1
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Jacobsen AL, Venturas MD, Hacke UG, Pratt RB. Sap flow through partially embolized xylem vessel networks. PLANT, CELL & ENVIRONMENT 2024; 47:3375-3392. [PMID: 38826042 DOI: 10.1111/pce.14990] [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: 11/14/2023] [Revised: 05/16/2024] [Accepted: 05/18/2024] [Indexed: 06/04/2024]
Abstract
Sap is transported through numerous conduits in the xylem of woody plants along the path from the soil to the leaves. When all conduits are functional, vessel lumen diameter is a strong predictor of hydraulic conductivity. As vessels become embolized, sap movement becomes increasingly affected by factors operating at scales beyond individual conduits, creating resistances that result in hydraulic conductivity diverging from diameter-based estimates. These effects include pit resistances, connectivity, path length, network topology, and vessel or sector isolation. The impact of these factors varies with the level and distribution of emboli within the network, and manifest as alterations in the relationship between the number and diameter of embolized vessels with measured declines in hydraulic conductivity across vulnerability to embolism curves. Divergences between measured conductivity and diameter-based estimates reveal functional differences that arise because of species- and tissue-specific vessel network structures. Such divergences are not uniform, and xylem tissues may diverge in different ways and to differing degrees. Plants regularly operate under nonoptimal conditions and contain numerous embolized conduits. Understanding the hydraulic implications of emboli within a network and the function of partially embolized networks are critical gaps in our understanding of plants occurring within natural environments.
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Affiliation(s)
- Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, California, USA
| | - Martin D Venturas
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, Madrid, Spain
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Robert Brandon Pratt
- Department of Biology, California State University, Bakersfield, California, USA
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2
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Silva LM, Pereira L, Kaack L, Guan X, Pfaff J, Trabi CL, Jansen S. The potential link between gas diffusion and embolism spread in angiosperm xylem: Evidence from flow-centrifuge experiments and modelling. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39119783 DOI: 10.1111/pce.15084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/19/2024] [Accepted: 07/27/2024] [Indexed: 08/10/2024]
Abstract
Understanding xylem embolism formation is challenging due to dynamic changes and multiphase interactions in conduits. Here, we hypothesise that embolism spread involves gas diffusion in xylem, and is affected by time. We measured hydraulic conductivity (Kh) in flow-centrifuge experiments over 1 h at a given pressure and temperature for stem samples of three angiosperm species. Temporal changes in Kh at 5, 22, and 35°C, and at various pressures were compared to modelled gas concentration changes in a recently embolised vessel in the centre of a centrifuge sample. Temporal changes in Kh were logarithmic and species-specific. Maximum relative increases of Kh between 6% and 40% happened at 22°C for low centrifugal speed (<3250 RPM), while maximum decreases between 41% and 61% occurred at higher speeds. These reductions in Kh were experimentally shown to be associated with a temporal increase of embolism at the centre of centrifuge samples, which was likely associated with gas concentration increases in recently embolized vessels. Although embolism is mostly pressure-driven, our experimental and modelled data indicate that time, conduit characteristics, and temperature are involved due to their potential role in gas diffusion. Gas diffusion, however, does not seem to cover the entire process of embolism spread.
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Affiliation(s)
| | | | - Lucian Kaack
- Institute of Botany, Ulm University, Ulm, Germany
- Botanical Garden of Ulm University, Hans-Krebs-Weg, Ulm, Germany
| | - Xinyi Guan
- Institute of Botany, Ulm University, Ulm, Germany
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Jonas Pfaff
- Institute of Botany, Ulm University, Ulm, Germany
| | - Christophe L Trabi
- Institute of Botany, Ulm University, Ulm, Germany
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Ulm, Germany
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3
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Ke Y, Zhang YB, Zhang FP, Yang D, Wang Q, Peng XR, Huang XY, Sher J, Zhang JL. Monocots and eudicots have more conservative flower water use strategies than basal angiosperms. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:621-632. [PMID: 38477557 DOI: 10.1111/plb.13637] [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: 12/22/2023] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Water balance is crucial for the growth and flowering of plants. However, the mechanisms by which flowers maintain water balance are poorly understood across different angiosperm branches. Here, we investigated 29 floral hydraulic and economic traits in 24 species from ANA grade, magnoliids, monocots, and eudicots. Our main objective was to compare differences in flower water use strategies between basal angiosperms (ANA grade and magnoliids) and derived group (monocots and eudicots). We found that basal angiosperms had richer petal stomatal density, higher pedicel hydraulic diameter, and flower mass per area, but lower pedicel vessel wall reinforcement and epidermal cell thickness compared to monocots and eudicots. We also observed significant trade-offs and coordination among different floral traits. Floral traits associated with reproduction, such as floral longevity and size, were strongly linked with physiological and anatomical traits. Our results systematically reveal the variation in flower economic and hydraulic traits from different angiosperm branches, deepening understanding of flower water use strategies among these plant taxa. We conclude that basal angiosperms maintain water balance with high water supply, whereas monocots and eudicots maintain a more conservative water balance.
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Affiliation(s)
- Y Ke
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Y-B Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - F-P Zhang
- College of Traditional Chinese Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan, China
| | - D Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - Q Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - X-R Peng
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - X-Y Huang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - J Sher
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - J-L Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
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4
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Li J, Ren J, Lei X, Fan W, Tang L, Zhang Q, Bao Z, Zhou W, Bai J, Zhang Y, Gong C. CsREV-CsTCP4-CsVND7 module shapes xylem patterns differentially between stem and leaf to enhance tea plant tolerance to drought. Cell Rep 2024; 43:113987. [PMID: 38517888 DOI: 10.1016/j.celrep.2024.113987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 01/22/2024] [Accepted: 03/07/2024] [Indexed: 03/24/2024] Open
Abstract
Cultivating drought-tolerant tea varieties enhances both yield and quality of tea plants in northern China. However, the mechanisms underlying their drought tolerance remain largely unknown. Here we identified a key regulator called CsREV, which differentially regulates xylem patterns between leaves and stems, thereby conferring drought tolerance in tea plants. When drought occurs, upregulation of CsREV activates the CsVND7a-dependent xylem vessel differentiation. However, when drought persists, the vessel differentiation is hindered as CsVND7a is downregulated by CsTCP4a. This, combined with the CsREV-promoted secondary-cell-wall thickness of xylem vessel, leads to the enhanced curling of leaves, a characteristic closely associated with plant drought tolerance. Notably, this inhibitory effect of CsTCP4a on CsVND7a expression is absent in stems, allowing stem xylem vessels to continuously differentiate. Overall, the CsREV-CsTCP4-CsVND7 module is differentially utilized to shape the xylem patterns in leaves and stems, potentially balancing water transportation and utilization to improve tea plant drought tolerance.
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Affiliation(s)
- Jiayang Li
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiejie Ren
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xingyu Lei
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wenmin Fan
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lei Tang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Qiqi Zhang
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zhulatai Bao
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wenfei Zhou
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Juan Bai
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yuzhou Zhang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Chunmei Gong
- College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China.
