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Xiang Y, Kagawa A, Nagai S, Yasuda Y, Utsumi Y. The difference in the functional water flow network between the stem and current-year root cross-sectional surfaces in Salix gracilistyla stem xylem. TREE PHYSIOLOGY 2023; 43:1326-1340. [PMID: 37098160 DOI: 10.1093/treephys/tpad056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 04/17/2023] [Accepted: 04/21/2023] [Indexed: 06/19/2023]
Abstract
The dye injection method has been applied to many species to analyze the xylem water transport pathway in trees. However, traditional dye injection methods introduced dye tracers from the surface of cut stems, including several annual rings. Furthermore, the traditional dye injection method did not evaluate radial water movement from the outermost annual rings to the inner annual rings. In this study, we assessed the difference in radial water movement visualized by an injected dye, between stem base cut and current-year root cut samples of Salix gracilistyla Miq., with current-year roots grown hydroponically. The results showed that the number of stained annual rings in the root cut samples was smaller than that in the stem cut samples, and the percentage of stained vessels in the root cut samples was significantly smaller than that in the stem base cut samples in the second and third annual rings. In the current-year root cut samples, water transport mainly occurred in the outermost rings from the current-year roots to leaves. In addition, the theoretical hydraulic conductivity of stained vessels in the stem cut samples was higher in the current-year root cut samples in the second and third annual rings. These findings indicate that the previously reported dye injection method using stem cut samples overestimated the water transport pathway in the inner part of the stems. Moreover, previous hydraulic conductivity measurement methods might not have considered the effects of radial resistance through the annual ring boundary, and they might have overestimated the hydraulic conductivity in the inner annual rings.
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Affiliation(s)
- Yan Xiang
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi Ward, Fukuoka city, Fukuoka, 819-0385, Japan
| | - Akira Kagawa
- Forestry and Forest Products Research Institute, Wood Anatomy and Quality Laboratory, 1 Matsunosato, Tsukuba, Ibaraki 300-1244, Japan
| | - Satoshi Nagai
- Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, Forestry and Forest Products Research Institute, 430 Yamasakicho Ikaba, Shiso, Hyogo 671-2515, Japan
| | - Yuko Yasuda
- Department of Environmental Sciences and Technology, Faculty of Agriculture, Kagoshima University, 1 Chome-21-24 Korimoto, Kagoshima City Kagoshima, 890-0065, Japan
| | - Yasuhiro Utsumi
- Kyushu University Forest, Kyushu University, 394-1 Tsubakuro, Sasaguri, Kasuya District, Fukuoka 811-2415, Japan
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2
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Pritzkow C, Brown MJM, Carins-Murphy MR, Bourbia I, Mitchell PJ, Brodersen C, Choat B, Brodribb TJ. Conduit position and connectivity affect the likelihood of xylem embolism during natural drought in evergreen woodland species. ANNALS OF BOTANY 2022; 130:431-444. [PMID: 35420657 PMCID: PMC9486930 DOI: 10.1093/aob/mcac053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Hydraulic failure is considered a main cause of drought-induced forest mortality. Yet, we have a limited understanding of how the varying intensities and long time scales of natural droughts induce and propagate embolism within the xylem. METHODS X-ray computed tomography (microCT) images were obtained from different aged branch xylem to study the number, size and spatial distribution of in situ embolized conduits among three dominant tree species growing in a woodland community. KEY RESULTS Among the three studied tree species, those with a higher xylem vulnerability to embolism (higher water potential at 50 % loss of hydraulic conductance; P50) were more embolized than species with lower P50. Within individual stems, the probability of embolism was independent of conduit diameter but associated with conduit position. Rather than the occurrence of random or radial embolism, we observed circumferential clustering of high and low embolism density, suggesting that embolism spreads preferentially among conduits of the same age. Older xylem also appeared more likely to accumulate embolisms than young xylem, but there was no pattern suggesting that branch tips were more vulnerable to cavitation than basal regions. CONCLUSIONS The spatial analysis of embolism occurrence in field-grown trees suggests that embolism under natural drought probably propagates by air spreading from embolized into neighbouring conduits in a circumferential pattern. This pattern offers the possibility to understand the temporal aspects of embolism occurrence by examining stem cross-sections.
