on the seed coat differentiation, mucilage production and composition, and seed germination in Lepidium perfoliatum (Brassicaceae), a desert annual with typical myxospermy in China. First, results indicated that mucilage was secreted uniformly at the outer tangential wall, resulting in compression of the cytoplasm to the bottom of the epidermal cells. Secondly, the inner tangential wall and two radial walls of the subepidermal cells were apparently thickened by production of a secondary cell wall material, which resulted in a 'typical' palisade appearance. Thirdly, immunohistochemical staining combined with the enzymatic digestion and infrared spectrum analysis of the mucilage indicated that, while one important component of the seed coat mucilage in L. perfoliatum was pectin, it also contained β-1,3-d-glucan and xyloglucan. Finally, seed germination showed that seeds with mucilage displayed significantly higher germination percentage than that of demucilaged seeds in abundant or excess water conditions. These results suggest that the possible ecological role of mucilage in L. perfoliatum is in the adaptation to habitats with well-watered and water-logged conditions, rather than water stress.
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Affiliation(s)
- Daihong Huang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China College of Life Science, Nankai University, Tianjin 300071, China
| | - Cui Wang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Junwen Yuan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Jing Cao
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Haiyan Lan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
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21
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Fichot R, Brignolas F, Cochard H, Ceulemans R. Vulnerability to drought-induced cavitation in poplars: synthesis and future opportunities. PLANT, CELL & ENVIRONMENT 2015; 38:1233-51. [PMID: 25444560 DOI: 10.1111/pce.12491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 11/12/2014] [Indexed: 05/04/2023]
Abstract
Vulnerability to drought-induced cavitation is a key trait of plant water relations. Here, we summarize the available literature on vulnerability to drought-induced cavitation in poplars (Populus spp.), a genus of agronomic, ecological and scientific importance. Vulnerability curves and vulnerability parameters (including the water potential inducing 50% loss in hydraulic conductivity, P50) were collected from 37 studies published between 1991 and 2014, covering a range of 10 species and 12 interspecific hybrid crosses. Results of our meta-analysis confirm that poplars are among the most vulnerable woody species to drought-induced cavitation (mean P50 = -1.44 and -1.55 MPa across pure species and hybrids, respectively). Yet, significant variation occurs among species (P50 range: 1.43 MPa) and among hybrid crosses (P50 range: 1.12 MPa), within species and hybrid crosses (max. P50 range reported: 0.8 MPa) as well as in response to environmental factors including nitrogen fertilization, irradiance, temperature and drought (max. P50 range reported: 0.75 MPa). Potential implications and gaps in knowledge are discussed in the context of poplar cultivation, species adaptation and climate modifications. We suggest that poplars represent a valuable model for studies on drought-induced cavitation, especially to elucidate the genetic and molecular basis of cavitation resistance in Angiosperms.
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Affiliation(s)
- Régis Fichot
- INRA, LBLGC, EA 1207, University of Orléans, Orléans, F-45067, France
| | - Franck Brignolas
- INRA, LBLGC, EA 1207, University of Orléans, Orléans, F-45067, France
| | - Hervé Cochard
- UMR547 PIAF, INRA, Clermont-Ferrand, F-63100, France
- UMR547 PIAF, Clermont Université, Université Blaise-Pascal, Clermont-Ferrand, F-63000, France
| | - Reinhart Ceulemans
- Department of Biology, Centre of Excellence, Plant and Vegetation Ecology (PLECO), University of Antwerp, Wilrijk, B-2610, Belgium
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Schenk HJ, Steppe K, Jansen S. Nanobubbles: a new paradigm for air-seeding in xylem. TRENDS IN PLANT SCIENCE 2015; 20:199-205. [PMID: 25680733 DOI: 10.1016/j.tplants.2015.01.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/13/2015] [Accepted: 01/17/2015] [Indexed: 05/23/2023]
Abstract
Long-distance water transport in plants relies on a system that typically operates under negative pressure and is prone to hydraulic failure due to gas bubble formation. One primary mechanism of bubble formation takes place at nanoporous pit membranes between neighboring conduits. We argue that this process is likely to snap off nanobubbles because the local increase in liquid pressure caused by entry of air-water menisci into the complex pit membrane pores would energetically favor nanobubble formation over instant cavitation. Nanobubbles would be stabilized by surfactants and by gas supersaturation of the sap, may dissolve, fragment into smaller bubbles, or create embolisms. The hypothesis that safe and stable nanobubbles occur in plants adds a new component supporting the cohesion-tension theory.
