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Feng F, Wagner Y, Klein T, Hochberg U. Xylem resistance to cavitation increases during summer in Pinus halepensis. PLANT, CELL & ENVIRONMENT 2023; 46:1849-1859. [PMID: 36793149 DOI: 10.1111/pce.14573] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 05/04/2023]
Abstract
Cavitation resistance has often been viewed as a relatively static trait, especially for stems of forest trees. Meanwhile, other hydraulic traits, such as turgor loss point (Ψtlp ) and xylem anatomy, change during the season. In this study, we hypothesized that cavitation resistance is also dynamic, changing in coordination with Ψtlp . We began with a comparison of optical vulnerability (OV), microcomputed tomography (µCT) and cavitron methods. All three methods significantly differed in the slope of the curve,Ψ12 and Ψ88 , but not in Ψ50 (xylem pressures that cause 12%, 88%, 50% cavitation, respectively). Thus, we followed the seasonal dynamics (across 2 years) of Ψ50 in Pinus halepensis under Mediterranean climate using the OV method. We found that Ψ50 is a plastic trait with a reduction of approximately 1 MPa from the end of the wet season to the end of the dry season, in coordination with the dynamics of the midday xylem water potential (Ψmidday ) and the Ψtlp . The observed plasticity enabled the trees to maintain a stable positive hydraulic safety margin and avoid cavitation during the long dry season. Seasonal plasticity is vital for understanding the actual risk of cavitation to plants and for modeling species' ability to tolerate harsh environments.
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Affiliation(s)
- Feng Feng
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Yael Wagner
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Tamir Klein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Uri Hochberg
- Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, Rishon LeZion, Israel
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2
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Song J, Trueba S, Yin XH, Cao KF, Brodribb TJ, Hao GY. Hydraulic vulnerability segmentation in compound-leaved trees: Evidence from an embolism visualization technique. PLANT PHYSIOLOGY 2022; 189:204-214. [PMID: 35099552 PMCID: PMC9070814 DOI: 10.1093/plphys/kiac034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/27/2021] [Indexed: 05/11/2023]
Abstract
The hydraulic vulnerability segmentation (HVS) hypothesis implies the existence of differences in embolism resistance between plant organs along the xylem pathway and has been suggested as an adaptation allowing the differential preservation of more resource-rich tissues during drought stress. Compound leaves in trees are considered a low-cost means of increasing leaf area and may thus be expected to show evidence of strong HVS, given the tendency of compound-leaved tree species to shed their leaf units during drought. However, the existence and role of HVS in compound-leaved tree species during drought remain uncertain. We used an optical visualization technique to estimate embolism occurrence in stems, petioles, and leaflets of shoots in two compound-leaved tree species, Manchurian ash (Fraxinus mandshurica) and Manchurian walnut (Juglans mandshurica). We found higher (less negative) water potentials corresponding to 50% loss of conductivity (P50) in leaflets and petioles than in stems in both species. Overall, we observed a consistent pattern of stem > petiole > leaflet in terms of xylem resistance to embolism and hydraulic safety margins (i.e. the difference between mid-day water potential and P50). The coordinated variation in embolism vulnerability between organs suggests that during drought conditions, trees benefit from early embolism and subsequent shedding of more expendable organs such as leaflets and petioles, as this provides a degree of protection to the integrity of the hydraulic system of the more carbon costly stems. Our results highlight the importance of HVS as an adaptive mechanism of compound-leaved trees to withstand drought stress.
