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Nardini A, Cochard H, Mayr S. Talk is cheap: rediscovering sounds made by plants. TRENDS IN PLANT SCIENCE 2024; 29:662-667. [PMID: 38218649 DOI: 10.1016/j.tplants.2023.11.023] [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: 09/22/2023] [Revised: 11/21/2023] [Accepted: 11/30/2023] [Indexed: 01/15/2024]
Abstract
A recent study and related commentaries have raised new interest in the phenomenon of ultrasonic sound production by plants exposed to stress, especially drought. While recent technological advancements have allowed the demonstration that these sounds can propagate in the air surrounding plants, we remind readers here that research on sound production by plants is more than 100 years old. The mechanisms and patterns of sound emission from plants subjected to different stress factors are also reasonably understood, thanks to the pioneering work of John Milburn and others. By contrast, experimental evidence for a role of these sounds in plant-animal or plant-plant communication remains lacking and, at present, these ideas remain highly speculative.
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Affiliation(s)
- Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy.
| | - Hervé Cochard
- Université Clermont-Auvergne, INRAE, PIAF, Clermont-Ferrand 63000, France
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
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2
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Sáez PL, Vallejos V, Sancho-Knapik D, Cavieres LA, Ramírez CF, Bravo LA, Javier Peguero-Pina J, Gil-Pelegrín E, Galmés J. Leaf hydraulic properties of Antarctic plants: effects of growth temperature and its coordination with photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2013-2026. [PMID: 38173309 DOI: 10.1093/jxb/erad474] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/02/2024] [Indexed: 01/05/2024]
Abstract
One of the well-documented effects of regional warming in Antarctica is the impact on flora. Warmer conditions modify several leaf anatomical traits of Antarctic vascular plants, increasing photosynthesis and growth. Given that CO2 and water vapor partially share their diffusion pathways through the leaf, changes in leaf anatomy could also affect the hydraulic traits of Antarctic plants. We evaluated the effects of growth temperature on several anatomical and hydraulic parameters of Antarctic plants and assessed the trait co-variation between these parameters and photosynthetic performance. Warmer conditions promoted an increase in leaf and whole plant hydraulic conductivity, correlating with adjustments in carbon assimilation. These adjustments were consistent with changes in leaf vasculature, where Antarctic species displayed different strategies. At higher temperature, Colobanthus quitensis decreased the number of leaf xylem vessels, but increased their diameter. In contrast, in Deschampsia antarctica the diameter did not change, but the number of vessels increased. Despite this contrasting behavior, some traits such as a small leaf diameter of vessels and a high cell wall rigidity were maintained in both species, suggesting a water-conservation response associated with the ability of Antarctic plants to cope with harsh environments.
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Affiliation(s)
- Patricia L Sáez
- Laboratorio de Fisiología y Biología Molecular Vegetal, Instituto de Agroindustria, Departamento de Ciencias Agronómicas y Recursos Naturales, Facultad de Ciencias Agropecuarias y Medioambiente, Universidad de La Frontera, Temuco, Chile
- Instituto de Ecología y Biodiversidad-IEB, Concepción, Chile
| | - Valentina Vallejos
- Laboratorio Cultivo de Tejidos Vegetales, Centro de Biotecnología, y Facultad de Ciencias Forestales, Universidad de Concepción, Concepción, Chile
| | - Domingo Sancho-Knapik
- Departamento de Sistemas Agrícolas, Forestales y Medio Ambiente, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, Zaragoza, España
| | - Lohengrin A Cavieres
- Instituto de Ecología y Biodiversidad-IEB, Concepción, Chile
- ECOBIOSIS, Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Barrio Universitario s/n, Concepción, Chile
| | - Constanza F Ramírez
- Laboratorio Cultivo de Tejidos Vegetales, Centro de Biotecnología, y Facultad de Ciencias Forestales, Universidad de Concepción, Concepción, Chile
| | - León A Bravo
- Laboratorio de Fisiología y Biología Molecular Vegetal, Instituto de Agroindustria, Departamento de Ciencias Agronómicas y Recursos Naturales, Facultad de Ciencias Agropecuarias y Medioambiente, Universidad de La Frontera, Temuco, Chile
| | - José Javier Peguero-Pina
- Departamento de Sistemas Agrícolas, Forestales y Medio Ambiente, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, Zaragoza, España
| | - Eustaquio Gil-Pelegrín
- Departamento de Sistemas Agrícolas, Forestales y Medio Ambiente, Centro de Investigación y Tecnología Agroalimentaria, Gobierno de Aragón, Zaragoza, España
| | - Jeroni Galmés
- Research Group on Plant Biology under Mediterranean Conditions, INAGEA-Universitat de les Illes Balears, Palma de Mallorca, Balearic Islands, Spain
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Li Z, Luo D, Ibrahim MM, Hou E, Wang C. Adaptive strategies to freeze-thaw cycles in branch hydraulics of tree species coexisting in a temperate forest. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108223. [PMID: 38043252 DOI: 10.1016/j.plaphy.2023.108223] [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: 09/06/2023] [Revised: 11/04/2023] [Accepted: 11/21/2023] [Indexed: 12/05/2023]
Abstract
Freeze-thaw cycles (FTCs) limit the distribution and survival of temperate tree species. Tree species with different wood types coexist in temperate forests and are subjected to the same FTCs. It is essential to understand how these trees differentially cope with xylem hydraulic failure induced by FTCs in the field. The branch hydraulic traits and nonstructural carbohydrate concentration of six coexisting tree species in a temperate forest were measured from mid-winter to early spring when the FTCs occurred from January to April. The percentage loss of hydraulic conductivity (PLC) was lower, and the water potential inducing a 50% loss of hydraulic conductivity (P50) was more negative in tracheid trees than in ring- and diffuse-porous trees, suggesting tracheid trees with narrow tracheid diameters showed less vulnerable to embolism and provided a lower degree of hydraulic failure during FTCs (stronger resistance). Ring-porous trees always showed lower hydraulic conductivity and higher PLC and P50, and these traits did not change during FTCs, suggesting that they might lose the hydraulic functions in winter and abandon the last year xylem. The P50 in diffuse-porous increased after several FTCs (frost fatigue), but that in tracheid species continued to increase (or even decrease) until the end of FTCs (69 cycles), suggesting that tracheid trees were less sensitive to frost fatigue than diffuse-porous trees. Soluble sugar concentration in deciduous trees negatively correlated with PLC at the end of FTCs, indicating that the effect of soluble sugar on refilling embolism occurred in early spring. While the soluble sugar concentration of deciduous trees decreased, that of two evergreen tracheid trees gradually increased, possibly due to the winter photosynthesis of evergreen leaves. Our results suggest temperate trees adopt different strategies to cope with the same FTCs. These findings enrich the understanding of plant hydraulics and carbon physiology in winter and provide insights into the response of different species coexisting in temperate forests under climate change.
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Affiliation(s)
- Zhimin Li
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin, 150040, China; Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
| | - Dandan Luo
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin, 150040, China
| | - Muhammed Mustapha Ibrahim
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Enqing Hou
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Chuankuan Wang
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China; Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, Northeast Forestry University, Harbin, 150040, China.
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Charra-Vaskou K, Lintunen A, Améglio T, Badel E, Cochard H, Mayr S, Salmon Y, Suhonen H, van Rooij M, Charrier G. Xylem embolism and bubble formation during freezing suggest complex dynamics of pressure in Betula pendula stems. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5840-5853. [PMID: 37463327 DOI: 10.1093/jxb/erad275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
Freeze-thaw-induced embolism, a key limiting factor for perennial plants results from the formation of gas bubbles during freezing and their expansion during thawing. However, the ice volumetric increase generates local pressures, which can affect the formation of bubbles. To characterize local dynamics of pressure tension and the physical state of the sap during freeze-thaw cycles, we simultaneously used ultrasonic acoustic emission analysis and synchrotron-based high-resolution computed tomography on the diffuse-porous species Betula pendula. Visualization of individual air-filled vessels and the distribution of gas bubbles in frozen xylem were performed.. Ultrasonic emissions occurred after ice formation, together with bubble formation, whereas the development of embolism took place after thawing. The pictures of frozen tissues indicated that the positive pressure induced by the volumetric increase of ice can provoke inward flow from the cell wall toward the lumen of the vessels. We found no evidence that wider vessels within a tissue were more prone to embolism, although the occurrence of gas bubbles in larger conduits would make them prone to earlier embolism. These results highlight the need to monitor local pressure as well as ice and air distribution during xylem freezing to understand the mechanism leading to frost-induced embolism.
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Affiliation(s)
| | - Anna Lintunen
- Institute for Atmospheric and Earth System Research/ Physics, Faculty of Science, University of Helsinki, Finland
- Institute for Atmospheric and Earth System Research/ Forest Science, Faculty of Agriculture and Forestry, University of Helsinki, Finland
| | - Thierry Améglio
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Eric Badel
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Hervé Cochard
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Stefan Mayr
- Institute for Botany, University of Innsbruck, Austria
| | - Yann Salmon
- Institute for Atmospheric and Earth System Research/ Physics, Faculty of Science, University of Helsinki, Finland
- Institute for Atmospheric and Earth System Research/ Forest Science, Faculty of Agriculture and Forestry, University of Helsinki, Finland
| | | | - Mahaut van Rooij
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
| | - Guillaume Charrier
- Université Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France
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Dai Y, Wang L, Wan X. Maintenance of xylem hydraulic function during winter in the woody bamboo Phyllostachys propinqua McClure. PeerJ 2023; 11:e15979. [PMID: 37719123 PMCID: PMC10504893 DOI: 10.7717/peerj.15979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 08/08/2023] [Indexed: 09/19/2023] Open
Abstract
Background Frost is a common environmental stress for temperate plants. Xylem embolism occurs in many overwintering plants due to freeze-thaw cycles, so coping with freeze-thaw-induced embolisms is essential for the survival of temperate plants. Methods This study was conducted on Phyllostachys propinqua McClure, a woody bamboo species that was grown under natural frost conditions to explore its responses to winter embolisms. From autumn to the following spring, the following measurements were recorded: predawn branch and leaf embolism, branch and leaf relative water content (RWC), root pressure and soil temperature, xylem sap osmotic potential, branch and leaf electrolyte leakage (EL), branch nonstructural carbohydrate (NSC) content and leaf net photosynthetic rate. Results P. propinqua had a mean vessel diameter of 68.95 ±1.27 µm but did not suffer severe winter embolism, peaking around 60% in winter (January), with a distinct reduction in March when root pressure returned. Leaves had a more severe winter embolism, up to 90%. Leaf RWC was much lower in winter, and leaf EL was significantly higher than branch EL in all seasons. Root pressure remained until November when soil temperature reached 9 °C, then appeared again in March when soil temperatures increased from -6 °C (January) to 11 °C. Xylem sap osmotic potential decreased from autumn to winter, reaching a minimum in March, and then increasing again. Soluble sugar (SS) concentration increased throughout the winter, peaked in March, and then decreased. Conclusions These results suggest that (1) there is a hydraulic segmentation between the stem and leaf, which could prevent stem water loss and further embolization in winter; (2) maintenance of root pressure in early winter played an important role in reducing the effect of freeze-thaw cycles on the winter embolism; (3) the physiological process that resulted in a decrease in xylem sap osmotic potential and tissue water content, and an accumulation of SS associated with cold acclimation also aided in reducing the extent of freeze-thaw-induced embolism. All these strategies could be helpful for the maintenance of xylem hydraulic function of this bamboo species during winter.