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, PO Box 6850, Fullerton, CA 92834-6850, USA
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Steven Jansen
- Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
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23
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Ménard D, Pesquet E. Cellular interactions during tracheary elements formation and function. CURRENT OPINION IN PLANT BIOLOGY 2015; 23:109-15. [PMID: 25545993 DOI: 10.1016/j.pbi.2014.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/17/2014] [Accepted: 12/11/2014] [Indexed: 05/08/2023]
Abstract
The survival of higher plant species on land depends on the development and function of an efficient vascular system distributing water and minerals absorbed by roots to all aerial organs. This conduction and distribution of plant sap relies on specialized cells named tracheary elements (TEs). In contrast to many other cell types in plants, TEs are functionalized by cell death that hollows the cell protoplast to make way for the sap. To maintain a stable conducting function during plant development, recovery from vascular damages as well as to adapt to environmental changes, TEs are completely dependent on direct cellular interactions with neighboring xylem parenchyma cells (XPs).
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Affiliation(s)
- Delphine Ménard
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, S-901 87 Umeå, Sweden
| | - Edouard Pesquet
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, S-901 87 Umeå, Sweden.
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24
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Herbette S, Bouchet B, Brunel N, Bonnin E, Cochard H, Guillon F. Immunolabelling of intervessel pits for polysaccharides and lignin helps in understanding their hydraulic properties in Populus tremula × alba. ANNALS OF BOTANY 2015; 115:187-99. [PMID: 25452248 PMCID: PMC4551089 DOI: 10.1093/aob/mcu232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 09/22/2014] [Accepted: 10/09/2014] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND AIMS The efficiency and safety functions of xylem hydraulics are strongly dependent on the pits that connect the xylem vessels. However, little is known about their biochemical composition and thus about their hydraulic properties. In this study, the distribution of the epitopes of different wall components (cellulose, hemicelluloses, pectins and lignins) was analysed in intervessel pits of hybrid poplar (Populus tremula × alba). METHODS Immunogold labelling with transmission electron microscopy was carried out with a set of antibodies raised against different epitopes for each wall polysaccharide type and for lignins. Analyses were performed on both immature and mature vessels. The effect of sap ionic strength on xylem conductance was also tested. KEY RESULTS In mature vessels, the pit membrane (PM) was composed of crystalline cellulose and lignins. None of the hemicellulose epitopes were found in the PM. Pectin epitopes in mature vessels were highly concentrated in the annulus, a restricted area of the PM, whereas they were initially found in the whole PM in immature vessels. The pit border also showed a specific labelling pattern, with higher cellulose labelling compared with the secondary wall of the vessel. Ion-mediated variation of 24 % was found for hydraulic conductance. CONCLUSIONS Cellulose microfibrils, lignins and annulus-restricted pectins have different physicochemical properties (rigidity, hydrophobicity, porosity) that have different effects on the hydraulic functions of the PM, and these influence both the hydraulic efficiency and vulnerability to cavitation of the pits, including ion-mediated control of hydraulic conductance. Impregnation of the cellulose microfibrils of the PM with lignins, which have low wettability, may result in lower cavitation pressure for a given pore size and thus help to explain the vulnerability of this species to cavitation.