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Affiliation(s)
- Jia Song
- CAS Key Laboratory of Forest Ecology and Management & Key Laboratory of Terrestrial Ecosystem Carbon Neutrality Liaoning Province, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China
- School of Environmental and Geographical Science, Shanghai Normal University, Shanghai 200234, China
- Yangtze River Delta National Observatory of Wetland Ecosystem, Shanghai Normal University, Shanghai 200234, China
| | - Santiago Trueba
- University of Bordeaux, INRAE, BIOGECO, 33615 Pessac, France
| | - Xiao-Han Yin
- CAS Key Laboratory of Forest Ecology and Management & Key Laboratory of Terrestrial Ecosystem Carbon Neutrality Liaoning Province, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning, China
| | - Kun-Fang Cao
- Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, and College of Forestry, Guangxi University, Nanning, Guangxi 530004, China
| | - Timothy J Brodribb
- Biological Sciences, School of Natural Sciences, University of Tasmania, Hobart, Tasmania 7001, Australia
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3
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Barbeta A, Burlett R, Martín-Gómez P, Fréjaville B, Devert N, Wingate L, Domec JC, Ogée J. Evidence for distinct isotopic compositions of sap and tissue water in tree stems: consequences for plant water source identification. THE NEW PHYTOLOGIST 2022; 233:1121-1132. [PMID: 34767646 DOI: 10.1111/nph.17857] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
The long-standing hypothesis that the isotopic composition of plant stem water reflects that of source water is being challenged by studies reporting bulk water from woody stems with an isotopic composition that cannot be attributed to any potential water source. The mechanism behind such source-stem water isotopic offsets is still poorly understood. Using a novel technique to extract selectively sap water from xylem conduits, we show that, in cut stems and potted plants, the isotopic composition of sap water reflects that of irrigation water, demonstrating unambiguously that no isotopic fractionation occurs during root water uptake or sap water extraction. By contrast, water in nonconductive xylem tissues is always depleted in deuterium compared with sap water, irrespective of wood anatomy. Previous studies have shown that isotopic heterogeneity also exists in soils at the pore scale in which water adsorbed onto soil particles is more depleted in deuterium than unbound water. Data collected at a riparian forest indicated that sap water matches best unbound soil water from depth below -70 cm, while bulk stem and soil water differ markedly. We conclude that source-stem isotopic offsets can be explained by micrometre-scale heterogeneity in the isotope ratios of water within woody stems and soil micro-pores.
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Affiliation(s)
- Adrià Barbeta
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
- BEECA, Universitat de Barcelona, Barcelona, Catalonia, 08028, Spain
| | - Régis Burlett
- Université de Bordeaux, INRAE, BIOGECO, Pessac, 33615, France
| | | | | | - Nicolas Devert
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
| | - Lisa Wingate
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
| | | | - Jérôme Ogée
- INRAE, Bordeaux Sciences Agro, ISPA, Villenave d'Ornon, 33140, France
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Lauriks F, Salomón RL, De Roo L, Goossens W, Leroux O, Steppe K. Limited plasticity of anatomical and hydraulic traits in aspen trees under elevated CO2 and seasonal drought. PLANT PHYSIOLOGY 2022; 188:268-284. [PMID: 34718790 PMCID: PMC8774844 DOI: 10.1093/plphys/kiab497] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
The timing of abiotic stress elicitors on wood formation largely affects xylem traits that determine xylem efficiency and vulnerability. Nonetheless, seasonal variability of elevated CO2 (eCO2) effects on tree functioning under drought remains largely unknown. To address this knowledge gap, 1-year-old aspen (Populus tremula L.) trees were grown under ambient (±445 ppm) and elevated (±700 ppm) CO2 and exposed to an early (spring/summer 2019) or late (summer/autumn 2018) season drought event. Stomatal conductance and stem shrinkage were monitored in vivo as xylem water potential decreased. Additional trees were harvested for characterization of wood anatomical traits and to determine vulnerability and desorption curves via bench dehydration. The abundance of narrow vessels decreased under eCO2 only during the early season. At this time, xylem vulnerability to embolism formation and hydraulic capacitance during severe drought increased under eCO2. Contrastingly, stomatal closure was delayed during the late season, while hydraulic vulnerability and capacitance remained unaffected under eCO2. Independently of the CO2 treatment, elastic, and inelastic water pools depleted simultaneously after 50% of complete stomatal closure. Our results suggest that the effect of eCO2 on drought physiology and wood traits are small and variable during the growing season and question a sequential capacitive water release from elastic and inelastic pools as drought proceeds.