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Affiliation(s)
- Yongxin Dai
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
| | - Lin Wang
- College of Forestry, Shanxi Agricultural University, Taigu, Shanxi, China
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
| | - Xianchong Wan
- Institute of New Forestry Technology, Chinese Academy of Forestry, Beijing, China
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Lammerant R, Rita A, Borghetti M, Muscarella R. Water-limited environments affect the association between functional diversity and forest productivity. Ecol Evol 2023; 13:e10406. [PMID: 37560182 PMCID: PMC10408253 DOI: 10.1002/ece3.10406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 07/23/2023] [Indexed: 08/11/2023] Open
Abstract
The link between biodiversity and ecosystem function can depend on environmental conditions. This contingency can impede our ability to predict how biodiversity-ecosystem function (BEF) relationships will respond to future environmental change, causing a clear need to explore the processes underlying shifts in BEF relationships across large spatial scales and broad environmental gradients. We compiled a dataset on five functional traits (maximum height, wood density, specific leaf area [SLA], seed size, and xylem vulnerability to embolism [P50]), covering 78%-90% of the tree species in the National Forest Inventory from Italy, to test (i) how a water limitation gradient shapes the functional composition and diversity of forests, (ii) how functional composition and diversity of trees relate to forest annual increment via mass ratio and complementarity effects, and (iii) how the relationship between functional diversity and annual increment varies between Mediterranean and temperate climate regions. Functional composition varied with water limitation; tree communities tended to have more conservative traits in sites with higher levels of water limitation. The response of functional diversity differed among traits and climatic regions but among temperate forest plots, we found a consistent increase of functional diversity with water limitation. Tree diversity was positively associated with annual increment of Italian forests through a combination of mass ratio and niche complementarity effects, but the relative importance of these effects depended on the trait and range of climate considered. Specifically, niche complementarity effects were more strongly associated with annual increment in the Mediterranean compared to temperate forests. Synthesis: Overall, our results suggest that biodiversity mediates forest annual increment under water-limited conditions by promoting beneficial interactions between species and complementarity in resource use. Our work highlights the importance of conserving functional diversity for future forest management to maintain forest annual increment under the expected increase in intensity and frequency of drought.
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Affiliation(s)
- Roel Lammerant
- Department of Ecology & GeneticsUppsala UniversityUppsalaSweden
- Present address:
Tvärminne Zoological StationUniversity of HelsinkiHankoFinland
| | - Angelo Rita
- Dipartimento di AgrariaUniversità degli Studi di Napoli Federico IIPortici (Napoli)Italy
| | - Marco Borghetti
- Scuola di Scienze Agrarie, Forestali, Alimentari ed AmbientaliUniversità degli Studi della BasilicataPotenzaItaly
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7
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Carluccio G, Greco D, Sabella E, Vergine M, De Bellis L, Luvisi A. Xylem Embolism and Pathogens: Can the Vessel Anatomy of Woody Plants Contribute to X. fastidiosa Resistance? Pathogens 2023; 12:825. [PMID: 37375515 DOI: 10.3390/pathogens12060825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
The maintenance of an intact water column in the xylem lumen several meters above the ground is essential for woody plant viability. In fact, abiotic and biotic factors can lead to the formation of emboli in the xylem, interrupting sap flow and causing consequences on the health status of the plant. Anyway, the tendency of plants to develop emboli depends on the intrinsic features of the xylem, while the cyto-histological structure of the xylem plays a role in resistance to vascular pathogens, as in the case of the pathogenic bacterium Xylella fastidiosa. Analysis of the scientific literature suggests that on grapevine and olive, some xylem features can determine plant tolerance to vascular pathogens. However, the same trend was not reported in citrus, indicating that X. fastidiosa interactions with host plants differ by species. Unfortunately, studies in this area are still limited, with few explaining inter-cultivar insights. Thus, in a global context seriously threatened by X. fastidiosa, a deeper understanding of the relationship between the physical and mechanical characteristics of the xylem and resistance to stresses can be useful for selecting cultivars that may be more resistant to environmental changes, such as drought and vascular pathogens, as a way to preserve agricultural productions and ecosystems.
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Affiliation(s)
- Giambattista Carluccio
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Davide Greco
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Erika Sabella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Marzia Vergine
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Luigi De Bellis
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Andrea Luvisi
- Department of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
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8
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Yin XH, Hao GY, Sterck F. Ring- and diffuse-porous tree species from a cold temperate forest diverge in stem hydraulic traits, leaf photosynthetic traits, growth rate and altitudinal distribution. TREE PHYSIOLOGY 2023; 43:722-736. [PMID: 36715627 DOI: 10.1093/treephys/tpad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 01/06/2023] [Accepted: 01/20/2023] [Indexed: 05/13/2023]
Abstract
In cold and humid temperate forests, low temperature, late frost and frequent freeze-thaw cycles are the main factors limiting tree growth and survival. Ring- and diffuse-porous tree species differing in xylem anatomy coexist in these forests, but their divergent adaptations to these factors have been poorly explored. To fill this knowledge gap, we compared four ring-porous and four diffuse-porous tree species from the same temperate forest in Northeast China by quantifying their leaf and stem functional traits, their stem growth rates using tree ring analysis and their resistance to cold represented by upper altitude species distribution borders from survey data. We found that the ring-porous trees were characterized by traits related to more rapid water transport, carbon gain and stem growth rates than those of the diffuse-porous species. Compared with the diffuse-porous species, the ring-porous species had a significantly higher shoot hydraulic conductance (Ks-shoot, 0.52 vs 1.03 kg m-1 s-1 MPa-1), leaf photosynthetic rate (An, 11.28 vs 15.83 μmol m-2 s-1), relative basal area increment (BAIr, 2.28 vs 0.72 cm year-1) and stem biomass increment (M, 0.34 vs 0.09 kg year-1 m-1). However, the observed upper elevational distribution limit of the diffuse-porous species was higher than that of the ring-porous species and was associated with higher values of conservative traits, such as longer leaf life span (R2 = 0.52). Correspondingly, BAIr and M showed significant positive correlations with acquisitive traits such as Ks-shoot (R2 = 0.77) and leaf photosynthetic rate (R2 = 0.73) across the eight species, with the ring-porous species occurring at the fast-acquisitive side of the spectrum and the diffuse-porous species located on the opposite side. The observed contrasts in functional traits between the two species groups improved our understanding of their differences in terms of growth strategies and adaptive capabilities in the cold, humid temperate forests.
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Affiliation(s)
- Xiao-Han Yin
- Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Shengyang, Liaoning 110016, China
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shengyang, Liaoning 110016, China
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
| | - Guang-You Hao
- Key Laboratory of Terrestrial Ecosystem Carbon Neutrality, Shengyang, Liaoning 110016, China
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shengyang, Liaoning 110016, China
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA Wageningen, The Netherlands
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9
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McCulloh KA, Augustine SP, Goke A, Jordan R, Krieg CP, O’Keefe K, Smith DD. At least it is a dry cold: the global distribution of freeze-thaw and drought stress and the traits that may impart poly-tolerance in conifers. TREE PHYSIOLOGY 2023; 43:1-15. [PMID: 36094836 PMCID: PMC9833871 DOI: 10.1093/treephys/tpac102] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/20/2022] [Accepted: 08/30/2022] [Indexed: 05/25/2023]
Abstract
Conifers inhabit some of the most challenging landscapes where multiple abiotic stressors (e.g., aridity, freezing temperatures) often co-occur. Physiological tolerance to multiple stressors ('poly-tolerance') is thought to be rare because exposure to one stress generally limits responses to another through functional trade-offs. However, the capacity to exhibit poly-tolerance may be greater when combined abiotic stressors have similar physiological impacts, such as the disruption of hydraulic function imposed by drought or freezing. Here, we reviewed empirical data in light of theoretical expectations for conifer adaptations to drought and freeze-thaw cycles with particular attention to hydraulic traits of the stem and leaf. Additionally, we examined the commonality and spatial distribution of poly-stress along indices of these combined stressors. We found that locations with the highest values of our poly-stress index (PSi) are characterized by moderate drought and moderate freeze-thaw, and most of the global conifer distribution occupies areas of moderate poly-stress. Among traits examined, we found diverse responses to the stressors. Turgor loss point did not correlate with freeze-thaw or drought stress individually, but did with the PSi, albeit inverse to what was hypothesized. Leaf mass per area was more strongly linked with drought stress than the poly-stress and not at all with freeze-thaw stress. In stems, the water potential causing 50% loss of hydraulic conductivity became more negative with increasing drought stress and poly-stress but did not correlate with freeze-thaw stress. For these traits, we identified a striking lack of coverage for substantial portions of species ranges, particularly at the upper boundaries of their respective PSis, demonstrating a critical gap in our understanding of trait prevalence and plasticity along these stress gradients. Future research should investigate traits that confer tolerance to both freeze-thaw and drought stress in a wide range of species across broad geographic scales.
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Affiliation(s)
| | - Steven P Augustine
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Alex Goke
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Rachel Jordan
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Christopher P Krieg
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Kimberly O’Keefe
- Department of Biological Sciences, Saint Edward’s University, Austin, TX 78704, USA
| | - Duncan D Smith
- Department of Botany, University of Wisconsin-Madison, Madison, WI, 53706, USA
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10
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Taneda H, Ogasa MY, Yazaki K, Funayama-Noguchi S, Miyazawa Y, Mayr S, Maruta E. Impact of freeze-thaw-induced pit aspiration on stem water transport in the subalpine conifer Abies veitchii. PLANT PHYSIOLOGY 2022; 190:1687-1698. [PMID: 35997583 PMCID: PMC9614463 DOI: 10.1093/plphys/kiac388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
During winter, subalpine conifers experience frequent freeze-thaw cycles in stem xylem that may cause embolism and pit aspiration due to increased water volume during the sap to ice transition. This study examined the occurrence and ecological impacts of a combination of freeze-thaw-induced pit aspiration and embolism triggered by natural and artificial stem freezing. In subalpine Veitch's fir (Abies veitchii) trees, the fraction of closed pits and embolized tracheids as well as conductivity losses were measured to examine pit aspiration and its effects. When trees incurred mild drought stress in February and early March, 70%-80% of stem conductivity was lost. Cryo-scanning electron microscopy indicated <20% embolized tracheids but ∼90% closed pits. Severe drought stress in late March caused 96% ± 1.2% (mean ± standard error) loss of stem conductivity, while the fraction of embolized tracheids increased to 64% ± 6.6%, and aspirated pit fraction decreased to 23% ± 5.6%. Experimental freeze-thaw cycles also increased pit aspiration from 7.1% ± 0.89% to 49% ± 10%, and the fraction of closed pits was positively correlated to the percent loss of stem hydraulic conductivity. The results indicated that freezing-induced pit aspiration is an important factor for stem xylem dysfunction under mild drought, and upon severe drought in winter; stem water transport is predominantly inhibited by xylem embolism.