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5
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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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6
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Yang D, Pereira L, Peng G, Ribeiro RV, Kaack L, Jansen S, Tyree MT. A unit pipe pneumatic model to simulate gas kinetics during measurements of embolism in excised angiosperm xylem. TREE PHYSIOLOGY 2023; 43:88-101. [PMID: 36049079 DOI: 10.1093/treephys/tpac105] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/30/2022] [Indexed: 06/15/2023]
Abstract
The pneumatic method has been introduced to quantify embolism resistance in plant xylem of various organs by applying a partial vacuum to cut-open xylem. Despite the similarity in vulnerability curves between the pneumatic and other methods, a modeling approach is needed to investigate if changes in xylem embolism during dehydration can be accurately quantified based on gas diffusion kinetics. Therefore, a unit pipe pneumatic (UPPn) model was developed to estimate gas extraction from intact conduits, which were axially interconnected by inter-conduit pit membranes to cut-open conduits. The physical laws used included Fick's law for diffusion, Henry's law for gas concentration partitioning between liquid and gas phases at equilibrium and the ideal gas law. The UPPn model showed that 91% of the extracted gas came from the first five series of embolized, intact conduits and only 9% from the aqueous phase after 15 s of simulation. Considering alternative gas sources, embolism resistance measured with a pneumatron device was systematically overestimated by 2-17%, which corresponded to a typical measuring error of 0.11 MPa for P50 (the water potential equivalent to 50% of the maximum amount of gas extracted). It is concluded that pneumatic vulnerability curves directly measure embolism of intact conduits due to the fast movement of gas across interconduit pit membranes, while gas extraction from sap and diffusion across hydrated cell walls is about 100 times slower. We expect that the UPPn model will also contribute to the understanding of embolism propagation based on temporal gas dynamics.
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Affiliation(s)
- Dongmei Yang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Luciano Pereira
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, P.O. Box 6109, University of Campinas (UNICAMP), Campinas 13083-970, Brazil
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11 Ulm D-89081, Germany
| | - Guoquan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Rafael V Ribeiro
- Laboratory of Crop Physiology, Department of Plant Biology, Institute of Biology, P.O. Box 6109, University of Campinas (UNICAMP), Campinas 13083-970, Brazil
| | - Lucian Kaack
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11 Ulm D-89081, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11 Ulm D-89081, Germany
| | - Melvin T Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
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7
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Lens F, Gleason SM, Bortolami G, Brodersen C, Delzon S, Jansen S. Functional xylem characteristics associated with drought-induced embolism in angiosperms. THE NEW PHYTOLOGIST 2022; 236:2019-2036. [PMID: 36039697 DOI: 10.1111/nph.18447] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Hydraulic failure resulting from drought-induced embolism in the xylem of plants is a key determinant of reduced productivity and mortality. Methods to assess this vulnerability are difficult to achieve at scale, leading to alternative metrics and correlations with more easily measured traits. These efforts have led to the longstanding and pervasive assumed mechanistic link between vessel diameter and vulnerability in angiosperms. However, there are at least two problems with this assumption that requires critical re-evaluation: (1) our current understanding of drought-induced embolism does not provide a mechanistic explanation why increased vessel width should lead to greater vulnerability, and (2) the most recent advancements in nanoscale embolism processes suggest that vessel diameter is not a direct driver. Here, we review data from physiological and comparative wood anatomy studies, highlighting the potential anatomical and physicochemical drivers of embolism formation and spread. We then put forward key knowledge gaps, emphasising what is known, unknown and speculation. A meaningful evaluation of the diameter-vulnerability link will require a better mechanistic understanding of the biophysical processes at the nanoscale level that determine embolism formation and spread, which will in turn lead to more accurate predictions of how water transport in plants is affected by drought.
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Affiliation(s)
- Frederic Lens
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
- Leiden University, Institute of Biology Leiden, Plant Sciences, Sylviusweg 72, 2333 BE, Leiden, the Netherlands
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
| | - Giovanni Bortolami
- Naturalis Biodiversity Center, PO Box 9517, 2300 RA, Leiden, the Netherlands
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, 06511, USA
| | - Sylvain Delzon
- University of Bordeaux, INRAE, BIOGECO, 33615, Pessac, France
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
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8
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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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9
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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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10
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Barbeta A, Burlett R, Martín-Gómez P, Fréjaville B, Devert N, Wingate L, Domec JC, Ogée J. Evidence for distinct isotopic compositions of sap and tissue water in tree stems: consequences for plant water source identification. THE NEW PHYTOLOGIST 2022; 233:1121-1132. [PMID: 34767646 DOI: 10.1111/nph.17857] [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: 07/19/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
The long-standing hypothesis that the isotopic composition of plant stem water reflects that of source water is being challenged by studies reporting bulk water from woody stems with an isotopic composition that cannot be attributed to any potential water source. The mechanism behind such source-stem water isotopic offsets is still poorly understood. Using a novel technique to extract selectively sap water from xylem conduits, we show that, in cut stems and potted plants, the isotopic composition of sap water reflects that of irrigation water, demonstrating unambiguously that no isotopic fractionation occurs during root water uptake or sap water extraction. By contrast, water in nonconductive xylem tissues is always depleted in deuterium compared with sap water, irrespective of wood anatomy. Previous studies have shown that isotopic heterogeneity also exists in soils at the pore scale in which water adsorbed onto soil particles is more depleted in deuterium than unbound water. Data collected at a riparian forest indicated that sap water matches best unbound soil water from depth below -70 cm, while bulk stem and soil water differ markedly. We conclude that source-stem isotopic offsets can be explained by micrometre-scale heterogeneity in the isotope ratios of water within woody stems and soil micro-pores.
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Affiliation(s)
- Adrià Barbeta
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
- BEECA, Universitat de Barcelona, Barcelona, Catalonia, 08028, Spain
| | - Régis Burlett
- Université de Bordeaux, INRAE, BIOGECO, Pessac, 33615, France
| | | | | | - Nicolas Devert
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
| | - Lisa Wingate
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
| | | | - Jérôme Ogée
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
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11
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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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12
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Vahdati K, Sarikhani S, Arab MM, Leslie CA, Dandekar AM, Aletà N, Bielsa B, Gradziel TM, Montesinos Á, Rubio-Cabetas MJ, Sideli GM, Serdar Ü, Akyüz B, Beccaro GL, Donno D, Rovira M, Ferguson L, Akbari M, Sheikhi A, Sestras AF, Kafkas S, Paizila A, Roozban MR, Kaur A, Panta S, Zhang L, Sestras RE, Mehlenbacher SA. Advances in Rootstock Breeding of Nut Trees: Objectives and Strategies. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112234. [PMID: 34834597 PMCID: PMC8623031 DOI: 10.3390/plants10112234] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 10/06/2021] [Accepted: 10/15/2021] [Indexed: 05/31/2023]
Abstract
The production and consumption of nuts are increasing in the world due to strong economic returns and the nutritional value of their products. With the increasing role and importance given to nuts (i.e., walnuts, hazelnut, pistachio, pecan, almond) in a balanced and healthy diet and their benefits to human health, breeding of the nuts species has also been stepped up. Most recent fruit breeding programs have focused on scion genetic improvement. However, the use of locally adapted grafted rootstocks also enhanced the productivity and quality of tree fruit crops. Grafting is an ancient horticultural practice used in nut crops to manipulate scion phenotype and productivity and overcome biotic and abiotic stresses. There are complex rootstock breeding objectives and physiological and molecular aspects of rootstock-scion interactions in nut crops. In this review, we provide an overview of these, considering the mechanisms involved in nutrient and water uptake, regulation of phytohormones, and rootstock influences on the scion molecular processes, including long-distance gene silencing and trans-grafting. Understanding the mechanisms resulting from rootstock × scion × environmental interactions will contribute to developing new rootstocks with resilience in the face of climate change, but also of the multitude of diseases and pests.
