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Jupa R, Plichta R, Plavcová L, Paschová Z, Gloser V. Adjustment of storage capacity for non-structural carbohydrates in response to limited water availability in two temperate woody species. PHYSIOLOGIA PLANTARUM 2024; 176:e14522. [PMID: 39248017 DOI: 10.1111/ppl.14522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 08/26/2024] [Indexed: 09/10/2024]
Abstract
Reserves of non-structural carbohydrates (NSC) stored in living cells are essential for drought tolerance of trees. However, little is known about the phenotypic plasticity of living storage compartments (SC) and their interactions with NSC reserves under changing water availability. Here, we examined adjustments of SC and NSC reserves in stems and roots of seedlings of two temperate tree species, Acer negundo L. and Betula pendula Roth., cultivated under different substrate water availability. We found that relative contents of soluble NSC, starch and total NSC increased with decreasing water availability in stems of both species, and similar tendencies were also observed in roots of A. negundo. In the roots of B. pendula, soluble NSC contents decreased along with the decreasing water availability, possibly due to phloem decoupling or NSC translocation to shoots. Despite the contrast in organ responses, NSC contents (namely starch) positively correlated with proportions of total organ SC. Individual types of SC showed markedly distinct plasticity upon decreasing water availability, suggesting that water availability changes the partitioning of organ storage capacity. We found an increasing contribution of parenchyma-rich bark to the total organ NSC storage capacity under decreasing water availability. However, xylem SC showed substantially greater plasticity than those in bark. Axial storage cells, namely living fibers in A. negundo, responded more sensitively to decreasing water availability than radial parenchyma. Our results demonstrate that drought-induced changes in carbon balance affect the organ storage capacity provided by living cells, whose proportions are sensitively coordinated along with changing NSC reserves.
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Affiliation(s)
- Radek Jupa
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Forest Botany, Dendrology and Geobiocoenology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic
| | - Roman Plichta
- Department of Forest Botany, Dendrology and Geobiocoenology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic
| | - Lenka Plavcová
- Department of Forest Ecology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Praha, Czech Republic
| | - Zuzana Paschová
- Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czech Republic
| | - Vít Gloser
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
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García-Hidalgo M, García-Pedrero Á, Rozas V, Sangüesa-Barreda G, García-Cervigón AI, Resente G, Wilmking M, Olano JM. Tree ring segmentation using UNEt TRansformer neural network on stained microsections for quantitative wood anatomy. FRONTIERS IN PLANT SCIENCE 2024; 14:1327163. [PMID: 38259935 PMCID: PMC10800830 DOI: 10.3389/fpls.2023.1327163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/14/2023] [Indexed: 01/24/2024]
Abstract
Forests are critical in the terrestrial carbon cycle, and the knowledge of their response to ongoing climate change will be crucial for determining future carbon fluxes and climate trajectories. In areas with contrasting seasons, trees form discrete annual rings that can be assigned to calendar years, allowing to extract valuable information about how trees respond to the environment. The anatomical structure of wood provides highly-resolved information about the reaction and adaptation of trees to climate. Quantitative wood anatomy helps to retrieve this information by measuring wood at the cellular level using high-resolution images of wood micro-sections. However, whereas large advances have been made in identifying cellular structures, obtaining meaningful cellular information is still hampered by the correct annual tree ring delimitation on the images. This is a time-consuming task that requires experienced operators to manually delimit ring boundaries. Classic methods of automatic segmentation based on pixel values are being replaced by new approaches using neural networks which are capable of distinguishing structures, even when demarcations require a high level of expertise. Although neural networks have been used for tree ring segmentation on macroscopic images of wood, the complexity of cell patterns in stained microsections of broadleaved species requires adaptive models to accurately accomplish this task. We present an automatic tree ring boundary delineation using neural networks on stained cross-sectional microsection images from beech cores. We trained a UNETR, a combined neural network of UNET and the attention mechanisms of Visual Transformers, to automatically segment annual ring boundaries. Its accuracy was evaluated considering discrepancies with manual segmentation and the consequences of disparity for the goals of quantitative wood anatomy analyses. In most cases (91.8%), automatic segmentation matched or improved manual segmentation, and the rate of vessels assignment to annual rings was similar between the two categories, even when manual segmentation was considered better. The application of convolutional neural networks-based models outperforms human operator segmentations when confronting ring boundary delimitation using specific parameters for quantitative wood anatomy analysis. Current advances on segmentation models may reduce the cost of massive and accurate data collection for quantitative wood anatomy.
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Affiliation(s)
| | - Ángel García-Pedrero
- Department of Computer Architecture and Technology, Universidad Politécnica de Madrid, Madrid, Spain
- Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain
| | - Vicente Rozas
- iuFOR, EiFAB, Universidad de Valladolid, Soria, Spain
| | | | | | - Giulia Resente
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
- Department DISAFA, University of Torino, Torino, Italy
| | - Martin Wilmking
- Institute of Botany and Landscape Ecology, University Greifswald, Greifswald, Germany
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Rezaie N, D'Andrea E, Scartazza A, Gričar J, Prislan P, Calfapietra C, Battistelli A, Moscatello S, Proietti S, Matteucci G. Upside down and the game of C allocation. TREE PHYSIOLOGY 2023:tpad034. [PMID: 36917230 DOI: 10.1093/treephys/tpad034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/02/2023] [Accepted: 03/11/2023] [Indexed: 06/18/2023]
Abstract
Non-structural carbohydrates (NSCs) represent the primary carbon (C) reserves and play a crucial role for plant functioning and resilience. Indeed, these compounds are involved in the regulation between C supply and demand, and in the maintenance of hydraulic efficiency. NSCs are stored in parenchyma of woody organs, which is recognized as a proxy for reserve storage capacity of tree. Notwithstanding the importance of NSCs for tree physiology, their long-term regulation and trade-offs against growth were not deeply investigated. This work evaluated the long-term dynamics of mature tree reserves in stem and root, proxied by parenchyma features, and focusing on the trade off and interplay between the resources allocation in radial growth and reserves in stem and coarse root. In a Mediterranean beech forest, NSCs content, stem and root wood anatomy analysis, and eddy covariance data, were combined. The parenchyma fraction (RAP) of beech root and stem was different, due to differences in axial parenchyma (AP) and narrow ray parenchyma (nRP) fractions. However, these parenchyma components and radial growth showed synchronous inter-annual dynamics between the two organs. In beech stem, positive correlations were found among soluble sugars content and nRP, and among starch content and the AP. Positive correlations were found among Net Ecosystem Exchange (NEE) and AP of both organs. In contrast, NEE was negatively correlated to radial growth of root and stem. Our results suggest a different contribution of stem and roots to reserves storage, and a putative partitioning in the functional roles of parenchyma components. Moreover, a long-term trade-off of C allocation between growth and reserve pool was evidenced. Indeed, in case of C source reduction, trees preferentially allocate C towards reserves pool. Conversely, in high productive years, growth represents the major C sink.