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Affiliation(s)
- Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Mayumi Y Ogasa
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto, Japan
| | - Kenichi Yazaki
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan
| | - Sachiko Funayama-Noguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | | | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Emiko Maruta
- Department of Biological Sciences, Faculty of Science, Kanagawa University, Yokohama, Japan
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11
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Maharjan SK, Sterck FJ, Raes N, Zhao Y, Poorter L. Climate change induced elevational range shifts of Himalayan tree species. Biotropica 2022. [DOI: 10.1111/btp.13159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Surya Kumar Maharjan
- Forest Ecology and Forest Management Group Wageningen University and Research Wageningen The Netherlands
- Rupantaran Nepal Kathmandu Nepal
- Department of Silviculture and Forest Biology, Institute of Forestry Tribhuvan University Hetauda Nepal
| | - Frank J. Sterck
- Forest Ecology and Forest Management Group Wageningen University and Research Wageningen The Netherlands
| | - Niels Raes
- NLBIF – Netherlands Biodiversity Information Facility Leiden The Netherlands
- Naturalis Biodiversity Center Leiden The Netherlands
| | - Yue Zhao
- Forest Ecology and Forest Management Group Wageningen University and Research Wageningen The Netherlands
| | - Lourens Poorter
- Forest Ecology and Forest Management Group Wageningen University and Research Wageningen The Netherlands
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12
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Olson ME. Linking xylem structure and function: the comparative method in from the cold. THE NEW PHYTOLOGIST 2022; 235:815-820. [PMID: 35770485 PMCID: PMC9328200 DOI: 10.1111/nph.18179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This article is a Commentary on Savage et al. (2022), 235: 953–964.
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Affiliation(s)
- Mark E. Olson
- Instituto de BiologíaUniversidad Nacional Autónoma de MéxicoTercer Circuito sn de Ciudad UniversitariaCiudad de México04510Mexico
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13
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Savage JA, Kiecker T, McMann N, Park D, Rothendler M, Mosher K. Leaf out time correlates with wood anatomy across large geographic scales and within local communities. THE NEW PHYTOLOGIST 2022; 235:953-964. [PMID: 35179794 PMCID: PMC9313884 DOI: 10.1111/nph.18041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
There is a long-standing idea that the timing of leaf production in seasonally cold climates is linked to xylem anatomy, specifically vessel diameter because of the hydraulic requirements of expanding leaves. We tested for a relationship between the timing of leaf out and vessel diameter in 220 plants in three common gardens accounting for species' phylogenetic relationships. We investigated how vessel diameter related to wood porosity, plant height and leaf length. We also used dye perfusion tests to determine whether plants relied on xylem produced during the previous growing season at the time of leaf out. In all three gardens, there was later leaf out in species with wider vessels. Ring-porous species had the widest vessels, exhibited latest leaf out and relied less on xylem made during the previous growing season than diffuse-porous species. Wood anatomy and leaf phenology did not exhibit a phylogenetic signal. The timing of leaf out is correlated with wood anatomy across species regardless of species' geographic origin and phylogenetic relationships. This correlation could be a result of developmental and physiological links between leaves and wood or tied to a larger safety efficiency trade-off.
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Affiliation(s)
| | - Thomas Kiecker
- Department of BiologyUniversity of MinnesotaDuluthMN55812USA
| | - Natalie McMann
- Department of BiologyUniversity of MinnesotaDuluthMN55812USA
| | - Daniel Park
- Department of Biological SciencesPurdue UniversityWest LafayetteIN47907USA
| | | | - Kennedy Mosher
- Department of BiologyUniversity of MinnesotaDuluthMN55812USA
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14
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Maruta E, Yazaki K, Ogasa MY, Taneda H. Pit aspiration causes an apparent loss of xylem hydraulic conductivity in a subalpine fir (Abies mariesii Mast.) overwintering at the alpine timberline. TREE PHYSIOLOGY 2022; 42:1228-1238. [PMID: 34962267 DOI: 10.1093/treephys/tpab173] [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: 04/20/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Conifers growing at the alpine timberline are exposed to combinatorial stresses that induce embolism in xylem during winter. We collected branches of Abies mariesii Mast. at the timberline on Mt Norikura of central Japan to evaluate the seasonal changes in the loss of xylem hydraulic conductivity (percent loss of hydraulic conductivity; PLC). Concurrently, we evaluated the distribution of embolized tracheids in native samples via cryo-scanning electron microscopic (cryo-SEM) observation in comparison with the drought-induced embolism samples used for the vulnerability curve. The twigs collected in late winter showed 100 PLC at a water potential of ~-3 MPa, and air-filled tracheids were observed sporadically in the cryo-SEM images. The cryo-SEM images also showed that nearly all pits of the samples from the timberline were aspirated in the xylem with 100 PLC. Conversely, in drought-induced samples used for vulnerability analysis, lower frequency of aspirated pits was observed at similar water potentials and all tracheids in the earlywood of xylem with 100 PLC were filled with air. We hypothesized that pit aspiration is the primary cause of the pronounced winter xylem conductivity loss at the timberline when water potential is near, but still above, the drought-induced vulnerability threshold. Pit aspiration before water loss may be an adaptation to severe winter conditions at timberlines to prevent widespread xylem embolism. The possible causes of pit aspiration are discussed in relation to complex stresses under harsh winter conditions at timberlines.
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Affiliation(s)
- Emiko Maruta
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
| | - Kenichi Yazaki
- Soil-Plant Ecosystem Group, Hokkaido Research Center, Forestry and Forest Products Research Institute, 7 Hitsujigaoka, Toyohira, Sapporo, Hokkaido 062-8516, Japan
| | - Mayumi Y Ogasa
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama-choh, Fushimi-ku, Kyoto, Kyoto 612-0855, Japan
| | - Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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15
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Cornelis S, Hazak O. Understanding the root xylem plasticity for designing resilient crops. PLANT, CELL & ENVIRONMENT 2022; 45:664-676. [PMID: 34971462 PMCID: PMC9303747 DOI: 10.1111/pce.14245] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 06/14/2023]
Abstract
Xylem is the main route for transporting water, minerals and a myriad of signalling molecules within the plant. With its onset during early embryogenesis, the development of the xylem relies on hormone gradients, the activity of unique transcription factors, the distribution of mobile microRNAs, and receptor-ligand pathways. These regulatory mechanisms are often interconnected and together contribute to the plasticity of this water-conducting tissue. Environmental stresses, such as drought and salinity, have a great impact on xylem patterning. A better understanding of how the structural properties of the xylem are regulated in normal and stress conditions will be instrumental in developing crops of the future. In addition, vascular wilt pathogens that attack the xylem are becoming increasingly problematic. Further knowledge of xylem development in response to these pathogens will bring new solutions against these diseases. In this review, we summarize recent findings on the molecular mechanisms of xylem formation that largely come from Arabidopsis research with additional insights from tomato and monocot species. We emphasize the impact of abiotic factors and pathogens on xylem plasticity and the urgent need to uncover the underlying mechanisms. Finally, we discuss the multidisciplinary approach to model xylem capacities in crops.
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Affiliation(s)
- Salves Cornelis
- Department of BiologyUniversity of FribourgFribourgSwitzerland
| | - Ora Hazak
- Department of BiologyUniversity of FribourgFribourgSwitzerland
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16
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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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17
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Losso A, Bär A, Unterholzner L, Bahn M, Mayr S. Branch water uptake and redistribution in two conifers at the alpine treeline. Sci Rep 2021; 11:22560. [PMID: 34799592 PMCID: PMC8604952 DOI: 10.1038/s41598-021-00436-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 10/05/2021] [Indexed: 11/21/2022] Open
Abstract
During winter, conifers at the alpine treeline suffer dramatic losses of hydraulic conductivity, which are successfully recovered during late winter. Previous studies indicated branch water uptake to support hydraulic recovery. We analyzed water absorption and redistribution in Picea abies and Larix decidua growing at the treeline by in situ exposure of branches to δ2H-labelled water. Both species suffered high winter embolism rates (> 40-60% loss of conductivity) and recovered in late winter (< 20%). Isotopic analysis showed water to be absorbed over branches and redistributed within the crown during late winter. Labelled water was redistributed over 425 ± 5 cm within the axes system and shifted to the trunk, lower and higher branches (tree height 330 ± 40 cm). This demonstrated relevant branch water uptake and re-distribution in treeline conifers. The extent of water absorption and re-distribution was species-specific, with L. decidua showing higher rates. In natura, melting snow might be the prime source for absorbed and redistributed water, enabling embolism repair and restoration of water reservoirs prior to the vegetation period. Pronounced water uptake in the deciduous L. decidua indicated bark to participate in the process of water absorption.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria.
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2753, Australia.
| | - Andreas Bär
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | | | - Michael Bahn
- Department of Ecology, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020, Innsbruck, Austria
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18
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Pampuch T, Anadon-Rosell A, Trouillier M, Lange J, Wilmking M. Direct and Indirect Effects of Environmental Limitations on White Spruce Xylem Anatomy at Treeline. FRONTIERS IN PLANT SCIENCE 2021; 12:748055. [PMID: 34759941 PMCID: PMC8573320 DOI: 10.3389/fpls.2021.748055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Treeline ecosystems are of great scientific interest to study the effects of limiting environmental conditions on tree growth. However, tree growth is multidimensional, with complex interactions between height and radial growth. In this study, we aimed to disentangle effects of height and climate on xylem anatomy of white spruce [Picea glauca (Moench) Voss] at three treeline sites in Alaska; i.e., one warm and drought-limited, and two cold, temperature-limited. To analyze general growth differences between trees from different sites, we used data on annual ring width, diameter at breast height (DBH), and tree height. A representative subset of the samples was used to investigate xylem anatomical traits. We then used linear mixed-effects models to estimate the effects of height and climatic variables on our study traits. Our study showed that xylem anatomical traits in white spruce can be directly and indirectly controlled by environmental conditions: hydraulic-related traits seem to be mainly influenced by tree height, especially in the earlywood. Thus, they are indirectly driven by environmental conditions, through the environment's effects on tree height. Traits related to mechanical support show a direct response to environmental conditions, mainly temperature, especially in the latewood. These results highlight the importance of assessing tree growth in a multidimensional way by considering both direct and indirect effects of environmental forcing to better understand the complexity of tree growth responses to the environment.
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Affiliation(s)
- Timo Pampuch
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
| | - Alba Anadon-Rosell
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
- CREAF – Centre for Research on Ecology and Forestry Applications, Barcelona, Spain
| | - Mario Trouillier
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
| | - Jelena Lange
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
- Department of Physical Geography and Geoecology, Charles University in Prague, Prague, Czechia
| | - Martin Wilmking
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
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19
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Freeze tolerance influenced forest cover and hydrology during the Pennsylvanian. Proc Natl Acad Sci U S A 2021; 118:2025227118. [PMID: 34635589 DOI: 10.1073/pnas.2025227118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2021] [Indexed: 11/18/2022] Open
Abstract
The distribution of forest cover alters Earth surface mass and energy exchange and is controlled by physiology, which determines plant environmental limits. Ancient plant physiology, therefore, likely affected vegetation-climate feedbacks. We combine climate modeling and ecosystem-process modeling to simulate arboreal vegetation in the late Paleozoic ice age. Using GENESIS V3 global climate model simulations, varying pCO2, pO2, and ice extent for the Pennsylvanian, and fossil-derived leaf C:N, maximum stomatal conductance, and specific conductivity for several major Carboniferous plant groups, we simulated global ecosystem processes at a 2° resolution with Paleo-BGC. Based on leaf water constraints, Pangaea could have supported widespread arboreal plant growth and forest cover. However, these models do not account for the impacts of freezing on plants. According to our interpretation, freezing would have affected plants in 59% of unglaciated land during peak glacial periods and 73% during interglacials, when more high-latitude land was unglaciated. Comparing forest cover, minimum temperatures, and paleo-locations of Pennsylvanian-aged plant fossils from the Paleobiology Database supports restriction of forest extent due to freezing. Many genera were limited to unglaciated land where temperatures remained above -4 °C. Freeze-intolerance of Pennsylvanian arboreal vegetation had the potential to alter surface runoff, silicate weathering, CO2 levels, and climate forcing. As a bounding case, we assume total plant mortality at -4 °C and estimate that contracting forest cover increased net global surface runoff by up to 6.1%. Repeated freezing likely influenced freeze- and drought-tolerance evolution in lineages like the coniferophytes, which became increasingly dominant in the Permian and early Mesozoic.