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Affiliation(s)
- Kourosh Vahdati
- Department of Horticulture, College of Aburaihan, University of Tehran, Tehran 3391653755, Iran; (S.S.); (M.M.A.); (M.R.R.)
| | - Saadat Sarikhani
- Department of Horticulture, College of Aburaihan, University of Tehran, Tehran 3391653755, Iran; (S.S.); (M.M.A.); (M.R.R.)
| | - Mohammad Mehdi Arab
- Department of Horticulture, College of Aburaihan, University of Tehran, Tehran 3391653755, Iran; (S.S.); (M.M.A.); (M.R.R.)
| | - Charles A. Leslie
- Department of Plant Sciences, University of California Davis, One Shields, Avenue, Davis, CA 95616, USA; (C.A.L.); (A.M.D.); (T.M.G.); (G.M.S.); (L.F.)
| | - Abhaya M. Dandekar
- Department of Plant Sciences, University of California Davis, One Shields, Avenue, Davis, CA 95616, USA; (C.A.L.); (A.M.D.); (T.M.G.); (G.M.S.); (L.F.)
| | - Neus Aletà
- Institut de Recerca i Tecnologia Agroalimentàries, IRTA Fruit Production, Torre Marimon, 08140 Caldes de Montbui, Spain;
| | - Beatriz Bielsa
- Unidad de Hortofruticultura, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón-IA2 (CITA-Universidad de Zaragoza), Av. Montañana 930, 50059 Zaragoza, Spain; (B.B.); (Á.M.); (M.J.R.-C.)
| | - Thomas M. Gradziel
- Department of Plant Sciences, University of California Davis, One Shields, Avenue, Davis, CA 95616, USA; (C.A.L.); (A.M.D.); (T.M.G.); (G.M.S.); (L.F.)
| | - Álvaro Montesinos
- Unidad de Hortofruticultura, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón-IA2 (CITA-Universidad de Zaragoza), Av. Montañana 930, 50059 Zaragoza, Spain; (B.B.); (Á.M.); (M.J.R.-C.)
| | - María José Rubio-Cabetas
- Unidad de Hortofruticultura, Centro de Investigación y Tecnología Agroalimentaria de Aragón, Instituto Agroalimentario de Aragón-IA2 (CITA-Universidad de Zaragoza), Av. Montañana 930, 50059 Zaragoza, Spain; (B.B.); (Á.M.); (M.J.R.-C.)
- Instituto Agroalimentario de Aragón–IA2 (CITA-Universidad de Zaragoza), 50059 Zaragoza, Spain
| | - Gina M. Sideli
- Department of Plant Sciences, University of California Davis, One Shields, Avenue, Davis, CA 95616, USA; (C.A.L.); (A.M.D.); (T.M.G.); (G.M.S.); (L.F.)
| | - Ümit Serdar
- Department of Horticulture, Faculty of Agriculture, Ondokuz Mayıs University, Samsun 55139, Turkey; (Ü.S.); (B.A.)
| | - Burak Akyüz
- Department of Horticulture, Faculty of Agriculture, Ondokuz Mayıs University, Samsun 55139, Turkey; (Ü.S.); (B.A.)
| | - Gabriele Loris Beccaro
- Department of Agricultural, Forest and Food Sciences, University of Torino, 10124 Torino, Italy; (G.L.B.); (D.D.)
| | - Dario Donno
- Department of Agricultural, Forest and Food Sciences, University of Torino, 10124 Torino, Italy; (G.L.B.); (D.D.)
| | - Mercè Rovira
- Institut de Recerca i Tecnologia Agroalimentàries, IRTA Fruit Production, Mas Bové, Ctra. Reus-El Morell, Km. 3.8, 43120 Constantí, Spain;
| | - Louise Ferguson
- Department of Plant Sciences, University of California Davis, One Shields, Avenue, Davis, CA 95616, USA; (C.A.L.); (A.M.D.); (T.M.G.); (G.M.S.); (L.F.)
| | | | - Abdollatif Sheikhi
- Department of Horticultural Sciences, College of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan 7718897111, Iran;
| | - Adriana F. Sestras
- Faculty of Horticulture, University of Agricultural Sciences and Veterinary Medicine, 400372 Cluj-Napoca, Romania;
| | - Salih Kafkas
- Department of Horticulture, Faculty of Agriculture, Cukurova University, Adana 01380, Turkey; (S.K.); (A.P.)
| | - Aibibula Paizila
- Department of Horticulture, Faculty of Agriculture, Cukurova University, Adana 01380, Turkey; (S.K.); (A.P.)
| | - Mahmoud Reza Roozban
- Department of Horticulture, College of Aburaihan, University of Tehran, Tehran 3391653755, Iran; (S.S.); (M.M.A.); (M.R.R.)
| | - Amandeep Kaur
- Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK 74078, USA; (A.K.); (S.P.); (L.Z.)
| | - Srijana Panta
- Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK 74078, USA; (A.K.); (S.P.); (L.Z.)
| | - Lu Zhang
- Department of Horticulture and Landscape Architecture, Oklahoma State University, Stillwater, OK 74078, USA; (A.K.); (S.P.); (L.Z.)
| | - Radu E. Sestras
- Faculty of Horticulture, University of Agricultural Sciences and Veterinary Medicine, 400372 Cluj-Napoca, Romania;
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13
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Lemaire C, Quilichini Y, Brunel-Michac N, Santini J, Berti L, Cartailler J, Conchon P, Badel É, Herbette S. Plasticity of the xylem vulnerability to embolism in Populus tremula x alba relies on pit quantity properties rather than on pit structure. TREE PHYSIOLOGY 2021; 41:1384-1399. [PMID: 33554260 DOI: 10.1093/treephys/tpab018] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
Knowledge on variations of drought resistance traits are needed to predict the potential of trees to acclimate to coming severe drought events. Xylem vulnerability to embolism is a key parameter related to such droughts, and its phenotypic variability relies mainly on environmental plasticity. We investigated the structural determinants controlling the plasticity of vulnerability to embolism, focusing on the key elements involved in the air bubble entry in vessels, especially the intervessel pits. Poplar saplings (Populus tremula x alba (Aiton) Sm., 1804) grown in contrasted water availability or light exposure exhibited differences in the vulnerability to embolism (P50) in a range of 0.76 MPa. We then characterized the structural changes in features related to pit quantity and pit structure, from the pit ultrastructure to the organization of xylem vessels, using different microscopy techniques (transmission electron microscopy, scanning electron microscopy, light microscopy). A multispectral combination of X-ray microtomography and light microscopy analysis allowed measuring the vulnerability of each single vessel and testing some of the relationships between structural traits and vulnerability to embolism inside the xylem. The pit ultrastructure did not change, whereas the vessel dimensions increased with the vulnerability to embolism and the grouping index and fraction of intervessel cell wall both decreased with the vulnerability to embolism. These findings hold when comparing between trees or between the vessels inside the xylem of an individual tree. These results evidenced that plasticity of vulnerability to embolism in hybrid poplar occurs through changes in the pit quantity properties such as pit area and vessel grouping rather than changes on the pit structure.
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Affiliation(s)
- Cédric Lemaire
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Yann Quilichini
- CNRS-Università di Corsica, UMR 6134 SPE, 20250 Corti, France
| | | | - Jérémie Santini
- CNRS-Università di Corsica, UMR 6134 SPE, 20250 Corti, France
| | - Liliane Berti
- CNRS-Università di Corsica, UMR 6134 SPE, 20250 Corti, France
| | - Julien Cartailler
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Pierre Conchon
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Éric Badel
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
| | - Stéphane Herbette
- Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France
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14
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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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15
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Meixner M, Foerst P, Windt CW. Reduced spatial resolution MRI suffices to image and quantify drought induced embolism formation in trees. PLANT METHODS 2021; 17:38. [PMID: 33823898 PMCID: PMC8025330 DOI: 10.1186/s13007-021-00732-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/18/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND Magnetic resonance imaging (MRI) is uniquely suited to non-invasively and continuously monitor embolism formation in trees. Depending on the MRI method used, quantitative parameter maps of water content and MRI signal relaxation behavior can be generated. The ability to measure dynamic differences in water content and relaxation behavior can be used to detect xylem embolism formation, even if xylem conduits are too small to be spatially resolved. This is especially advantageous when using affordable small-scale low-field MRI scanners. The amount of signal that can be obtained from an object strongly depends on the strength of the magnetic field of the imager's magnet. Imaging at lower resolutions thus would allow to reduce the cost, size and weight of the MRI scanner and to shorten image acquisition times. RESULTS We investigated how much spatial resolution can be sacrificed without losing the ability to monitor embolism formation in coniferous softwood (spruce, Picea abies) and diffuse porous beech (Fagus sylvatica). Saplings of both species were bench dehydrated, while they were continuously imaged at stepwise decreasing spatial resolutions. Imaging was done by means of a small-scale MRI device, utilizing image matrix sizes of 128 × 128, 64 × 64 and 32 × 32 pixels at a constant FOV of 19 and 23 mm, respectively. While images at the lowest resolutions (pixel sizes 0.59 × 0.59 mm and 0.72 × 0.72 mm) were no longer sufficient to resolve finer details of the stem anatomy, they did permit an approximate localization of embolism formation and the generation of accurate vulnerability curves. CONCLUSIONS When using MRI, spatial resolution can be sacrificed without losing the ability to visualize and quantify embolism formation. Imaging at lower spatial resolution to monitor embolism formation has two advantages. Firstly, the acquisition time per image can be reduced dramatically. This enables continuous imaging at high time resolution, which may be beneficial to monitor rapid dynamics of embolism formation. Secondly, if the requirements for spatial resolution are relaxed, much simpler MRI devices can be used. This has the potential to make non-invasive MR imaging of embolism formation much more affordable and more widely available.
