1
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Gerolamo CS, Pereira L, Costa FRC, Jansen S, Angyalossy V, Nogueira A. Lianas in tropical dry seasonal forests have a high hydraulic efficiency but not always a higher embolism resistance than lianas in rainforests. ANNALS OF BOTANY 2024; 134:337-350. [PMID: 38721801 PMCID: PMC11232521 DOI: 10.1093/aob/mcae077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 05/07/2024] [Indexed: 07/10/2024]
Abstract
BACKGROUND AND AIMS Lianas have higher relative abundance and biomass in drier seasonal forests than in rainforests, but whether this difference is associated with their hydraulic strategies is unclear. Here, we investigate whether lianas of seasonally dry forests are safer and more efficient in water transport than rainforest lianas, explaining patterns of liana abundance. METHODS We measured hydraulic traits on five pairs of congeneric lianas of the tribe Bignonieae in two contrasting forest sites: the wet 'Dense Ombrophilous Forest' in Central Amazonia (~2 dry months) and the drier 'Semideciduous Seasonal Forest' in the inland Atlantic Forest (~6 dry months). We also gathered a broader database, including 197 trees and 58 liana species from different tropical forests, to compare hydraulic safety between habits and forest types. KEY RESULTS Bignonieae lianas from both forests had high and similar hydraulic efficiency but exhibited variability in resistance to embolism across forest types when phylogenetic relationships were taken into account. Three genera had higher hydraulic safety in the seasonal forest than in the rainforest, but species across both forests had similar positive hydraulic safety margins despite lower predawn water potential values of seasonal forest lianas. We did not find the safety-efficiency trade-off. Merging our results with previously published data revealed a high variability of resistance to embolism in both trees and lianas, independent of forest types. CONCLUSIONS The high hydraulic efficiency of lianas detected here probably favours their rapid growth across tropical forests, but differences in hydraulic safety highlight that some species are highly vulnerable and may rely on other mechanisms to cope with drought. Future research on the lethal dehydration threshold and the connection between hydraulic resistance strategies and liana abundance could offer further insights into tropical forest dynamics under climatic threats.
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Affiliation(s)
- Caian S Gerolamo
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil
| | - Luciano Pereira
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm D-89081, Germany
| | - Flavia R C Costa
- Instituto Nacional de Pesquisas da Amazônia - INPA, Manaus, AM, 69011-970, Brazil
| | - Steven Jansen
- Institute of Botany, Ulm University, Albert-Einstein-Allee 11, Ulm D-89081, Germany
| | - Veronica Angyalossy
- Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, 05508-090, Brazil
| | - Anselmo Nogueira
- Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC, São Bernardo do Campo, SP, 09606-070, Brazil
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2
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Prats KA, Fanton AC, Brodersen CR, Furze ME. Starch depletion in the xylem and phloem ray parenchyma of grapevine stems under drought. AOB PLANTS 2023; 15:plad062. [PMID: 37899975 PMCID: PMC10601394 DOI: 10.1093/aobpla/plad062] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/29/2023] [Indexed: 10/31/2023]
Abstract
While nonstructural carbohydrate (NSC) storage can support long-lived woody plants during abiotic stress, the timing and extent of their use are less understood, as are the thresholds for cell mortality as NSCs and water supplies are consumed. Here, we combine physiological and imaging tools to study the response of Vitis riparia to a 6-week experimental drought. We focused on the spatial and temporal dynamics of starch consumption and cell viability in the xylem and phloem of the stem. Starch dynamics were further corroborated with enzymatic starch digestion and X-ray microcomputed tomography imaging. Starch depletion in the stems of droughted plants was detected after 2 weeks and continued over time. We observed distinct differences in starch content and cell viability in the xylem and phloem. By the end of the drought, nearly all the starch was consumed in the phloem ray parenchyma (98 % decrease), and there were almost no metabolically active cells in the phloem. In contrast, less starch was consumed in the xylem ray parenchyma (30 % decrease), and metabolically active cells remained in the ray and vessel-associated parenchyma in the xylem. Our data suggest that the higher proportion of living cells in the phloem and cambium, combined with smaller potential NSC storage area, rapidly depleted starch, which led to cell death. In contrast, the larger cross-sectional area of the xylem ray parenchyma with higher NSC storage and lower metabolically active cell populations depleted starch at a slower pace. Why NSC source-sink relationships between xylem and phloem do not allow for a more uniform depletion of starch in ray parenchyma over time is unclear. Our data help to pinpoint the proximate and ultimate causes of plant death during prolonged drought exposure and highlight the need to consider the influence of within-organ starch dynamics and cell mortality on abiotic stress response.
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Affiliation(s)
- Kyra A Prats
- Department of Botany and Plant Pathology, Purdue University, 915 Mitch Daniels Blvd, West Lafayette, IN 47907, USA
- Center for Plant Biology, Purdue University, 915 Mitch Daniels Blvd, West Lafayette, IN 47907, USA
| | - Ana C Fanton
- Ecophysiologie et Génomique Fonctionnelle de la Vigne, INRAE, 210 Chemin de Leysotte, Villenave-d’Ornon 33140, France
| | - Craig R Brodersen
- School of the Environment, Yale University, 195 Prospect St, New Haven, CT 06511, USA
| | - Morgan E Furze
- Department of Botany and Plant Pathology, Purdue University, 915 Mitch Daniels Blvd, West Lafayette, IN 47907, USA
- Center for Plant Biology, Purdue University, 915 Mitch Daniels Blvd, West Lafayette, IN 47907, USA
- Department of Forestry and Natural Resources, Purdue University, 715 Mitch Daniels Blvd, West Lafayette, IN 47907, USA
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3
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Vuerich M, Petrussa E, Boscutti F, Braidot E, Filippi A, Petruzzellis F, Tomasella M, Tromba G, Pizzuto M, Nardini A, Secchi F, Casolo V. Contrasting Responses of Two Grapevine Cultivars to Drought: The Role of Non-structural Carbohydrates in Xylem Hydraulic Recovery. PLANT & CELL PHYSIOLOGY 2023; 64:920-932. [PMID: 37384580 DOI: 10.1093/pcp/pcad066] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/18/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Xylem embolism is one of the possible outcomes of decreasing xylem pressure when plants face drought. Recent studies have proposed a role for non-structural carbohydrates (NSCs) in osmotic pressure generation, required for refilling embolized conduits. Potted cuttings of grapevine Grenache and Barbera, selected for their adaptation to different climatic conditions, were subjected to a drought stress followed by re-irrigation. Stem embolism rate and its recovery were monitored in vivo by X-ray micro-computed tomography (micro-CT). The same plants were further analyzed for xylem conduit dimension and NSC content. Both cultivars significantly decreased Ψpd in response to drought and recovered from xylem embolism after re-irrigation. However, although the mean vessel diameter was similar between the cultivars, Barbera was more prone to embolism. Surprisingly, vessel diameter was apparently reduced during recovery in this cultivar. Hydraulic recovery was linked to sugar content in both cultivars, showing a positive relationship between soluble NSCs and the degree of xylem embolism. However, when starch and sucrose concentrations were considered separately, the relationships showed cultivar-specific and contrasting trends. We showed that the two cultivars adopted different NSC-use strategies in response to drought, suggesting two possible scenarios driving conduit refilling. In Grenache, sucrose accumulation seems to be directly linked to embolism formation and possibly sustains refilling. In Barbera, maltose/maltodextrins could be involved in a conduit recovery strategy via the formation of cell-wall hydrogels, likely responsible for the reduction of conduit lumen detected by micro-CT.
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Affiliation(s)
- Marco Vuerich
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Via delle Scienze 91, Udine 33100, Italy
| | - Elisa Petrussa
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Via delle Scienze 91, Udine 33100, Italy
| | - Francesco Boscutti
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Via delle Scienze 91, Udine 33100, Italy
| | - Enrico Braidot
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Via delle Scienze 91, Udine 33100, Italy
| | - Antonio Filippi
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Via delle Scienze 91, Udine 33100, Italy
- Dipartimento di Area Medica, Università di Udine, Piazzale Kolbe 4, Udine 33100, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Martina Tomasella
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, Basovizza, Trieste 34149, Italy
| | - Mauro Pizzuto
- Vivai Cooperativi Rauscedo, Via Udine, 39, Rauscedo (PN) 33095, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, Trieste 34127, Italy
| | - Francesca Secchi
- Dipartimento di Scienze Agrarie, Forestali, Alimentari (DISAFA), Università di Torino, Largo Paolo Braccini 2, Grugliasco (TO) 10095, Italy
| | - Valentino Casolo
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Via delle Scienze 91, Udine 33100, Italy
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Robinson JA, Rennie M, Clearwater M, Holland DJ, van den Berg AK, Watson M. Examination of embolisms in maple and birch saplings utilising microCT. Micron 2023; 168:103438. [PMID: 36889230 DOI: 10.1016/j.micron.2023.103438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
We demonstrate the application of synchrotron x-ray microtomography (microCT) to non-invasively examine the internal structure of a maple and birch sapling. We show that, through the use of standard image analysis techniques, embolised vessels can be extracted from reconstructed slices of the stem. By combining these thresholded images with connectivity analysis, we map out the embolisms within the sapling in three dimensions and evaluate the size distribution, showing that large embolisms over 0.005 mm3 in volume compose the majority of the saplings' total embolised volume. Finally we evaluate the radial distribution of embolisms, showing that in maple fewer embolisms are present towards the cambium, while birch has a more uniform distribution.
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Affiliation(s)
- James A Robinson
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand.
| | - Matt Rennie
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
| | - Mike Clearwater
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Daniel J Holland
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
| | - Abby K van den Berg
- Proctor Maple Research Center, University of Vermont, Underhill, VT, United States
| | - Matthew Watson
- Biomolecular Interaction Center & Chemical and Process Engineering Department, University of Canterbury, Christchurch, New Zealand
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5
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Guo L, Liu Y, Liu L, Yin P, Liu C, Li J. Study of the mechanism of embolism removal in xylem vessels by using microfluidic devices. LAB ON A CHIP 2023; 23:737-747. [PMID: 36594973 DOI: 10.1039/d2lc00945e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Determining the mechanism that effects embolism repair in the xylem vessels of plants is of great significance in predicting plant distribution and the screening of drought-resistant plants. However, the mechanism of perforation plates of xylem vessels in the acceleration of embolism repair is still not clear by using conventional methods of anatomy and visualization technology. Microfluidic devices have shown their ability to simulate physiological environments and conduct quantitative experiments. This work proposes a biomimetic microfluidic device to study the mechanism of perforation plates of xylem vessels in the acceleration of embolism repair. The results proffered that the perforation plates increase the rate of embolism removal by increasing the pressure differential through the vessel, and the rate of embolism removal is related to the structural parameters of the perforation plate. A combination of the perforation size, the vessel diameter and the perforation plate angle can be optimised to generate higher pressure differentials, which can accelerate the process of embolism repair. This work provides a new method for studying the mechanism of microstructures of natural plants. Furthermore, the mechanism that perforation plates accelerate embolism repair was applied to an electrochemical flow sensor for online determination of heavy metal ions. Test results of this application indicate that the mechanism can be applied in the engineering field to solve the problems of reduced sensitivity of devices, inaccuracy of analysis results and poor reaction performance caused by bubbles that are generated or introduced easily in microdevices, which paves the way for applying the theory to engineering.