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Affiliation(s)
- Negar Rezaie
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), Via P. Castellino n. 111, 80131 Napoli, Italy
| | - Ettore D'Andrea
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), via Marconi 2, 05010 Porano (TR), Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Andrea Scartazza
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), Via Moruzzi 1, 56124 Pisa, Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Jožica Gričar
- Slovenian Forestry Institute, Večna pot 2, 1000 Ljubljana, Slovenia
| | - Peter Prislan
- Slovenian Forestry Institute, Večna pot 2, 1000 Ljubljana, Slovenia
| | - Carlo Calfapietra
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), via Marconi 2, 05010 Porano (TR), Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
| | - Alberto Battistelli
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), via Marconi 2, 05010 Porano (TR), Italy
| | - Stefano Moscatello
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), via Marconi 2, 05010 Porano (TR), Italy
| | - Simona Proietti
- Research Institute on Terrestrial Ecosystems, National Research Council of Italy (CNR-IRET), via Marconi 2, 05010 Porano (TR), Italy
| | - Giorgio Matteucci
- Institute for BioEconomy, National Research Council of Italy (CNR-IBE), via Madonna del Piano, 10 - 50019 Sesto Fiorentino (FI), Italy
- National Biodiversity Future Center (NBFC), Palermo, Italy
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Hietz P, Rungwattana K, Scheffknecht S, George JP. Effects of Provenance, Growing Site, and Growth on Quercus robur Wood Anatomy and Density in a 12-Year-Old Provenance Trial. FRONTIERS IN PLANT SCIENCE 2022; 13:795941. [PMID: 35574121 PMCID: PMC9100569 DOI: 10.3389/fpls.2022.795941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 03/22/2022] [Indexed: 06/15/2023]
Abstract
Vessels are responsible for an efficient and safe water transport in angiosperm xylem. Whereas large vessels efficiently conduct the bulk of water, small vessels might be important under drought stress or after winter when large vessels are embolized. Wood anatomy can adjust to the environment by plastic adaptation, but is also modified by genetic selection, which can be driven by climate or other factors. To distinguish between plastic and genetic components on wood anatomy, we used a Quercus robur trial where trees from ten Central European provenances were planted in three locations in Austria along a rainfall gradient. Because wood anatomy also adjusts to tree size and in ring-porous species, the vessel size depends on the amount of latewood and thereby ring width, we included tree size and ring width in the analysis. We found that the trees' provenance had a significant effect on average vessel area (VA), theoretical specific hydraulic conductivity (Ks), and the vessel fraction (VF), but correlations with annual rainfall of provenances were at best weak. The trial site had a strong effect on growth (ring width, RW), which increased from the driest to the wettest site and wood density (WD), which increased from wet to dry sites. Significant site x provenance interactions were seen only for WD. Surprisingly, the drier site had higher VA, higher VF, and higher Ks. This, however, is mainly a result of greater RW and thus a greater proportion of latewood in the wetter forest. The average size of vessels > 70 μm diameter increased with rainfall. We argue that Ks, which is measured per cross-sectional area, is not an ideal parameter to compare the capacity of ring-porous trees to supply leaves with water. Small vessels (<70 μm) on average contributed only 1.4% to Ks, and we found no evidence that their number or size was adaptive to aridity. RW and tree size had strong effect on all vessel parameters, likely via the greater proportion of latewood in wide rings. This should be accounted for when searching for wood anatomical adaptations to the environment.
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Affiliation(s)
- Peter Hietz
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Kanin Rungwattana
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria
- Department of Botany, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Susanne Scheffknecht
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Jan-Peter George
- Department of Forest Genetics, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Vienna, Austria
- Faculty of Science and Technology, University of Tartu, Tartu, Estonia
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Zheng J, Li Y, Morris H, Vandelook F, Jansen S. Variation in Tracheid Dimensions of Conifer Xylem Reveals Evidence of Adaptation to Environmental Conditions. FRONTIERS IN PLANT SCIENCE 2022; 13:774241. [PMID: 35251072 PMCID: PMC8893226 DOI: 10.3389/fpls.2022.774241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Globally distributed extant conifer species must adapt to various environmental conditions, which would be reflected in their xylem structure, especially in the tracheid characteristics of earlywood and latewood. With an anatomical trait dataset of 78 conifer species growing throughout China, an interspecific study within a phylogenetic context was conducted to quantify variance of tracheid dimensions and their response to climatic and soil conditions. There was a significant difference in tracheid diameter between earlywood and latewood while no significant difference was detected in tracheid wall thickness through a phylogenetically paired t-test. Through a phylogenetic principle component analysis, Pinaceae species were found to be strongly divergent in their tracheid structure in contrast to a conservative tracheid structure in species of Cupressaceae, Taxaceae, and Podocarpaceae. Tracheid wall thickness decreased from high to low latitudes in both earlywood and latewood, with tracheid diameter decreasing for latewood only. According to the most parsimonious phylogenetic general least square models, environment and phylogeny together could explain about 21∼56% of tracheid structure variance. Our results provide insights into the effects of climate and soil on the xylem structure of conifer species thus furthering our understanding of the trees' response to global change.
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Affiliation(s)
- Jingming Zheng
- Beijing Key Laboratory for Forest Resources and Ecosystem Processes, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Yajin Li
- Beijing Key Laboratory for Forest Resources and Ecosystem Processes, School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China
| | - Hugh Morris
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Filip Vandelook
- Living Collections Department, Meise Botanic Garden, Meise, Belgium
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Ulm, Germany
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Influence of Colder Temperature on the Axial and Radial Parenchyma Fraction of Quercus ciliaris C.C.Huang & Y.T.Chang Wood and Its Relationship with Carbohydrate Reserve (NSC). FORESTS 2022. [DOI: 10.3390/f13020169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Parenchyma in the secondary xylem comprises the main tissue for the storage of non-structural carbohydrates (NSC) in woody plants. Across species, the amount of parenchyma depends on the general environment of the distribution area and determines to a large extent the NSC storage. However, little information is available on the relationship between parenchyma fractions, NSC storage, and the environmental influences within individual species. This information is crucial to assessing the adaptive capacities of tree populations in the context of increasing the frequency and severity of stress-inducing events. In this study, parenchyma fractions and NSC concentrations of the secondary xylem in trunks of a subtropical evergreen oak (Quercus ciliaris C.C.Huang & Y.T.Chang) were quantified along an elevational gradient from 700 m to 1200 m a.s.l. in eastern China. Air temperatures within the distribution area correlated with altitude were recorded. The results showed that the total parenchyma fractions did not covary with the colder temperatures. However, axial parenchyma fractions were lower with a colder climate, while the fractions of multiseriate rays and total ray parenchyma were higher. Higher concentrations of starch and NSC were significantly associated with larger axial parenchyma fractions. The sugar concentration displayed no significant relationship with parenchyma fractions. These findings suggest that the total parenchyma fractions in secondary xylem do not increase in response to a colder climate, while colder temperatures drive changes in the composition of parenchyma for Q. ciliaris.