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Affiliation(s)
- Carola Pritzkow
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | - Matilda J M Brown
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Ibrahim Bourbia
- School of Biology, University of Tasmania, Hobart, TAS, 7005, Australia
| | | | - Craig Brodersen
- School of the Environment, Yale University, New Haven, CT 06511, USA
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW 2750, Australia
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Wang YH, Hou LL, Wu XQ, Zhu ML, Dai Y, Zhao YJ. Mycorrhiza helper bacterium Bacillus pumilus HR10 improves growth and nutritional status of Pinus thunbergii by promoting mycorrhizal proliferation. TREE PHYSIOLOGY 2022; 42:907-918. [PMID: 34730183 DOI: 10.1093/treephys/tpab139] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Mycorrhizal helper bacteria (MHB) play an important role in mediating mycorrhizal symbiosis, which improves the growth and nutrient uptake of plants. This study examined the growth-promoting effects and mechanisms of pine growth after inoculation with the MHB Bacillus pumilus HR10 and/or Hymenochaete sp. Rl. The effect of B. pumilus HR10 on Hymenochaete sp. Rl growth, enzyme activity and gene expression related to mycorrhiza formation were determined. The growth, root activity, nitrogen, phosphorus, and potassium content and chlorophyll fluorescence activity of Pinus thunbergii and the mycorrhizal colonization intensity of Hymenochaete sp. Rl-inoculated pine seedlings after inoculation with B. pumilus HR10 were also evaluated. The results showed that B. pumilus HR10 promoted growth, regulated the expression of mycorrhizal-related genes and affected the β-1,3-glucanase activity of Hymenochaete sp. Rl. The mycorrhizal colonization intensity of pine seedlings co-inoculated with B. pumilus HR10 and Hymenochaete sp. Rl was 1.58-fold higher than seedlings inoculated with only Hymenochaete sp. Rl. Inoculation with B. pumilus HR10 and/or Hymenochaete sp. Rl increased lateral root number and root activity of pine seedlings and chlorophyll fluorescence activity of pine needles compared with the control. Bacillus pumilus HR10 facilitated nutrient uptake by enhancing the mycorrhizal proliferation of pine and induced greater photosynthesis and root activity of pine seedlings, which confirms its role as an outstanding plant-growth-promoting rhizobacterium. These findings improve our understanding of the mechanism of B. pumilus HR10 promotion of mycorrhizal symbiosis.
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Affiliation(s)
- Ya-Hui Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Liang-Liang Hou
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Xiao-Qin Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Mei-Ling Zhu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Yun Dai
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Yin-Juan Zhao
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
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Pervaiz T, Liu SW, Uddin S, Amjid MW, Niu SH, Wu HX. The Transcriptional Landscape and Hub Genes Associated with Physiological Responses to Drought Stress in Pinus tabuliformis. Int J Mol Sci 2021; 22:9604. [PMID: 34502511 PMCID: PMC8431770 DOI: 10.3390/ijms22179604] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/11/2021] [Accepted: 09/01/2021] [Indexed: 01/18/2023] Open
Abstract
Drought stress has an extensive impact on regulating various physiological, metabolic, and molecular responses. In the present study, the Pinus tabuliformis transcriptome was studied to evaluate the drought-responsive genes using RNA- Sequencing approache. The results depicted that photosynthetic rate and H2O conductance started to decline under drought but recovered 24 h after re-watering; however, the intercellular CO2 concentration (Ci) increased with the onset of drought. We identified 84 drought-responsive transcription factors, 62 protein kinases, 17 transcriptional regulators, and 10 network hub genes. Additionally, we observed the expression patterns of several important gene families, including 2192 genes positively expressed in all 48 samples, and 40 genes were commonly co-expressed in all drought and recovery stages compared with the control samples. The drought-responsive transcriptome was conserved mainly between P. tabuliformis and A. thaliana, as 70% (6163) genes had a homologous in arabidopsis, out of which 52% homologous (3178 genes corresponding to 2086 genes in Arabidopsis) were also drought response genes in arabidopsis. The collaborative network exhibited 10 core hub genes integrating with ABA-dependent and independent pathways closely conserved with the ABA signaling pathway in the transcription factors module. PtNCED3 from the ABA family genes had shown significantly different expression patterns under control, mild, prolonged drought, and recovery stages. We found the expression pattern was considerably increased with the prolonged drought condition. PtNCED3 highly expressed in all drought-tested samples; more interestingly, expression pattern was higher under mild and prolonged drought. PtNCED3 is reported as one of the important regulating enzymes in ABA synthesis. The continuous accumulation of ABA in leaves increased resistance against drought was due to accumulation of PtNCED3 under drought stress in the pine needles.