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20
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Abstract
Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.
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21
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Jacobsen AL. Diversity in conduit and pit structure among extant gymnosperm taxa. AMERICAN JOURNAL OF BOTANY 2021; 108:559-570. [PMID: 33861866 DOI: 10.1002/ajb2.1641] [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: 09/15/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
Gymnosperm taxa are incredibly diverse in many traits, including taxa with evergreen or deciduous leaves; broad, compound, needle-like or scale-like leaves; trees, shrubs, and lianas; and taxa with seed cones that range from fleshy to woody. Although less appreciated, xylem conduits are also diverse in structure among extant gymnosperm taxa. Within the xylem of gymnosperms, axial transport occurs predominantly via tracheids, although 10-40% of gymnosperm taxa, particularly within the Gnetophyta and Cycadophyta, also contain vessels. Gymnosperm taxa vary greatly in their inter-conduit pit structure, with different types of pit membranes and pitting arrangements. While some taxa display torus-margo bordered pits (60%), many others do not contain tori (40%), and at least some taxa without tori occur within each of the four extant phyla (Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta). Pit membrane types vary within families but appear relatively conserved within genera. Woody species with torus-bearing pit membranes occur in colder environments (lower mean annual temperature) compared to those without tori; but occurrence does not differ with mean annual precipitation. Detailed descriptions of pit membrane types are lacking for many species and genera, indicating a need for increased anatomical study. Increased knowledge of these traits could provide a unique experimental context in which to study the evolution of conduit networks, the hydraulic implications of conduit and pit structure, and the diverse structural and functional strategies utilized by gymnosperms. There are myriad potential study questions and research opportunities within this unique and diverse group of plants.
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Affiliation(s)
- Anna L Jacobsen
- Department of Biology, California State University, 9001 Stockdale Hwy, Bakersfield, CA, 93311, USA
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22
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Olson ME, Anfodillo T, Gleason SM, McCulloh KA. Tip-to-base xylem conduit widening as an adaptation: causes, consequences, and empirical priorities. THE NEW PHYTOLOGIST 2021; 229:1877-1893. [PMID: 32984967 DOI: 10.1111/nph.16961] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/14/2020] [Indexed: 06/11/2023]
Abstract
In the stems of terrestrial vascular plants studied to date, the diameter of xylem water-conducting conduits D widens predictably with distance from the stem tip L approximating D ∝ Lb , with b ≈ 0.2. Because conduit diameter is central for conductance, it is essential to understand the cause of this remarkably pervasive pattern. We give reason to suspect that tip-to-base conduit widening is an adaptation, favored by natural selection because widening helps minimize the increase in hydraulic resistance that would otherwise occur as an individual stem grows longer and conductive path length increases. Evidence consistent with adaptation includes optimality models that predict the 0.2 exponent. The fact that this prediction can be made with a simple model of a single capillary, omitting much biological detail, itself makes numerous important predictions, e.g. that pit resistance must scale isometrically with conduit resistance. The idea that tip-to-base conduit widening has a nonadaptive cause, with temperature, drought, or turgor limiting the conduit diameters that plants are able to produce, is less consistent with the data than an adaptive explanation. We identify empirical priorities for testing the cause of tip-to-base conduit widening and underscore the need to study plant hydraulic systems leaf to root as integrated wholes.
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Affiliation(s)
- Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Mexico City, 04510, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Legnaro (PD), 35020, Italy
| | - Sean M Gleason
- Water Management and Systems Research Unit, United States Department of Agriculture, Agricultural Research Service, Fort Collins, CO, 80526, USA
- Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA
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23
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Long RW, Medeiros JS. Water in, water out: root form influences leaf function. THE NEW PHYTOLOGIST 2021; 229:1186-1188. [PMID: 33085085 DOI: 10.1111/nph.16962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Randall W Long
- Holden Arboretum, 9550 Sperry Rd, Kirtland, OH, 44094, USA
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24
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Olson ME, Anfodillo T, Rosell JA, Martínez-Méndez N. Across climates and species, higher vapour pressure deficit is associated with wider vessels for plants of the same height. PLANT, CELL & ENVIRONMENT 2020; 43:3068-3080. [PMID: 32909290 DOI: 10.1111/pce.13884] [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: 07/17/2019] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
While plant height is the main driver of variation in mean vessel diameter at the stem base (VD) across angiosperms, climate, specifically temperature, does play an explanatory role, with vessels being wider with warmer temperature for plants of the same height. Using a comparative approach sampling 537 species of angiosperms across 19 communities, we rejected selection favouring freezing-induced embolism resistance as being able to account for wider vessels for a given height in warmer climates. Instead, we give reason to suspect that higher vapour pressure deficit (VPD) accounts for the positive scaling of height-standardized VD (and potential xylem conductance) with temperature. Selection likely favours conductive systems that are able to meet the higher transpirational demand of warmer climates, which have higher VPD, resulting in wider vessels for a given height. At the same time, wider vessels are likely more vulnerable to dysfunction. With future climates likely to experience ever greater extremes of VPD, future forests could be increasingly vulnerable.
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Affiliation(s)
- Mark E Olson
- Instituto de Biología, Departamento de Botánica, Universidad Nacional Autónoma de México, Tercer Circuito sn de Ciudad Universitaria, Ciudad de México, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Padova, Italy
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Norberto Martínez-Méndez
- Laboratorio de Bioconservación y Manejo, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Unidad Profesional Lázaro Cárdenas, Ciudad de México, Mexico
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25
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Prats KA, Brodersen CR. Seasonal coordination of leaf hydraulics and gas exchange in a wintergreen fern. AOB PLANTS 2020; 12:plaa048. [PMID: 33324481 PMCID: PMC7724977 DOI: 10.1093/aobpla/plaa048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/08/2020] [Indexed: 05/27/2023]
Abstract
Wintergreen fern Polystichum acrostichoides has fronds that are photosynthetically active year-round, despite diurnal and seasonal changes in soil moisture, air temperature and light availability. This species can fix much of its annual carbon during periods when the deciduous canopy is open. Yet, remaining photosynthetically active year-round requires the maintenance of photosynthetic and hydraulic systems that are vulnerable to freeze-thaw cycles. We aimed to determine the anatomical and physiological strategies P. acrostichoides uses to maintain positive carbon gain, and the coordination between the hydraulic and photosynthetic systems. We found that the first night below 0 °C led to 25 % loss of conductivity (PLC) in stipes, suggesting that winter-induced embolism occurred. Maximum photosynthetic rate and chlorophyll fluorescence declined during winter but recovered by spring, despite PLC remaining high; the remaining hydraulic capacity was sufficient to supply the leaves with water. The onset of colder temperatures coincided with the development of a necrotic hinge zone at the stipe base, allowing fronds to overwinter lying prostrate and maintain a favourable leaf temperature. Our conductivity data show that the hinge zone did not affect leaf hydraulics because of the flexibility of the vasculature. Collectively, these strategies help P. acrostichoides to survive in northeastern forests.
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Affiliation(s)
- Kyra A Prats
- School of the Environment, Yale University, New Haven, CT, USA
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26
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Olson ME. From Carlquist's ecological wood anatomy to Carlquist's Law: why comparative anatomy is crucial for functional xylem biology. AMERICAN JOURNAL OF BOTANY 2020; 107:1328-1341. [PMID: 33078405 DOI: 10.1002/ajb2.1552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
All students of xylem structure-function relations need to be familiar with the work of Sherwin Carlquist. He studies xylem through the lens of the comparative method, which uses the appearance of similar anatomical features under similar conditions of natural selection to infer function. "Function" in biology implies adaptation; maximally supported adaptation inferences require experimental and comparative xylem scientists to work with one another. Engaging with comparative inferences of xylem function will, more likely sooner rather than later, bring one to the work of Sherwin Carlquist. To mark his 90th birthday, I highlight just a few examples of his extraordinarily perceptive and general comparative insights. One is "Carlquist's Law", the pervasive tendency for vessels to be solitary when background cells are conductive. I cover his pioneering of "ecological" wood anatomy, viewing xylem variation as reflecting the effects of selection across climate and habit variation. Another is the embolism vulnerability-conduit diameter relationship, one of the most widely invoked structure-function relationships in xylem biology. I discuss the inferential richness within the notion of Carlquistian paedomorphosis, including detailed functional inferences regarding ray cell orientation. My final example comes from his very recent work offering the first satisfactory hypothesis accounting for the geographical and histological distribution of scalariform perforation plates as an adaptation, including "Carlquist's Ratchet", why scalariform plates are adaptive but do not re-evolve once lost. This extraordinarily rich production over six decades is filled with comparative inferences that should keep students of xylem function busy testing for decades to come.
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Affiliation(s)
- Mark E Olson
- Instituto de Biología, Universidad Nacional Autónoma de México, Tercer Circuito s/n de Ciudad Universitaria, Mexico, DF, 04510, México
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Soriano D, Echeverría A, Anfodillo T, Rosell JA, Olson ME. Hydraulic traits vary as the result of tip-to-base conduit widening in vascular plants. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4232-4242. [PMID: 32219309 DOI: 10.1093/jxb/eraa157] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 03/26/2020] [Indexed: 06/10/2023]
Abstract
Plant hydraulic traits are essential metrics for characterizing variation in plant function, but they vary markedly with plant size and position in a plant. We explore the potential effect of conduit widening on variation in hydraulic traits along the stem. We examined three species that differ in conduit diameter at the stem base for a given height (Moringa oleifera, Casimiroa edulis, and Pinus ayacahuite). We made anatomical and hydraulic measurements at different distances from the stem tip, constructed vulnerability curves, and examined the safety-efficiency trade-off with height-standardized data. Our results showed that segment-specific hydraulic resistance varied predictably along the stem, paralleling changes in mean conduit diameter and total number of conduits. The Huber value and leaf specific conductivity also varied depending on the sampling point. Vulnerability curves were markedly less noisy with height standardization, making the vulnerability-efficiency trade-off clearer. Because conduits widen predictably along the stem, taking height and distance from the tip into account provides a way of enhancing comparability and interpretation of hydraulic traits. Our results suggest the need for rethinking hydraulic sampling for comparing plant functional differences and strategies across individuals.