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Affiliation(s)
- Stéphane Herbette
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France
| | - Brigitte Bouchet
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France
| | - Nicole Brunel
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France
| | - Estelle Bonnin
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France
| | - Hervé Cochard
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France
| | - Fabienne Guillon
- Clermont Université, Université Blaise Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France, INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France and INRA, UR1268 Biopolymers Interactions Assemblies, BP 71627, F-44316 Nantes, France
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25
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Hacke UG, Venturas MD, MacKinnon ED, Jacobsen AL, Sperry JS, Pratt RB. The standard centrifuge method accurately measures vulnerability curves of long-vesselled olive stems. THE NEW PHYTOLOGIST 2015; 205:116-27. [PMID: 25229841 DOI: 10.1111/nph.13017] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/01/2014] [Indexed: 05/02/2023]
Abstract
The standard centrifuge method has been frequently used to measure vulnerability to xylem cavitation. This method has recently been questioned. It was hypothesized that open vessels lead to exponential vulnerability curves, which were thought to be indicative of measurement artifact. We tested this hypothesis in stems of olive (Olea europea) because its long vessels were recently claimed to produce a centrifuge artifact. We evaluated three predictions that followed from the open vessel artifact hypothesis: shorter stems, with more open vessels, would be more vulnerable than longer stems; standard centrifuge-based curves would be more vulnerable than dehydration-based curves; and open vessels would cause an exponential shape of centrifuge-based curves. Experimental evidence did not support these predictions. Centrifuge curves did not vary when the proportion of open vessels was altered. Centrifuge and dehydration curves were similar. At highly negative xylem pressure, centrifuge-based curves slightly overestimated vulnerability compared to the dehydration curve. This divergence was eliminated by centrifuging each stem only once. The standard centrifuge method produced accurate curves of samples containing open vessels, supporting the validity of this technique and confirming its utility in understanding plant hydraulics. Seven recommendations for avoiding artefacts and standardizing vulnerability curve methodology are provided.
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Affiliation(s)
- Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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26
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Rockwell FE, Wheeler JK, Holbrook NM. Cavitation and its discontents: opportunities for resolving current controversies. PLANT PHYSIOLOGY 2014; 164:1649-60. [PMID: 24501002 PMCID: PMC3982731 DOI: 10.1104/pp.113.233817] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/02/2014] [Indexed: 05/18/2023]
Abstract
Cavitation has long been recognized as a key constraint on the structure and functional integrity of the xylem. Yet, recent results call into question how well we understand cavitation in plants. Here, we consider embolism formation in angiosperms at two scales. The first focuses on how air-seeding occurs at the level of pit membranes, raising the question of whether capillary failure is an appropriate physical model. The second addresses methodological uncertainties that affect our ability to infer the formation of embolism and its reversal in plant stems. Overall, our goal is to open up fresh perspectives on the structure-function relationships of xylem.
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Affiliation(s)
- Fulton E. Rockwell
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853 (F.E.R.); and
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (J.K.W., N.M.H.)
| | - James K. Wheeler
- School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853 (F.E.R.); and
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (J.K.W., N.M.H.)
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27
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Spicer R. Symplasmic networks in secondary vascular tissues: parenchyma distribution and activity supporting long-distance transport. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1829-48. [PMID: 24453225 DOI: 10.1093/jxb/ert459] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Stems that develop secondary vascular tissue (i.e. xylem and phloem derived from the vascular cambium) have unique demands on transport owing to their mass and longevity. Transport of water and assimilates must occur over long distances, while the increasing physical separation of xylem and phloem requires radial transport. Developing secondary tissue is itself a strong sink positioned between xylem and phloem along the entire length of the stem, and the integrity of these transport tissues must be maintained and protected for years if not decades. Parenchyma cells form an interconnected three-dimensional lattice throughout secondary xylem and phloem and perform critical roles in all of these tasks, yet our understanding of their physiology, the nature of their symplasmic connections, and their activity at the symplast-apoplast interface is very limited. This review highlights key historical work as well as current research on the structure and function of parenchyma in secondary vascular tissue in the hopes of spurring renewed interest in this area, which has important implications for whole-plant transport processes and resource partitioning.