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Tabakova MA, Tabakova KA, Khotcinskaia KI, Sergeeva OV, Arzac A. Exploration of the Climate Sensitivity of Xylem Parenchyma in Pinus sylvestris L. in the Forest-steppe of Southern Siberia. RUSS J ECOL+ 2021. [DOI: 10.1134/s106741362105012x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Słupianek A, Dolzblasz A, Sokołowska K. Xylem Parenchyma-Role and Relevance in Wood Functioning in Trees. PLANTS (BASEL, SWITZERLAND) 2021; 10:1247. [PMID: 34205276 PMCID: PMC8235782 DOI: 10.3390/plants10061247] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem parenchyma cells, which constitute a significant functional fraction of the wood tissue, have been strongly neglected in studies on tree biology. Although there has recently been increased research interest in xylem parenchyma cells, the mechanisms that operate in these cells are poorly understood. Therefore, the present review focuses on selected roles of xylem parenchyma and its relevance in wood functioning. In addition, to elucidate the importance of xylem parenchyma, we have compiled evidence supporting the hypothesis on the significance of parenchyma cells in tree functioning and identified the key unaddressed questions in the field.
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Affiliation(s)
- Aleksandra Słupianek
- Department of Plant Developmental Biology, Faculty of Biological Sciences, University of Wrocław, Kanonia 6/8, 50-328 Wrocław, Poland; (A.D.); (K.S.)
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Kotowska MM, Wright IJ, Westoby M. Parenchyma Abundance in Wood of Evergreen Trees Varies Independently of Nutrients. FRONTIERS IN PLANT SCIENCE 2020; 11:86. [PMID: 32180778 PMCID: PMC7045414 DOI: 10.3389/fpls.2020.00086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 01/21/2020] [Indexed: 05/25/2023]
Abstract
The abundance of living cells in wood-mainly as interconnected axial and ray parenchyma networks-varies widely between species. However, the functional significance of this variation and its role in plant ecological strategies is poorly understood, as is the extent to which different parenchyma fractions are favored in relation to soil nutrients and hydraulic functions. We analyzed wood tissue fractions of 16 Australian angiosperm species sampled from two nearby areas with similar climate but very different soil nutrient profiles and investigated structure-function links with soil and tissue nutrient concentrations and other plant traits. We expected the variation in parenchyma fractions to influence nutrient concentrations in wood xylem, and to find species with lower parenchyma fractions and accordingly lower nutrient requirements on lower-nutrient soils. Surprisingly, both axial and ray parenchyma fractions were mostly unrelated to tissue and soil nutrient concentrations, except for nitrogen concentration in stem sapwood. Species from low nutrient soils showed higher fractional P translocation from both leaves and sapwood, but little patterning with respect to tissue nitrogen. While species from high and low nutrient soils clearly clustered along the soil-fertility axis, their tissue composition varied independently from plant functional traits related to construction costs and hydraulic anatomy. Our findings imply that there is considerable variation among species in the nutrient concentrations within different parenchyma tissues. The anatomical composition of wood tissue seems unrelated to plant nutrient requirements. Even though xylem parenchyma is involved in metabolic functions such as nutrient translocation and storage, parenchyma abundance on its own does not directly explain variation in these functions, even in co-occurring species. While parenchyma is highly abundant in wood of angiosperm trees, we are still lacking a convincing ecological interpretation of its variability and role in whole-tree nutrient budgets.
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Affiliation(s)
- Martyna M. Kotowska
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
- Department of Plant Ecology and Ecosystems Research, University of Göttingen, Göttingen, Germany
| | - Ian J. Wright
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
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De Mil T, Hubau W, Angoboy Ilondea B, Rocha Vargas MA, Boeckx P, Steppe K, Van Acker J, Beeckman H, Van den Bulcke J. Asynchronous leaf and cambial phenology in a tree species of the Congo Basin requires space-time conversion of wood traits. ANNALS OF BOTANY 2019; 124:245-253. [PMID: 31170728 PMCID: PMC6758582 DOI: 10.1093/aob/mcz069] [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: 09/20/2018] [Accepted: 04/22/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND AND AIMS Wood traits are increasingly being used to document tree performance. In the Congo Basin, however, weaker seasonality causes asynchrony of wood traits between trees. Here, we monitor growth and phenology data to date the formation of traits. METHODS For two seasons, leaf and cambial phenology were monitored on four Terminalia superba trees (Mayombe) using cameras, cambial pinning and dendrometers. Subsequently, vessel lumen and parenchyma fractions as well as high-resolution isotopes (δ13C/δ18O) were quantified on the formed rings. All traits were dated and related to weather data. KEY RESULTS We observed between-tree differences in green-up of 45 d, with trees flushing before and after the rainy season. The lag between green-up and onset of xylem formation was 59 ± 21 d. The xylem growing season lasted 159 ± 17 d with between-tree differences of up to 53 d. Synchronized vessel, parenchyma and δ13C profiles were related to each other. Only parenchyma fraction and δ13C were correlated to weather variables, whereas the δ18O pattern showed no trend. CONCLUSIONS Asynchrony of leaf and cambial phenology complicates correct interpretation of environmental information recorded in wood. An integrated approach including high-resolution measurements of growth, stable isotopes and anatomical features allows exact dating of the formation of traits. This methodology offers a means to explore the asynchrony of growth in a rainforest and contribute to understanding this aspect of forest resilience.