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Affiliation(s)
- Diana Soriano
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, CP, CDMX, México
| | - Alberto Echeverría
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, CP, CDMX, México
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, Legnaro (PD), Italy
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, CDMX, México
| | - Mark E Olson
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, CP, CDMX, México
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Olson M, Rosell JA, Martínez‐Pérez C, León‐Gómez C, Fajardo A, Isnard S, Cervantes‐Alcayde MA, Echeverría A, Figueroa‐Abundiz VA, Segovia‐Rivas A, Trueba S, Vázquez‐Segovia K. Xylem vessel‐diameter–shoot‐length scaling: ecological significance of porosity types and other traits. ECOL MONOGR 2020. [DOI: 10.1002/ecm.1410] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Mark Olson
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Julieta A. Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad Instituto de Ecología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Cecilia Martínez‐Pérez
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Calixto León‐Gómez
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP) Camino Baguales s/n Coyhaique 5951601 Chile
| | - Sandrine Isnard
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Centre de Coopération Internationale en Recherche Agronomique pour le Développement Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique Université de Montpellier Montpellier 34398 France
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Herbier de Nouvelle‐Caledonia Nouméa 98848 New Caledonia
| | - María Angélica Cervantes‐Alcayde
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Alberto Echeverría
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Víctor A. Figueroa‐Abundiz
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Alí Segovia‐Rivas
- Instituto de Biología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
| | - Santiago Trueba
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Centre de Coopération Internationale en Recherche Agronomique pour le Développement Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique Université de Montpellier Montpellier 34398 France
- Botanique et Modélisation de l’Architecture de Plantes de des Végétations Institut de Recherche pourle Développement Herbier de Nouvelle‐Caledonia Nouméa 98848 New Caledonia
- School of Forestry & Environmental Studies Yale University New Haven Connecticut 06511 USA
| | - Karen Vázquez‐Segovia
- Laboratorio Nacional de Ciencias de la Sostenibilidad Instituto de Ecología Universidad Nacional Autónoma de México Tercer Circuito s/n de Ciudad Universitaria Ciudad de México 04510 México
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Maruta E, Kubota M, Ikeda T. Effects of xylem embolism on the winter survival of Abies veitchii shoots in an upper subalpine region of central Japan. Sci Rep 2020; 10:6594. [PMID: 32313053 PMCID: PMC7171099 DOI: 10.1038/s41598-020-62651-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 03/11/2020] [Indexed: 11/09/2022] Open
Abstract
At high elevations, winter climatic conditions frequently cause excessive drought stress, which can induce embolism in conifer trees. We investigated the formation and repair of winter embolism in subalpine fir (Abies veitchii) growing near the timberline. We found a complete loss in xylem conductivity [100% percent loss of conductivity (PLC)] at the wind-exposed site (W+) and 40% PLC at the wind-protected site (W−). A PLC of 100% was far above the embolism rate expected from the drought-induced vulnerability analysis in the laboratory. At the W+ site, a PLC of 100% was maintained until May; this suddenly decreased to a negligible value in June, whereas the recovery at the W− site started in late winter and proceeded stepwise. The contrast between the two sites may have occurred because of the different underlying mechanisms of winter embolism. If most tracheids in the xylem of 100% PLC are air-filled, it will be difficult to refill quickly. However, embolism caused by pit aspiration could be restored rapidly, because aspirated pits isolate tracheids from each other and prevent the spread of cavitation. Although severe embolism may cause frost damage of needles, it may have a role in holding water within the stem.
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Affiliation(s)
- Emiko Maruta
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8520, Japan. .,Department of Biological Science, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa, 259-1293, Japan.
| | - Mitsumasa Kubota
- Department of Bioresource Science, Faculty of Agriculture, Shizuoka University, 836 Oya, Surugaku, Shizuoka, 422-8529, Japan.,Daitou Techuno Green Inc., 1-2-3 Haramachida, Machida, Tokyo, 194-0013, Japan
| | - Takefumi Ikeda
- Department of Forest Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, 1-5 Shimogamohangi-cho, Sakyo-ku, Kyoto, 606-8522, Japan
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Mayr S, Schmid P, Beikircher B, Feng F, Badel E. Die hard: timberline conifers survive annual winter embolism. THE NEW PHYTOLOGIST 2020; 226:13-20. [PMID: 31677276 PMCID: PMC7065000 DOI: 10.1111/nph.16304] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 10/27/2019] [Indexed: 05/02/2023]
Abstract
During winter, timberline trees are exposed to drought and frost, factors known to induce embolism. Studies indicated that conifers cope with winter embolism by xylem refilling. We analysed the loss of hydraulic conductivity (LC) in Picea abies branch xylem over 10 years, and correlated winter embolism to climate parameters. LC was investigated by direct X-ray micro-computer tomography (micro-CT) observations and potential cavitation fatigue by Cavitron measurements. Trees showed up to 100% winter embolism, whereby LC was highest, when climate variables indicated frost drought and likely freeze-thaw stress further increased LC. During summer, LC never exceeded 16%, due to hydraulic recovery. Micro-CT revealed homogenous embolism during winter and that recovery was based on xylem refilling. Summer samples exhibited lower LC in outermost compared to older tree rings, although no cavitation fatigue was detected. Long-term data and micro-CT observations demonstrate that timberline trees can survive annual cycles of pronounced winter-embolism followed by xylem refilling. Only a small portion of the xylem conductivity cannot be restored during the first year, while remaining conduits are refilled without fatigue during consecutive years. We identify important research topics to better understand the complex induction and repair of embolism at the timberline and its relevance to general plant hydraulics.
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Affiliation(s)
- Stefan Mayr
- Department of BotanyUniversity of InnsbruckSternwartestr. 156020InnsbruckAustria
| | - Peter Schmid
- Department of BotanyUniversity of InnsbruckSternwartestr. 156020InnsbruckAustria
| | - Barbara Beikircher
- Department of BotanyUniversity of InnsbruckSternwartestr. 156020InnsbruckAustria
| | - Feng Feng
- College of ForestryNorthwest A&F University3 Taicheng RdYangling712100ShaanxiChina
| | - Eric Badel
- INRA, PIAFUniversité Clermont AuvergneF‐63000Clermont–FerrandFrance
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31
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He P, Gleason SM, Wright IJ, Weng E, Liu H, Zhu S, Lu M, Luo Q, Li R, Wu G, Yan E, Song Y, Mi X, Hao G, Reich PB, Wang Y, Ellsworth DS, Ye Q. Growing-season temperature and precipitation are independent drivers of global variation in xylem hydraulic conductivity. GLOBAL CHANGE BIOLOGY 2020; 26:1833-1841. [PMID: 31749261 DOI: 10.1111/gcb.14929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Stem xylem-specific hydraulic conductivity (KS ) represents the potential for plant water transport normalized by xylem cross section, length, and driving force. Variation in KS has implications for plant transpiration and photosynthesis, growth and survival, and also the geographic distribution of species. Clarifying the global-scale patterns of KS and its major drivers is needed to achieve a better understanding of how plants adapt to different environmental conditions, particularly under climate change scenarios. Here, we compiled a xylem hydraulics dataset with 1,186 species-at-site combinations (975 woody species representing 146 families, from 199 sites worldwide), and investigated how KS varied with climatic variables, plant functional types, and biomes. Growing-season temperature and growing-season precipitation drove global variation in KS independently. Both the mean and the variation in KS were highest in the warm and wet tropical regions, and lower in cold and dry regions, such as tundra and desert biomes. Our results suggest that future warming and redistribution of seasonal precipitation may have a significant impact on species functional diversity, and is likely to be particularly important in regions becoming warmer or drier, such as high latitudes. This highlights an important role for KS in predicting shifts in community composition in the face of climate change.
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Affiliation(s)
- 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
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Sean M Gleason
- USDA-ARS Water Management and Systems Research Unit, Fort Collins, CO, USA
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ensheng Weng
- Center for Climate Systems Research, Columbia University, New York, NY, USA
| | - 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
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Shidan Zhu
- Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, China
| | - Mingzhen Lu
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Qi Luo
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Ronghua Li
- Institute of Tropical and Subtropical Ecology, South China Agricultural University, Guangzhou, China
| | - Guilin Wu
- 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
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Enrong Yan
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yanjun Song
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xiangcheng Mi
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Guangyou Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN, USA
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Yingping Wang
- 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
- CSIRO Oceans and Atmosphere, Aspendale, Vic., Australia
| | - David S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - 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
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
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32
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Lintunen A, Losso A, Aalto J, Chan T, Hölttä T, Mayr S. Propagating ice front induces gas bursts and ultrasonic acoustic emissions from freezing xylem. TREE PHYSIOLOGY 2020; 40:170-182. [PMID: 31860711 DOI: 10.1093/treephys/tpz123] [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: 06/14/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
Ice formation and propagation in the xylem of plants is a complex process. During freezing of xylem sap, gases dissolved in liquid sap are forced out of the ice lattice due to their low solubility in ice, and supersaturation of xylem sap as well as low water potential (Ѱ) are induced at the ice-liquid interface. Supersaturation of gases near the ice front may lead to bubble formation and potentially to cavitation and/or to burst of gases driven out from the branch. In this study, we investigated the origin and dynamics of freezing-related gas bursts and ultrasonic acoustic emissions (AEs), which are suggested to indicate cavitation. Picea abies (L.) H. Karst. and Salix caprea L. branch segments were exposed to frost cycles in a temperature test chamber, and CO2 efflux (indicating gas bursts) and AEs were recorded. On freezing, two-thirds of the observed gas bursts originated from the xylem and only one-third from the bark. Simultaneously with gas bursts, AEs were detected. Branch Ѱ affected both gas bursts and AEs, with high gas burst in saturated and dry samples but relevant AEs only in the latter. Repeated frost cycles led to decreasing gas burst volumes and AE activity. Experiments revealed that the expanding ice front in freezing xylem was responsible for observed gas bursts and AEs, and that branch Ѱ influenced both processes. Results also indicated that gas bursts and cavitation are independently induced by ice formation, though both may be relevant for bubble dynamics during freezing.
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Affiliation(s)
- Anna Lintunen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00014, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, Helsinki FI-00014, Finland
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestrasse 15, Innsbruck A-6020, Austria
| | - Juho Aalto
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00014, Finland
| | - Tommy Chan
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00014, Finland
| | - Teemu Hölttä
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Latokartanonkaari 7, Helsinki FI-00014, Finland
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestrasse 15, Innsbruck A-6020, Austria
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Torquato PR, Zou CB, Adhikari A, Adams HD, Will RE. Drought Tolerance and Competition in Eastern Redcedar ( Juniperus virginiana) Encroachment of the Oak-Dominated Cross Timbers. FRONTIERS IN PLANT SCIENCE 2020; 11:59. [PMID: 32117395 PMCID: PMC7020614 DOI: 10.3389/fpls.2020.00059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/15/2020] [Indexed: 06/10/2023]
Abstract
On the dry, western edge of the eastern deciduous forest of the USA (Cross Timbers), the drought-tolerant, evergreen eastern redcedar (Juniperus virginiana) is encroaching into post oak- (Quercus stellata) dominated woodlands. The overall goal of this study was to examine whether the drought tolerance strategies of eastern redcedar provide it a competitive advantage over post oak and whether this is a key attribute facilitating its successful establishment in the Cross Timbers. Specifically, we assessed xylem water potential and leaf gas exchange of these two species growing in single-species stands and in a mixed-species stand. We found that both species exhibit a similar degree of isohydry and close their stomates to the same extent in response to declining xylem water potentials. Both species had similar relative reductions in gas exchange in response to drought, despite differences in xylem anatomy. However, post oak had leaf-level gas exchange rates approximately 5× greater than eastern redcedar during periods of high moisture availability. Therefore, it did not appear that eastern redcedar encroachment into an oak-dominated forest is facilitated by growing season differences in carbon gain, although evergreen eastern redcedar can conduct gas exchange year-round when conditions are favorable while post oak is deciduous. We found that volumetric soil water content (0-45 cm) was lower in the pure eastern redcedar stand than the mixed-species or pure post oak stand which may indicate that eastern redcedar may experience favorable soil moisture conditions when encroaching into open oak woodlands. Moreover, water potentials in eastern redcedar tended to be more negative in pure stands compared to the mixed stand. Our results suggest the two species may be using water from different depths, reducing competition. Overall, our findings indicate that eastern redcedar encroachment into formerly oak-dominated Cross Timbers forests likely will continue under moderate drought, in the absence of fire, with consequences for water budgets, carbon cycling, grazing forage, wildlife habitat, and wildfire risk.