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Affiliation(s)
- Tariq Pervaiz
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; (T.P.); (S.-W.L.); (S.U.)
| | - Shuang-Wei Liu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; (T.P.); (S.-W.L.); (S.U.)
| | - Saleem Uddin
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; (T.P.); (S.-W.L.); (S.U.)
| | - Muhammad Waqas Amjid
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cotton Germplasm Enhancement and Application Engineering Research Center (Ministry of Education), Nanjing Agricultural University, Nanjing 210095, China;
| | - Shi-Hui Niu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; (T.P.); (S.-W.L.); (S.U.)
| | - Harry X. Wu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China; (T.P.); (S.-W.L.); (S.U.)
- Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Linnaeus vag 6, SE-901 83 Umea, Sweden
- CSIRO National Research Collection Australia, Black Mountain Laboratory, Canberra, ACT 2601, Australia
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Meixner M, Foerst P, Windt CW. Reduced spatial resolution MRI suffices to image and quantify drought induced embolism formation in trees. PLANT METHODS 2021; 17:38. [PMID: 33823898 PMCID: PMC8025330 DOI: 10.1186/s13007-021-00732-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/18/2021] [Indexed: 05/12/2023]
Abstract
BACKGROUND Magnetic resonance imaging (MRI) is uniquely suited to non-invasively and continuously monitor embolism formation in trees. Depending on the MRI method used, quantitative parameter maps of water content and MRI signal relaxation behavior can be generated. The ability to measure dynamic differences in water content and relaxation behavior can be used to detect xylem embolism formation, even if xylem conduits are too small to be spatially resolved. This is especially advantageous when using affordable small-scale low-field MRI scanners. The amount of signal that can be obtained from an object strongly depends on the strength of the magnetic field of the imager's magnet. Imaging at lower resolutions thus would allow to reduce the cost, size and weight of the MRI scanner and to shorten image acquisition times. RESULTS We investigated how much spatial resolution can be sacrificed without losing the ability to monitor embolism formation in coniferous softwood (spruce, Picea abies) and diffuse porous beech (Fagus sylvatica). Saplings of both species were bench dehydrated, while they were continuously imaged at stepwise decreasing spatial resolutions. Imaging was done by means of a small-scale MRI device, utilizing image matrix sizes of 128 × 128, 64 × 64 and 32 × 32 pixels at a constant FOV of 19 and 23 mm, respectively. While images at the lowest resolutions (pixel sizes 0.59 × 0.59 mm and 0.72 × 0.72 mm) were no longer sufficient to resolve finer details of the stem anatomy, they did permit an approximate localization of embolism formation and the generation of accurate vulnerability curves. CONCLUSIONS When using MRI, spatial resolution can be sacrificed without losing the ability to visualize and quantify embolism formation. Imaging at lower spatial resolution to monitor embolism formation has two advantages. Firstly, the acquisition time per image can be reduced dramatically. This enables continuous imaging at high time resolution, which may be beneficial to monitor rapid dynamics of embolism formation. Secondly, if the requirements for spatial resolution are relaxed, much simpler MRI devices can be used. This has the potential to make non-invasive MR imaging of embolism formation much more affordable and more widely available.