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Affiliation(s)
- Marco Meixner
- Chair of Process Systems Engineering, Technical University Munich, Munich, Germany
- IBG-2: Plant Sciences, Forschungszentrum Jülich, Jülich, Germany
| | - Petra Foerst
- Chair of Process Systems Engineering, Technical University Munich, Munich, Germany
| | - Carel W Windt
- IBG-2: Plant Sciences, Forschungszentrum Jülich, Jülich, Germany.
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16
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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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17
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Liu J, Gu L, Yu Y, Huang P, Wu Z, Zhang Q, Qian Y, Wan X, Sun Z. Corticular photosynthesis drives bark water uptake to refill embolized vessels in dehydrated branches of Salix matsudana. PLANT, CELL & ENVIRONMENT 2019; 42:2584-2596. [PMID: 31083779 DOI: 10.1111/pce.13578] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
It is well known that xylem embolism can be repaired by bark water uptake and that the sugar required for embolism refilling can be provided by corticular photosynthesis. However, the relationship between corticular photosynthesis and embolism repair by bark water uptake is still poorly understood. In this study, the role of corticular photosynthesis in embolism repair was assessed using Salix matsudana branch segments dehydrated to -1.9 MPa (P50 , water potential at 50% loss of conductivity). The results indicated that corticular photosynthesis significantly promoted water uptake and nonstructural carbohydrate (NSC) accumulation in the bark and xylem during soaking, thereby effectively enhancing the refilling of the embolized vessels and the recovery of hydraulic conductivity. Furthermore, the influence of the extent of dehydration on the embolism refilling enhanced by corticular photosynthesis was investigated. The enhanced refilling effects were much higher in the mildly dehydrated (-1.5 MPa) and moderately dehydrated (-1.9 MPa) branch segments than in the severely dehydrated (-2.2 MPa) branch segments. This study provides evidence that corticular photosynthesis plays a crucial role in xylem embolism repair by bark water uptake for mildly and moderately dehydrated branches.
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Affiliation(s)
- Junxiang Liu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Lin Gu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Yongchang Yu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Ping Huang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Zhigang Wu
- School of Civil Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Qian Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Yongqiang Qian
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, China
| | - Zhenyuan Sun
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
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18
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Volumetric estimate of bordered pits in Pinus sylvestris based on X-ray tomography and light microscopy imaging. Micron 2019; 124:102704. [PMID: 31344654 DOI: 10.1016/j.micron.2019.102704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 11/21/2022]
Abstract
Bordered pits are a major determinant for the hydraulic function of wood tissues. Unlike microscopic imaging (e.g. light and electron microscopy) that is constrained to two-dimensional (2D) information, X-ray micro-computed tomography (XμCT) contributes to three-dimensional (3D) analysis. This advantage was used to estimate the volume of bordered pits in Pinus sylvestris. The 3D data obtained by XμCT were compared with two mathematical models (ellipsoid model and spherical cap model) using 2D data obtained by transmission light microscopy and XμCT. The findings of this study showed that the volume approximation using the ellipsoid model revealed values close to the volumes, which were three-dimensionally obtained by XμCT. This trend, however, is more pronounced for pits in earlywood than in latewood. Nevertheless, this study demonstrated that microscopic images can also be used for the approximation of pit volumes to some extent. Researchers should be aware of limitations that come with the 3D method (e.g. resolution, image analysis) and 2D method (unknown location of the section in the pit) as well as the natural variation of the pit morphology.
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19
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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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20
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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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21
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De Baerdemaeker NJF, Stock M, Van den Bulcke J, De Baets B, Van Hoorebeke L, Steppe K. X-ray microtomography and linear discriminant analysis enable detection of embolism-related acoustic emissions. PLANT METHODS 2019; 15:153. [PMID: 31889977 PMCID: PMC6916244 DOI: 10.1186/s13007-019-0543-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/05/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND Acoustic emission (AE) sensing is in use since the late 1960s in drought-induced embolism research as a non-invasive and continuous method. It is very well suited to assess a plant's vulnerability to dehydration. Over the last couple of years, AE sensing has further improved due to progress in AE sensors, data acquisition methods and analysis systems. Despite these recent advances, it is still challenging to detect drought-induced embolism events in the AE sources registered by the sensors during dehydration, which sometimes questions the quantitative potential of AE sensing. RESULTS In quest of a method to separate embolism-related AE signals from other dehydration-related signals, a 2-year-old potted Fraxinus excelsior L. tree was subjected to a drought experiment. Embolism formation was acoustically measured with two broadband point-contact AE sensors while simultaneously being visualized by X-ray computed microtomography (µCT). A machine learning method was used to link visually detected embolism formation by µCT with corresponding AE signals. Specifically, applying linear discriminant analysis (LDA) on the six AE waveform parameters amplitude, counts, duration, signal strength, absolute energy and partial power in the range 100-200 kHz resulted in an embolism-related acoustic vulnerability curve (VCAE-E) better resembling the standard µCT VC (VCCT), both in time and in absolute number of embolized vessels. Interestingly, the unfiltered acoustic vulnerability curve (VCAE) also closely resembled VCCT, indicating that VCs constructed from all registered AE signals did not compromise the quantitative interpretation of the species' vulnerability to drought-induced embolism formation. CONCLUSION Although machine learning could detect similar numbers of embolism-related AE as µCT, there still is insufficient model-based evidence to conclusively attribute these signals to embolism events. Future research should therefore focus on similar experiments with more in-depth analysis of acoustic waveforms, as well as explore the possibility of Fast Fourier transformation (FFT) to remove non-embolism-related AE signals.
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Affiliation(s)
- Niels J. F. De Baerdemaeker
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Michiel Stock
- KERMIT, Department of Data Analysis and Mathematical Modelling, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Jan Van den Bulcke
- UGent-Woodlab-Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
- Ghent University Centre for X-Ray Tomography (UGCT), Proeftuinstraat 86, 9000 Ghent, Belgium
| | - Bernard De Baets
- KERMIT, Department of Data Analysis and Mathematical Modelling, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Luc Van Hoorebeke
- Ghent University Centre for X-Ray Tomography (UGCT), Proeftuinstraat 86, 9000 Ghent, Belgium
- Radiation Physics Group, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
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22
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Mrad A, Domec JC, Huang CW, Lens F, Katul G. A network model links wood anatomy to xylem tissue hydraulic behaviour and vulnerability to cavitation. PLANT, CELL & ENVIRONMENT 2018; 41:2718-2730. [PMID: 30071137 DOI: 10.1111/pce.13415] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/13/2018] [Accepted: 07/25/2018] [Indexed: 05/06/2023]
Abstract
Plant xylem response to drought is routinely represented by a vulnerability curve (VC). Despite the significance of VCs, the connection between anatomy and tissue-level hydraulic response to drought remains a subject of inquiry. We present a numerical model of water flow in flowering plant xylem that combines current knowledge on diffuse-porous anatomy and embolism spread to explore this connection. The model produces xylem networks and uses different parameterizations of intervessel connection vulnerability to embolism spread: the Young-Laplace equation and pit membrane stretching. Its purpose is upscaling processes occurring on the microscopic length scales, such as embolism propagation through pit membranes, to obtain tissue-scale hydraulics. The terminal branch VC of Acer glabrum was successfully reproduced relying only on real observations of xylem tissue anatomy. A sensitivity analysis shows that hydraulic performance and VC shape and location along the water tension axis are heavily dependent on anatomy. The main result is that the linkage between pit-scale and vessel-scale anatomical characters, along with xylem network topology, affects VCs significantly. This work underscores the importance of stepping up research related to the three-dimensional network structure of xylem tissues. The proposed model's versatility makes it an important tool to explore similar future questions.