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Affiliation(s)
- Lihua Guo
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Yuanchang Liu
- Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK
| | - Li Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Penghe Yin
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Chong Liu
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
| | - Jingmin Li
- Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian, China.
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6
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Zhang YJ, Hochberg U, Rockwell FE, Ponomarenko A, Chen YJ, Manandhar A, Graham AC, Holbrook NM. Xylem conduit deformation across vascular plants: an evolutionary spandrel or protective valve? THE NEW PHYTOLOGIST 2023; 237:1242-1255. [PMID: 36307967 DOI: 10.1111/nph.18584] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
The hydraulic system of vascular plants and its integrity is essential for plant survival. To transport water under tension, the walls of xylem conduits must approximate rigid pipes. Against this expectation, conduit deformation has been reported in the leaves of a few species and hypothesized to function as a 'circuit breaker' against embolism. Experimental evidence is lacking, and its generality is unknown. We demonstrated the role of conduit deformation in protecting the upstream xylem from embolism through experiments on three species and surveyed a diverse selection of vascular plants for conduit deformation in leaves. Conduit deformation in minor veins occurred before embolism during slow dehydration. When leaves were exposed to transient increases in transpiration, conduit deformation was accompanied by large water potential differences from leaf to stem and minimal embolism in the upstream xylem. In the three species tested, collapsible vein endings provided clear protection of upstream xylem from embolism during transient increases in transpiration. We found conduit deformation in diverse vascular plants, including 11 eudicots, ginkgo, a cycad, a fern, a bamboo, and a grass species, but not in two bamboo and a palm species, demonstrating that the potential for 'circuit breaker' functionality may be widespread across vascular plants.
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Affiliation(s)
- Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Climate Change Institute, University of Maine, Orono, ME, 04469, USA
| | - Uri Hochberg
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- ARO Volcani Center, Institute of Soil, Water and Environmental Sciences, Rishon Lezion, 7505101, Israel
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Alexandre Ponomarenko
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Ya-Jun Chen
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, 666303, China
| | - Anju Manandhar
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Adam C Graham
- Center for Nanoscale Systems, Harvard University, Cambridge, MA, 02138, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
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7
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Soheili F, Abdul-Hamid H, Almasi I, Heydari M, Tongo A, Woodward S, Naji HR. How Tree Decline Varies the Anatomical Features in Quercus brantii. PLANTS (BASEL, SWITZERLAND) 2023; 12:377. [PMID: 36679089 PMCID: PMC9866467 DOI: 10.3390/plants12020377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
Drought has serious effects on forests, especially semi-arid and arid forests, around the world. Zagros Forest in Iran has been severely affected by drought, which has led to the decline of the most common tree species, Persian oak (Quercus brantii). The objective of this study was to determine the effects of drought on the anatomical structure of Persian oak. Three healthy and three declined trees were sampled from each of two forest sites in Ilam Forest. Discs were cut at breast height, and three sapwood blocks were taken near the bark of each tree for sectioning. The anatomical characteristics measured included fiber length (FL), fiber wall thickness (FWT), number of axial parenchymal cells (NPC), ray number (RN), ray width (RW), and number of calcium oxalate crystals. Differences between healthy and declined trees were observed in the abundance of NPC and in RN, FL, and FWT, while no differences occurred in the number of oxalate crystals. The decline had uncertain effects on the FL of trees from sites A and B, which showed values of 700.5 and 837.3 μm compared with 592.7 and 919.6 μm in healthy trees. However, the decline resulted in an increase in the FWT of trees from sites A and B (9.33 and 11.53 μm) compared with healthy trees (5.23 and 9.56 μm). NPC, RN, and RW also increased in declined individuals from sites A and B (28.40 and 28.40 mm−1; 41.06 and 48.60 mm−1; 18.60 and 23.20 μm, respectively) compared with healthy trees (20.50 and 19.63 mm−2; 31.60 and 28.30 mm−2; 17.93 and 15.30 μm, respectively). Thus, drought caused measurable changes in the anatomical characteristics of declined trees compared with healthy trees.
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Affiliation(s)
- Forough Soheili
- Department of Forest Sciences, Ilam University, Ilam 67187-73654, Iran
| | - Hazandy Abdul-Hamid
- Faculty of Forestry and Environment, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
| | - Isaac Almasi
- Faculty of Science, Department of Statistics, Razi University, Kermanshah 67144-14971, Iran
| | - Mehdi Heydari
- Department of Forest Sciences, Ilam University, Ilam 67187-73654, Iran
| | - Afsaneh Tongo
- Department of Forest Science and Engineering, Sari University of Agricultural Sciences and Natural Resources, Sari 48181-68984, Iran
| | - Stephen Woodward
- School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK
| | - Hamid Reza Naji
- Department of Forest Sciences, Ilam University, Ilam 67187-73654, Iran
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Wang L, Li J, Wang Y, Xue H, Dai Y, Han Y. Interactive effect between tree ageing and trunk-boring pest reduces hydraulics and carbon metabolism in Hippophae rhamnoides. AOB PLANTS 2022; 14:plac051. [PMID: 36545298 PMCID: PMC9762721 DOI: 10.1093/aobpla/plac051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 10/21/2022] [Indexed: 06/17/2023]
Abstract
Sea-buckthorn (Hippophae rhamnoides) is widely distributed across the Eurasian continent. Recently sea-buckthorn has shown premature ageing and decline when confronted with water deficiency and Holcocerus hippophaecolus damage in northwest China and the Loess Plateau region. However, the physiological process of sea-buckthorn senescence in response to drought and pest damage is still unknown. In this study, 4-year-old (4y), 15-year-old normal growth (15yN) and 15-year-old seriously moth-damaged sea-buckthorn plants (15yH) were used as the research objects. The growth of branches and roots, branch water potential and percentage loss of conductivity (PLC), branch vulnerability to embolism (quantified by P50, xylem water potential at 50 % of PLC), branch xylem parenchyma cell viability, photosynthesis and the non-structural carbohydrate (NSC) content in branches and roots in dry and wet seasons were measured. The results showed that the length, basal diameter of 1-year-old branches and the leaf area of 4y trees were significantly larger than that of 15yN and 15yH trees, and the fine root density of 15yH trees was significantly lower than that of 15yN trees in all measured areas. The branch-specific hydraulic conductivity of 15yN and 15yH trees was only 50.2 % and 12.3 % of that of 4y trees, and the P50 of 4y, 15yH and 15yN trees was -3.69 MPa, -2.71 MPa and -1.15 MPa, respectively. The midday water potential and photosynthetic rate were highest in 4y trees, followed by 15yN and then 15yH trees in both the dry season and wet seasons, while branch PLC declined in the opposite direction (15yH trees highest, 4y trees lowest). The degree of PLC repair within a day was highest in 4y trees, followed by 15yN and then 15yH trees, and the viability of xylem cells was consistent with this pattern. The branch xylem starch and NSC content of 4y and 15yN trees were significantly higher than that of 15yH trees in the dry season, and the root starch and NSC content of 4y trees were significantly higher than that of 15yH trees in the two seasons. The above results suggest that the hydraulic properties of the normal elderly and seriously pest-damaged sea-buckthorn were significantly worse than in juvenile plants. Narrower early wood width and vessel density, high embolism vulnerability and weak embolism repair capacity led to the decline in water-conducting ability, and similarly further affected photosynthesis and the root NSC content. The decline in xylem parenchyma cell viability was the main reason for the limited embolism repair in the branches.
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Affiliation(s)
- Lin Wang
- Corresponding author’s e-mail address:
| | - Junpeng Li
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Yang Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Hao Xue
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Yongxin Dai
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
| | - Youzhi Han
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi 030801, P.R. China
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9
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Arend M, Link RM, Zahnd C, Hoch G, Schuldt B, Kahmen A. Lack of hydraulic recovery as a cause of post-drought foliage reduction and canopy decline in European beech. THE NEW PHYTOLOGIST 2022; 234:1195-1205. [PMID: 35238410 PMCID: PMC9310744 DOI: 10.1111/nph.18065] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 02/19/2022] [Indexed: 05/06/2023]
Abstract
European beech (Fagus sylvatica) was among the most affected tree species during the severe 2018 European drought. It not only suffered from instant physiological stress but also showed severe symptoms of defoliation and canopy decline in the following year. To explore the underlying mechanisms, we used the Swiss-Canopy-Crane II site and studied in branches of healthy and symptomatic trees the repair of hydraulic function and concentration of carbohydrates during the 2018 drought and in 2019. We found loss of hydraulic conductance in 2018, which did not recover in 2019 in trees that developed defoliation symptoms in the year after drought. Reduced branch foliation in symptomatic trees was associated with a gradual decline in wood starch concentration throughout summer 2019. Visualization of water transport in healthy and symptomatic branches in the year after the drought confirmed the close relationship between xylem functionality and supported branch leaf area. Our findings showed that embolized xylem does not regain function in the season following a drought and that sustained branch hydraulic dysfunction is counterbalanced by the reduction in supported leaf area. It suggests acclimation of leaf development after drought to mitigate disturbances in canopy hydraulic function.
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Affiliation(s)
- Matthias Arend
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Roman Mathias Link
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Cedric Zahnd
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Günter Hoch
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
| | - Bernhard Schuldt
- Ecophysiology and Vegetation EcologyUniversität Würzburg97082WürzburgGermany
| | - Ansgar Kahmen
- Physiological Plant EcologyUniversity of Basel4056BaselSwitzerland
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10
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Schreel JDM, Brodersen C, De Schryver T, Dierick M, Rubinstein A, Dewettinck K, Boone MN, Van Hoorebeke L, Steppe K. Foliar water uptake does not contribute to embolism repair in beech (Fagus sylvatica L.). ANNALS OF BOTANY 2022; 129:555-566. [PMID: 35141741 PMCID: PMC9007097 DOI: 10.1093/aob/mcac016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/02/2022] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS Foliar water uptake has recently been suggested as a possible mechanism for the restoration of hydraulically dysfunctional xylem vessels. In this paper we used a combination of ecophysiological measurements, X-ray microcomputed tomography and cryo-scanning electron microscopy during a drought treatment to fully evaluate this hypothesis. KEY RESULTS Based on an assessment of these methods in beech (Fagus sylvatica L.) seedlings we were able to (1) confirm an increase in the amount of hydraulically redistributed water absorbed by leaves when the soil water potential decreased, and (2) locate this redistributed water in hydraulically active vessels in the stem. However, (3) no embolism repair was observed irrespective of the organ under investigation (i.e. stem, petiole or leaf) or the intensity of drought. CONCLUSIONS Our data provide evidence for a hydraulic pathway from the leaf surface to the stem xylem following a water potential gradient, but this pathway exists only in functional vessels and does not play a role in embolism repair for beech.