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Affiliation(s)
- Fran Lauriks
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Roberto Luis Salomón
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
- Grupo de Investigación Sistemas Naturales e Historia Forestal, Universidad Politécnica de Madrid, Madrid 28040, Spain
| | - Linus De Roo
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Willem Goossens
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
| | - Olivier Leroux
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
- Department of Biology, Faculty of Sciences, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Ghent, Belgium
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Feng F, Losso A, Tyree M, Zhang S, Mayr S. Cavitation fatigue in conifers: a study on eight European species. PLANT PHYSIOLOGY 2021; 186:1580-1590. [PMID: 33905499 PMCID: PMC8260135 DOI: 10.1093/plphys/kiab170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/27/2021] [Indexed: 06/12/2023]
Abstract
After drought-induced embolism and repair, tree xylem may be weakened against future drought events (cavitation fatigue). As there are few data on cavitation fatigue in conifers available, we quantified vulnerability curves (VCs) after embolism/repair cycles on eight European conifer species. We induced 50% and 100% loss of conductivity (LC) with a cavitron, and analyzed VCs. Embolism repair was obtained by vacuum infiltration. All species demonstrated complete embolism repair and a lack of any cavitation fatigue after 50% LC . After 100% LC, European larch (Larix decidua), stone pine (Pinus cembra), Norway spruce (Picea abies), and silver fir (Abies alba) remained unaffected, while mountain pine (Pinus mugo), yew (Taxus baccata), and common juniper (Juniperus communis) exhibited 0.4-0.9 MPa higher vulnerability to embolism. A small cavitation fatigue observed in Scots pine (Pinus sylvestris) was probably biased by incomplete embolism repair, as indicated by a correlation of vulnerability shifts and conductivity restoration. Our data demonstrate that cavitation fatigue in conifers is species-specific and depends on the intensity of preceding LC. The lack of fatigue effects after moderate LC, and relevant effects in only three species after high LC, indicate that conifers are relatively resistant against cavitation fatigue. This is remarkable considering the complex and delicate conifer pit architecture and may be important considering climate change projections.
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Affiliation(s)
- Feng Feng
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, Shaanxi 711600, China
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck 6020, Austria
| | - Melvin Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang 321004, China
| | - Shuoxin Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
- Qinling National Forest Ecosystem Research Station, Huoditang, Ningshan, Shaanxi 711600, China
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck 6020, Austria
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Brunetti C, Savi T, Nardini A, Loreto F, Gori A, Centritto M. Changes in abscisic acid content during and after drought are related to carbohydrate mobilization and hydraulic recovery in poplar stems. TREE PHYSIOLOGY 2020; 40:1043-1057. [PMID: 32186735 DOI: 10.1093/treephys/tpaa032] [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: 06/02/2019] [Revised: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 06/10/2023]
Abstract
Drought compromises plant's ability to replace transpired water vapor with water absorbed from the soil, leading to extensive xylem dysfunction and causing plant desiccation and death. Short-term plant responses to drought rely on stomatal closure, and on the plant's ability to recover hydraulic functioning after drought relief. We hypothesize a key role for abscisic acid (ABA) not only in the control of stomatal aperture, but also in hydraulic recovery. Young plants of Populus nigra L. were used to investigate possible relationships among ABA, non-structural carbohydrates (NSC) and xylem hydraulic function under drought and after re-watering. In Populus nigra L. plants subjected to drought, water transport efficiency and hydraulic recovery after re-watering were monitored by measuring the percentage loss of hydraulic conductivity (PLC) and stem specific hydraulic conductivity (Kstem). In the same plants ABA and NSC were quantified in wood and bark. Drought severely reduced stomatal conductance (gL) and markedly increased the PLC. Leaf and stem water potential, and stem hydraulic efficiency fully recovered within 24 h after re-watering, but gL values remained low. After re-watering, we found significant correlations between changes in ABA content and hexoses concentration both in wood and bark. Our findings suggest a role for ABA in the regulation of stem carbohydrate metabolism and starch mobilization upon drought relief, possibly promoting the restoration of xylem transport capacity.