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Affiliation(s)
- Assaad Mrad
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Jean-Christophe Domec
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, 33175, Gradignan Cedex, France
| | - Cheng-Wei Huang
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131-0001
| | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, P.O. Box 9517, 2300 RA Leiden, The Netherlands
| | - Gabriel Katul
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
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23
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Petruzzellis F, Pagliarani C, Savi T, Losso A, Cavalletto S, Tromba G, Dullin C, Bär A, Ganthaler A, Miotto A, Mayr S, Zwieniecki MA, Nardini A, Secchi F. The pitfalls of in vivo imaging techniques: evidence for cellular damage caused by synchrotron X-ray computed micro-tomography. THE NEW PHYTOLOGIST 2018; 220:104-110. [PMID: 30040128 DOI: 10.1111/nph.15368] [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: 06/02/2018] [Accepted: 07/04/2018] [Indexed: 05/26/2023]
Abstract
Synchrotron X-ray computed micro-tomography (microCT) has emerged as a promising noninvasive technique for in vivo monitoring of xylem function, including embolism build-up under drought and hydraulic recovery following re-irrigation. Yet, the possible harmful effects of ionizing radiation on plant tissues have never been quantified. We specifically investigated the eventual damage suffered by stem living cells of three different species exposed to repeated microCT scans. Stem samples exposed to one, two or three scans were used to measure cell membrane and RNA integrity, and compared to controls never exposed to X-rays. Samples exposed to microCT scans suffered serious alterations to cell membranes, as revealed by marked increase in relative electrolyte leakage, and also underwent severe damage to RNA integrity. The negative effects of X-rays were apparent in all species tested, but the magnitude of damage and the minimum number of scans inducing negative effects were species-specific. Our data show that multiple microCT scans lead to disruption of fundamental cellular functions and processes. Hence, microCT investigation of phenomena that depend on physiological activity of living cells may produce erroneous results and lead to incorrect conclusions.
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Affiliation(s)
- Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Chiara Pagliarani
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, 10135, Torino, Italy
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
- Division of Viticulture and Pomology, Department of Crop Sciences, University of Natural Resources and Life Sciences, Konrad Lorenz Straße 24, A-3430, Tulln, Vienna, Austria
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Silvia Cavalletto
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
| | - Giuliana Tromba
- Elettra Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy
| | - Christian Dullin
- Elettra Sincrotrone Trieste, Area Science Park, 34149, Basovizza, Trieste, Italy
- Institute for Diagnostic and Interventional Radiology, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
- Max-Plank-Institute for Experimental Medicine, Hermann-Rein-Straße 3, 37075, Göttingen, Germany
| | - Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Andrea Miotto
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, One Shields Ave, Davis, CA, 95616, USA
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Francesca Secchi
- Dipartimento di Scienze Agrarie, Forestali e Alimentari, Università di Torino, Largo Paolo Braccini 2, 10095, Grugliasco, TO, Italy
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24
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Knipfer T, Barrios-Masias FH, Cuneo IF, Bouda M, Albuquerque CP, Brodersen CR, Kluepfel DA, McElrone AJ. Variations in xylem embolism susceptibility under drought between intact saplings of three walnut species. TREE PHYSIOLOGY 2018; 38:1180-1192. [PMID: 29850910 DOI: 10.1093/treephys/tpy049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
A germplasm collection containing varied Juglans genotypes holds potential to improve drought resistance of plant materials for commercial production. We used X-ray computed microtomography to evaluate stem xylem embolism susceptibility/repair in relation to vessel anatomical features (size, arrangement, connectivity and pit characteristics) in 2-year-old saplings of three Juglans species. In vivo analysis revealed interspecific variations in embolism susceptibility among Juglans microcarpa, J. hindsii (both native to arid habitats) and J. ailantifolia (native to mesic habitats). Stem xylem of J. microcarpa was more resistant to drought-induced embolism as compared with J. hindsii and J. ailantifolia (differences in embolism susceptibility among older and current year xylem were not detected in any species). Variations in most vessel anatomical traits were negligible among the three species; however, we detected substantial interspecific differences in intervessel pit characteristics. As compared with J. hindsii and J. ailantifolia, low embolism susceptibility in J. microcarpa was associated with smaller pit size in larger diameter vessels, a smaller area of the shared vessel wall occupied by pits, lower pit frequency and no changes in pit characteristics as vessel diameters increased. Changes in amount of embolized vessels following 40 days of re-watering were minor in intact saplings of all three species highlighting that an embolism repair mechanism did not contribute to drought recovery. In conclusion, our data indicate that interspecific variations in drought-induced embolism susceptibility are associated with species-specific pit characteristics, and these traits may provide a future target for breeding efforts aimed at selecting walnut germplasm with improved drought resistance.
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Affiliation(s)
- Thorsten Knipfer
- Department of Viticulture & Enology, University of California, Davis, CA, USA
| | | | - Italo F Cuneo
- Department of Viticulture & Enology, University of California, Davis, CA, USA
| | - Martin Bouda
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
| | | | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA
| | - Daniel A Kluepfel
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA, USA
| | - Andrew J McElrone
- Department of Viticulture & Enology, University of California, Davis, CA, USA
- USDA-ARS, Crops Pathology and Genetics Research Unit, Davis, CA, USA
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25
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Choat B, Brodribb TJ, Brodersen CR, Duursma RA, López R, Medlyn BE. Triggers of tree mortality under drought. Nature 2018; 558:531-539. [DOI: 10.1038/s41586-018-0240-x] [Citation(s) in RCA: 647] [Impact Index Per Article: 107.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 05/02/2018] [Indexed: 01/08/2023]
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26
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Morris H, Gillingham MAF, Plavcová L, Gleason SM, Olson ME, Coomes DA, Fichtler E, Klepsch MM, Martínez-Cabrera HI, McGlinn DJ, Wheeler EA, Zheng J, Ziemińska K, Jansen S. Vessel diameter is related to amount and spatial arrangement of axial parenchyma in woody angiosperms. PLANT, CELL & ENVIRONMENT 2018; 41:245-260. [PMID: 29047119 DOI: 10.1111/pce.13091] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/22/2017] [Accepted: 09/28/2017] [Indexed: 05/13/2023]
Abstract
Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.