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Affiliation(s)
- Marco Meixner
- Chair of Process Systems Engineering, Technical University Munich, Munich, Germany
- IBG-2: Plant Sciences, Forschungszentrum Jülich, Jülich, Germany
| | - Petra Foerst
- Chair of Process Systems Engineering, Technical University Munich, Munich, Germany
| | - Carel W Windt
- IBG-2: Plant Sciences, Forschungszentrum Jülich, Jülich, Germany.
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6
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Cryo-Scanning Electron Microscopy to Study the Freezing Behavior of Plant Tissues. Methods Mol Biol 2020. [PMID: 32607978 DOI: 10.1007/978-1-0716-0660-5_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
A cryo-scanning electron microscope (cryo-SEM) is a valuable tool for observing bulk frozen samples to monitor freezing responses of plant tissues and cells. Here, the essential processes of a cryo-SEM to observe freezing behaviors of plant tissue cells are described.
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7
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Meixner M, Tomasella M, Foerst P, Windt CW. A small-scale MRI scanner and complementary imaging method to visualize and quantify xylem embolism formation. THE NEW PHYTOLOGIST 2020; 226:1517-1529. [PMID: 31958150 DOI: 10.1111/nph.16442] [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: 09/17/2019] [Accepted: 01/12/2020] [Indexed: 05/13/2023]
Abstract
Magnetic resonance imaging (MRI) is a useful tool to image xylem embolism formation in plants. MRI scanners configured to accept intact plants are rare and expensive. Here, we investigate if affordable small-scale, custom-built low-field MRI scanners would suffice for the purpose. A small-scale, C-shaped permanent magnet was paired with open, plane parallel imaging gradients. The setup was small enough to fit between leaves or branches and offered open access for plant stems of arbitrary length. To counter the two main drawbacks of the system, low signal to noise and reduced magnetic field homogeneity, a multi-spin echo (MSE) pulse sequence was implemented, allowing efficient signal acquisition and quantitative imaging of water content and T2 signal relaxation. The system was tested visualizing embolism formation in Fagus sylvatica during bench dehydration. High-quality images of water content and T2 were readily obtained, which could be utilized to detect the cavitation of vessels smaller than could be spatially resolved. A multiplication of both map types yielded images in which filled xylem appeared with even greater contrast. T2 imaging with small-scale MRI devices allows straightforward visualization of the spatial and temporal dynamics of embolism formation and the derivation of vulnerability curves.