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Affiliation(s)
- Tom De Mil
- UGCT-UGent-Woodlab, Ghent University, Laboratory of Wood Technology, Department of Environment, Gent, Belgium
- Royal Museum for Central Africa, Wood Biology Service, Tervuren, Belgium
| | - Wannes Hubau
- Royal Museum for Central Africa, Wood Biology Service, Tervuren, Belgium
| | - Bhély Angoboy Ilondea
- UGCT-UGent-Woodlab, Ghent University, Laboratory of Wood Technology, Department of Environment, Gent, Belgium
- Royal Museum for Central Africa, Wood Biology Service, Tervuren, Belgium
- Institut National pour l’Etude et la Recherche Agronomiques, Kinshasa, Democratic Republic of the Congo
| | - Mirvia Angela Rocha Vargas
- UGCT-UGent-Woodlab, Ghent University, Laboratory of Wood Technology, Department of Environment, Gent, Belgium
- Isotope Bioscience Laboratory – ISOFYS, Ghent University, Department of Green Chemistry and Technology, Gent, Belgium
| | - Pascal Boeckx
- Isotope Bioscience Laboratory – ISOFYS, Ghent University, Department of Green Chemistry and Technology, Gent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Gent, Belgium
| | - Joris Van Acker
- UGCT-UGent-Woodlab, Ghent University, Laboratory of Wood Technology, Department of Environment, Gent, Belgium
| | - Hans Beeckman
- Royal Museum for Central Africa, Wood Biology Service, Tervuren, Belgium
| | - Jan Van den Bulcke
- UGCT-UGent-Woodlab, Ghent University, Laboratory of Wood Technology, Department of Environment, Gent, Belgium
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Anadon-Rosell A, Dawes MA, Fonti P, Hagedorn F, Rixen C, von Arx G. Xylem anatomical and growth responses of the dwarf shrub Vaccinium myrtillus to experimental CO 2 enrichment and soil warming at treeline. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:1172-1183. [PMID: 30045499 DOI: 10.1016/j.scitotenv.2018.06.117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/08/2018] [Accepted: 06/10/2018] [Indexed: 06/08/2023]
Abstract
Plant growth responses to environmental changes may be linked to xylem anatomical adjustments. The study of such links is essential for improving our understanding of plant functioning under global change. We investigated the xylem anatomy and above-ground growth of the dwarf shrub Vaccinium myrtillus in the understorey of Larix decidua and Pinus uncinata at the Swiss treeline after 9 years of free-air CO2 enrichment (+200 ppm) and 6 years of soil warming (+4 °C). We aimed to determine the responses of xylem anatomical traits and growth to these treatments, and to analyse xylem anatomy-growth relationships. We quantified anatomical characteristics of vessels and ray parenchyma and measured xylem ring width (RW), above-ground biomass and shoot elongation as growth parameters. Our results showed strong positive correlations between theoretical hydraulic conductivity (Kh) and shoot increment length or total biomass across all treatments. However, while soil warming stimulated shoot elongation and RW, it reduced vessel size (Dh) by 14%. Elevated CO2 had smaller effects than soil warming: it increased Dh (5%) in the last experimental years and only influenced growth by increasing basal stem size. The abundance of ray parenchyma, representing storage capacity, did not change under any treatment. Our results demonstrate a link between growth and stem Kh in V. myrtillus, but its growth responses to warming were not explained by the observed xylem anatomical changes. Smaller Dh under warming may increase resistance to freezing events frequently occurring at treeline and suggests that hydraulic efficiency is not limiting for V. myrtillus growing on moist soils at treeline. Our findings suggest that future higher atmospheric CO2 concentrations will have smaller effects on V. myrtillus growth and functioning than rising temperatures at high elevations; further, growth stimulation of this species under future warmer conditions may not be synchronized with xylem adjustments favouring hydraulic efficiency.
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Affiliation(s)
- Alba Anadon-Rosell
- Institute of Botany and Landscape Ecology, University of Greifswald, Soldmannstrasse 15, D-17487 Greifswald, Germany; Department of Evolutionary Biology, Ecology and Environmental Sciences, University of Barcelona, Av. Diagonal 643, E-08028 Barcelona, Catalonia, Spain; Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8093 Birmensdorf, Switzerland.
| | - Melissa A Dawes
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8093 Birmensdorf, Switzerland; WSL Institute for Snow and Avalanche Research - SLF, Flüelastrasse 11, CH-7260 Davos, Switzerland
| | - Patrick Fonti
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8093 Birmensdorf, Switzerland
| | - Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8093 Birmensdorf, Switzerland
| | - Christian Rixen
- WSL Institute for Snow and Avalanche Research - SLF, Flüelastrasse 11, CH-7260 Davos, Switzerland
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8093 Birmensdorf, Switzerland; Climatic Change and Climate Impacts, Institute for Environmental Sciences, 66 Blvd Carl Vogt, CH-1205 Geneva, Switzerland
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12
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Carrer M, Unterholzner L, Castagneri D. Wood anatomical traits highlight complex temperature influence on Pinus cembra at high elevation in the Eastern Alps. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2018; 62:1745-1753. [PMID: 29961923 DOI: 10.1007/s00484-018-1577-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/11/2018] [Accepted: 06/21/2018] [Indexed: 06/08/2023]
Abstract
Climate sensitivity of populations at the margins of their distribution range is of key importance to understand species' responses to future warming conditions. Pinus cembra is of particular interest being a typical high-elevation taxon, spread with mostly scattered populations within its actual range, but still overlooked in traditional dendrochronological researches due to low tree-ring variability and climate sensitivity. With a different approach, we analyzed time series of xylem anatomical traits, split into intra-ring sectors, and used daily climate records over 89 years (1926-2014) aiming to improve the quality and time resolution of the climate/growth associations. From nine trees growing at their altitudinal limit and on 1.5 × 106 tracheids, we measured ring width (MRW), cell number per ring, lumen area (LA), and cell-wall thickness (CWT). We then computed correlations with monthly and fortnightly climate data. Late-spring and summer temperature emerged as the most important factors. LA and especially CWT showed a stronger temperature response than MRW, starting in mid-May and early June, respectively. CWT also evidenced the longest period of correlations with temperature and a significant difference between latewood radial and tangential walls. Analysis of xylem anatomical traits at intra-ring level and the use of daily temperature records proved to be useful for high resolution and detailed climate/growth association inferences in Pinus cembra.