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Affiliation(s)
- Rachel Spicer
- Department of Botany, Connecticut College, New London, CT 06320, USA
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28
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Dusotoit-Coucaud A, Brunel N, Tixier A, Cochard H, Herbette S. Hydrolase treatments help unravel the function of intervessel pits in xylem hydraulics. PHYSIOLOGIA PLANTARUM 2014; 150:388-396. [PMID: 23981110 DOI: 10.1111/ppl.12092] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/18/2013] [Accepted: 07/14/2013] [Indexed: 06/02/2023]
Abstract
Intervessel pits are structures that play a key role in the efficiency and safety functions of xylem hydraulics. However, little is known about the components of the pit membrane (PM) and their role in hydraulic functions, especially in resistance to cavitation. We tested the effect of commercial chemicals including a cellulase, a hemicellulase, a pectolyase, a proteinase and DTT on xylem hydraulic properties: vulnerability to cavitation (VC) and conductance. The effects were tested on branch segments from Fagus sylvatica (where the effects on pit structure were analyzed using TEM) and Populus tremula. Cellulose hydrolysis resulted in a sharp increase in VC and a significant increase in conductance, related to complete breakdown of the PM. Pectin hydrolysis also induced a sharp increase in VC but with no effect on conductance or pit structure observable by TEM. The other treatments with hemicellulase, proteinase or DTT showed no effect. This study brings evidence that cellulose and pectins are critical components underpinning VC, and that PM components may play distinct roles in the xylem hydraulic safety and efficiency.
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Affiliation(s)
- Anaïs Dusotoit-Coucaud
- INRA, UMR547 PIAF, 5 Chemin de Beaulieu, 63039, Clermont-Ferrand, Cedex 02, France; Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, 63000, Clermont-Ferrand, France
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29
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Affiliation(s)
- Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB T6G 2E3, Canada
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30
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Lens F, Tixier A, Cochard H, Sperry JS, Jansen S, Herbette S. Embolism resistance as a key mechanism to understand adaptive plant strategies. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:287-92. [PMID: 23453076 DOI: 10.1016/j.pbi.2013.02.005] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 02/07/2013] [Indexed: 05/21/2023]
Abstract
One adaptation of plants to cope with drought or frost stress is to develop wood that is able to withstand the formation and distribution of air bubbles (emboli) in its water conducting xylem cells under negative pressure. The ultrastructure of interconduit pits strongly affects drought-induced embolism resistance, but also mechanical properties of the xylem are involved. The first experimental evidence for a lower embolism resistance in stems of herbaceous plants compared to stems of their secondarily woody descendants further supports this mechanical-functional trade-off. An integrative approach combining (ultra)structural observations of the xylem, safety-efficiency aspects of the hydraulic pipeline, and xylem-phloem interactions will shed more light on the multiple adaptive strategies of embolism resistance in plants.
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Affiliation(s)
- Frederic Lens
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9514, NL-2300 RA Leiden, The Netherlands.