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Affiliation(s)
- Hugh Morris
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Laboratory for Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Testing and Research, St. Gallen, 9014, Switzerland
| | - Mark A F Gillingham
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm University, Albert-Einstein-Allee 11, D-89069, Ulm, Germany
| | - Lenka Plavcová
- Department of Biology, Faculty of Science, University of Hradec Králové, Rokitanského 62, 500 03, Hradec Králové, Czech Republic
| | - Sean M Gleason
- USDA-ARS Water Management and Systems Research Unit, Fort Collins, CO, 80526, USA
| | - Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de CU, Mexico, DF, 04510, Mexico
| | - David A Coomes
- Forest Ecology and Conservation Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Esther Fichtler
- Department of Crop Sciences, Tropical Plant Production and Agricultural Systems Modelling, Göttingen University, Grisebachstrasse 6, 37077, Göttingen, Germany
| | - Matthias M Klepsch
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | | | - Daniel J McGlinn
- Department of Biology, College of Charleston, Charleston, SC, 29424, USA
| | - Elisabeth A Wheeler
- Department of Forest Biomaterials, NC State University, Raleigh, NC, 27695-8005, USA
- North Carolina Museum of Natural Sciences, 11 West Jones St., Raleigh, NC, 27601, USA
| | - Jingming Zheng
- Zheng JingminG, College of Forestry, Beijing Forestry University, Beijing, 100083, China
| | - Kasia Ziemińska
- Arnold Arboretum of Harvard University, 1300 Centre St, Boston, MA, 02130, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
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27
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Brodersen CR, Knipfer T, McElrone AJ. In vivo visualization of the final stages of xylem vessel refilling in grapevine (Vitis vinifera) stems. THE NEW PHYTOLOGIST 2018; 217:117-126. [PMID: 28940305 DOI: 10.1111/nph.14811] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/22/2017] [Indexed: 05/14/2023]
Abstract
Embolism removal is critical for restoring hydraulic pathways in some plants, as residual gas bubbles should expand when vessels are reconnected to the transpiration stream. Much of our understanding of embolism removal remains theoretical as a consequence of the lack of in vivo images of the process at high magnification. Here, we used in vivo X-ray micro-computed tomography (microCT) to visualize the final stages of xylem refilling in grapevine (Vitis vinifera) paired with scanning electron microscopy. Before refilling, vessel walls were covered with a surface film, but vessel perforation plate openings and intervessel pits were filled with air. Bubbles were removed from intervessel pits first, followed by bubbles within perforation plates, which hold the last volumes of air which eventually dissolve. Perforation plates were dimorphic, with more steeply angled scalariform plates in narrow diameter vessels, compared with the simple perforation plates in older secondary xylem, which may favor rapid refilling and compartmentalization of embolisms that occur in small vessels, while promoting high hydraulic conductivity in large vessels. Our study provides direct visual evidence of the spatial and temporal dynamics of the final stages of embolism removal.
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Affiliation(s)
- Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, CA, 95618, USA
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, CA, 95618, USA
- Crops Pathology and Genetics Research Unit, USDA-ARS, Davis, CA, 95618, USA
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28
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Knipfer T, Cuneo IF, Earles JM, Reyes C, Brodersen CR, McElrone AJ. Storage Compartments for Capillary Water Rarely Refill in an Intact Woody Plant. PLANT PHYSIOLOGY 2017; 175:1649-1660. [PMID: 29042460 PMCID: PMC5717732 DOI: 10.1104/pp.17.01133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/14/2017] [Indexed: 05/02/2023]
Abstract
Water storage is thought to play an integral role in the maintenance of whole-plant water balance. The contribution of both living and dead cells to water storage can be derived from rehydration and water-release curves on excised plant material, but the underlying tissue-specific emptying/refilling dynamics remain unclear. Here, we used x-ray computed microtomography to characterize the refilling of xylem fibers, pith cells, and vessels under both excised and in vivo conditions in Laurus nobilis In excised stems supplied with water, water uptake exhibited a biphasic response curve, and x-ray computed microtomography images showed that high water storage capacitance was associated with fiber and pith refilling as driven by capillary forces: fibers refilled more rapidly than pith cells, while vessel refilling was minimal. In excised stems that were sealed, fiber and pith refilling was associated with vessel emptying, indicating a link between tissue connectivity and water storage. In contrast, refilling of fibers, pith cells, and vessels was negligible in intact saplings over two time scales, 24 h and 3 weeks. However, those compartments did refill slowly when the shoot was covered to prevent transpiration. Collectively, our data (1) provide direct evidence that storage compartments for capillary water refill in excised stems but rarely under in vivo conditions, (2) highlight that estimates of capacitance from excised samples should be interpreted with caution, as certain storage compartments may not be utilized in the intact plant, and (3) question the paradigm that fibers play a substantial role in daily discharge/recharge of stem capacitance in an intact tree.
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Affiliation(s)
- Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, California 95616
| | - Italo F Cuneo
- School of Agronomy, Pontificia Universidad Católica de Valparaíso, Quillota, Chile
| | - 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
| | - Clarissa Reyes
- Department of Viticulture and Enology, University of California, Davis, California 95616
| | - 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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29
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Trifilò P, Casolo V, Raimondo F, Petrussa E, Boscutti F, Lo Gullo MA, Nardini A. Effects of prolonged drought on stem non-structural carbohydrates content and post-drought hydraulic recovery in Laurus nobilis L.: The possible link between carbon starvation and hydraulic failure. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 120:232-241. [PMID: 29073538 DOI: 10.1016/j.plaphy.2017.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/15/2017] [Accepted: 10/09/2017] [Indexed: 05/17/2023]
Abstract
Drought-induced tree decline is a complex event, and recent hypotheses suggest that hydraulic failure and carbon starvation are co-responsible for this process. We tested the possible role of non-structural carbohydrates (NSC) content on post-drought hydraulic recovery, to verify the hypothesis that embolism reversal represents a mechanistic link between carbon starvation and stem hydraulics. Measurements were performed in laurel plants subjected to similar water stress levels either over short or long term, to induce comparable embolism levels. Plants subjected to mild and prolonged water shortage (S) showed reduced growth, adjustment of turgor loss point driven by changes in both osmotic potential at full turgor and bulk modulus of elasticity, a lower content of soluble NSC and a higher content of starch with respect to control (C) plants. Moreover, S plants showed a lower ability to recover from xylem embolism than C plants, even after irrigation. Our data suggest that plant carbon status might indirectly influence plant performance during and after drought via effects on xylem hydraulic functioning, supporting the view of a possible mechanistic link between the two processes.
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Affiliation(s)
- Patrizia Trifilò
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, 98166 Messina, Italy.
| | - Valentino Casolo
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, via delle Scienze 91, 33100 Udine, Italy
| | - Fabio Raimondo
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, 98166 Messina, Italy
| | - Elisa Petrussa
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, via delle Scienze 91, 33100 Udine, Italy
| | - Francesco Boscutti
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, via delle Scienze 91, 33100 Udine, Italy
| | - Maria Assunta Lo Gullo
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, salita F. Stagno D'Alcontres 31, 98166 Messina, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
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30
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Wason JW, Huggett BA, Brodersen CR. MicroCT imaging as a tool to study vessel endings in situ. AMERICAN JOURNAL OF BOTANY 2017; 104:1424-1430. [PMID: 29885240 DOI: 10.3732/ajb.1700199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/16/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Despite the strong influence of the frequency and distribution of vessel endings on both hydraulic safety and efficiency, detailed anatomical descriptions or measurements of these structures are generally lacking. METHODS Here we used high-resolution x-ray microcomputed tomography (microCT) to identify and describe xylem vessel endings within Acer rubrum root segments (1.0-2.1 mm diameter, ∼2 mm long). We then compared vessel-lumen diameter, pit density, vessel element length, and perforation plate angle between non-ending vessels (those that traverse an entire segment) and those that end within a segment using three-dimensional image analysis. KEY RESULTS We found 214 vessel endings, 37 complete vessels, and 385 non-ending vessels within four A. rubrum root segments. Vessels that ended within the segments tended to have more acute perforation plate angles and had a smaller diameter than those that did not end within the segments. Most vessel diameters tapered within the last few vessel elements, but the perforation plate angle apparently changed over longer distances. Intervessel pit density and vessel element length did not differ between ending and non-ending vessels. CONCLUSIONS Vessel endings were surprisingly frequent in A. rubrum roots despite the common perception that root vessels are longer than vessels in other tissues. MicroCT proved to be a useful tool for studying the three-dimensional arrangement of vessel endings within xylem networks, and these data will be helpful in developing a better understanding of vessel ending microstructure and function.