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Affiliation(s)
- Jeroen D M Schreel
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
- Institute of Environment, Department of Biological Sciences, Florida International University, Miami, FL, USA
- For correspondence. E-mail
| | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT, USA
| | - Thomas De Schryver
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Manuel Dierick
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | | | - Koen Dewettinck
- Food Structure & Function Research Group, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
| | - Matthieu N Boone
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Luc Van Hoorebeke
- UGent Centre for X-ray Tomography (UGCT) – Radiation Physics Group, Department of Physics & Astronomy, Ghent University, Proeftuinstraat 86, 9000 Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
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11
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Kawai K, Minagi K, Nakamura T, Saiki ST, Yazaki K, Ishida A. Parenchyma underlies the interspecific variation of xylem hydraulics and carbon storage across 15 woody species on a subtropical island in Japan. TREE PHYSIOLOGY 2022; 42:337-350. [PMID: 34328187 DOI: 10.1093/treephys/tpab100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 07/07/2021] [Indexed: 06/13/2023]
Abstract
Parenchyma is an important component of the secondary xylem. It has multiple functions and its fraction is known to vary substantially across angiosperm species. However, the physiological significance of this variation is not yet fully understood. Here, we examined how different types of parenchyma (ray parenchyma [RP], axial parenchyma [AP] and AP in direct contact with vessels [APV]) are coordinated with three essential xylem functions: water conduction, storage of non-structural carbohydrate (NSC) and mechanical support. Using branch sapwood of 15 co-occurring drought-adapted woody species from the subtropical Bonin Islands, Japan, we quantified 10 xylem anatomical traits and examined their linkages to hydraulic properties, storage of soluble sugars and starch and sapwood density. The fractions of APV and AP in the xylem transverse sections were positively correlated with the percentage loss of conductivity in the native condition, whereas that of RP was negatively correlated with the maximum conductivity across species. Axial and ray parenchyma fractions were positively associated with concentrations of starch and NSC. The fraction of parenchyma was independent of sapwood density, regardless of parenchyma type. We also identified a negative relationship between hydraulic conductivity and NSC storage and sapwood density, mirroring the negative relationship between the fractions of parenchyma and vessels. These results suggest that parenchyma fraction underlies species variation in xylem hydraulic and carbon use strategies, wherein xylem with a high fraction of AP may adopt an embolism repair strategy through an increased starch storage with low cavitation resistance.
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Affiliation(s)
- Kiyosada Kawai
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
- Forestry Division, Japan International Research Center for Agricultural Sciences, Ohwashi 1-1 Tsukuba, Ibaraki 305-8686, Japan
| | - Kanji Minagi
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
| | - Tomomi Nakamura
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
| | - Shin-Taro Saiki
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
| | - Kenichi Yazaki
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki 305-8687, Japan
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, Hitsujigaoka 7, Sapporo, Hokkaido 062-8516, Japan
| | - Atsushi Ishida
- Center for Ecological Research, Kyoto University, Hirano 2 509-3 Otsu, Shiga 520-2113, Japan
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12
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Lintunen A, Salmon Y, Hölttä T, Suhonen H. Inspection of gas bubbles in frozen Betula pendula xylem with micro‐CT: Conduit size, water status and bark permeability affect bubble characteristics. PHYSIOLOGIA PLANTARUM 2022. [PMCID: PMC9540547 DOI: 10.1111/ppl.13749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bubbles of gas trapped in the xylem during freezing are a major cause of damage for trees growing at high altitudes or latitudes, as the bubbles may cause embolism during thawing. Yet the factors controlling bubble formation upon freeze–thaw cycles remain poorly understood. Especially the size of the bubbles formed in the ice is crucial for winter embolism formation. We used high‐resolution X‐ray microtomography combined with freezing experiments to investigate the size and shape of 68,343 gas bubbles in frozen conduits in branches of Betula pendula. We also studied how conduit size, tree water status (−0.2 MPa vs. −0.6 MPa) and bark permeability to gases (decreased by Vaseline‐coating) affect the gas bubbles characteristics. High‐resolution X‐ray images allowed us to detect gas bubbles down to 1.0 μm in diameter and revealed that not only small spherical gas bubbles but also gaseous volumes of various shapes and sizes were found from the frozen xylem indicating that gas bubbles may have started to grow already during the freezing propagation. Most of the gas bubbles were found in fibers, but the rare gas bubbles found in the vessels were larger than those in the fibers. Bubble volume increased with conduit volume in both fibers and vessels, but conduit size alone could not explain gas bubble volume. Low water potential and restriction of gas escape from the branch seem to cause more, larger, and less spherical bubbles and thus increase the risk of embolism formation. These findings open new research avenues for further studies of winter embolism formation.
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Affiliation(s)
- Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/Physics, Faculty of ScienceUniversity of HelsinkiHelsinkiFinland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and ForestryUniversity of HelsinkiHelsinkiFinland
| | - Heikki Suhonen
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
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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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Hamilton CD, Steidl OR, MacIntyre AM, Hendrich CG, Allen C. Ralstonia solanacearum Depends on Catabolism of Myo-Inositol, Sucrose, and Trehalose for Virulence in an Infection Stage-Dependent Manner. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:669-679. [PMID: 33487004 DOI: 10.1094/mpmi-10-20-0298-r] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The soilborne pathogen Ralstonia solanacearum causes a lethal bacterial wilt disease of tomato and many other crops by infecting host roots, then colonizing the water-transporting xylem vessels. Tomato xylem sap is nutritionally limiting but it does contain some carbon sources, including sucrose, trehalose, and myo-inositol. Transcriptomic analyses revealed that R. solanacearum expresses distinct catabolic pathways at low cell density (LCD) and high cell density (HCD). To investigate the links between bacterial catabolism, infection stage, and virulence, we measured in planta fitness of bacterial mutants lacking specific carbon catabolic pathways expressed at either LCD or HCD. We hypothesized that early in disease, during root infection, the bacterium depends on carbon sources catabolized at LCD, while HCD carbon sources are only required later in disease during stem colonization. A R. solanacearum ΔiolG mutant unable to use the LCD-catabolized nutrient myo-inositol was defective in tomato root colonization, but after it reached the stem this strain colonized and caused symptoms as well as wild type. In contrast, R. solanacearum mutants unable to use the HCD-catabolized nutrients sucrose (ΔscrA), trehalose (ΔtreA), or both (ΔscrA/treA), infected roots as well as wild-type R. solanacearum but were defective in colonization and competitive fitness in midstems and had reduced virulence. Further, xylem sap from tomato plants colonized by ΔscrA, ΔtreA, or ΔscrA/treA R. solanacearum mutants contained twice as much sucrose as sap from plants colonized by wild-type R. solanacearum. Together, these findings suggest that quorum sensing specifically adapts R. solanacearum metabolism for success in the different nutritional environments of plant roots and xylem sap.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Corri D Hamilton
- Department of Plant Pathology University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
| | - Olivia R Steidl
- Department of Plant Pathology University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
| | - April M MacIntyre
- Department of Plant Pathology University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
| | - Connor G Hendrich
- Department of Plant Pathology University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
| | - Caitilyn Allen
- Department of Plant Pathology University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, U.S.A
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15
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Matallana-Ramirez LP, Whetten RW, Sanchez GM, Payn KG. Breeding for Climate Change Resilience: A Case Study of Loblolly Pine ( Pinus taeda L.) in North America. FRONTIERS IN PLANT SCIENCE 2021; 12:606908. [PMID: 33995428 PMCID: PMC8119900 DOI: 10.3389/fpls.2021.606908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 04/08/2021] [Indexed: 05/25/2023]
Abstract
Earth's atmosphere is warming and the effects of climate change are becoming evident. A key observation is that both the average levels and the variability of temperature and precipitation are changing. Information and data from new technologies are developing in parallel to provide multidisciplinary opportunities to address and overcome the consequences of these changes in forest ecosystems. Changes in temperature and water availability impose multidimensional environmental constraints that trigger changes from the molecular to the forest stand level. These can represent a threat for the normal development of the tree from early seedling recruitment to adulthood both through direct mortality, and by increasing susceptibility to pathogens, insect attack, and fire damage. This review summarizes the strengths and shortcomings of previous work in the areas of genetic variation related to cold and drought stress in forest species with particular emphasis on loblolly pine (Pinus taeda L.), the most-planted tree species in North America. We describe and discuss the implementation of management and breeding strategies to increase resilience and adaptation, and discuss how new technologies in the areas of engineering and genomics are shaping the future of phenotype-genotype studies. Lessons learned from the study of species important in intensively-managed forest ecosystems may also prove to be of value in helping less-intensively managed forest ecosystems adapt to climate change, thereby increasing the sustainability and resilience of forestlands for the future.
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Affiliation(s)
- Lilian P. Matallana-Ramirez
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, Raleigh, NC, United States
| | - Ross W. Whetten
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, Raleigh, NC, United States
| | - Georgina M. Sanchez
- Center for Geospatial Analytics, North Carolina State University, Raleigh, Raleigh, NC, United States
| | - Kitt G. Payn
- Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, Raleigh, NC, United States
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16
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Schenk HJ, Jansen S, Hölttä T. Positive pressure in xylem and its role in hydraulic function. THE NEW PHYTOLOGIST 2021; 230:27-45. [PMID: 33206999 DOI: 10.1111/nph.17085] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 10/13/2020] [Indexed: 05/29/2023]
Abstract
Although transpiration-driven transport of xylem sap is well known to operate under absolute negative pressure, many terrestrial, vascular plants show positive xylem pressure above atmospheric pressure on a seasonal or daily basis, or during early developmental stages. The actual location and mechanisms behind positive xylem pressure remain largely unknown, both in plants that show seasonal xylem pressure before leaf flushing, and those that show a diurnal periodicity of bleeding and guttation. Available evidence shows that positive xylem pressure can be driven based on purely physical forces, osmotic exudation into xylem conduits, or hydraulic pressure in parenchyma cells associated with conduits. The latter two mechanisms may not be mutually exclusive and can be understood based on a similar modelling scenario. Given the renewed interest in positive xylem pressure, this review aims to provide a constructive way forward by discussing similarities and differences of mechanistic models, evaluating available evidence for hydraulic functions, such as rehydration of tissues, refilling of water stores, and embolism repair under positive pressure, and providing recommendations for future research, including methods that avoid or minimise cutting artefacts.
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, PO Box 6850, Fullerton, CA, 92834, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Teemu Hölttä
- Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, PO Box 27, Helsinki, FI-00014, Finland
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17
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Drobnitch ST, Comas LH, Flynn N, Ibarra Caballero J, Barton RW, Wenz J, Person T, Bushey J, Jahn CE, Gleason SM. Drought-Induced Root Pressure in Sorghum bicolor. FRONTIERS IN PLANT SCIENCE 2021; 12:571072. [PMID: 33613594 PMCID: PMC7886691 DOI: 10.3389/fpls.2021.571072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 01/08/2021] [Indexed: 05/26/2023]
Abstract
Root pressure, also manifested as profusive sap flowing from cut stems, is a phenomenon in some species that has perplexed biologists for much of the last century. It is associated with increased crop production under drought, but its function and regulation remain largely unknown. In this study, we investigated the initiation, mechanisms, and possible adaptive function of root pressure in six genotypes of Sorghum bicolor during a drought experiment in the greenhouse. We observed that root pressure was induced in plants exposed to drought followed by re-watering but possibly inhibited by 100% re-watering in some genotypes. We found that root pressure in drought stressed and re-watered plants was associated with greater ratio of fine: coarse root length and shoot biomass production, indicating a possible role of root allocation in creating root pressure and adaptive benefit of root pressure for shoot biomass production. Using RNA-Seq, we identified gene transcripts that were up- and down-regulated in plants with root pressure expression, focusing on genes for aquaporins, membrane transporters, and ATPases that could regulate inter- and intra-cellular transport of water and ions to generate positive xylem pressure in root tissue.