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Affiliation(s)
- Marco Meixner
- Process Systems Engineering, Technical University of Munich, Gregor-Mendel-Straße 4, 85354, Freising, Germany
- IBG-2: Plant Sciences Institute, Forschungszentrum Jülich, Leo-Brandt-Straße 1, 52428, Jülich, Germany
| | - Martina Tomasella
- Chair for Ecophysiology of Plants, Technical University Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127, Trieste, Italy
| | - Petra Foerst
- Process Systems Engineering, Technical University of Munich, Gregor-Mendel-Straße 4, 85354, Freising, Germany
| | - Carel W Windt
- IBG-2: Plant Sciences Institute, Forschungszentrum Jülich, Leo-Brandt-Straße 1, 52428, Jülich, Germany
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8
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Terada Y, Horikawa Y, Nagata A, Kose K, Fukuda K. Dynamics of xylem and phloem sap flow in an outdoor zelkova tree visualized by magnetic resonance imaging. TREE PHYSIOLOGY 2020; 40:290-304. [PMID: 31860722 DOI: 10.1093/treephys/tpz120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/17/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Xylem and phloem sap flows in an intact, young Japanese zelkova tree (Zelkova serrata (Thunb.) Makino) growing outdoors were measured using magnetic resonance imaging (MRI). Two propagator-based sequences were developed for q-space imaging: pulse field gradient (PFG) with spin echo (PFG-SE) and stimulated echo (PFG-STE), which were used for xylem and phloem flow measurements, respectively. The data evaluation methods were improved to image fast xylem flow and slow phloem flow. Measurements were taken every 2-3 h for several consecutive days in August 2016, and diurnal changes in xylem and phloem sap flows in a cross-section of the trunk were quantified at a resolution of 1 mm2. During the day, apparent xylem flow volume exhibited a typical diurnal pattern following a vapor pressure deficit. The velocity mapping of xylem sap flow across the trunk cross section revealed that the greatest flow volume was found in current-year earlywood that had differentiated in April-May. The combined xylem flow in the 1- and 2-year-old annual rings also contributed to one-third of total sap flow. In the phloem, downward sap flow did not exhibit diurnal changes. This novel application of MRI in visualization of xylem and phloem sap flow by MRI is a promising tool for in vivo study of water transport in mature trees.
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Affiliation(s)
- Yasuhiko Terada
- Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Yusuke Horikawa
- Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Akiyoshi Nagata
- Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Katsumi Kose
- Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577, Japan
| | - Kenji Fukuda
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Umebayashi T, Sperry JS, Smith DD, Love DM. 'Pressure fatigue': the influence of sap pressure cycles on cavitation vulnerability in Acer negundo. TREE PHYSIOLOGY 2019; 39:740-746. [PMID: 30799506 DOI: 10.1093/treephys/tpy148] [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: 10/04/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 05/11/2023]
Abstract
Vulnerability-to-cavitation curves (VCs) can vary within a tree crown in relation to position or branch age. We tested the hypothesis that VC variation can arise from differential susceptibility to the number of diurnal sap pressure cycles experienced. We designed a method to distinguish between effects of cycling vs exposure time to negative pressure, and tested the influence of sap pressure cycles on cavitation vulnerability between upper and lower branches in Acer negundo L. trees using static and flow centrifuge, and air-injection methods. Branches from the upper crown had greater hydraulic conductivity and were more resistant to cavitation than branches from the lower crown. Upper branches also showed little change after exposure to 10 or 20 pressure cycles between -0.5 MPa and -2.0 MPa. Lower branches, however, showed a marked increase in vulnerability to cavitation after pressure-cycling. This result suggests that 'cavitation fatigue' can occur without the actual induction (and reversal) of cavitation as documented previously, but simply from the cycling of pressures in the sub-cavitation range. This 'pressure fatigue' may explain age-related shifts in VCs that could eventually induce dieback in suppressed branches or trees. Pressure fatigue may help explain developmental variation in hydraulic capacity of branches within individuals.
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Affiliation(s)
- Toshihiro Umebayashi
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - John S Sperry
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - Duncan D Smith
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
| | - David M Love
- School of Biological Sciences, University of Utah, 257 S 1400E, Salt Lake City, UT, USA
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10
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Yazaki K, Takanashi T, Kanzaki N, Komatsu M, Levia DF, Kabeya D, Tobita H, Kitao M, Ishida A. Pine wilt disease causes cavitation around the resin canals and irrecoverable xylem conduit dysfunction. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:589-602. [PMID: 29240955 DOI: 10.1093/jxb/erx417] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Physiological mechanisms of irreversible hydraulic dysfunction in seedlings infected with pine wilt disease (PWD) are still unclear. We employed cryo-scanning electron microscopy (cryo-SEM) to investigate the temporal and spatial changes in water distribution within the xylem of the main stem of 2-year-old Japanese black pine seedlings infested by pine wood nematodes (PWNs). Our experiment was specifically designed to compare the water relations among seedlings subjected to the following water treatment and PWN combinations: (i) well-watered versus prolonged drought (no PWNs); and (ii) well-watered with PWNs versus water-stressed with PWNs (four treatments in total). Cryo-SEM imaging observations chronicled the development of patchy cavitations in the xylem tracheids of the seedlings influenced by PWD. With the progression of drought, many pit membranes of bordered pits in the xylem of the main stem were aspirated with the decrease in water potential without xylem cavitation, indicating that hydraulic segmentation may exist between tracheids. This is the first study to demonstrate conclusively that explosive and irreversible cavitations occurred around the hydraulically vulnerable resin canals with the progression of PWD. Our findings provide a more comprehensive understanding of stressors on plant-water relations that may eventually better protect trees from PWD and assist with the breeding of trees more tolerant to PWD.