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Affiliation(s)
- Jay W Wason
- School of Forestry and Environmental Studies, Yale University, 370 Prospect St., New Haven, Connecticut, 06511 USA
| | - Brett A Huggett
- Department of Biology, Bates College, 44 Campus Avenue, Lewiston, Maine 04240 USA
| | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, 370 Prospect St., New Haven, Connecticut, 06511 USA
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31
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Scoffoni C, Sack L, Ort D. The causes and consequences of leaf hydraulic decline with dehydration. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4479-4496. [PMID: 28981777 DOI: 10.1093/jxb/erx252] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Resolving the drivers of hydraulic decline during drought is crucial for understanding drought tolerance in crops and natural ecosystems. In the past 15 years, studies of the decline of leaf hydraulic conductance (Kleaf) have supported a major role in controlling plant drought responses. We analyzed the variation in Kleaf decline with dehydration in a global database of 310 species, providing novel insights into its underlying mechanisms, its co-ordination with stem hydraulics, its influence on gas exchange and drought tolerance, and its linkage with species ecological distributions. Kleaf vulnerability varied strongly within and across lineages, growth forms, and biomes. A critical literature review indicates that changes in hydraulic conductance outside the xylem with dehydration drive the overall decline of Kleaf. We demonstrate a significant leaf hydraulic safety-efficiency trade-off across angiosperm species and discuss the importance of the large variation around this trend. Leaves tend to be more vulnerable than stems, with their vulnerabilities co-ordinated across species, and importantly linked with adaptation across biomes. We hypothesize a novel framework to explain diversity across species in the co-ordination of Kleaf and gas exchange during dehydration. These findings reflect considerable recent progress, yet new tools for measurement, visualization, and modeling will result in ongoing discoveries important across fields in plant biology.
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Affiliation(s)
- Christine Scoffoni
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095, USA
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Pratt RB, Jacobsen AL. Conflicting demands on angiosperm xylem: Tradeoffs among storage, transport and biomechanics. PLANT, CELL & ENVIRONMENT 2017; 40:897-913. [PMID: 27861981 DOI: 10.1111/pce.12862] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 10/31/2016] [Indexed: 05/26/2023]
Abstract
The secondary xylem of woody plants transports water mechanically supports the plant body and stores resources. These three functions are interdependent giving rise to tradeoffs in function. Understanding the relationships among these functions and their structural basis forms the context in which to interpret xylem evolution. The tradeoff between xylem transport efficiency and safety from cavitation has been carefully examined with less focus on other functions, particularly storage. Here, we synthesize data on all three xylem functions in angiosperm branch xylem in the context of tradeoffs. Species that have low safety and efficiency, examined from a resource economics perspective, are predicted to be adapted for slow resource acquisition and turnover as characterizes some environments. Tradeoffs with water storage primarily arise because of differences in fibre traits, while tradeoffs in carbohydrate storage are driven by parenchyma content of tissue. We find support for a tradeoff between safety from cavitation and storage of both water and starch in branch xylem tissue and between water storage capacity and mechanical strength. Living fibres may facilitate carbohydrate storage without compromising mechanical strength. The division of labour between different xylem cell types allows for considerable functional and structural diversity at multiple scales.
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Affiliation(s)
- R Brandon Pratt
- California State University, Bakersfield, Department of Biology, Bakersfield, CA, 93311, USA
| | - Anna L Jacobsen
- California State University, Bakersfield, Department of Biology, Bakersfield, CA, 93311, USA
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33
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Nolf M, Lopez R, Peters JMR, Flavel RJ, Koloadin LS, Young IM, Choat B. Visualization of xylem embolism by X-ray microtomography: a direct test against hydraulic measurements. THE NEW PHYTOLOGIST 2017; 214:890-898. [PMID: 28195328 DOI: 10.1111/nph.14462] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/22/2016] [Indexed: 05/26/2023]
Abstract
X-ray microtomography (microCT) is becoming a valuable noninvasive tool for advancing our understanding of plant-water relations. Laboratory-based microCT systems are becoming more affordable and provide better access than synchrotron facilities. However, some systems come at the cost of comparably lower signal quality and spatial resolution than synchrotron facilities. In this study, we evaluated laboratory-based X-ray microCT imaging as a tool to nondestructively analyse hydraulic vulnerability to drought-induced embolism in a woody plant species. We analysed the vulnerability to drought-induced embolism of benchtop-dehydrated Eucalyptus camaldulensis plants using microCT and hydraulic flow measurements on the same sample material, allowing us to directly compare the two methods. Additionally, we developed a quantitative procedure to improve microCT image analysis at limited resolution and accurately measure vessel lumens. Hydraulic measurements matched closely with microCT imaging of the current-year growth ring, with similar hydraulic conductivity and loss of conductivity due to xylem embolism. Optimized thresholding of vessel lumens during image analysis, based on a physiologically meaningful parameter (theoretical conductivity), allowed us to overcome common potential constraints of some lab-based systems. Our results indicate that estimates of vulnerability to embolism provided by microCT visualization agree well with those obtained from hydraulic measurements on the same sample material.
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Affiliation(s)
- Markus Nolf
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Rosana Lopez
- 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
| | - Richard J Flavel
- School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - Leah S Koloadin
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
| | - Iain M Young
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, NSW, 2006, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia
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Skelton RP, Brodribb TJ, Choat B. Casting light on xylem vulnerability in an herbaceous species reveals a lack of segmentation. THE NEW PHYTOLOGIST 2017; 214:561-569. [PMID: 28124474 DOI: 10.1111/nph.14450] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/22/2016] [Indexed: 05/13/2023]
Abstract
Finding thresholds at which loss of plant functionality occurs during drought is critical for predicting future crop productivity and survival. Xylem resistance to embolism has been suggested as a key trait associated with water-stress tolerance. Although a substantial literature exists describing the vulnerability of woody stems to embolism, leaves and roots of herbaceous species remain under-represented. Also, little is known about vulnerability to embolism at a whole-plant scale or propagation of embolism within plants. New techniques to view the process of embolism formation provide opportunities to resolve long-standing questions. Here, we used multiple visual techniques, including X-ray micro-computed tomography and the optical vulnerability method, to investigate the spread of embolism within intact stems, leaves and roots of Solanum lycopersicum (common tomato). We found that roots, stems and leaves of tomato plants all exhibited similar vulnerability to embolism, suggesting that embolism rapidly propagates among tissues. Although we found scarce evidence for differentiation of xylem vulnerability among tissues at the scale of the whole plant, within a leaf the midrib embolized at higher water potentials than lower order veins. Substantial overlap between the onset of cavitation and incipient leaf damage suggests that cavitation represents a substantial damage to plants, but the point of lethal cavitation in this herbaceous species remains uncertain.
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Affiliation(s)
- Robert P Skelton
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia
| | - Timothy 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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Scoffoni C, Albuquerque C, Brodersen CR, Townes SV, John GP, Cochard H, Buckley TN, McElrone AJ, Sack L. Leaf vein xylem conduit diameter influences susceptibility to embolism and hydraulic decline. THE NEW PHYTOLOGIST 2017; 213:1076-1092. [PMID: 27861926 DOI: 10.1111/nph.14256] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/10/2016] [Indexed: 05/24/2023]
Abstract
Ecosystems worldwide are facing increasingly severe and prolonged droughts during which hydraulic failure from drought-induced embolism can lead to organ or whole plant death. Understanding the determinants of xylem failure across species is especially critical in leaves, the engines of plant growth. If the vulnerability segmentation hypothesis holds within leaves, higher order veins that are most terminal in the plant hydraulic system should be more susceptible to embolism to protect the rest of the water transport system. Increased vulnerability in the higher order veins would also be consistent with these experiencing the greatest tensions in the plant xylem network. To test this hypothesis, we combined X-ray micro-computed tomography imaging, hydraulic experiments, cross-sectional anatomy and 3D physiological modelling to investigate how embolisms spread throughout petioles and vein orders during leaf dehydration in relation to conduit dimensions. Decline of leaf xylem hydraulic conductance (Kx ) during dehydration was driven by embolism initiating in petioles and midribs across all species, and Kx vulnerability was strongly correlated with petiole and midrib conduit dimensions. Our simulations showed no significant impact of conduit collapse on Kx decline. We found xylem conduit dimensions play a major role in determining the susceptibility of the leaf water transport system during strong leaf dehydration.