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Affiliation(s)
- Sarah Tepler Drobnitch
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, United States
| | - Louise H. Comas
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Nora Flynn
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Jorge Ibarra Caballero
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, United States
| | - Ryan W. Barton
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Joshua Wenz
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Taylor Person
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, United States
| | - Julie Bushey
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
| | - Courtney E. Jahn
- Department of Agricultural Biology, Colorado State University, Fort Collins, CO, United States
| | - Sean M. Gleason
- Water Management Research Unit, Agricultural Research Service, USDA, Ft. Collins, CO, United States
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18
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Sorek Y, Greenstein S, Netzer Y, Shtein I, Jansen S, Hochberg U. An increase in xylem embolism resistance of grapevine leaves during the growing season is coordinated with stomatal regulation, turgor loss point and intervessel pit membranes. THE NEW PHYTOLOGIST 2021; 229:1955-1969. [PMID: 33098088 DOI: 10.1111/nph.17025] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/02/2020] [Indexed: 05/27/2023]
Abstract
Although xylem embolism resistance is traditionally considered as static, we hypothesized that in grapevine (Vitis vinifera) leaf xylem becomes more embolism-resistant over the growing season. We evaluated xylem architecture, turgor loss point (ΨTLP ) and water potentials leading to 25% of maximal stomatal conductance (gs25 ) or 50% embolism in the leaf xylem (P50 ) in three irrigation treatments and at three time points during the growing season, while separating the effects of leaf age and time of season. Hydraulic traits acclimated over the growing season in a coordinated manner. Without irrigation, ΨTLP , gs25 , and P50 decreased between late May and late August by 0.95, 0.77 and 0.71 MPa, respectively. A seasonal shift in P50 occurred even in mature leaves, while irrigation had only a mild effect (< 0.2 MPa) on P50 . Vessel size and pit membrane thickness were also seasonally dynamic, providing a plausible explanation for the shift in P50 . Our findings provide clear evidence that grapevines can modify their hydraulic traits along a growing season to allow lower xylem water potential, without compromising gas exchange, leaf turgor or xylem integrity. Seasonal changes should be considered when modeling ecosystem vulnerability to drought or comparing datasets acquired at different phenological stages.
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Affiliation(s)
- Yonatan Sorek
- Institute of Soil, Water and Environmental Science, Volcani Center, Agricultural Research Organization, PO Box 6, Bet-Dagan, 50250, Israel
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Smadar Greenstein
- Institute of Soil, Water and Environmental Science, Volcani Center, Agricultural Research Organization, PO Box 6, Bet-Dagan, 50250, Israel
| | - Yishai Netzer
- Department of Chemical engineering, Ariel University, Ariel, 40700, Israel
- Agriculture and Oenology Department, Eastern R&D Center, Ariel, 40700, Israel
| | - Ilana Shtein
- Agriculture and Oenology Department, Eastern R&D Center, Ariel, 40700, Israel
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, D-89081, Germany
| | - Uri Hochberg
- Institute of Soil, Water and Environmental Science, Volcani Center, Agricultural Research Organization, PO Box 6, Bet-Dagan, 50250, Israel
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19
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Ouadi L, Bruez E, Bastien S, Yacoub A, Coppin C, Guérin-Dubrana L, Fontaine F, Domec JC, Rey P. Sap Flow Disruption in Grapevine Is the Early Signal Predicting the Structural, Functional, and Genetic Responses to Esca Disease. FRONTIERS IN PLANT SCIENCE 2021; 12:695846. [PMID: 34276744 PMCID: PMC8281252 DOI: 10.3389/fpls.2021.695846] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/07/2021] [Indexed: 05/11/2023]
Abstract
Fungal species involved in Esca cause the formation of grapevine wood necroses. It results in the deterioration of vascular network transport capacity and the disturbance of the physiological processes, leading to gradual or sudden grapevine death. Herein, for two consecutive growing seasons, a detailed analysis of the structural (wood necrosis and leaf discoloration) and physiological parameters related to the water use of healthy and esca-symptomatic grapevines was conducted. Measurements were carried out on 17-year-old grapevines that expressed, or not, Esca-leaf symptoms in a vineyard of the Bordeaux region (France). Whole-plant transpiration was recorded continuously from pre-veraison to harvest, using noninvasive sap flow sensors. Whole-plant transpiration was systematically about 40-50% lower in Esca-diseased grapevines compared with controls, and this difference can be observed around 2 weeks before the first Esca-foliar symptoms appeared in the vineyard. Unlike grapevine sap flow disruption, structural (e.g., leaf discolorations), functional (e.g., stomatal conductance, photosynthetic activity, phenolic compounds), and genetic (e.g., expression of leaf-targeted genes) plant responses were only significantly impacted by Esca at the onset and during leaf symptoms development. We conclude that sap flow dynamic, which was related to a high level of a white-rot necrosis, provides a useful tool to predict plant disorders due to Esca-grapevine disease.
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Affiliation(s)
- Loris Ouadi
- INRAE, ISVV, UMR1065 Santé et Agroécologie du Vignoble (SAVE), Villenave d’Ornon, France
| | - Emilie Bruez
- Université de Bordeaux, ISVV, UR Œnologie, Villenave d’Ornon, France
- Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine, Bordeaux Sciences Agro, UMR1065 Santé et Agroécologie du Vignoble (SAVE), ISVV, Gradignan, France
| | - Sylvie Bastien
- Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine, Bordeaux Sciences Agro, UMR1065 Santé et Agroécologie du Vignoble (SAVE), ISVV, Gradignan, France
| | - Amira Yacoub
- INRAE, ISVV, UMR1065 Santé et Agroécologie du Vignoble (SAVE), Villenave d’Ornon, France
| | - Cindy Coppin
- Université de Reims Champagne-Ardenne, Résistance Induite et Bioprotection des Plantes (RIBP), EA 4707 – USC INRAE 1488, Reims, France
| | - Lucia Guérin-Dubrana
- INRAE, ISVV, UMR1065 Santé et Agroécologie du Vignoble (SAVE), Villenave d’Ornon, France
- Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine, Bordeaux Sciences Agro, UMR1065 Santé et Agroécologie du Vignoble (SAVE), ISVV, Gradignan, France
| | - Florence Fontaine
- Université de Reims Champagne-Ardenne, Résistance Induite et Bioprotection des Plantes (RIBP), EA 4707 – USC INRAE 1488, Reims, France
| | - Jean-Christophe Domec
- Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine, Bordeaux Sciences Agro, INRAE UMR1391 Interactions Sol Plante Atmosphère (ISPA), Villenave d’Ornon, France
| | - Patrice Rey
- INRAE, ISVV, UMR1065 Santé et Agroécologie du Vignoble (SAVE), Villenave d’Ornon, France
- Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine, Bordeaux Sciences Agro, UMR1065 Santé et Agroécologie du Vignoble (SAVE), ISVV, Gradignan, France
- *Correspondence: Patrice Rey,
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20
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Secchi F, Pagliarani C, Cavalletto S, Petruzzellis F, Tonel G, Savi T, Tromba G, Obertino MM, Lovisolo C, Nardini A, Zwieniecki MA. Chemical inhibition of xylem cellular activity impedes the removal of drought-induced embolisms in poplar stems - new insights from micro-CT analysis. THE NEW PHYTOLOGIST 2021; 229:820-830. [PMID: 32890423 DOI: 10.1111/nph.16912] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
In drought-stressed plants a coordinated cascade of chemical and transcriptional adjustments occurs at the same time as embolism formation. While these processes do not affect embolism formation during stress, they may prime stems for recovery during rehydration by modifying apoplast pH and increasing sugar concentration in the xylem sap. Here we show that in vivo treatments modifying apoplastic pH (stem infiltration with a pH buffer) or reducing stem metabolic activity (infiltration with sodium vanadate and sodium cyanide; plant exposure to carbon monoxide) can reduce sugar accumulation, thus disrupting or delaying the recovery process. Application of the vanadate treatment (NaVO3, an inhibitor of many ATPases) completely halted recovery from drought-induced embolism for up to 24 h after re-irrigation, while partial recovery was observed in vivo in control plants using X-ray microcomputed tomography. Our results suggest that stem hydraulic recovery in poplar is a biological, energy-dependent process that coincides with accumulation of sugars in the apoplast during stress. Recovery and damage are spatially coordinated, with embolism formation occurring from the inside out and refilling from the outside in. The outside-in pattern highlights the importance of xylem proximity to the sugars within the phloem to the embolism recovery process.
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Affiliation(s)
- Francesca Secchi
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Chiara Pagliarani
- Institute for Sustainable Plant Protection, National Research Council, Strada delle Cacce 73, Torino, 10135, Italy
| | - Silvia Cavalletto
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, University of Trieste, via Giorgieri 10, Trieste, 34127, Italy
| | - Giulia Tonel
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Tadeja Savi
- Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU, Gregor-Mendel-Straße 33, Vienna, 1180, Austria
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, Basovizza, Trieste, 34149, Italy
| | - Maria Margherita Obertino
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Claudio Lovisolo
- Department of Agricultural, Forest and Food Sciences, University of Turin, Largo Paolo Braccini 2, Grugliasco, 10095, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, University of Trieste, via Giorgieri 10, Trieste, 34127, Italy
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA, 95616, USA
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21
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Albuquerque C, Scoffoni C, Brodersen CR, Buckley TN, Sack L, McElrone AJ. Coordinated decline of leaf hydraulic and stomatal conductances under drought is not linked to leaf xylem embolism for different grapevine cultivars. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:7286-7300. [PMID: 33306796 DOI: 10.1093/jxb/eraa392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 10/27/2020] [Indexed: 06/12/2023]
Abstract
Drought decreases water transport capacity of leaves and limits gas exchange, which involves reduced leaf leaf hydraulic conductance (Kleaf) in both the xylem and outside-xylem pathways. Some literature suggests that grapevines are hyper-susceptible to drought-induced xylem embolism. We combined Kleaf and gas exchange measurements, micro-computed tomography of intact leaves, and spatially explicit modeling of the outside-xylem pathways to evaluate the role of vein embolism and Kleaf in the responses of two different grapevine cultivars to drought. Cabernet Sauvignon and Chardonnay exhibited similar vulnerabilities of Kleaf and gs to dehydration, decreasing substantially prior to leaf xylem embolism. Kleaf and gs decreased by 80% for both cultivars by Ψ leaf approximately -0.7 MPa and -1.2 MPa, respectively, while leaf xylem embolism initiated around Ψ leaf = -1.25 MPa in the midribs and little to no embolism was detected in minor veins even under severe dehydration for both cultivars. Modeling results indicated that reduced membrane permeability associated with a Casparian-like band in the leaf vein bundle sheath would explain declines in Kleaf of both cultivars. We conclude that during moderate water stress, changes in the outside-xylem pathways, rather than xylem embolism, are responsible for reduced Kleaf and gs. Understanding this mechanism could help to ensure adequate carbon capture and crop performance under drought.