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Affiliation(s)
- Cecilia Brunetti
- National Research Council of Italy, Institute for Sustainable Plant Protection, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Florence), Italy
| | - Tadeja Savi
- University of Natural Resources and Life Sciences, Institute of Botany, Department of Integrative Biology and Biodiversity Research, BOKU, Gregor-Mendel-Straße 33, 1190, Vienna, Austria Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Francesco Loreto
- National Research Council of Italy, Department of Biology, Agriculture and Food Sciences, Piazzale Aldo Moro 7, 00185 Roma, Italy
| | - Antonella Gori
- Department of Agri-Food Production and Environmental Sciences, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino (Florence), Italy
| | - Mauro Centritto
- National Research Council of Italy, Institute for Sustainable Plant Protection, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Florence), Italy
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Peng G, Yang D, Liang Z, Li J, Tyree MT. An improved centrifuge method for determining water extraction curves and vulnerability curves in the long-vessel species Robinia pseudoacacia. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:4865-4876. [PMID: 31056686 PMCID: PMC6760279 DOI: 10.1093/jxb/erz206] [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: 10/21/2018] [Accepted: 04/26/2019] [Indexed: 05/29/2023]
Abstract
Significant improvements to the centrifuge water-extraction method of measuring the percentage loss volume of water (PLV) and corresponding vulnerability curves (VCs) are reported. Cochard and Sperry rotors are both incapable of measuring the VCs of species with long vessels because of premature embolism induced by hypothetical nanoparticles that can be drawn into segments during flow measurement. In contrast, water extraction pushes nanoparticles out of the sample. This study focuses on a long-vessel species, Robinia pseudoacacia, for which many VCs have been constructed by different methods, and the daily water relations have been quantified. PLV extraction curves have dual Weibull curves, and this paper focuses on the second Weibull curve because it involves the extraction of water from vessels, as proven by staining methods. We demonstrate an improved water extraction method after evaporation correction that has accuracy to within 0.5%, shows good agreement with two traditional methods that are slower and less accurate, and is immune to nanoparticle artefacts. Using Poiseuille's Law and the geometry of vessels, we argue that the percentage loss of conductivity (PLC) equals 2PLV-PLV2 in a special case where all vessels, regardless of size, have the same vulnerability curve. In this special case, this equation predicts the data reasonably well.
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Affiliation(s)
- Guoquan Peng
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Dongmei Yang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Zhao Liang
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Junhui Li
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
| | - Melvin T Tyree
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
- Center for Nano- and Micro-Mechanics, Engineering Mechanics, Tsinghua University, Beijing, China
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8
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Rosner S, Heinze B, Savi T, Dalla‐Salda G. Prediction of hydraulic conductivity loss from relative water loss: new insights into water storage of tree stems and branches. PHYSIOLOGIA PLANTARUM 2019; 165:843-854. [PMID: 29923608 PMCID: PMC7379737 DOI: 10.1111/ppl.12790] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 06/04/2018] [Accepted: 06/15/2018] [Indexed: 05/23/2023]
Abstract
More frequently occurring, drought waves call for a deeper understanding of tree hydraulics and fast and easily applicable methods to measure drought stress. The aim of this study was to establish empirical relationships between the percent loss of hydraulic conductivity (PLC) and the relative water loss (RWL) in woody stem axes with different P50 , i.e. the water potential (Ψ) that causes 50% conductivity loss. Branches and saplings of temperate conifer (Picea abies, Larix decidua) and angiosperm species (Acer campestre, Fagus sylvatica, Populus x canescens, Populus tremula, Sorbus torminalis) and trunk wood of mature P. abies trees were analyzed. P50 was calculated from hydraulic measurements following bench top dehydration or air injection. RWL and PLC were fitted by linear, quadratic or cubic equations. Species- or age-specific RWLs at P50 varied between 10 and 25% and P88 , the Ψ that causes 88% conductivity loss, between 18 and 44%. P50 was predicted from the relationship between Ψ and the RWL. The predictive quality for P50 across species was almost 1:1 (r2 = 0.99). The approach presented allows thus reliable and fast prediction of PLC from RWL. Branches and saplings with high hydraulic vulnerability tended to have lower RWLs at P50 and at P88 . The results are discussed with regard to the different water storage capacities in sapwood and survival strategies under drought stress. Potential applications are screening trees for drought sensitivity and a fast interpretation of diurnal, seasonal or drought induced changes in xylem water content upon their impact on conductivity loss.