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Affiliation(s)
- Patricia R. Torquato
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, United States
- School of Ecosystem and Forest Sciences, The University of Melbourne, Burnley, VIC, Australia
| | - Chris B. Zou
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, United States
| | - Arjun Adhikari
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, United States
| | - Henry D. Adams
- Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater, OK, United States
| | - Rodney E. Will
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, United States
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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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Abstract
Research Highlights: Pronounced winter embolism and recovery were observed in the Alpine conifer shrub Pinus mugo L. Data indicated that the hydraulic courses and underlying mechanism were similar to timberline trees. Background and Objectives: At high elevation, plants above the snow cover are exposed to frost drought and temperature stress during winter. Previous studies demonstrated winter stress to induce low water potentials (Ψ) and significant xylem embolism (loss of conductivity, or LC) in evergreen conifer trees, and recovery from embolism in late winter. Here, we analyzed xylem hydraulics and related structural and cellular changes in a conifer shrub species. Materials and Methods: The uppermost branches of Pinus mugo shrubs growing at the Alpine timberline were harvested over one year, and the Ψ, water content, LC, proportion of aspirated pits, and carbohydrate contents were analyzed. Results: Minimum Ψ (−1.82 ± 0.04 MPa) and maximum LC (39.9% ± 14.5%) values were observed in mid and late winter, followed by a recovery phase. The proportion of aspirated pits was also highest in winter (64.7% ± 6.9% in earlywood, 27.0% ± 1.4% in latewood), and decreased in parallel with hydraulic recovery in late winter and spring. Glucose and fructose contents gradually decreased over the year, while starch contents (also microscopically visible as starch grains in needle and stem tissues) increased from May to July. Conclusions: The formation and recovery of embolism in Pinus mugo were similar to those of timberline trees, as were the underlying mechanisms, with pit aspiration enabling the isolation of embolized tracheids, and changes in carbohydrate contents indicating adjustments of osmotic driving forces for water re-distribution. The effects of future changes in snow cover regimes may have pronounced and complex effects on shrub-like growth forms, because a reduced snow cover may shorten the duration of frost drought, but expose the plants to increased temperature stress and impair recovery processes.
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Ogasa MY, Taneda H, Ooeda H, Ohtsuka A, Maruta E. Repair of severe winter xylem embolism supports summer water transport and carbon gain in flagged crowns of the subalpine conifer Abies veitchii. TREE PHYSIOLOGY 2019; 39:1725-1735. [PMID: 31211390 DOI: 10.1093/treephys/tpz066] [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: 10/26/2018] [Revised: 02/15/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Xylem embolism induced by winter drought is a serious dysfunction in evergreen conifers growing at wind-exposed sites in the mountains. Some coniferous species can recover from winter embolism. The aim of this study was to determine whether wind direction influences embolism formation and/or repair dynamics on short windward and long leeward branches of asymmetrical `flagged' crowns. We analyzed the effect of branch orientation on percentage loss of xylem conductive area (PLC), leaf functional traits and the xylem:leaf area ratio for subalpine, wind-exposed flagged-crown Abies veitchii trees in the northern Yatsugatake Mountains of central Japan. In late winter, the shoot water potential was below -2.5 MPa, and the PLC exceeded 80% in 2-year-old branches, independent of branch orientation within a flagged crown. Both of these parameters almost fully recovered by summer. At branch internodes 4 years of age and older, seasonal changes in PLC were not found in either windward or leeward branches, but the PLC was higher in less leafy windward branches. The leaf nitrogen content and water-use efficiency of mature leaves were comparable between windward branches and leafy leeward branches. The ratio of xylem conductive area to total leaf area was the same for windward and leeward branches. These results indicate that the repair of winter xylem embolism allows leaf physiological functions to be maintained under sufficient leaf water supply, even on winter-wind-exposed branches. This permits substantial photosynthetic carbon gain during the following growing season on both windward and leeward branches. Thus, xylem recovery from winter embolism is a key trait for the survival of harsh winters and to support productivity on the individual level in flagged-crown A. veitchii trees.
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Affiliation(s)
- Mayumi Y Ogasa
- Department of Plant Ecology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
- Forest Ecology Group, Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama-choh, Fushimi-ku, Kyoto, Kyoto 612-0855, Japan
| | - Haruhiko Taneda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroki Ooeda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Simplex Inc., 1-23-1 Toranomon, Minato-ku, Tokyo 105-6319, Japan
| | - Akihiro Ohtsuka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Asahi Kasei Corp., 1-105 Kandajimbochoh, Chiyoda-ku, Tokyo 100-8550, Japan; orcid.org/0000-0002-3814-4937
| | - Emiko Maruta
- Department of Biological Sciences, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293, Japan
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Conflicting functional effects of xylem pit structure relate to the growth-longevity trade-off in a conifer species. Proc Natl Acad Sci U S A 2019; 116:15282-15287. [PMID: 31209057 DOI: 10.1073/pnas.1900734116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Consistent with a ubiquitous life history trade-off, trees exhibit a negative relationship between growth and longevity both among and within species. However, the mechanistic basis of this life history trade-off is not well understood. In addition to resource allocation conflicts among multiple traits, functional conflicts arising from individual morphological traits may also contribute to life history trade-offs. We hypothesized that conflicting functional effects of xylem structural traits contribute to the growth-longevity trade-off in trees. We tested this hypothesis by examining the extent to which xylem morphological traits (i.e., wood density, tracheid diameters, and pit structure) relate to growth rates and longevity in two natural populations of the conifer species Pinus ponderosa Hydraulic constraints arise as trees grow larger and xylem anatomical traits adjust to compensate. We disentangled the effects of size through ontogeny in individual trees and growth rates among trees on xylem traits by sampling each tree at multiple trunk diameters. We found that the oldest trees had slower lifetime growth rates compared with younger trees in the studied populations, indicating a growth-longevity trade-off. We further provide evidence that a single xylem trait, pit structure, with conflicting effects on xylem function (hydraulic safety and efficiency) relates to the growth-longevity trade-off in a conifer species. This study highlights that, in addition to trade-offs among multiple traits, functional constraints based on individual morphological traits like that of pit structure provide mechanistic insight into how and when life history trade-offs arise.
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Zhang W, Jiang Z, Zhao H, Feng F, Cai J. Frost fatigue response to simulated frost drought using a centrifuge in Acer mono Maxim. PHYSIOLOGIA PLANTARUM 2019; 166:677-687. [PMID: 30136279 DOI: 10.1111/ppl.12816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/17/2018] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
In the coldest part of winter, water uptake is blocked by the frozen soil and frozen stems known as 'frost drought' causing severe embolisms in woody plants. Frost drought in stems was simulated in a centrifuge by a synergy between freeze-thaw cycles and the different tensions induced by changing the rotation speed. Frost fatigue was defined as a reduction of embolism resistance after a freeze-thaw cycle and determined from 'vulnerability curves', which showed percent losses of conductivity vs tension (positive value) or xylem pressure (negative value). Different tensions combined with a controlled freeze-thaw cycle were induced to investigate the effects on frost resistance over the course of year. During the growing season, Acer mono Maxim. developed significant frost fatigue, and a significant positive correlation was found between frost fatigue response and exogenous tension. During the dormant season, A. mono showed very high embolism resistance to frost drought, even under a tension of 2 MPa. When the exogenous tension was increased to 3 MPa while the stem was frozen, significant frost fatigue occurred. Longer freezing times had more serious effects on frost fatigue in A. mono. A hypothesis was raised that at the same low temperature, the severer the drought (higher tension) when stems were frozen, the higher frost fatigue response would be induced.
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Affiliation(s)
- Wen Zhang
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
- Institute of Environment and Ecology, Shandong Normal University, Ji'nan, Shandong, 250014, China
| | - Zaimin Jiang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Han Zhao
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Feng Feng
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jing Cai
- College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
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de Boer HJ, Robertson I, Clisby R, Loader NJ, Gagen M, Young GHF, Wagner-Cremer F, Hipkin CR, McCarroll D. Tree-ring isotopes suggest atmospheric drying limits temperature-growth responses of treeline bristlecone pine. TREE PHYSIOLOGY 2019; 39:983-999. [PMID: 30976807 PMCID: PMC6642877 DOI: 10.1093/treephys/tpz018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 04/24/2019] [Indexed: 06/02/2023]
Abstract
Altitudinally separated bristlecone pine populations in the White Mountains (California, USA) exhibit differential climate-growth responses as temperature and tree-water relations change with altitude. These populations provide a natural experiment to explore the ecophysiological adaptations of this unique tree species to the twentieth century climate variability. We developed absolutely dated annual ring-width chronologies, and cellulose stable carbon and oxygen isotope chronologies from bristlecone pine growing at the treeline (~3500 m) and ~200 m below for the period AD 1710-2010. These chronologies were interpreted in terms of ecophysiological adaptations to climate variability with a dual-isotope model and a leaf gas exchange model. Ring widths show positive tree growth anomalies at treeline and consistent slower growth below treeline in relation to the twentieth century warming and associated atmospheric drying until the 1980s. Growth rates of both populations declined during and after the 1980s when growing-season temperature and atmospheric vapour pressure deficit continued to increase. Our model-based interpretations of the cellulose stable isotopes indicate that positive treeline growth anomalies prior to the 1980s were related to increased stomatal conductance and leaf-level transpiration and photosynthesis. Reduced growth since the 1980s occurred with a shift to more conservative leaf gas exchange in both the treeline and below-treeline populations, whereas leaf-level photosynthesis continued to increase in response to rising atmospheric CO2 concentrations. Our results suggest that warming-induced atmospheric drying confounds positive growth responses of apparent temperature-limited bristlecone pine populations at treeline. In addition, the observed ecophysiological responses of attitudinally separated bristlecone pine populations illustrate the sensitivity of conifers to climate change.
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Affiliation(s)
- Hugo J de Boer
- Department of Environmental Sciences, Utrecht University, Utrecht, The Netherlands
| | - Iain Robertson
- Department of Geography, Swansea University, Swansea, UK
| | - Rory Clisby
- Department of Geography, Swansea University, Swansea, UK
| | - Neil J Loader
- Department of Geography, Swansea University, Swansea, UK
| | - Mary Gagen
- Department of Geography, Swansea University, Swansea, UK
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Wang N, Palmroth S, Maier CA, Domec JC, Oren R. Anatomical changes with needle length are correlated with leaf structural and physiological traits across five Pinus species. PLANT, CELL & ENVIRONMENT 2019; 42:1690-1704. [PMID: 30684950 DOI: 10.1111/pce.13516] [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: 05/14/2018] [Revised: 12/22/2018] [Accepted: 12/27/2018] [Indexed: 06/09/2023]
Abstract
The genus Pinus has wide geographical range and includes species that are the most economically valued among forest trees worldwide. Pine needle length varies greatly among species, but the effects of needle length on anatomy, function, and coordination and trade-offs among traits are poorly understood. We examined variation in leaf morphological, anatomical, mechanical, chemical, and physiological characteristics among five southern pine species: Pinus echinata, Pinus elliottii, Pinus palustris, Pinus taeda, and Pinus virginiana. We found that increasing needle length contributed to a trade-off between the relative fractions of support versus photosynthetic tissue (mesophyll) across species. From the shortest (7 cm) to the longest (36 cm) needles, mechanical tissue fraction increased by 50%, whereas needle dry density decreased by 21%, revealing multiple adjustments to a greater need for mechanical support in longer needles. We also found a fourfold increase in leaf hydraulic conductance over the range of needle length across species, associated with weaker upward trends in stomatal conductance and photosynthetic capacity. Our results suggest that the leaf size strongly influences their anatomical traits, which, in turn, are reflected in leaf mechanical support and physiological capacity.