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Affiliation(s)
- Kenichi Yazaki
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Takuma Takanashi
- Department of Forest Entomology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute (FFPRI), Kyoto, Japan
| | - Masabumi Komatsu
- Department of Mushroom Science and Forest Microbiology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Delphis F Levia
- Departments of Geography and Plant & Soil Science, University of Delaware, USA
| | - Daisuke Kabeya
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Hiroyuki Tobita
- Department of Plant Ecology, Forestry and Forest Products Research Institute (FFPRI), Tsukuba, Japan
| | - Mitsutoshi Kitao
- Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI), Sappro, Japan
| | - Atsushi Ishida
- Center for Ecological Research, Kyoto University, Otsu, Japan
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11
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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: 37] [Impact Index Per Article: 5.3] [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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Umebayashi T, Utsumi Y, Koga S, Murata I, Fukuda K. Differences in drought- and freeze-induced embolisms in deciduous ring-porous plant species in Japan. PLANTA 2016; 244:753-760. [PMID: 27376942 DOI: 10.1007/s00425-016-2564-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/22/2016] [Indexed: 06/06/2023]
Abstract
Deciduous ring-porous species in Japan shed all of their leaves under severe water stress before large vessels in earlywood are embolized, and embolization take place during winter. Water in deciduous ring-porous species is mainly conducted upward via large earlywood vessels of the current year. Water columns in large vessels are vulnerable to drought-induced and freeze stress-induced embolisms. Although a vulnerability curve can be created to estimate the hydraulic capacity of plants, it remains unclear why the loss of conductivity in potted plants of ring-porous species does not reach 100 % under severe drought stress. In this study, two deciduous ring-porous species in Japan (Kalopanax septemlobus and Toxicodendron trichocarpum) were used to explain the species-specific pattern in the water-conducting pathway of the stem. We monitored and visualized the spatial distribution of xylem embolisms in the stem of K. septemlobus saplings under drought stress and freeze stress using compact magnetic resonance imaging and cryo-scanning microscopy. In addition, we evaluated the water ascent in the stems of both species using a dye uptake method. Although embolisms of large vessels were observed under drought stress and in winter, all leaves were dropped to avoid fatal water loss after embolization of some large vessels. In contrast, all large vessels were embolized in winter. Larger-diameter vessels of latewood in T. trichocarpum tended to function in trees growing in the warm temperate zone. Thus, our results suggest that the unclear curve may be derived from a discrepancy between leaf water potential and actual water potential in the xylem under severe drought stress. The frequency of xylem embolisms in deciduous ring-porous species in Japan mainly depends on the number of freeze-thaw cycles.
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Affiliation(s)
- Toshihiro Umebayashi
- Laboratory of Evaluation of Natural Environment, Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
| | | | - Shinya Koga
- Kasuya Research Forest, Kyushu University, Sasaguri, Japan
| | - Ikue Murata
- Kasuya Research Forest, Kyushu University, Sasaguri, Japan
| | - Kenji Fukuda
- Laboratory of Evaluation of Natural Environment, Department of Natural Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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