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Affiliation(s)
- Christine Scoffoni
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
- Department of Biology, Utah State University, Logan, UT, 84322, USA
| | - Caetano Albuquerque
- Department of Viticulture and Enology, University of California, Davis, CA, 95616, USA
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, 195 Prospect Street, New Haven, CT, 06511, USA
| | - Shatara V Townes
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Grace P John
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Hervé Cochard
- PIAF, INRA, Univ. Clermont-Auvergne, Clermont-Ferrand, 63100, France
| | - Thomas N Buckley
- Plant Breeding Institute, Faculty of Agriculture and Environment, The University of Sydney, 12656 Newell Hwy, Narrabri, NSW, 2390, Australia
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, CA, 95616, USA
- USDA-Agricultural Research Service, Davis, CA, 95616, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
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Yang Q, Beers MH, Mehta V, Gao T, Parkinson D. Effect of Thermal Annealing on the Electrical Conductivity of Copper-Tin Polymer Composites. ACS APPLIED MATERIALS & INTERFACES 2017; 9:958-964. [PMID: 27933764 DOI: 10.1021/acsami.6b13956] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Polyvinylidene fluoride (PVDF) copolymer conductive composites containing 40 vol % copper (Cu) and tin (Sn) fillers are prepared by injection molding. Postmolding thermal annealing is found to increase the electrical conductivity of the composites by an order of magnitude. The volume ratio between Cu and Sn is found to have a significant effect on filler distribution but a weaker effect on electrical conductivity compared to the annealing conditions. Synchrotron X-ray tomography is used to visualize and quantitatively analyze the morphology and distribution of the filler particles, indicating that higher conductivity can be attributed to better dispersion of the low-melting-point Sn filler, which provides better interparticle contact in the Cu network.
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Affiliation(s)
- Qing Yang
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Megan Hoarfrost Beers
- Tyco Electronics Corporation, TE Connectivity Ltd. , Menlo Park, California 94025, United States
| | - Vishrut Mehta
- Tyco Electronics Corporation, TE Connectivity Ltd. , Menlo Park, California 94025, United States
| | - Ting Gao
- Tyco Electronics Corporation, TE Connectivity Ltd. , Menlo Park, California 94025, United States
| | - Dilworth Parkinson
- Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
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37
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Nardini A, Savi T, Trifilò P, Lo Gullo MA. Drought Stress and the Recovery from Xylem Embolism in Woody Plants. PROGRESS IN BOTANY VOL. 79 2017. [DOI: 10.1007/124_2017_11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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38
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Torres-Ruiz JM, Cochard H, Mencuccini M, Delzon S, Badel E. Direct observation and modelling of embolism spread between xylem conduits: a case study in Scots pine. PLANT, CELL & ENVIRONMENT 2016; 39:2774-2785. [PMID: 27739597 DOI: 10.1111/pce.12840] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 09/29/2016] [Accepted: 10/04/2016] [Indexed: 06/06/2023]
Abstract
Xylem embolism is one of the main processes involved in drought-related plant mortality. Although its consequences for plant physiology are already well described, embolism formation and spread are poorly evaluated and modelled, especially for tracheid-based species. The aim of this study was to assess the embolism formation and spread in Pinus sylvestris as a case study using X-ray microtomography and hydraulics methods. We also evaluated the potential effects of cavitation fatigue on vulnerability to embolism and the micro-morphology of the bordered pits using scanning electron microscopy (SEM) to test for possible links between xylem anatomy and embolism spread. Finally, a novel model was developed to simulate the spread of embolism in a 2D anisotropic cellular structure. Results showed a large variability in the formation and spread of embolism within a ring despite no differences being observed in intertracheid pit membrane anatomical traits. Simulations from the model showed a highly anisotropic tracheid-to-tracheid embolism spreading pattern, which confirms the major role of tracheid-to-tracheid air seeding to explain how embolism spreads in Scots pine. The results also showed that prior embolism removal from the samples reduced the resistance to embolism of the xylem and could result in overestimates of vulnerability to embolism.
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Affiliation(s)
| | - Hervé Cochard
- PIAF, INRA, Univ. Clermont Auvergne, 63000, Clermont-Ferrand, France
| | - Maurizio Mencuccini
- School of Geosciences, University of Edinburgh, Crew Building, The Kings Buildings, West Main Road, EH93JF, Edinburgh, UK
- ICREA at CREAF, 08193, Cerdanyola del Vallès, Barcelona, Spain
| | | | - Eric Badel
- PIAF, INRA, Univ. Clermont Auvergne, 63000, Clermont-Ferrand, France
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39
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Knipfer T, Cuneo IF, Brodersen CR, McElrone AJ. In Situ Visualization of the Dynamics in Xylem Embolism Formation and Removal in the Absence of Root Pressure: A Study on Excised Grapevine Stems. PLANT PHYSIOLOGY 2016; 171:1024-36. [PMID: 27208267 PMCID: PMC4902599 DOI: 10.1104/pp.16.00136] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/19/2016] [Indexed: 05/17/2023]
Abstract
Gas embolisms formed during drought can disrupt long-distance water transport through plant xylem vessels, but some species have the ability to remove these blockages. Despite evidence suggesting that embolism removal is linked to the presence of vessel-associated parenchyma, the underlying mechanism remains controversial and is thought to involve positive pressure generated by roots. Here, we used in situ x-ray microtomography on excised grapevine stems to determine if embolism removal is possible without root pressure, and if the embolism formation/removal affects vessel functional status after sample excision. Our data show that embolism removal in excised stems was driven by water droplet growth and was qualitatively identical to refilling in intact plants. When stem segments were rehydrated with H2O after excision, vessel refilling occurred rapidly (<1 h). The refilling process was substantially slower when polyethylene glycol was added to the H2O source, thereby providing new support for an osmotically driven refilling mechanism. In contrast, segments not supplied with H2O showed no refilling and increased embolism formation. Dynamic changes in liquid/wall contact angles indicated that the processes of embolism removal (i.e. vessel refilling) by water influx and embolism formation by water efflux were directly linked to the activity of vessel-associated living tissue. Overall, our results emphasize that root pressure is not required as a driving force for vessel refilling, and care should be taken when performing hydraulics measurements on excised plant organs containing living vessel-associated tissue, because the vessel behavior may not be static.
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Affiliation(s)
- Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, California 95616 (T.K., I.F.C., A.J.M.); School of Agronomy, Pontificia Universidad Católica de Valparaíso, Quillota, Chile (I.F.C.); School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.R.B.); and United States Department of Agriculture-Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, California 95618 (A.J.M.)
| | - Italo F Cuneo
- Department of Viticulture and Enology, University of California, Davis, California 95616 (T.K., I.F.C., A.J.M.); School of Agronomy, Pontificia Universidad Católica de Valparaíso, Quillota, Chile (I.F.C.); School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.R.B.); and United States Department of Agriculture-Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, California 95618 (A.J.M.)
| | - Craig R Brodersen
- Department of Viticulture and Enology, University of California, Davis, California 95616 (T.K., I.F.C., A.J.M.); School of Agronomy, Pontificia Universidad Católica de Valparaíso, Quillota, Chile (I.F.C.); School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.R.B.); and United States Department of Agriculture-Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, California 95618 (A.J.M.)
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, California 95616 (T.K., I.F.C., A.J.M.); School of Agronomy, Pontificia Universidad Católica de Valparaíso, Quillota, Chile (I.F.C.); School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.R.B.); and United States Department of Agriculture-Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, California 95618 (A.J.M.)
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