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Affiliation(s)
- Na Wang
- School of Forestry, Northeast Forestry University, Harbin, 150040, China
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | - Sari Palmroth
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
| | | | - Jean-Christophe Domec
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Bordeaux Sciences Agro, UMR 1391 INRA-ISPA, 33175 Gradignan Cedex, France
| | - Ram Oren
- Nicholas School of the Environment, Duke University, Durham, NC, 27708, USA
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
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41
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Jin Y, Wang C, Zhou Z. Conifers but not angiosperms exhibit vulnerability segmentation between leaves and branches in a temperate forest. TREE PHYSIOLOGY 2019; 39:454-462. [PMID: 30321431 DOI: 10.1093/treephys/tpy111] [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: 04/05/2018] [Revised: 09/04/2018] [Accepted: 09/16/2018] [Indexed: 05/23/2023]
Abstract
Vulnerability segmentation (VS), an important mechanism for protecting plants from drought, hypothesizes that the distal organs of a plant should be more susceptible to embolism than the basal organs. However, experimental studies testing the VS hypothesis for trees are limited and have reached inconsistent conclusions. Here, we tested the VS hypothesis with three angiosperms and four conifers co-existing in a temperate forest in northeastern China. The results showed that the difference in vulnerability to cavitation between leaves and branches (P50leaf-branch) was positive for the conifers but negative for the angiosperms, implying that the conifers rather than the angiosperms exhibited VS. The conifers had lower leaf hydraulic safety margins and more embolism-resistant branches than the angiosperms. Although the angiosperms did not display VS, they took a hydraulic compensatory strategy (e.g., great leaf and branch hydraulic conductivities) to maintain the water supply of their leaves. In addition, we found a significant trade-off between the sapwood-specific hydraulic conductivity (KSS) and xylem pressure inducing 50% loss of hydraulic conductivity (P50branch) across all species. Both KSS and P50branch increased with the area-based light-saturated photosynthetic rate (Aarea), suggesting that increased embolism resistance of branches comes at the cost of reduced hydraulic efficiency, which in turn constrains the photosynthesis. Aarea was negatively correlated with P50leaf-branch, further indicating that the conifers had strong VS and were associated with a conservative strategy. Conversely, the angiosperms displayed an acquisitive strategy, tending to have higher Aarea, leaf and branch hydraulic conductivities, but lower embolism resistance. These differentiations in the functional traits between the angiosperms and conifers provide potential mechanisms for their co-existence in this temperate forest community.
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Affiliation(s)
- Ying Jin
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, China
| | - Chuankuan Wang
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, China
| | - Zhenghu Zhou
- Center for Ecological Research, Northeast Forestry University, 26 Hexing Road, Harbin, China
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42
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Liu H, Gleason SM, Hao G, Hua L, He P, Goldstein G, Ye Q. Hydraulic traits are coordinated with maximum plant height at the global scale. SCIENCE ADVANCES 2019; 5:eaav1332. [PMID: 30788435 PMCID: PMC6374111 DOI: 10.1126/sciadv.aav1332] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 01/04/2019] [Indexed: 05/17/2023]
Abstract
Water must be transported long distances in tall plants, resulting in increasing hydraulic resistance, which may place limitations on the maximum plant height (H max) in a given habitat. However, the coordination of hydraulic traits with H max and habitat aridity remains poorly understood. To explore whether H max modifies the trade-off between hydraulic efficiency and safety or how water availability might influence the relationship between H max and other hydraulic traits, we compiled a dataset including H max and 11 hydraulic traits for 1281 woody species from 369 sites worldwide. We found that taller species from wet habitats exhibited greater xylem efficiency and lower hydraulic safety, wider conduits, lower conduit density, and lower sapwood density, which were all associated with habitat water availability. Plant height and hydraulic functioning appear to represent a single, coordinated axis of variation, aligned primarily with water availability, thus suggesting an important role for this axis in species sorting processes.
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Affiliation(s)
- Hui Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
| | - Sean M. Gleason
- Water Management and Systems Research Unit, USDA-ARS, Fort Collins, CO 80526, USA
| | - Guangyou Hao
- Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110010, China
| | - Lei Hua
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - Pengcheng He
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
- University of Chinese Academy of Sciences, Yuquan Road 19A, Beijing 100049, China
| | - Guillermo Goldstein
- Department of Biology, University of Miami, PO Box 249118, Coral Gables, FL 33124, USA
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Nuñez, Buenos Aires C1428EGA, Argentina
| | - Qing Ye
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China
- Corresponding author.
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Messier J, Violle C, Enquist BJ, Lechowicz MJ, McGill BJ. Similarities and differences in intrapopulation trait correlations of co-occurring tree species: consistent water-use relationships amid widely different correlation patterns. AMERICAN JOURNAL OF BOTANY 2018; 105:1477-1490. [PMID: 30216410 DOI: 10.1002/ajb2.1146] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY General relationships among functional traits have been identified across species, but the forces shaping these relationships remain largely unknown. Adopting an approach from evolutionary biology, we studied similarities and differences in intrapopulation trait correlations among locally co-occurring tree species to assess the roles of constraints, phylogeny, and the environmental niche in shaping multivariate phenotypes. We tested the hypotheses (1) that intrapopulation correlations among functional traits are largely shaped by fundamental trade-offs or constraints and (2) that differences among species reflect adaptation to their environmental niches. METHODS We compared pairwise correlations and correlation matrices of 17 key functional traits within and among temperate tree species. These traits describe three well-established trade-off dimensions characterizing interspecific relationships among physiological functions: resource acquisition and conservation; sap transport and mechanical support; and branch architecture. KEY RESULTS Six trait pairs are consistently correlated within populations. Of these, only one involves dimensionally independent traits: LMA-δ13 C. For all other traits, intrapopulation functional trait correlations are weak, are species-specific, and differ from interspecific correlations. Species intrapopulation correlation matrices are related to neither phylogeny nor environmental niche. CONCLUSIONS The results (1) suggest that the functional design of these species is centered on efficient water use, (2) highlight flexibility in plant functional design across species, and (3) suggest that intrapopulation, local interspecific, and global interspecific correlations are shaped by processes acting at each of these scales.
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Affiliation(s)
- Julie Messier
- Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, 85721, USA
- Département de Biologie, Université de Sherbrooke, Sherbrooke, Quebec, J1K 2R1, Canada
| | - Cyrille Violle
- CNRS, CEFE UMR 5175, Université de Montpellier-Université Paul Valéry-EPHE, Montpellier, 34293, France
| | - Brian J Enquist
- Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, 85721, USA
- Santa Fe Institute, Santa Fe, New Mexico, 87501, USA
| | | | - Brian J McGill
- School of Biology and Ecology, University of Maine, Orono, Maine, 04469, USA
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Stewart JJ, Baker CR, Sharpes CS, Wong-Michalak ST, Polutchko SK, Adams WW, Demmig-Adams B. Effects of Foliar Redox Status on Leaf Vascular Organization Suggest Avenues for Cooptimization of Photosynthesis and Heat Tolerance. Int J Mol Sci 2018; 19:ijms19092507. [PMID: 30149544 PMCID: PMC6164678 DOI: 10.3390/ijms19092507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 08/19/2018] [Accepted: 08/22/2018] [Indexed: 01/23/2023] Open
Abstract
The interaction of heat stress with internal signaling networks was investigated through Arabidopsisthaliana mutants that were deficient in either tocopherols (vte1 mutant) or non-photochemical fluorescence quenching (NPQ; npq1, npq4, and npq1 npq4 mutants). Leaves of both vte1 and npq1 npq4 mutants that developed at a high temperature exhibited a significantly different leaf vascular organization compared to wild-type Col-0. Both mutants had significantly smaller water conduits (tracheary elements) of the xylem, but the total apparent foliar water-transport capacity and intrinsic photosynthetic capacity were similarly high in mutants and wild-type Col-0. This was accomplished through a combination of more numerous (albeit narrower) water conduits per vein, and a significantly greater vein density in both mutants relative to wild-type Col-0. The similarity of the phenotypes of tocopherol-deficient and NPQ-deficient mutants suggests that leaf vasculature organization is modulated by the foliar redox state. These results are evaluated in the context of interactions between redox-signaling pathways and other key regulators of plant acclimation to growth temperature, such as the C-repeat binding factor (CBF) transcription factors, several of which were upregulated in the antioxidant-deficient mutants. Possibilities for the future manipulation of the interaction between CBF and redox-signaling networks for the purpose of cooptimizing plant productivity and plant tolerance to extreme temperatures are discussed.
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Affiliation(s)
- Jared J Stewart
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
- School of Education, University of Colorado, Boulder, CO 80309-0249, USA.
| | - Christopher R Baker
- Department of Plant & Microbial Biology, University of California, Berkeley, CA 94720-3102, USA.
| | - Carlie S Sharpes
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| | | | - Stephanie K Polutchko
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| | - William W Adams
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
| | - Barbara Demmig-Adams
- Department of Ecology & Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA.
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Olson ME, Soriano D, Rosell JA, Anfodillo T, Donoghue MJ, Edwards EJ, León-Gómez C, Dawson T, Camarero Martínez JJ, Castorena M, Echeverría A, Espinosa CI, Fajardo A, Gazol A, Isnard S, Lima RS, Marcati CR, Méndez-Alonzo R. Plant height and hydraulic vulnerability to drought and cold. Proc Natl Acad Sci U S A 2018; 115:7551-7556. [PMID: 29967148 PMCID: PMC6055177 DOI: 10.1073/pnas.1721728115] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding how plants survive drought and cold is increasingly important as plants worldwide experience dieback with drought in moist places and grow taller with warming in cold ones. Crucial in plant climate adaptation are the diameters of water-transporting conduits. Sampling 537 species across climate zones dominated by angiosperms, we find that plant size is unambiguously the main driver of conduit diameter variation. And because taller plants have wider conduits, and wider conduits within species are more vulnerable to conduction-blocking embolisms, taller conspecifics should be more vulnerable than shorter ones, a prediction we confirm with a plantation experiment. As a result, maximum plant size should be short under drought and cold, which cause embolism, or increase if these pressures relax. That conduit diameter and embolism vulnerability are inseparably related to plant size helps explain why factors that interact with conduit diameter, such as drought or warming, are altering plant heights worldwide.