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Affiliation(s)
- Marco Carrer
- Università degli Studi di Padova, Dip. TeSAF - Agripolis, I-35020, Legnaro, PD, Italy.
| | - Lucrezia Unterholzner
- Università degli Studi di Padova, Dip. TeSAF - Agripolis, I-35020, Legnaro, PD, Italy
| | - Daniele Castagneri
- Università degli Studi di Padova, Dip. TeSAF - Agripolis, I-35020, Legnaro, PD, Italy
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13
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Variation in the Climate Sensitivity Dependent on Neighbourhood Composition in a Secondary Mixed Forest. FORESTS 2018. [DOI: 10.3390/f9010043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Olano JM, González-Muñoz N, Arzac A, Rozas V, von Arx G, Delzon S, García-Cervigón AI. Sex determines xylem anatomy in a dioecious conifer: hydraulic consequences in a drier world. TREE PHYSIOLOGY 2017; 37:1493-1502. [PMID: 28575521 DOI: 10.1093/treephys/tpx066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/18/2017] [Indexed: 05/13/2023]
Abstract
Increased drought frequency and severity may reshape tree species distribution in arid environments. Dioecious tree species may be more sensitive to climate warming if sex-related vulnerability to drought occurs, since lower performance of one sex may drive differential stress tolerance, sex-related mortality rates and biased sex ratios. We explored the effect of sex and environment on branch hydraulic (hydraulic conductivity and vulnerability to embolism) and trunk anatomical traits in both sexes of the dioecious conifer Juniperus thurifera L. at two sites with contrasting water availability. Additionally, we tested for a trade-off between hydraulic safety (vulnerability to embolism) and efficiency (hydraulic conductivity). Vulnerability to embolism and hydraulic conductivity were unaffected by sex or site at branch level. In contrast, sex played a significant role in xylem anatomy. We found a trade-off between hydraulic safety and efficiency, with larger conductivities related to higher vulnerabilities to embolism. At the anatomical level, females' trunk showed xylem anatomical traits related to greater hydraulic efficiency (higher theoretical hydraulic conductivity) over safety (thinner tracheid walls, lower Mork's Index), whereas males' trunk anatomy followed a more conservative strategy, especially in the drier site. Reconciling the discrepancy between branch hydraulic function and trunk xylem anatomy would require a thorough and integrated understanding of the tree structure-function relationship at the whole-plant level. Nevertheless, lower construction costs and higher efficiency in females' xylem anatomy at trunk level might explain the previously observed higher growth rates in mesic habitats. However, prioritizing efficiency over safety in trunk construction might make females more sensitive to drought, endangering the species' persistence in a drier world.
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Affiliation(s)
- José M Olano
- Área de Botánica, Departamento de Ciencias Agroforestales, EU de Ingenierías Agrarias, iuFOR-Universidad de Valladolid, Campus Duques de Soria, 42004 Soria, Spain
| | | | - Alberto Arzac
- Institute of Ecology and Geography, Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk, Russia
| | - Vicente Rozas
- Área de Botánica, Departamento de Ciencias Agroforestales, EU de Ingenierías Agrarias, iuFOR-Universidad de Valladolid, Campus Duques de Soria, 42004 Soria, Spain
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf 8903, Switzerland
- Climatic Change and Climate Impacts, Institute for Environmental Sciences, 66 Blvd Carl Vogt, CH-1205 Geneva, Switzerland
| | - Sylvain Delzon
- BIOGECO, INRA, University of Bordeaux, 33615 Pessac, France
| | - Ana I García-Cervigón
- CASEM - Facultad de Ciencias del Mar y Ambientales,Campus Universitario de Puerto Real, 11510 Puerto Real (Cádiz), Spain
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15
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Prendin AL, Petit G, Fonti P, Rixen C, Dawes MA, Arx G. Axial xylem architecture of
Larix decidua
exposed to CO
2
enrichment and soil warming at the tree line. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12986] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Angela Luisa Prendin
- Dipartimento Territorio e Sistemi Agro‐ForestaliUniversità degli Studi di Padova Legnaro PD Italy
| | - Giai Petit
- Dipartimento Territorio e Sistemi Agro‐ForestaliUniversità degli Studi di Padova Legnaro PD Italy
| | - Patrick Fonti
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland
| | - Christian Rixen
- WSL Institute for Snow and Avalanche Research SLF Davos Switzerland
| | - Melissa Autumn Dawes
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland
- WSL Institute for Snow and Avalanche Research SLF Davos Switzerland
| | - Georg Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL Birmensdorf Switzerland
- Climatic Change and Climate ImpactsInstitute for Environmental Sciences Geneva Switzerland
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16
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Hari P, Aakala T, Hilasvuori E, Häkkinen R, Korhola A, Korpela M, Linkosalo T, Mäkinen H, Nikinmaa E, Nöjd P, Seppä H, Sulkava M, Terhivuo J, Tuomenvirta H, Weckström J, Hollmén J. Reliability of temperature signal in various climate indicators from northern Europe. PLoS One 2017; 12:e0180042. [PMID: 28662166 PMCID: PMC5491121 DOI: 10.1371/journal.pone.0180042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 06/08/2017] [Indexed: 11/21/2022] Open
Abstract
We collected relevant observational and measured annual-resolution time series dealing with climate in northern Europe, focusing in Finland. We analysed these series for the reliability of their temperature signal at annual and seasonal resolutions. Importantly, we analysed all of the indicators within the same statistical framework, which allows for their meaningful comparison. In this framework, we employed a cross-validation procedure designed to reduce the adverse effects of estimation bias that may inflate the reliability of various temperature indicators, especially when several indicators are used in a multiple regression model. In our data sets, timing of phenological observations and ice break-up were connected with spring, tree ring characteristics (width, density, carbon isotopic composition) with summer and ice formation with autumn temperatures. Baltic Sea ice extent and the duration of ice cover in different watercourses were good indicators of winter temperatures. Using combinations of various temperature indicator series resulted in reliable temperature signals for each of the four seasons, as well as a reliable annual temperature signal. The results hence demonstrated that we can obtain reliable temperature information over different seasons, using a careful selection of indicators, combining the results with regression analysis, and by determining the reliability of the obtained indicator.