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Affiliation(s)
- Sabine Rosner
- Institute of BotanyBOKU University ViennaGregor Mendel Straße 33, 1180ViennaAustria
| | - Berthold Heinze
- Department of Forest Genetics, Federal Research and Training Centre for ForestsNatural Hazards and LandscapeSeckendorff-Gudent-Weg 8, 1130ViennaAustria
| | - Tadeja Savi
- Institute of BotanyBOKU University ViennaGregor Mendel Straße 33, 1180ViennaAustria
- Division of Viticulture and PomologyBOKU University ViennaKonrad Lorenz‐Straβe 243430 Tulln an der DonauAustria
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9
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Du G, Feng F, Wang Y, Tyree MT. Do nano-particles cause recalcitrant vulnerability curves in Robinia? Testing with a four-cuvette Cochard rotor and with water extraction curves. TREE PHYSIOLOGY 2019; 39:156-165. [PMID: 29788216 DOI: 10.1093/treephys/tpy051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
Cavitation resistance is a key trait for characterizing the drought adaption in plants and is usually presented in terms of vulnerability curves. Three principal techniques have been developed to produce vulnerability curves, but curves generated with centrifugation are reported to suffer from artifacts when applied to long-vesseled species. The main cause of this artifact is the issue of open vessels, resulting in a nano-particle effect that may seed premature embolism. We used two methods to test the potential mechanism behind the nano-particle effect in centrifuge-based vulnerability curves. A four-cuvette rotor system based on a traditional Cochard rotor was designed to inhibit effervescence while injecting water, but the recalcitrant vulnerability curves in Robinia could not be eliminated. There may be multiple sources, besides effervescence, of hypothetical nano-particles: they may arise from cut surfaces or they may be always present in the injected water, leading to the premature embolisms. To prevent the entry of the hypothetical nano-particles, water extraction curves in terms of PLV (percentage loss volume of extracted water from stems) vs tensions were constructed. The PLV curves of Robinia showed s-shaped characteristics after subtracting the first Weibull components from water extraction curves, which were not related to the water loss from vessels according to dye staining experiments. The differences between T50 (xylem tension at which 50% of hydraulic conductivity is lost) in mean PLV curve and T50 in percentage loss of conductivity curves determined by the four-cuvette rotor system and by the bench dehydration method were 3.9 MPa and 0.7 MPa, respectively. Hence, PLV curves may be a valid way to measure the cavitation resistance in long-vesseled species with centrifugation. Keeping bark intact in the process of measurement is recommended, otherwise it would increase evaporation from the entire system.
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Affiliation(s)
- Guangyuan Du
- College of Science, Northwest A&F University, Yangling, Shaanxi, China
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Feng Feng
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
| | - Yujie Wang
- Biology Department, University of Utah, Salt Lake City, UT, USA
| | - Melvin T Tyree
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
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10
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Pivovaroff AL, Cook VMW, Santiago LS. Stomatal behaviour and stem xylem traits are coordinated for woody plant species under exceptional drought conditions. PLANT, CELL & ENVIRONMENT 2018; 41:2617-2626. [PMID: 29904932 DOI: 10.1111/pce.13367] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/04/2018] [Accepted: 06/06/2018] [Indexed: 06/08/2023]
Abstract
Isohydry (maintenance of plant water potential at the cost of carbon gain) and anisohydry (gas exchange maintenance at the cost of declining plant water status) make up two ends of a stomatal drought response strategy continuum. However, few studies have merged measures of stomatal regulation with xylem hydraulic safety strategies based on in situ field measurements. The goal of this study was to characterize the stomatal and xylem hydraulic safety strategies of woody species in the biodiverse Mediterranean-type ecosystem region of California. Measurements were conducted in situ when California was experiencing the most severe drought conditions in the past 1,200 years. We found coordination among stomatal, hydraulic, and standard leaf functional traits. For example, stem xylem vulnerability to cavitation (P50 ) was correlated with the water potential at stomatal closure (Pclose ); more resistant species had a more negative water potential at stomatal closure. The degree of isohydry-anisohydry, defined at Pclose -P50 , was correlated with the hydraulic safety margin across species; more isohydric species had a larger hydraulic safety margin. In addition, we report for the first time Pclose values below -10 MPa. Measuring these traits in a biodiverse region under exceptional drought conditions contributes to our understanding of plant drought responses.