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31
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Trifil P, Lo Gullo MA, Raimondo F, Salleo S, Nardini A. Effects of NaCl addition to the growing medium on plant hydraulics and water relations of tomato. FUNCTIONAL PLANT BIOLOGY : FPB 2013; 40:459-465. [PMID: 32481122 DOI: 10.1071/fp12287] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 01/07/2013] [Indexed: 06/11/2023]
Abstract
This work reports on experimental evidence for the role of ion-mediated changes of xylem hydraulic conductivity in the functional response of Solanum lycopersicum L. cv. Naomi to moderate salinity levels. Measurements were performed in fully developed 12-week-old plants grown in half-strength Hoagland solution (control, C-plants) or in the same solution added with 35mM NaCl (NaCl-plants). NaCl-plants produced a significantly less but heavier leaves and fruits but had similar gas-exchange rates as control plants. Moreover, NaCl-plants showed higher vessel multiple fraction (FVM) than control plants. Xylem sap potassium and sodium concentrations were significantly higher in NaCl-plants than in control plants. When stems were perfused with 10mM NaCl or KCl, the hydraulic conductance of NaCl plants was nearly 1.5 times higher than in control plants. Accordingly, stem hydraulic conductance measured in planta was higher in NaCl- than in control plants. Our data suggest that tomato plants grown under moderate salinity upregulate xylem sap [Na+] and [K+], as well as sensitivity of xylem hydraulics to sap ionic content, thus, increasing water transport capacity.
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Affiliation(s)
- Patrizia Trifil
- Dipartimento di Scienze Biologiche e Ambientali, Università di Messina, viale F. Stagno D'Alcontres, 31, 98166 Messina, Italia
| | - Maria Assunta Lo Gullo
- Dipartimento di Scienze Biologiche e Ambientali, Università di Messina, viale F. Stagno D'Alcontres, 31, 98166 Messina, Italia
| | - Fabio Raimondo
- Dipartimento di Scienze Biologiche e Ambientali, Università di Messina, viale F. Stagno D'Alcontres, 31, 98166 Messina, Italia
| | - Sebastiano Salleo
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italia
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italia
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Plavcová L, Jansen S, Klepsch M, Hacke UG. Nobody's perfect: can irregularities in pit structure influence vulnerability to cavitation? FRONTIERS IN PLANT SCIENCE 2013; 4:453. [PMID: 24273549 PMCID: PMC3824106 DOI: 10.3389/fpls.2013.00453] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/22/2013] [Indexed: 05/04/2023]
Abstract
Recent studies have suggested that species-specific pit properties such as pit membrane thickness, pit membrane porosity, torus-to-aperture diameter ratio and pit chamber depth influence xylem vulnerability to cavitation. Despite the indisputable importance of using mean pit characteristics, considerable variability in pit structure within a single species or even within a single pit field should be acknowledged. According to the rare pit hypothesis, a single pit that is more air-permeable than many neighboring pits is sufficient to allow air-seeding. Therefore, any irregularities or morphological abnormalities in pit structure allowing air-seeding should be associated with increased vulnerability to cavitation. Considering the currently proposed models of air-seeding, pit features such as rare, large pores in the pit membrane, torus extensions, and plasmodesmatal pores in a torus can represent potential glitches. These aberrations in pit structure could either result from inherent developmental flaws, or from damage caused to the pit membrane by chemical and physical agents. This suggests the existence of interesting feedbacks between abiotic and biotic stresses in xylem physiology.
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Affiliation(s)
- Lenka Plavcová
- Institute for Systematic Botany and Ecology, Ulm UniversityUlm, Germany
- *Correspondence: Lenka Plavcová, Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany e-mail:
| | - Steven Jansen
- Institute for Systematic Botany and Ecology, Ulm UniversityUlm, Germany
| | - Matthias Klepsch
- Institute for Systematic Botany and Ecology, Ulm UniversityUlm, Germany
| | - Uwe G. Hacke
- Department of Renewable Resources, University of AlbertaEdmonton, AB, Canada
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33
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van Doorn WG, Hiemstra T, Fanourakis D. Hydrogel regulation of xylem water flow: an alternative hypothesis. PLANT PHYSIOLOGY 2011; 157:1642-9. [PMID: 22025608 PMCID: PMC3327220 DOI: 10.1104/pp.111.185314] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 10/10/2011] [Indexed: 05/18/2023]
Affiliation(s)
- Wouter G van Doorn
- Mann Laboratory, Department of Plant Sciences, University of California, Davis, California 95616, USA.
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