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Affiliation(s)
- Pertti Hari
- University of Helsinki, Department of Forest Sciences, Helsinki, Finland
| | - Tuomas Aakala
- University of Helsinki, Department of Forest Sciences, Helsinki, Finland
- * E-mail:
| | - Emmi Hilasvuori
- Laboratory of Chronology, Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Risto Häkkinen
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Atte Korhola
- University of Helsinki, Department of Environmental Sciences, Helsinki, Finland
| | - Mikko Korpela
- Aalto University, Department of Information and Computer Science, Aalto, Espoo, Finland
- University of Helsinki, Department of Geosciences and Geography, Helsinki, Finland
| | - Tapio Linkosalo
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Harri Mäkinen
- Natural Resources Institute Finland (Luke), Aalto, Espoo, Finland
| | - Eero Nikinmaa
- University of Helsinki, Department of Forest Sciences, Helsinki, Finland
| | - Pekka Nöjd
- Natural Resources Institute Finland (Luke), Aalto, Espoo, Finland
| | - Heikki Seppä
- University of Helsinki, Department of Geosciences and Geography, Helsinki, Finland
| | - Mika Sulkava
- Natural Resources Institute Finland (Luke) Statistical services, Helsinki, Finland
| | - Juhani Terhivuo
- University of Helsinki, Finnish Museum of Natural History, Helsinki, Finland
| | | | - Jan Weckström
- University of Helsinki, Department of Environmental Sciences, Helsinki, Finland
| | - Jaakko Hollmén
- Aalto University, Department of Information and Computer Science, Aalto, Espoo, Finland
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17
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Carrer M, Castagneri D, Prendin AL, Petit G, von Arx G. Retrospective Analysis of Wood Anatomical Traits Reveals a Recent Extension in Tree Cambial Activity in Two High-Elevation Conifers. FRONTIERS IN PLANT SCIENCE 2017; 8:737. [PMID: 28533792 PMCID: PMC5420594 DOI: 10.3389/fpls.2017.00737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 04/20/2017] [Indexed: 05/17/2023]
Abstract
The study of xylogenesis or wood formation is a powerful, yet labor intensive monitoring approach to investigate intra-annual tree growth responses to environmental factors. However, it seldom covers more than a few growing seasons, so is in contrast to the much longer lifespan of woody plants and the time scale of many environmental processes. Here we applied a novel retrospective approach to test the long-term (1926-2012) consistency in the timing of onset and ending of cambial activity, and in the maximum cambial cell division rate in two conifer species, European larch and Norway spruce at high-elevation in the Alps. We correlated daily temperature with time series of cell number and lumen area partitioned into intra-annual sectors. For both species, we found a good correspondence (1-10 days offset) between the periods when anatomical traits had significant correlations with temperature in recent decades (1969-2012) and available xylogenesis data (1996-2005), previously collected at the same site. Yet, results for the 1926-1968 period indicate a later onset and earlier ending of the cambial activity by 6-30 days. Conversely, the peak in the correlation between annual cell number and temperature, which should correspond to the peak in secondary growth rate, was quite stable over time, with just a minor advance of 4-5 days in the recent decades. Our analyses on time series of wood anatomical traits proved useful to infer on past long-term changes in xylogenetic phases. Combined with intensive continuous monitoring, our approach will improve the understanding of tree responses to climate variability in both the short- and long-term context.
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Affiliation(s)
- Marco Carrer
- Dipartimento Territorio e Sistemi Agro-Forestali, Universitá degli Studi di PadovaLegnaro, Italy
| | - Daniele Castagneri
- Dipartimento Territorio e Sistemi Agro-Forestali, Universitá degli Studi di PadovaLegnaro, Italy
| | - Angela L. Prendin
- Dipartimento Territorio e Sistemi Agro-Forestali, Universitá degli Studi di PadovaLegnaro, Italy
| | - Giai Petit
- Dipartimento Territorio e Sistemi Agro-Forestali, Universitá degli Studi di PadovaLegnaro, Italy
| | - Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf, Switzerland
- Climatic Change and Climate Impacts, Institute for Environmental SciencesGeneva, Switzerland
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18
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von Arx G, Arzac A, Fonti P, Frank D, Zweifel R, Rigling A, Galiano L, Gessler A, Olano JM. Responses of sapwood ray parenchyma and non‐structural carbohydrates of
Pinus sylvestris
to drought and long‐term irrigation. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12860] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Georg von Arx
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- SwissForestLab Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
| | - Alberto Arzac
- School of Ecology and Geography Siberian Federal University 79 Svobodny pr 660041 Krasnoyarsk Russia
- Departamento de Biología Vegetal y Ecología Facultad de Ciencia y Tecnología Universidad del País Vasco Barrio Sarriena s/n E–48940 Leioa Spain
| | - Patrick Fonti
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- SwissForestLab Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
| | - David Frank
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- SwissForestLab Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- Laboratory of Tree‐Ring Research University of Arizona Tucson AZ85721 USA
| | - Roman Zweifel
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- SwissForestLab Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
| | - Andreas Rigling
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- SwissForestLab Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
| | - Lucia Galiano
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
| | - Arthur Gessler
- Swiss Federal Institute for Forest Snow and Landscape Research WSL Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
- SwissForestLab Zuercherstrasse 111 CH‐8903 Birmensdorf Switzerland
| | - José Miguel Olano
- Departamento de Ciencias Agroforestales EU de Ingenierías Agrarias iuFOR‐Universidad de Valladolid Campus Duques de Soria 42004 Soria Spain
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19
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Evaristo J, McDonnell JJ. Prevalence and magnitude of groundwater use by vegetation: a global stable isotope meta-analysis. Sci Rep 2017; 7:44110. [PMID: 28281644 PMCID: PMC5345103 DOI: 10.1038/srep44110] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 02/02/2017] [Indexed: 11/09/2022] Open
Abstract
The role of groundwater as a resource in sustaining terrestrial vegetation is widely recognized. But the global prevalence and magnitude of groundwater use by vegetation is unknown. Here we perform a meta-analysis of plant xylem water stable isotope (δ2H and δ18O, n = 7367) information from 138 published papers - representing 251 genera, and 414 species of angiosperms (n = 376) and gymnosperms (n = 38). We show that the prevalence of groundwater use by vegetation (defined as the number of samples out of a universe of plant samples reported to have groundwater contribution to xylem water) is 37% (95% confidence interval, 28-46%). This is across 162 sites and 12 terrestrial biomes (89% of heterogeneity explained; Q-value = 1235; P < 0.0001). However, the magnitude of groundwater source contribution to the xylem water mixture (defined as the proportion of groundwater contribution in xylem water) is limited to 23% (95% CI, 20-26%; 95% prediction interval, 3-77%). Spatial analysis shows that the magnitude of groundwater source contribution increases with aridity. Our results suggest that while groundwater influence is globally prevalent, its proportional contribution to the total terrestrial transpiration is limited.
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Affiliation(s)
- Jaivime Evaristo
- Global Institute for Water Security and School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Canada
| | - Jeffrey J. McDonnell
- Global Institute for Water Security and School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Canada
- School of Geosciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
- Department of Forest Engineering, Resources and Management, Oregon State University, Corvallis, Oregon 97330 USA
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20
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Matheny AM, Mirfenderesgi G, Bohrer G. Trait-based representation of hydrological functional properties of plants in weather and ecosystem models. PLANT DIVERSITY 2017; 39:1-12. [PMID: 30159486 PMCID: PMC6112282 DOI: 10.1016/j.pld.2016.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 10/03/2016] [Accepted: 10/08/2016] [Indexed: 05/14/2023]
Abstract
Land surface models and dynamic global vegetation models typically represent vegetation through coarse plant functional type groupings based on leaf form, phenology, and bioclimatic limits. Although these groupings were both feasible and functional for early model generations, in light of the pace at which our knowledge of functional ecology, ecosystem demographics, and vegetation-climate feedbacks has advanced and the ever growing demand for enhanced model performance, these groupings have become antiquated and are identified as a key source of model uncertainty. The newest wave of model development is centered on shifting the vegetation paradigm away from plant functional types (PFTs) and towards flexible trait-based representations. These models seek to improve errors in ecosystem fluxes that result from information loss due to over-aggregation of dissimilar species into the same functional class. We advocate the importance of the inclusion of plant hydraulic trait representation within the new paradigm through a framework of the whole-plant hydraulic strategy. Plant hydraulic strategy is known to play a critical role in the regulation of stomatal conductance and thus transpiration and latent heat flux. It is typical that coexisting plants employ opposing hydraulic strategies, and therefore have disparate patterns of water acquisition and use. Hydraulic traits are deterministic of drought resilience, response to disturbance, and other demographic processes. The addition of plant hydraulic properties in models may not only improve the simulation of carbon and water fluxes but also vegetation population distributions.