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Affiliation(s)
- Alexandria L Pivovaroff
- Departments of Biology and Environmental Science, Whittier College, Whittier, California
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California
| | - Victoria M W Cook
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California
| | - Louis S Santiago
- Department of Botany and Plant Sciences, University of California Riverside, Riverside, California
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Lobo A, Torres-Ruiz JM, Burlett R, Lemaire C, Parise C, Francioni C, Truffaut L, Tomášková I, Hansen JK, Kjær ED, Kremer A, Delzon S. Assessing inter- and intraspecific variability of xylem vulnerability to embolism in oaks. FOREST ECOLOGY AND MANAGEMENT 2018; 424:53-61. [PMID: 29910530 PMCID: PMC5997172 DOI: 10.1016/j.foreco.2018.04.031] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The genus Quercus comprises important species in forestry not only for their productive value but also for their ability to withstand drought. Hence an evaluation of inter- and intraspecific variation in drought tolerance is important for selecting the best adapted species and provenances for future afforestation. The presence of long vessels makes it difficult to assess xylem vulnerability to embolism in oak. Thanks to the development of an in situ flow centrifuge equipped with a large rotor, we quantified (i) the between species variability of embolism resistance in four native and two exotic species of oaks in Europe and (ii) the within species variability in Quercus petraea. Embolism resistance varied significantly among species, with the pressure inducing 50% loss of hydraulic conductivity (P50 ) ranging between - 7.0 and -4.2 MPa. Species native to the Mediterranean region were more resistant than pan-European species. In contrast, intraspecific variability in embolism resistance in Q. petraea was low within provenances and null among provenances. A positive correlation between P50 and vessel diameter among the six oak species indicates that the more embolism resistant species had narrower xylem vessels. However, this tradeoff between hydraulic efficiency and safety was not observed between Q. petraea provenances.
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Affiliation(s)
- Albin Lobo
- Department of Geosciences and Natural Resource Management (IGN), University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | | | | | | | | | | | | | - Ivana Tomášková
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Praha 6 – Suchdol, Czech Republic
| | - Jon Kehlet Hansen
- Department of Geosciences and Natural Resource Management (IGN), University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
| | - Erik Dahl Kjær
- Department of Geosciences and Natural Resource Management (IGN), University of Copenhagen, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
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Ahmad HB, Lens F, Capdeville G, Burlett R, Lamarque LJ, Delzon S. Intraspecific variation in embolism resistance and stem anatomy across four sunflower (Helianthus annuus L.) accessions. PHYSIOLOGIA PLANTARUM 2018; 163:59-72. [PMID: 29057474 DOI: 10.1111/ppl.12654] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/04/2017] [Accepted: 10/17/2017] [Indexed: 05/27/2023]
Abstract
Drought-induced xylem embolism is a key process closely related to plant mortality during extreme drought events. However, this process has been poorly investigated in crop species to date, despite the observed decline of crop productivity under extreme drought conditions. Interspecific variation in hydraulic traits has frequently been reported, but less is known about intraspecific variation in crops. We assessed the intraspecific variability of embolism resistance in four sunflower (Helianthus annuus L.) accessions grown in well-watered conditions. Vulnerability to embolism was determined by the in situ flow-centrifuge method (cavitron), and possible trade-offs between xylem safety, xylem efficiency and growth were assessed. The relationship between stem anatomy and hydraulic traits was also investigated. Mean P50 was -3 MPa, but significant variation was observed between accessions, with values ranging between -2.67 and -3.22 MPa. Embolism resistance was negatively related to growth and positively related to xylem-specific hydraulic conductivity. There is, therefore, a trade-off between hydraulic safety and growth but not between hydraulic safety and efficiency. Finally, we found that a few anatomical traits, such as vessel density and the area of the vessel lumen relative to that of the secondary xylem, were related to embolism resistance, whereas stem tissue lignification was not. Further investigations are now required to investigate the link between the observed variability of embolism resistance and yield, to facilitate the identification of breeding strategies to improve yields in an increasingly arid world.
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Affiliation(s)
- Hafiz B Ahmad
- BIOGECO, INRA, University of Bordeaux, Cestas, France
| | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, PO Box 9517, Leiden, the Netherlands
| | | | - Régis Burlett
- BIOGECO, INRA, University of Bordeaux, Cestas, France
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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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14
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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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