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Affiliation(s)
- Caetano Albuquerque
- Department of Viticulture and Enology, University of California, Davis, 595 Hilgard Lane, Davis, CA, USA
| | - Christine Scoffoni
- Department of Biological Sciences, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA, USA
| | - Craig R Brodersen
- School of the Environment, Yale University, 195 Prospect Street, New Haven, CT, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, USA
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, 595 Hilgard Lane, Davis, CA, USA
- USDA-Agricultural Research Service, Davis, CA, USA
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22
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Ziemińska K, Rosa E, Gleason SM, Holbrook NM. Wood day capacitance is related to water content, wood density, and anatomy across 30 temperate tree species. PLANT, CELL & ENVIRONMENT 2020; 43:3048-3067. [PMID: 32935340 DOI: 10.1111/pce.13891] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 09/05/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
Water released from wood during transpiration (capacitance) can meaningfully affect daily water use and drought response. To provide context for better understanding of capacitance mechanisms, we investigated links between capacitance and wood anatomy. On twigs of 30 temperate angiosperm tree species, we measured day capacitance (between predawn and midday), water content, wood density, and anatomical traits, that is, vessel dimensions, tissue fractions, and vessel-tissue contact fractions (fraction of vessel circumference in contact with other tissues). Across all species, wood density (WD) and predawn lumen volumetric water content (VWCL-pd ) together were the strongest predictors of day capacitance (r2adj = .44). Vessel-tissue contact fractions explained an additional ~10% of the variation in day capacitance. Regression models were not improved by including tissue lumen fractions. Among diffuse-porous species, VWCL-pd and vessel-ray contact fraction together were the best predictors of day capacitance, whereas among semi/ring-porous species, VWCL-pd , WD and vessel-fibre contact fraction were the best predictors. At predawn, wood was less than fully saturated for all species (lumen relative water content = 0.52 ± 0.17). Our findings imply that day capacitance depends on the amount of stored water, tissue connectivity and the bulk wood properties arising from WD (e.g., elasticity), rather than the fraction of any particular tissue.
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Affiliation(s)
- Kasia Ziemińska
- Arnold Arboretum of Harvard University, Boston, Massachusetts, USA
- Department of Plant Ecology and Evolution, Uppsala University, Uppsala, Sweden
| | - Emily Rosa
- Department of Biology, Sonoma State University, Rohnert Park, California, USA
| | - Sean M Gleason
- United States Department of Agriculture - Agricultural Research Service, Water Management and Systems Research Unit, Fort Collins, Colorado, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
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23
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Gebauer R, Plichta R, Urban J, Volařík D, Hájíčková M. The resistance and resilience of European beech seedlings to drought stress during the period of leaf development. TREE PHYSIOLOGY 2020; 40:1147-1164. [PMID: 32470134 DOI: 10.1093/treephys/tpaa066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/27/2020] [Indexed: 05/26/2023]
Abstract
Spring drought is becoming a frequently occurring stress factor in temperate forests. However, the understanding of tree resistance and resilience to the spring drought remains insufficient. In this study, European beech (Fagus sylvatica L.) seedlings at the early stage of leaf development were moderately and severely drought stressed for 1 month and then subjected to a 2-week recovery period after rewatering. The study aimed to disentangle the complex relationships between leaf gas exchange, vascular anatomy, tree morphology and patterns of biomass allocation. Stomatal conductance decreased by 80 and 85% upon moderate and severe drought stress, respectively, which brought about a decline in net photosynthesis. However, drought did not affect the indices of slow chlorophyll fluorescence, indicating no permanent damage to the light part of the photosynthetic apparatus. Stem hydraulic conductivity decreased by more than 92% at both drought levels. Consequently, the cambial activity of stressed seedlings declined, which led to lower stem biomass, reduced tree ring width and a lower number of vessels in the current tree ring, these latter also with smaller dimensions. In contrast, the petiole structure was not affected, but at the cost of reduced leaf biomass. Root biomass was reduced only by severe drought. After rewatering, the recovery of gas exchange and regrowth of the current tree ring were observed, all delayed by several days and by lower magnitudes in severely stressed seedlings. The reduced stem hydraulic conductivity inhibited the recovery of gas exchange, but xylem function started to recover by regrowth and refilling of embolized vessels. Despite the damage to conductive xylem, no mortality occurred. These results suggest the low resistance but high resilience of European beech to spring drought. Nevertheless, beech resilience could be weakened if the period between drought events is short, as the recovery of severely stressed seedlings took longer than 14 days.
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Affiliation(s)
- Roman Gebauer
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Roman Plichta
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Josef Urban
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
- Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk, Russia
| | - Daniel Volařík
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
| | - Martina Hájíčková
- Department of Forest Botany, Dendrology and Geobiocoenology, Mendel University in Brno, Zemědělská 3, 61300 Brno, Czech Republic
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24
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Chen Z, Zhu S, Zhang Y, Luan J, Li S, Sun P, Wan X, Liu S. Tradeoff between storage capacity and embolism resistance in the xylem of temperate broadleaf tree species. TREE PHYSIOLOGY 2020; 40:1029-1042. [PMID: 32310276 DOI: 10.1093/treephys/tpaa046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
Xylem traits are critical plant functional traits associated with water transport, mechanical support, and carbohydrate and water storage. Studies on the xylem hydraulic efficiency-safety tradeoff are numerous; however, the storage function of xylem parenchyma is rarely considered. The effects of a substantial number of xylem traits on water transport, embolism resistance, mechanical support, storage capacity and nonstructural carbohydrate (NSC) content were investigated in 19 temperate broadleaf species planted in an arid limestone habitat in northern China. There was no xylem hydraulic efficiency-safety tradeoff in the 19 broadleaf species. The total parenchyma fraction was negatively correlated with the fiber fraction. Embolism resistance was positively correlated with indicators of xylem mechanical strength such as vessel wall reinforcement, vessel wall thickness and fiber wall thickness, and was negatively related to the axial parenchyma fraction, especially the paratracheal parenchyma fraction. The paratracheal parenchyma fraction was positively correlated with the ratio of the paratracheal parenchyma fraction to the vessel fraction. In addition, the xylem NSC concentration was positively related to the total parenchyma fraction and axial parenchyma fraction. There was a storage capacity-embolism resistance tradeoff in the xylem of 19 broadleaf species in arid limestone habitats. We speculate that the temperate broadleaf species may show a spectrum of xylem hydraulic strategies, from the embolism resistance strategy related to a more negative P50 (the water potential corresponding to 50% loss of xylem conductivity) to the embolization repair strategy based on more paratracheal parenchyma.
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Affiliation(s)
- Zhicheng Chen
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530004, China
| | - Yongtao Zhang
- Mountain Tai Forest Ecosystem Research Station of National Forestry and Grassland Administration, Forestry College of Shandong Agricultural University, Taian 271018, China
| | - Junwei Luan
- Key Laboratory of Bamboo and Rattan Science and Technology, Institute for Resources and Environment, International Centre for Bamboo and Rattan, National Forestry and Grassland Administration, Beijing 100102, China
| | - Shan Li
- Department of Wood Anatomy and Utilization, Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China
| | - Pengsen Sun
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
| | - Xianchong Wan
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Shirong Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
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25
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Pratt RB, Castro V, Fickle JC, Madsen A, Jacobsen AL. Factors controlling drought resistance in grapevine (Vitis vinifera, chardonnay): application of a new microCT method to assess functional embolism resistance. AMERICAN JOURNAL OF BOTANY 2020; 107:618-627. [PMID: 32232845 DOI: 10.1002/ajb2.1450] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/15/2020] [Indexed: 06/10/2023]
Abstract
PREMISE Quantifying resistance to embolism in woody plants is important for understanding their drought response. Methods to accurately quantify resistance to embolism continue to be debated. METHODS We used a new microCT-based approach that quantifies embolized conduits and also analyzes conductive conduits by using an x-ray-dense, iodine-rich tracer that moves though the vascular system and can easily be observed in microCT images. Many previous microCT studies assumed that all conduits were initially conductive, which may not be the case if there are developing or occluded conduits. We compared microCT results to a standard benchtop dehydration method and a centrifuge method. During dehydration, we measured gas exchange and quantified water potential at mortality. RESULTS Our microCT curves agreed with previously published microCT curves from the same greenhouse-grown cultivar. We found a significant difference in embolism estimates if we assumed that all water-filled conduits were functional rather than only those containing tracer. Embolism estimates from microCT differed from both the benchtop and centrifuge methods. The benchtop and centrifuge methods did not differ from one another. CONCLUSIONS The new microCT method presented here is valuable in sampling species that may contain nonconductive conduits. Disagreement between microCT and two other methods was likely due to differences in the ways they quantify embolism. MicroCT assess the theoretical effect of embolism, whereas benchtop and centrifuge methods directly measure hydraulic conductivity. The theoretical approach does not fully account for the resistances of flow through a complex 3D vascular network.
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Affiliation(s)
- R Brandon Pratt
- Department of Biology, California State University-Bakersfield, Bakersfield, CA, 93311, USA
| | - Viridiana Castro
- Department of Biology, California State University-Bakersfield, Bakersfield, CA, 93311, USA
| | - Jaycie C Fickle
- Department of Biology, California State University-Bakersfield, Bakersfield, CA, 93311, USA
| | - Angela Madsen
- Department of Biology, California State University-Bakersfield, Bakersfield, CA, 93311, USA
| | - Anna L Jacobsen
- Department of Biology, California State University-Bakersfield, Bakersfield, CA, 93311, USA
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26
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MacIntyre AM, Barth JX, Pellitteri Hahn MC, Scarlett CO, Genin S, Allen C. Trehalose Synthesis Contributes to Osmotic Stress Tolerance and Virulence of the Bacterial Wilt Pathogen Ralstonia solanacearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:462-473. [PMID: 31765286 DOI: 10.1094/mpmi-08-19-0218-r] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The xylem-dwelling plant pathogen Ralstonia solanacearum changes the chemical composition of host xylem sap during bacterial wilt disease. The disaccharide trehalose, implicated in stress tolerance across all kingdoms of life, is enriched in sap from R. solanacearum-infected tomato plants. Trehalose in xylem sap could be synthesized by the bacterium, the plant, or both. To investigate the source and role of trehalose metabolism during wilt disease, we evaluated the effects of deleting the three trehalose synthesis pathways in the pathogen: TreYZ, TreS, and OtsAB, as well as its sole trehalase, TreA. A quadruple treY/treS/otsA/treA mutant produced 30-fold less intracellular trehalose than the wild-type strain missing the trehalase enzyme. This trehalose-nonproducing mutant had reduced tolerance to osmotic stress, which the bacterium likely experiences in plant xylem vessels. Following naturalistic soil-soak inoculation of tomato plants, this triple mutant did not cause disease as well as wild-type R. solanacearum. Further, the wild-type strain out-competed the trehalose-nonproducing mutant by over 600-fold when tomato plants were coinoculated with both strains, showing that trehalose biosynthesis helps R. solanacearum overcome environmental stresses during infection. An otsA (trehalose-6-phosphate synthase) single mutant behaved similarly to ΔtreY/treS/otsA in all experimental settings, suggesting that the OtsAB pathway is the dominant trehalose synthesis pathway in R. solanacearum.
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Affiliation(s)
- April M MacIntyre
- Department of Plant Pathology, University of Wisconsin-Madison, U.S.A
| | - John X Barth
- Department of Plant Pathology, University of Wisconsin-Madison, U.S.A
| | | | - Cameron O Scarlett
- Analytical Instrumentation Center, School of Pharmacy, University of Wisconsin-Madison
| | - Stéphane Genin
- LIPM, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan, France
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, U.S.A
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27
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Dai Y, Wang L, Wan X. Frost fatigue and its spring recovery of xylem conduits in ring-porous, diffuse-porous, and coniferous species in situ. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 146:177-186. [PMID: 31756604 DOI: 10.1016/j.plaphy.2019.11.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/07/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Frost-induced embolism and frost fatigue are two major aspects of frost damage to xylem water transport in trees. In this study, three species of each ring-porous, diffuse-porous, and coniferous trees growing in situ were used to explore their differences in winter embolism and frost fatigue. Changes in predawn water potential, predawn native embolism, maximal specific conductivity (Kmax), and cavitation resistance (P50, xylem water potential at 50% loss of conductivity) of current-year branches were measured from autumn to spring. Maximum native embolism of late winter was near 100% for ring-porous species, approximately 80% for diffuse-porous species, and below 50% for conifers. In early spring, there was no significant reduction of native embolism until formation of new vessels in ring-porous trees, while diffuse-porous trees and conifers exhibited a reduction in native embolism before development of new xylem. There was a significant decrease in P50 of ring- and diffuse-porous species over winter; however, in May P50 was markedly reduced along with formation of new vessels. Kmax of ring- and diffuse-porous species significantly decreased from autumn to late winter. The results revealed that vulnerability to cavitation and frost fatigue was related to conduit diameter. The strategies for coping with winter embolism differed among the three wood types: in ring-porous species there was no active embolism refilling; in diffuse-porous species there was refilling associated with positive xylem pressure; and in conifers there was refilling without positive xylem pressure. New vessels could completely restore stem hydraulic conductivity but only partially restore xylem cavitation resistance in spring.