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Affiliation(s)
- Ashley M. Matheny
- Department of Civil, Environmental, and Geodetic Engineering, The Ohio State University, Columbus, OH, USA
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21
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Borghetti M, Gentilesca T, Leonardi S, van Noije T, Rita A, Mencuccini M. Long-term temporal relationships between environmental conditions and xylem functional traits: a meta-analysis across a range of woody species along climatic and nitrogen deposition gradients. TREE PHYSIOLOGY 2017; 37:4-17. [PMID: 28173594 DOI: 10.1093/treephys/tpw087] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/11/2016] [Accepted: 08/20/2016] [Indexed: 05/12/2023]
Abstract
The objectives of this study were to provide a quantitative description of the long-term effects of environmental variability on xylem functional traits, in order to better assess xylem capacity to change in response to climate change. Twenty-six sites throughout the world, primarily in Europe, were chosen where results from long-term measurements of anatomical traits were previously published. Published data on long-term xylem anatomy (conduit size and density) and ring width variability were compiled across a range of tree species, which was subsequently related to variability in temperature, precipitation and nitrogen deposition rates across the study sites using generalized additive models and Bayesian methods. We found some appreciable relationships between xylem traits (conduit area Ac and conduit density Dc) and environmental variables; whereas combined trait indices (lumen fraction: Ac × Dc and vessel composition: Ac/Dc) were found to be rather constant across a wide range of environmental conditions and to be decoupled from tree growth rates. Overall, results suggested xylem traits coordinated towards a homeostasis in xylem function, which appeared to act across a wide range of environmental conditions. Results showed also nitrogen deposition was associated with xylem traits and vessel composition: increased nitrogen availability due to nitrogen deposition might facilitate construction of a xylem structure efficient for water transport, and concurrently provide capacity to withstand the risks of drought-induced embolism.
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Affiliation(s)
- Marco Borghetti
- Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università della Basilicata, viale dell'Ateneo Lucano 10, Potenza, Italy
| | - Tiziana Gentilesca
- Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università della Basilicata, viale dell'Ateneo Lucano 10, Potenza, Italy
| | - Stefano Leonardi
- Dipartimento di Bioscienze, Università di Parma, viale Usberti 11, Parma, Italy
| | - Twan van Noije
- Royal Netherlands Meteorological Institute (KNMI), AE De Bilt, The Netherlands
| | - Angelo Rita
- Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali, Università della Basilicata, viale dell'Ateneo Lucano 10, Potenza, Italy
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22
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Ziaco E, Biondi F, Heinrich I. Wood Cellular Dendroclimatology: Testing New Proxies in Great Basin Bristlecone Pine. FRONTIERS IN PLANT SCIENCE 2016; 7:1602. [PMID: 27826315 PMCID: PMC5078726 DOI: 10.3389/fpls.2016.01602] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/11/2016] [Indexed: 05/28/2023]
Abstract
Dendroclimatic proxies can be generated from the analysis of wood cellular structures, allowing for a more complete understanding of the physiological mechanisms that control the climatic response of tree species. Century-long (1870-2013) time series of anatomical parameters were developed for Great Basin bristlecone pine (Pinus longaeva D.K. Bailey) by capturing strongly contrasted microscopic images through a Confocal Laser Scanning Microscope. Environmental information embedded in wood anatomical series was analyzed in comparison with ring-width series using measures of empirical signal strength. Response functions were calculated against monthly climatic variables to evaluate climate sensitivity of cellular features (e.g., lumen area; lumen diameter) for the period 1950-2013. Calibration-verification tests were used to determine the potential to generate long climate reconstructions from these anatomical proxies. A total of eight tree-ring parameters (two ring-width and six chronologies of xylem anatomical parameters) were analyzed. Synchronous variability among samples varied among tree-ring parameters, usually decreasing from ring-width to anatomical features. Cellular parameters linked to plant hydraulic performance (e.g., tracheid lumen area and radial lumen diameter) showed empirical signal strength similar to ring-width series, while noise was predominant in chronologies of lumen tangential width and cell wall thickness. Climatic signals were different between anatomical and ring-width chronologies, revealing a positive and temporally stable correlation of tracheid size (i.e., lumen and cell diameter) with monthly (i.e., March) and seasonal precipitation. In particular, tracheid lumen diameter emerged as a reliable moisture indicator and was then used to reconstruct total March-August precipitation from 1870 to 2013. Wood anatomy holds great potential to refine and expand dendroclimatic records by allowing estimates of plant physiological adaptations to external stressors. Integrating xylem cellular features with ring-width chronologies can widen our understanding of past climatic variability (including annual extreme events) and improve the evaluation of long-term plant response to drought, especially in connection with future warming scenarios.
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Affiliation(s)
| | | | - Ingo Heinrich
- GFZ German Research Centre for GeosciencesPotsdam, Germany
- Institute of Geography, Humboldt-UniversityBerlin, Germany
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23
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Pellizzari E, Camarero JJ, Gazol A, Sangüesa-Barreda G, Carrer M. Wood anatomy and carbon-isotope discrimination support long-term hydraulic deterioration as a major cause of drought-induced dieback. GLOBAL CHANGE BIOLOGY 2016; 22:2125-37. [PMID: 26790660 DOI: 10.1111/gcb.13227] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/23/2015] [Accepted: 12/30/2015] [Indexed: 05/04/2023]
Abstract
Hydraulic impairment due to xylem embolism and carbon starvation are the two proposed mechanisms explaining drought-induced forest dieback and tree death. Here, we evaluate the relative role played by these two mechanisms in the long-term by quantifying wood-anatomical traits (tracheid size and area of parenchyma rays) and estimating the intrinsic water-use efficiency (iWUE) from carbon isotopic discrimination. We selected silver fir and Scots pine stands in NE Spain with ongoing dieback processes and compared trees showing contrasting vigour (declining vs nondeclining trees). In both species earlywood tracheids in declining trees showed smaller lumen area with thicker cell wall, inducing a lower theoretical hydraulic conductivity. Parenchyma ray area was similar between the two vigour classes. Wet spring and summer conditions promoted the formation of larger lumen areas, particularly in the case of nondeclining trees. Declining silver firs presented a lower iWUE than conspecific nondeclining trees, but the reverse pattern was observed in Scots pine. The described patterns in wood anatomical traits and iWUE are coherent with a long-lasting deterioration of the hydraulic system in declining trees prior to their dieback. Retrospective quantifications of lumen area permit to forecast dieback in declining trees 2-5 decades before growth decline started. Wood anatomical traits provide a robust tool to reconstruct the long-term capacity of trees to withstand drought-induced dieback.