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Affiliation(s)
- Mark E Olson
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico;
| | - Diana Soriano
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Julieta A Rosell
- Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México, 04510 CDMX, Mexico
| | - Tommaso Anfodillo
- Department Territorio e Sistemi Agro-Forestali, University of Padova, 35020 Legnaro (PD), Italy
| | - Michael J Donoghue
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8106;
| | - Erika J Edwards
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520-8106
| | - Calixto León-Gómez
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Todd Dawson
- Department of Integrative Biology, University of California, Berkeley, CA 94720-3140
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720-3140
| | - J Julio Camarero Martínez
- Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas, 50059 Zaragoza, Spain
| | - Matiss Castorena
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Alberto Echeverría
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Ciudad de México (CDMX), Mexico
| | - Carlos I Espinosa
- Universidad Técnica Particular de Loja, San Cayetano Alto sn, Loja, Ecuador
| | - Alex Fajardo
- Centro de Investigación en Ecosistemas de la Patagonia Conicyt-Regional R10C1003, Universidad Austral de Chile, 5951601 Coyhaique, Chile
| | - Antonio Gazol
- Instituto Pirenaico de Ecología, Consejo Superior de Investigaciones Científicas, 50059 Zaragoza, Spain
| | - Sandrine Isnard
- Botany and Modelling of Plant Architecture and Vegetation Joint Research Unit, Institut de Recherche pour le Développement, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université Montpellier, 98800 Nouméa, New Caledonia
| | - Rivete S Lima
- Departamento de Sistemática e Ecologia, Universidade Federal da Paraíba, João Pessoa, 58051-900 Paraíba, Brazil
| | - Carmen R Marcati
- Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, 18603970 São Paulo, Brazil
| | - Rodrigo Méndez-Alonzo
- Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada, 22860 Baja California, Mexico
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Yin XH, Sterck F, Hao GY. Divergent hydraulic strategies to cope with freezing in co-occurring temperate tree species with special reference to root and stem pressure generation. THE NEW PHYTOLOGIST 2018; 219:530-541. [PMID: 29682759 DOI: 10.1111/nph.15170] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/18/2018] [Indexed: 05/23/2023]
Abstract
Some temperate tree species mitigate the negative impacts of frost-induced xylem cavitation by restoring impaired hydraulic function via positive pressures, and may therefore be more resistant to frost fatigue (the phenomenon that post-freezing xylem becomes more susceptible to hydraulic dysfunction) than nonpressure-generating species. We test this hypothesis and investigate underlying anatomical/physiological mechanisms. Using a common garden experiment, we studied key hydraulic traits and detailed xylem anatomical characteristics of 18 sympatric tree species. These species belong to three functional groups, that is, one generating both root and stem pressures (RSP), one generating only root pressure (RP), and one unable to generate such pressures (NP). The three functional groups diverged substantially in hydraulic efficiency, resistance to drought-induced cavitation, and frost fatigue resistance. Most notably, RSP and RP were more resistant to frost fatigue than NP, but this was at the cost of reduced hydraulic conductivity for RSP and reduced resistance to drought-induced cavitation for RP. Our results show that, in environments with strong frost stress: these groups diverge in hydraulic functioning following multiple trade-offs between hydraulic efficiency, resistance to drought and resistance to frost fatigue; and how differences in anatomical characteristics drive such divergence across species.
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Affiliation(s)
- Xiao-Han Yin
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Frank Sterck
- Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, 6700 AA, Wageningen, the Netherlands
| | - Guang-You Hao
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
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47
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Fernández-Pérez L, Villar-Salvador P, Martínez-Vilalta J, Toca A, Zavala MA. Distribution of pines in the Iberian Peninsula agrees with species differences in foliage frost tolerance, not with vulnerability to freezing-induced xylem embolism. TREE PHYSIOLOGY 2018; 38:507-516. [PMID: 29325114 DOI: 10.1093/treephys/tpx171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/09/2017] [Indexed: 06/07/2023]
Abstract
Drought and frosts are major determinants of plant functioning and distribution. Both stresses can cause xylem embolism and foliage damage. The objective of this study was to analyse if the distribution of six common pine species along latitudinal and altitudinal gradients in Europe is related to their interspecific differences in frost tolerance and to the physiological mechanisms underlying species-specific frost tolerance. We also evaluate if frost tolerance depends on plant water status. We studied survival to a range of freezing temperatures in 2-year-old plants and assessed the percentage loss of hydraulic conductivity (PLC) due xylem embolism formation and foliage damage determined by needle electrolyte leakage (EL) after a single frost cycle to -15 °C and over a range of predawn water potential (ψpd) values. Species experiencing cold winters in their range (Pinus nigra J.F. Arnold, Pinus sylvestris L. and Pinus uncinata Raymond ex A. DC.) had the highest frost survival rates and lowest needle EL and soluble sugar (SS) concentration. In contrast, the pines inhabiting mild or cool winter locations (especially Pinus halepensis Mill. and Pinus pinea L. and, to a lesser extent, Pinus pinaster Ait.) had the lowest frost survival and highest needle EL and SS values. Freezing-induced PLC was very low and differences among species were not related to frost damage. Reduction in ψpd decreased leaf frost damage in P. pinea and P. sylvestris, increased it in P. uncinata and had a neutral effect on the rest of the species. This study demonstrates that freezing temperatures are a major environmental driver for pine distribution and suggests that interspecific differences in leaf frost sensitivity rather than vulnerability to freezing-induced embolism or SS explain pine juvenile frost survival.
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Affiliation(s)
- Laura Fernández-Pérez
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Pedro Villar-Salvador
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Jordi Martínez-Vilalta
- CREAF, Campus UAB, Edifici C, Cerdanyola del Vallès 08193, Barcelona, Spain
- Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia, Univ. Autònoma Barcelona, Edifici C, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Andrei Toca
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
| | - Miguel A Zavala
- Forest Ecology and Restoration Group, Departmento de Ciencias de la Vida, Universidad de Alcalá, Apdo 20, Alcalá de Henares, 28805 Madrid, Spain
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Losso A, Anfodillo T, Ganthaler A, Kofler W, Markl Y, Nardini A, Oberhuber W, Purin G, Mayr S. Robustness of xylem properties in conifers: analyses of tracheid and pit dimensions along elevational transects. TREE PHYSIOLOGY 2018; 38:212-222. [PMID: 29309674 DOI: 10.1093/treephys/tpx168] [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: 07/20/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
In alpine regions, tree hydraulics are limited by low temperatures that restrict xylem growth and induce winter frost drought and freezing stress. While several studies have dealt with functional limitations, data on elevational changes in functionally relevant xylem anatomical parameters are still scarce. In wood cores of Pinus cembra L. and Picea abies (L.) Karst. trunks, harvested along five elevational transects, xylem anatomical parameters (tracheid hydraulic diameter dh, wall reinforcement (t/b)2), pit dimensions (pit aperture Da, pit membrane Dm and torus Dt diameters) and respective functional indices (torus overlap O, margo flexibility) were measured. In both species, tracheid diameters decreased and (t/b)2 increased with increasing elevation, while pit dimensions and functional indices remained rather constant (P. cembra: Dt 10.3 ± 0.2 μm, O 0.477 ± 0.005; P. abies: Dt 9.30 ± 0.18 μm, O 0.492 ± 0.005). However, dh increased with tree height following a power trajectory with an exponent of 0.21, and also pit dimensions increased with tree height (exponents: Dm 0.18; Dt 0.14; Da 0.11). Observed elevational trends in xylem structures were predominantly determined by changes in tree size. Tree height-related changes in anatomical traits showed a remarkable robustness, regardless of the distributional ranges of study species. Despite increasing stress intensities towards the timberline, no adjustment in hydraulic safety at the pit level was observed.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Tommaso Anfodillo
- Dipartimento Territorio e Sistemi Agro Forestali, Università degli Studi di Padova, 35020 Legnaro, PD, Italy
| | - Andrea Ganthaler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Werner Kofler
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Yvonne Markl
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Andrea Nardini
- Dipartimento di Scienze della Vita, Università di Trieste, Via L. Giorgieri 10, 34127 Trieste, Italy
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
| | - Gerhard Purin
- Sportgymnasium Dornbirn, Messestraße 4, 6850 Dornbirn, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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49
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Lintunen A, Mayr S, Salmon Y, Cochard H, Hölttä T. Drivers of apoplastic freezing in gymnosperm and angiosperm branches. Ecol Evol 2018; 8:333-343. [PMID: 29321875 PMCID: PMC5756836 DOI: 10.1002/ece3.3665] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/02/2017] [Accepted: 11/03/2017] [Indexed: 11/11/2022] Open
Abstract
It is not well understood what determines the degree of supercooling of apoplastic sap in trees, although it determines the number and duration of annual freeze-thaw cycles in a given environment. We studied the linkage between apoplastic ice nucleation temperature, tree water status, and conduit size. We used branches of 10 gymnosperms and 16 angiosperms collected from an arboretum in Helsinki (Finland) in winter and spring. Branches with lower relative water content froze at lower temperatures, and branch water content was lower in winter than in spring. A bench drying experiment with Picea abies confirmed that decreasing branch water potential decreases apoplastic ice nucleation temperature. The studied angiosperms froze on average 2.0 and 1.8°C closer to zero Celsius than the studied gymnosperms during winter and spring, respectively. This was caused by higher relative water content in angiosperms; when branches were saturated with water, apoplastic ice nucleation temperature of gymnosperms increased to slightly higher temperature than that of angiosperms. Apoplastic ice nucleation temperature in sampled branches was positively correlated with xylem conduit diameter as shown before, but saturating the branches removed the correlation. Decrease in ice nucleation temperature decreased the duration of freezing, which could have an effect on winter embolism formation via the time available for gas escape during ice propagation. The apoplastic ice nucleation temperature varied not only between branches but also within a branch between consecutive freeze-thaw cycles demonstrating the stochastic nature of ice nucleation.
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Affiliation(s)
- Anna Lintunen
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Stefan Mayr
- Institute of BotanyUniversity of InnsbruckInnsbruckAustria
| | - Yann Salmon
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Hervé Cochard
- University of Clermont‐AuvergneClermont‐FerrandFrance
| | - Teemu Hölttä
- Department of Forest SciencesUniversity of HelsinkiHelsinkiFinland
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Losso A, Beikircher B, Dämon B, Kikuta S, Schmid P, Mayr S. Xylem Sap Surface Tension May Be Crucial for Hydraulic Safety. PLANT PHYSIOLOGY 2017; 175:1135-1143. [PMID: 28982780 PMCID: PMC5664478 DOI: 10.1104/pp.17.01053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/02/2017] [Indexed: 05/05/2023]
Abstract
The surface tension (γ) of xylem sap plays a key role in stabilizing air-water interfaces at the pits between water- and gas-filled conduits to avoid air seeding at low water potentials. We studied seasonal changes in xylem sap γ in Picea abies and Pinus mugo growing at the alpine timberline. We analyzed their vulnerability to drought-induced embolism using solutions of different γ and estimated the potential effect of seasonal changes in γ on hydraulic vulnerability. In both species, xylem sap γ showed distinct seasonal courses between about 50 and 68 mn m-1 Solutions with low γ caused higher vulnerability to drought-induced xylem embolism. The water potential at 50% loss of hydraulic conductivity in P. abies and P. mugo was -3.35 and -3.86 MPa at γ of 74 mn m-1 but -2.11 and -2.09 MPa at 45 mn m-1 This indicates up to about 1 MPa seasonal variation in 50% loss of hydraulic conductivity. The results revealed pronounced effects of changes in xylem sap γ on the hydraulic safety of trees in situ. These effects also are relevant in vulnerability analyses, where the use of standard solutions with high γ overestimates hydraulic safety. Thus, γ should be considered carefully in hydraulic studies.
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Affiliation(s)
- Adriano Losso
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Birgit Dämon
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | - Silvia Kikuta
- Institute of Botany, University of Natural Resources and Life Sciences, BOKU Vienna, 1180 Vienna, Austria
| | - Peter Schmid
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, 6020 Innsbruck, Austria
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