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Affiliation(s)
- Yongxin Dai
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, PR China; College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, 030801, PR China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, 100091, PR China.
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28
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Tomasella M, Petrussa E, Petruzzellis F, Nardini A, Casolo V. The Possible Role of Non-Structural Carbohydrates in the Regulation of Tree Hydraulics. Int J Mol Sci 2019; 21:E144. [PMID: 31878253 PMCID: PMC6981889 DOI: 10.3390/ijms21010144] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/13/2019] [Accepted: 12/22/2019] [Indexed: 12/29/2022] Open
Abstract
The xylem is a complex system that includes a network of dead conduits ensuring long-distance water transport in plants. Under ongoing climate changes, xylem embolism is a major and recurrent cause of drought-induced tree mortality. Non-structural carbohydrates (NSC) play key roles in plant responses to drought and frost stress, and several studies putatively suggest their involvement in the regulation of xylem water transport. However, a clear picture on the roles of NSCs in plant hydraulics has not been drawn to date. We summarize the current knowledge on the involvement of NSCs during embolism formation and subsequent hydraulic recovery. Under drought, sugars are generally accumulated in xylem parenchyma and in xylem sap. At drought-relief, xylem functionality is putatively restored in an osmotically driven process involving wood parenchyma, xylem sap and phloem compartments. By analyzing the published data on stem hydraulics and NSC contents under drought/frost stress and subsequent stress relief, we found that embolism build-up positively correlated to stem NSC depletion, and that the magnitude of post-stress hydraulic recovery positively correlated to consumption of soluble sugars. These findings suggest a close relationship between hydraulics and carbohydrate dynamics. We call for more experiments on hydraulic and NSC dynamics in controlled and field conditions.
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Affiliation(s)
- Martina Tomasella
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Elisa Petrussa
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 91, 33100 Udine, Italy; (E.P.); (V.C.)
| | - Francesco Petruzzellis
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Andrea Nardini
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; (F.P.); (A.N.)
| | - Valentino Casolo
- Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 91, 33100 Udine, Italy; (E.P.); (V.C.)
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29
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De Baerdemaeker NJF, Arachchige KNR, Zinkernagel J, Van den Bulcke J, Van Acker J, Schenk HJ, Steppe K. The stability enigma of hydraulic vulnerability curves: addressing the link between hydraulic conductivity and drought-induced embolism. TREE PHYSIOLOGY 2019; 39:1646-1664. [PMID: 31274162 DOI: 10.1093/treephys/tpz078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/29/2019] [Accepted: 06/13/2019] [Indexed: 05/29/2023]
Abstract
Maintaining xylem water transport under drought is vital for plants, but xylem failure does occur when drought-induced embolisms form and progressively spread through the xylem. The hydraulic method is widely considered the gold standard to quantify drought-induced xylem embolism. The method determines hydraulic conductivity (Kh) in cut branch samples, dehydrated to specific drought levels, by pushing water through them. The technique is widely considered for its reliable Kh measurements, but there is some uncertainty in the literature over how to define stable Kh and how that relates to the degree of xylem embolism formation. Therefore, the most common setup for this method was extended to measure four parameters: (i) inlet Kh, (ii) outlet Kh, (iii) radial flow from xylem to surrounding living tissue and (iv) the pressure difference across the sample. From a strictly theoretical viewpoint, hydraulic steady state, where inflow equals outflow and radial flow is zero, will result in stable Kh. Application of the setup to Malus domestica Borkh. branches showed that achieving hydraulic steady state takes considerable time (up to 300 min) and that time to reach steady state increased with declining xylem water potentials. During each experimental run, Kh and xylem water potentials dynamically increased, which was supported by X-ray computed microtomography visualizations of embolism refilling under both high- (8 kPa) and low-pressure (2 kPa) heads. Supplying pressurized water can hence cause artificial refilling of vessels, which makes it difficult to achieve a truly stable Kh in partially embolized xylem.
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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, B-9000 Ghent, Belgium
| | | | - Jana Zinkernagel
- Department of Vegetable Crops, Hochschule Geisenheim University, 65366 Geisenheim, Germany
| | - Jan Van den Bulcke
- UGCT-Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - Joris Van Acker
- UGCT-Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
| | - H Jochen Schenk
- Plants and H2O Laboratory, Department of Biological Science, California State University Fullerton, PO Box 6850, Fullerton, CA 92834-6850, USA
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
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30
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Liu X, Liu H, Gleason SM, Goldstein G, Zhu S, He P, Hou H, Li R, Ye Q. Water transport from stem to stomata: the coordination of hydraulic and gas exchange traits across 33 subtropical woody species. TREE PHYSIOLOGY 2019; 39:1665-1674. [PMID: 31314105 DOI: 10.1093/treephys/tpz076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 04/28/2019] [Accepted: 06/23/2019] [Indexed: 06/10/2023]
Abstract
Coordination between sapwood-specific hydraulic conductivity (Ks) and stomatal conductance (gs) has been identified in previous studies; however, coordination between leaf hydraulic conductance (Kleaf) and gs, as well as between Kleaf and Ks is not always consistent. This suggests that there is a need to improve our understanding of the coordination among hydraulic and gas exchange traits. In this study, hydraulic traits (e.g., Ks and Kleaf) and gas exchange traits, including gs, transpiration (E) and net CO2 assimilation (Aarea), were measured across 33 co-occurring subtropical woody species. Kleaf was divided into two components: leaf hydraulic conductance inside the xylem (Kleaf-x) and outside the xylem (Kleaf-ox). We found that both Kleaf-x and Kleaf-ox were coordinated with gs and E, but the correlations between Kleaf-ox and gs (or E) were substantially weaker, and that Ks was coordinated with Kleaf-x, but not with Kleaf-ox. In addition, we found that Ks, Kleaf-x and Kleaf-ox together explained 63% of the variation in gs and 42% of the variation in Aarea across species, with Ks contributing the largest proportion of explanatory power, whereas Kleaf-ox contributed the least explanatory power. Our results demonstrate that the coordination between leaf water transport and gas exchange, as well as the hydraulic linkage between leaf and stem, were weakened by Kleaf-ox. This highlights the possibility that water transport efficiencies of stem and leaf xylem, rather than that of leaf tissues outside the xylem, are important determinants of stomatal conductance and photosynthetic capacity across species.
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Affiliation(s)
- Xiaorong Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Sean M Gleason
- Water Management and Systems Research Unit, USDA-ARS, Fort Collins, CO, USA
| | - Guillermo Goldstein
- Laboratorio de Ecología Funcional, Instituto de Ecologia Genetica y Evolucion, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Pengcheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Hao Hou
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Ronghua Li
- Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou, China
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- College of Life Sciences, Gannan Normal University, Ganzhou, China
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31
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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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32
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Smith MS, Centinari M. Young grapevines exhibit interspecific differences in hydraulic response to freeze stress but not in recovery. PLANTA 2019; 250:495-505. [PMID: 31089803 DOI: 10.1007/s00425-019-03183-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
This study demonstrated that freeze-induced hydraulic failure varies between two Vitis species that have different xylem vessel frequency and grouping. However, seasonal recovery of young grapevines was similar between the species. Sub-freezing temperatures after budburst represent a major threat for the cultivation of fruit crops in temperate regions. Freeze stress might disrupt xylem hydraulic functionality and plant growth; however, it is unclear if hydraulic traits influence the ability of woody plants to cope with freeze stress. We investigated if a grapevine species (Vitis hybrid) with earlier budburst had anatomical traits that cause higher freeze-induced hydraulic failure but also confer a greater ability for seasonal recovery compared to a Vitis vinifera species. Two-year-old Vitis hybrid and vinifera grapevines were container-grown outdoors, assigned to either a control (n = 40) or a freeze-stressed (n = 40) treatment and exposed to a controlled-temperature (- 4 °C) freeze stress shortly after budburst. We found that the Vitis hybrid had greater stem-specific hydraulic conductivity (Ks) and was more vulnerable to freeze-induced embolism compared to the V. vinifera species, which exhibited a less efficient but safer water transport strategy. Seventy-two hours after the freeze stress, Ks of freeze-stressed V. vinifera was 77.8% higher than that of the control, indicating hydraulic recovery. While the two species did not differ in xylem vessel diameter, Vitis hybrid exhibited higher vessel frequency and percentage of vessel grouping, which could explain its higher Ks and greater freeze-induced Ks loss compared to the V. vinifera vines. While the two species varied in the short-term hydraulic response, they exhibited similar and full hydraulic and vegetative recovery by midseason, including bud freeze tolerance during the following fall and mid-winter.
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Affiliation(s)
- Maria S Smith
- Department of Plant Science, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, 44691, USA
| | - Michela Centinari
- Department of Plant Science, The Pennsylvania State University, University Park, PA, 16802, USA.
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33
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Trifilò P, Kiorapostolou N, Petruzzellis F, Vitti S, Petit G, Lo Gullo MA, Nardini A, Casolo V. Hydraulic recovery from xylem embolism in excised branches of twelve woody species: Relationships with parenchyma cells and non-structural carbohydrates. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 139:513-520. [PMID: 31015090 DOI: 10.1016/j.plaphy.2019.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/10/2019] [Accepted: 04/10/2019] [Indexed: 05/26/2023]
Abstract
Embolism repair ability has been documented in numerous species. Although the actual mechanism driving this phenomenon is still debated, experimental findings suggest that non-structural carbohydrates (NSC) stored in wood parenchyma would provide the osmotic forces to drive the refilling of embolized conduits. We selected 12 broadleaved species differing in vulnerability to xylem embolism (P50) and amount of wood parenchyma in order to check direct evidence about the possible link(s) between parenchyma cells abundance, NSC availability and species-specific capacity to reverse xylem embolism. Branches were dehydrated until ∼50% loss of hydraulic conductivity was recorded (PLC ∼50%). Hydraulic recovery (ΔPLC) and NSC content was, then, assessed after 1h of rehydration. Species showed a different ability to recover their hydraulic conductivity from PLC∼50%. Removing the bark in the species showing hydraulic recovery inhibited the embolism reversal. Strong correlations between the ΔPLC and: a) the amount of parenchyma cells (mainly driven by the pith area), b) the consumption of soluble NSC have been recorded. Our results support the hypothesis that refilling of embolized vessels is mediated by the mobilization of soluble NSC and it is mainly recorded in species with a higher percentage of parenchyma cells that may be important in the hydraulic recovery mechanism as a source of carbohydrates and/or as a source of water.
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Affiliation(s)
- Patrizia Trifilò
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166, Messina, Italy.
| | - Natasa Kiorapostolou
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Stefano Vitti
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy; Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, Via delle Scienze 91, 33100, Udine, Italy
| | - Giai Petit
- Dipartimento Territorio e Sistemi Agro-Forestali, Università di Padova, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Maria A Lo Gullo
- Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche ed Ambientali, Università di Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166, Messina, Italy
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Valentino Casolo
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, Via delle Scienze 91, 33100, Udine, Italy
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Knipfer T, Reyes C, Earles JM, Berry ZC, Johnson DM, Brodersen CR, McElrone AJ. Spatiotemporal Coupling of Vessel Cavitation and Discharge of Stored Xylem Water in a Tree Sapling. PLANT PHYSIOLOGY 2019; 179:1658-1668. [PMID: 30718351 PMCID: PMC6446773 DOI: 10.1104/pp.18.01303] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/25/2019] [Indexed: 05/06/2023]
Abstract
Water discharge from stem internal storage compartments is thought to minimize the risk of vessel cavitation. Based on this concept, one would expect that water storage compartments involved in the buffering of xylem tensions empty before the onset of vessel cavitation under drought stress, and potentially refill after soil saturation. However, scant in vivo data exist that elucidate this localized spatiotemporal coupling. In this study on intact saplings of American chestnut (Castanea dentata), x-ray computed microtomography (microCT) showed that the xylem matrix surrounding vessels releases stored water and becomes air-filled either concurrent to or after vessel cavitation under progressive drought stress. Among annual growth rings, the xylem matrix of the current year remained largely water-filled even under severe drought stress. In comparison, microtomography images collected on excised stems showed that applied pressures of much greater than 0 MPa were required to induce water release from the xylem matrix. Viability staining highlighted that water release from the xylem matrix was associated primarily with emptying of dead fibers. Refilling of the xylem matrix and vessels was detected in intact saplings when the canopy was bagged and stem water potential was close to 0 MPa, and in leafless saplings over the winter period. In conclusion, this study indicates that the bulk of water stored in the xylem matrix is released after the onset of vessel cavitation, and suggests that capillary water contributes to overall stem water storage under drought but is not used primarily for the prevention of drought-induced vessel cavitation in this species.
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Affiliation(s)
- Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, California 95616
| | - Clarissa Reyes
- Department of Viticulture and Enology, University of California, Davis, California 95616
| | - J Mason Earles
- Department of Viticulture and Enology, University of California, Davis, California 95616
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511
| | - Z Carter Berry
- Schmid College of Science and Technology, Chapman University, Orange, California 92866
| | - Daniel M Johnson
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, Georgia 30602
| | - Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, California 95616
- U.S. Department of Agriculture-Agricultural Research Service, Crops Pathology and Genetics Research Unit, Davis, California 95618
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35
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Losso A, Bär A, Dämon B, Dullin C, Ganthaler A, Petruzzellis F, Savi T, Tromba G, Nardini A, Mayr S, Beikircher B. Insights from in vivo micro-CT analysis: testing the hydraulic vulnerability segmentation in Acer pseudoplatanus and Fagus sylvatica seedlings. THE NEW PHYTOLOGIST 2019; 221:1831-1842. [PMID: 30347122 PMCID: PMC6492020 DOI: 10.1111/nph.15549] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 10/14/2018] [Indexed: 05/23/2023]
Abstract
The seedling stage is the most susceptible one during a tree's life. Water relations may be crucial for seedlings due to their small roots, limited water buffers and the effects of drought on water transport. Despite obvious relevance, studies on seedling xylem hydraulics are scarce as respective methodical approaches are limited. Micro-CT scans of intact Acer pseudoplatanus and Fagus sylvatica seedlings dehydrated to different water potentials (Ψ) allowed the simultaneous observation of gas-filled versus water-filled conduits and the calculation of percentage loss of conductivity (PLC) in stems, roots and leaves (petioles or main veins). Additionally, anatomical analyses were performed and stem PLC measured with hydraulic techniques. In A. pseudoplatanus, petioles showed a higher Ψ at 50% PLC (Ψ50 -1.13MPa) than stems (-2.51 MPa) and roots (-1.78 MPa). The main leaf veins of F. sylvatica had similar Ψ50 values (-2.26 MPa) to stems (-2.74 MPa) and roots (-2.75 MPa). In both species, no difference between root and stems was observed. Hydraulic measurements on stems closely matched the micro-CT based PLC calculations. Micro-CT analyses indicated a species-specific hydraulic architecture. Vulnerability segmentation, enabling a disconnection of the hydraulic pathway upon drought, was observed in A. pseudoplatanus but not in the especially shade-tolerant F. sylvatica. Hydraulic patterns could partly be related to xylem anatomical traits.
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Affiliation(s)
- Adriano Losso
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Andreas Bär
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Birgit Dämon
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Christian Dullin
- Institute for Diagnostic and Interventional RadiologyUniversity Medical Center GoettingenRobert‐Koch‐Straße 40Göttingen37075Germany
- Max‐Plank‐Institute for Experimental MedicineHermann‐Rein‐Straße 3Göttingen37075Germany
- Elettra‐Sincrotrone TriesteArea Science ParkTriesteBasovizza34149Italy
| | - Andrea Ganthaler
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Francesco Petruzzellis
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Tadeja Savi
- Department of Crop SciencesDivision of Viticulture and PomologyUniversity of Natural Resources and Life Sciences ViennaKonrad Lorenzstrasse 24TullnA‐3430Austria
| | - Giuliana Tromba
- Elettra‐Sincrotrone TriesteArea Science ParkTriesteBasovizza34149Italy
| | - Andrea Nardini
- Dipartimento di Scienze della VitaUniversità di TriesteVia L. Giorgieri 10Trieste34127Italy
| | - Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
| | - Barbara Beikircher
- Department of BotanyUniversity of InnsbruckSternwarterstrasse 15InnsbruckA‐6020Austria
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36
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Barrios-Masias FH, Knipfer T, Walker MA, McElrone AJ. Differences in hydraulic traits of grapevine rootstocks are not conferred to a common Vitis vinifera scion. FUNCTIONAL PLANT BIOLOGY : FPB 2019; 46:228-235. [PMID: 32172766 DOI: 10.1071/fp18110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/02/2018] [Indexed: 05/16/2023]
Abstract
Cultivars of grapevine are commonly grafted onto rootstocks to improve resistance against biotic and abiotic stress, however, it is not clear whether known differences in hydraulic traits are conferred from rootstocks to a common scion. We recently found that Vitis riparia and Vitis champinii differed in drought-induced embolism susceptibility and repair, which was related to differences in root pressure generation after rewatering (Knipfer et al. 2015). In the present study, we tested whether these and other physiological responses to drought are conferred to a common V. vinifera scion (Cabernet Sauvignon) grafted on V. riparia and V. champinii rootstocks. We measured xylem embolism formation/repair using in vivo microCT imaging, which was accompanied with analysis of leaf gas exchange, osmotic adjustment and root pressure. Our data indicate that differences in scion physiological behaviour for both rootstock combinations were negligible, suggesting that the sensitivity of Cabernet Sauvignon scion to xylem embolism formation/repair, leaf gas exchange and osmotic adjustment is unaffected by either V. riparia or V. champinii rootstock in response to drought stress.
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Affiliation(s)
- Felipe H Barrios-Masias
- Department of Agriculture, Veterinary and Rangeland Sciences, University of Nevada, Reno, NV 89557, USA
| | - Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
| | - M Andrew Walker
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, CA 95616, USA
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37
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Gričar J, Zavadlav S, Jyske T, Lavrič M, Laakso T, Hafner P, Eler K, Vodnik D. Effect of soil water availability on intra-annual xylem and phloem formation and non-structural carbohydrate pools in stem of Quercus pubescens. TREE PHYSIOLOGY 2019; 39:222-233. [PMID: 30239939 DOI: 10.1093/treephys/tpy101] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 08/16/2018] [Accepted: 08/21/2018] [Indexed: 06/08/2023]
Abstract
Non-structural carbohydrates (NSCs, i.e., starch and soluble sugars) are frequently quantified in the context of tree response to stressful events (e.g., drought), because they serve as a carbon reservoir for growth and respiration, as well as providing a critical osmotic function to maintain turgor and vascular transport under different environmental conditions. We investigated the impact of soil water availability on intra-annual leaf phenology, radial growth dynamics and variation in NSC amounts in the stem of pubescent oak (Quercus pubescens Willd.). from a sub-Mediterranean region. For this purpose, trees growing at two nearby plots differing in bedrock and, consequently, soil characteristics (F-eutric cambisol on eocene flysch bedrock and L-rendzic leptosol on paleogenic limestone bedrock) were sampled. Non-structural carbohydrates were analysed in outer xylem and living phloem (separately for non-collapsed and collapsed parts). Results showed that xylem and phloem increments were 41.6% and 21.2%, respectively, wider in trees from F plot due to a higher rate of cell production. In contrast, the amount of NSCs and of soluble sugars significantly differed among the tissue parts and sampling dates but not between the two plots. Starch amounts were the highest in xylem, which could be explained by the abundance of xylem parenchyma cells. Two clear seasonal peaks of the starch amount were detected in all tissues, the first in September-November, in the period of leaf colouring and falling, and the second in March-April, i.e., at the onset of cambial cell production followed by bud development. The amounts of free sugars were highest in inner phloem + cambium, at the sites of active growth. Soil water availability substantially influenced secondary growth in the stem of Q. pubescens, whereas NSC amounts seemed to be less affected. The results show how the intricate relationships between soil properties, such as water availability, and tree performance should be considered when studying the impact of stressful events on the growth and functioning of trees.
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Affiliation(s)
- Jožica Gričar
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, Ljubljana, Slovenia
| | - Saša Zavadlav
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, Ljubljana, Slovenia
| | - Tuula Jyske
- Natural Resources Institute Finland, Production Systems Unit, Biomass Properties and Characterization, Tietotie 2, Espoo, Finland
| | - Martina Lavrič
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, Ljubljana, Slovenia
| | - Tapio Laakso
- Natural Resources Institute Finland, Production Systems Unit, Biomass Properties and Characterization, Tietotie 2, Espoo, Finland
| | - Polona Hafner
- Department of Yield and Silviculture, Slovenian Forestry Institute, Vecna pot 2, Ljubljana, Slovenia
| | - Klemen Eler
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, Ljubljana, Slovenia
| | - Dominik Vodnik
- Department of Agronomy, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, Ljubljana, Slovenia
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38
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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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39
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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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40
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Lowe-Power TM, Khokhani D, Allen C. How Ralstonia solanacearum Exploits and Thrives in the Flowing Plant Xylem Environment. Trends Microbiol 2018; 26:929-942. [PMID: 29941188 DOI: 10.1016/j.tim.2018.06.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 05/24/2018] [Accepted: 06/04/2018] [Indexed: 10/28/2022]
Abstract
The plant wilt pathogen Ralstonia solanacearum thrives in the water-transporting xylem vessels of its host plants. Xylem is a relatively nutrient-poor, high-flow environment but R. solanacearum succeeds there by tuning its own metabolism and altering xylem sap biochemistry. Flow influences many traits that the bacterium requires for pathogenesis. Most notably, a quorum sensing system mediates the pathogen's major transition from a rapidly dividing early phase that voraciously consumes diverse food sources and avidly adheres to plant surfaces to a slower-growing late phase that can use fewer nutrients but produces virulence factors and disperses effectively. This review discusses recent findings about R. solanacearum pathogenesis in the context of its flowing in planta niche, with emphasis on R. solanacearum metabolism in plants.
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Affiliation(s)
- Tiffany M Lowe-Power
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA; Current address: Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA 94720, USA
| | - Devanshi Khokhani
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA; Current address: Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Caitilyn Allen
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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41
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Cuneo IF, Knipfer T, Mandal P, Brodersen CR, McElrone AJ. Water uptake can occur through woody portions of roots and facilitates localized embolism repair in grapevine. THE NEW PHYTOLOGIST 2018; 218:506-516. [PMID: 29460963 DOI: 10.1111/nph.15032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/23/2017] [Indexed: 06/08/2023]
Abstract
Water acquisition is thought to be limited to the unsuberized surface located close to root tips. However, there are recurring periods when the unsuberized surfaces are limited in woody root systems, and radial water uptake across the bark of woody roots might play an important physiological role in hydraulic functioning. Using X-ray microcomputed tomography (microCT) and hydraulic conductivity measurements (Lpr ), we examined water uptake capacity of suberized woody roots in vivo and in excised samples. Bark hydration in grapevine woody roots occurred quickly upon exposure to water (c. 4 h). Lpr measurements through the bark of woody roots showed that it is permeable to water and becomes more so upon wetting. After bark hydration, microCT analysis showed that absorbed water was utilized to remove embolism locally, where c. 20% of root xylem vessels refilled completely within 15 h. Embolism removal did not occur in control roots without water. Water uptake through the bark of woody roots probably plays an important role when unsuberized tissue is scarce/absent, and would be particularly relevant following large irrigation events or in late winter when soils are saturated, re-establishing hydraulic functionality before bud break.
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Affiliation(s)
- Italo F Cuneo
- Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Quillota 2260000, Chile
| | - Thorsten Knipfer
- Department of Viticulture and Enology, University of California, Davis, CA 95618, USA
| | - Pratiti Mandal
- Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, CA 94720, USA
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, New Haven, CT 06511, USA
| | - Andrew J McElrone
- Department of Viticulture and Enology, University of California, Davis, CA 95618, USA
- Crops Pathology and Genetics Research Unit, USDA-ARS, Davis, CA 95618, USA
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42
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Schenk HJ, Espino S, Rich-Cavazos SM, Jansen S. From the sap's perspective: The nature of vessel surfaces in angiosperm xylem. AMERICAN JOURNAL OF BOTANY 2018; 105:172-185. [PMID: 29578294 DOI: 10.1002/ajb2.1034] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 12/14/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Xylem sap in angiosperms moves under negative pressure in conduits and cell wall pores that are nanometers to micrometers in diameter, so sap is always very close to surfaces. Surfaces matter for water transport because hydrophobic ones favor nucleation of bubbles, and surface chemistry can have strong effects on flow. Vessel walls contain cellulose, hemicellulose, lignin, pectins, proteins, and possibly lipids, but what is the nature of the inner, lumen-facing surface that is in contact with sap? METHODS Vessel lumen surfaces of five angiosperms from different lineages were examined via transmission electron microscopy and confocal and fluorescence microscopy, using fluorophores and autofluorescence to detect cell wall components. Elemental composition was studied by energy-dispersive X-ray spectroscopy, and treatments with phospholipase C (PLC) were used to test for phospholipids. KEY RESULTS Vessel surfaces consisted mainly of lignin, with strong cellulose signals confined to pit membranes. Proteins were found mainly in inter-vessel pits and pectins only on outer rims of pit membranes and in vessel-parenchyma pits. Continuous layers of lipids were detected on most vessel surfaces and on most pit membranes and were shown by PLC treatment to consist at least partly of phospholipids. CONCLUSIONS Vessel surfaces appear to be wettable because lignin is not strongly hydrophobic and a coating with amphiphilic lipids would render any surface hydrophilic. New questions arise about these lipids and their possible origins from living xylem cells, especially about their effects on surface tension, surface bubble nucleation, and pit membrane function.
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Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Susana Espino
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Sarah M Rich-Cavazos
- Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081, Ulm, Germany
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43
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Jochen Schenk H. Wood: Biology of a living tissue. AMERICAN JOURNAL OF BOTANY 2018; 105:139-141. [PMID: 29569710 DOI: 10.1002/ajb2.1039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 02/21/2018] [Indexed: 06/08/2023]
Affiliation(s)
- H Jochen Schenk
- Department of Biological Science, California State University Fullerton, 800 N. State College Boulevard, Fullerton, CA, 92831, USA
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44
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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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45
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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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46
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Savi T, Miotto A, Petruzzellis F, Losso A, Pacilè S, Tromba G, Mayr S, Nardini A. Drought-induced embolism in stems of sunflower: A comparison of in vivo micro-CT observations and destructive hydraulic measurements. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 120:24-29. [PMID: 28968592 DOI: 10.1016/j.plaphy.2017.09.017] [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: 08/06/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 05/23/2023]
Abstract
Vulnerability curves (VCs) are a useful tool to investigate the susceptibility of plants to drought-induced hydraulic failure, and several experimental techniques have been used for their measurement. The validity of the bench dehydration method coupled to hydraulic measurements, considered as a 'golden standard', has been recently questioned calling for its validation with non-destructive methods. We compared the VCs of a herbaceous crop plant (Helianthus annuus) obtained during whole-plant dehydration followed by i) hydraulic flow measurements in stem segments (classical destructive method) or by ii) in vivo micro-CT observations of stem xylem conduits in intact plants. The interpolated P50 values (xylem water potential inducing 50% loss of hydraulic conductance) were -1.74 MPa and -0.87 MPa for the hydraulic and the micro-CT VC, respectively. Interpolated P20 values were similar, while P50 and P80 were significantly different, as evidenced by non-overlapping 95% confidence intervals. Our results did not support the tension-cutting artefact, as no overestimation of vulnerability was observed when comparing the hydraulic VC to that obtained with in vivo imaging. After one scan, 25% of plants showed signs of x-ray induced damage, while three successive scans caused the formation of a circular brownish scar in all tested plants. Our results support the validity of hydraulic measurements of samples excised under tension provided standard sampling and handling protocols are followed, but also show that caution is needed when investigating vital plant processes with x-ray imaging.
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Affiliation(s)
- Tadeja Savi
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy.
| | - Andrea Miotto
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Francesco Petruzzellis
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Adriano Losso
- Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020 Innsbruck, Austria
| | - Serena Pacilè
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy; Dipartimento di Ingegneria e Architettura, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy
| | - Giuliana Tromba
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Stefan Mayr
- Institut für Botanik, Universität Innsbruck, Sternwarterstrasse 15, A-6020 Innsbruck, Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
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47
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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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48
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Tomasella M, Häberle KH, Nardini A, Hesse B, Machlet A, Matyssek R. Post-drought hydraulic recovery is accompanied by non-structural carbohydrate depletion in the stem wood of Norway spruce saplings. Sci Rep 2017; 7:14308. [PMID: 29085007 PMCID: PMC5662761 DOI: 10.1038/s41598-017-14645-w] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/12/2017] [Indexed: 11/30/2022] Open
Abstract
Hydraulic failure and carbon starvation are recognized as main causes of drought-induced forest decline. As water transport and carbon dynamics are strictly interdependent, it is necessary to clarify how dehydration-rehydration cycles are affecting the relations between stem embolism and non-structural carbohydrates (NSC). This is particularly needed for conifers whose embolism repair capability is still controversial. Potted Norway spruce saplings underwent two drought-re-irrigation cycles of same intensity, but performed in two consecutive summers. During the second cycle, stem percent loss of hydraulic conductivity (PLC) and NSC content showed no carry-over effects from the previous drought, indicating complete long-term recovery. The second drought treatment induced moderate PLC (20%) and did not affect total NSCs content, while starch was converted to soluble sugars in the bark. After one week of re-irrigation, PLC recovered to pre-stress values (0%) and NSCs were depleted, only in the wood, by about 30%. Our data suggest that spruce can repair xylem embolism and that, when water is newly available, NSCs stored in xylem parenchyma can be mobilized over short term to sustain respiration and/or for processes involved in xylem transport restoration. This, however, might imply dependency on sapwood NSC reserves for survival, especially if frequent drought spells occur.
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Affiliation(s)
- Martina Tomasella
- Department of Ecology and Ecosystem Management- Chair for Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz Platz 2, 85354, Freising, Germany.
| | - Karl-Heinz Häberle
- Department of Ecology and Ecosystem Management- Chair for Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz Platz 2, 85354, Freising, Germany
| | - Andrea Nardini
- Department of Life Sciences, Università degli Studi di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Benjamin Hesse
- Department of Ecology and Ecosystem Management- Chair for Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz Platz 2, 85354, Freising, Germany
| | - Anna Machlet
- Department of Ecology and Ecosystem Management- Chair for Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz Platz 2, 85354, Freising, Germany
| | - Rainer Matyssek
- Department of Ecology and Ecosystem Management- Chair for Ecophysiology of Plants, Technische Universität München, Hans-Carl-von-Carlowitz Platz 2, 85354, Freising, Germany
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49
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Venturas MD, Sperry JS, Hacke UG. Plant xylem hydraulics: What we understand, current research, and future challenges. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:356-389. [PMID: 28296168 DOI: 10.1111/jipb.12534] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/09/2017] [Indexed: 05/22/2023]
Abstract
Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connection with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality.
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Affiliation(s)
- Martin D Venturas
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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50
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Hochberg U, Windt CW, Ponomarenko A, Zhang YJ, Gersony J, Rockwell FE, Holbrook NM. Stomatal Closure, Basal Leaf Embolism, and Shedding Protect the Hydraulic Integrity of Grape Stems. PLANT PHYSIOLOGY 2017; 174:764-775. [PMID: 28351909 PMCID: PMC5462014 DOI: 10.1104/pp.16.01816] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 03/25/2017] [Indexed: 05/05/2023]
Abstract
The time scale of stomatal closure and xylem cavitation during plant dehydration, as well as the fate of embolized organs, are under debate, largely due to methodological limitations in the evaluation of embolism. While some argue that complete stomatal closure precedes the occurrence of embolism, others believe that the two are contemporaneous processes that are accompanied by daily xylem refilling. Here, we utilize an optical light transmission method to continuously monitor xylem cavitation in leaves of dehydrating grapevine (Vitis vinifera) in concert with stomatal conductance and stem and petiole hydraulic measurements. Magnetic resonance imaging was used to continuously monitor xylem cavitation and flow rates in the stem of an intact vine during 10 d of dehydration. The results showed that complete stomatal closure preceded the appearance of embolism in the leaves and the stem by several days. Basal leaves were more vulnerable to xylem embolism than apical leaves and, once embolized, were shed, thereby preventing further water loss and protecting the hydraulic integrity of younger leaves and the stem. As a result, embolism in the stem was minimal even when drought led to complete leaf shedding. These findings suggest that grapevine avoids xylem embolism rather than tolerates it.
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Affiliation(s)
- Uri Hochberg
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
| | - Carel W Windt
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
| | - Alexandre Ponomarenko
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
| | - Yong-Jiang Zhang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
| | - Jessica Gersony
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 (U.H., A.P., Y.-J.Z., J.G., F.E.R., N.M.H.); and
- Forschungszentrum Jülich, Institute for Bio- and Geosciences 2: Plant Sciences, 52425 Juelich, Germany (C.W.W.)
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