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Affiliation(s)
- Elena Pellizzari
- Dip. TeSAF, Universitá degli Studi di Padova, Agripolis I-35020, Legnaro, Italy
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda Montañana 1005, Zaragoza, 50059, Spain
| | - Antonio Gazol
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda Montañana 1005, Zaragoza, 50059, Spain
| | | | - Marco Carrer
- Dip. TeSAF, Universitá degli Studi di Padova, Agripolis I-35020, Legnaro, Italy
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24
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Morris H, Plavcová L, Cvecko P, Fichtler E, Gillingham MAF, Martínez‐Cabrera HI, McGlinn DJ, Wheeler E, Zheng J, Ziemińska K, Jansen S. A global analysis of parenchyma tissue fractions in secondary xylem of seed plants. THE NEW PHYTOLOGIST 2016; 209:1553-65. [PMID: 26551018 PMCID: PMC5063116 DOI: 10.1111/nph.13737] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 09/28/2015] [Indexed: 05/18/2023]
Abstract
Parenchyma is an important tissue in secondary xylem of seed plants, with functions ranging from storage to defence and with effects on the physical and mechanical properties of wood. Currently, we lack a large-scale quantitative analysis of ray parenchyma (RP) and axial parenchyma (AP) tissue fractions. Here, we use data from the literature on AP and RP fractions to investigate the potential relationships of climate and growth form with total ray and axial parenchyma fractions (RAP). We found a 29-fold variation in RAP fraction, which was more strongly related to temperature than with precipitation. Stem succulents had the highest RAP values (mean ± SD: 70.2 ± 22.0%), followed by lianas (50.1 ± 16.3%), angiosperm trees and shrubs (26.3 ± 12.4%), and conifers (7.6 ± 2.6%). Differences in RAP fraction between temperate and tropical angiosperm trees (21.1 ± 7.9% vs 36.2 ± 13.4%, respectively) are due to differences in the AP fraction, which is typically three times higher in tropical than in temperate trees, but not in RP fraction. Our results illustrate that both temperature and growth form are important drivers of RAP fractions. These findings should help pave the way to better understand the various functions of RAP in plants.
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Affiliation(s)
- Hugh Morris
- Institute of Systematic Botany and EcologyUlm UniversityAlbert‐Einstein‐Allee 11D‐89081UlmGermany
| | - Lenka Plavcová
- Institute of Systematic Botany and EcologyUlm UniversityAlbert‐Einstein‐Allee 11D‐89081UlmGermany
| | - Patrick Cvecko
- Institute of Evolutionary Ecology and Conservation GenomicsUlm UniversityAlbert‐Einstein‐Allee 11D‐89069UlmGermany
| | - Esther Fichtler
- Institute of Agronomy in the TropicsUniversity of GöttingenGrisebachstrasse 637077GöttingenGermany
| | - Mark A. F. Gillingham
- Institute of Evolutionary Ecology and Conservation GenomicsUlm UniversityAlbert‐Einstein‐Allee 11D‐89069UlmGermany
| | - Hugo I. Martínez‐Cabrera
- Département des Sciences BiologiquesUniversité du Québec à MontréalUQÁMCP 8888Succ. Centre Ville MontréalMontréalQCH3C 3P8Canada
| | | | - Elisabeth Wheeler
- Department of Forest BiomaterialsNC State University RaleighRaleighNC27695‐8005USA
| | - Jingming Zheng
- Key Laboratory for Silviculture and Conservation of the Ministry of EducationBeijing Forestry UniversityBeijing100083China
| | - Kasia Ziemińska
- Department of Biological SciencesMacquarie UniversitySydneyNSW2109Australia
| | - Steven Jansen
- Institute of Systematic Botany and EcologyUlm UniversityAlbert‐Einstein‐Allee 11D‐89081UlmGermany
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von Arx G, Crivellaro A, Prendin AL, Čufar K, Carrer M. Quantitative Wood Anatomy-Practical Guidelines. FRONTIERS IN PLANT SCIENCE 2016; 7:781. [PMID: 27375641 PMCID: PMC4891576 DOI: 10.3389/fpls.2016.00781] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/20/2016] [Indexed: 05/04/2023]
Abstract
Quantitative wood anatomy analyzes the variability of xylem anatomical features in trees, shrubs, and herbaceous species to address research questions related to plant functioning, growth, and environment. Among the more frequently considered anatomical features are lumen dimensions and wall thickness of conducting cells, fibers, and several ray properties. The structural properties of each xylem anatomical feature are mostly fixed once they are formed, and define to a large extent its functionality, including transport and storage of water, nutrients, sugars, and hormones, and providing mechanical support. The anatomical features can often be localized within an annual growth ring, which allows to establish intra-annual past and present structure-function relationships and its sensitivity to environmental variability. However, there are many methodological challenges to handle when aiming at producing (large) data sets of xylem anatomical data. Here we describe the different steps from wood sample collection to xylem anatomical data, provide guidance and identify pitfalls, and present different image-analysis tools for the quantification of anatomical features, in particular conducting cells. We show that each data production step from sample collection in the field, microslide preparation in the lab, image capturing through an optical microscope and image analysis with specific tools can readily introduce measurement errors between 5 and 30% and more, whereby the magnitude usually increases the smaller the anatomical features. Such measurement errors-if not avoided or corrected-may make it impossible to extract meaningful xylem anatomical data in light of the rather small range of variability in many anatomical features as observed, for example, within time series of individual plants. Following a rigid protocol and quality control as proposed in this paper is thus mandatory to use quantitative data of xylem anatomical features as a powerful source for many research topics.
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Affiliation(s)
- Georg von Arx
- Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf, Switzerland
- *Correspondence: Georg von Arx
| | - Alan Crivellaro
- Dipartimento Territorio e Sistemi Agro Forestali, Università degli Studi di PadovaPadua, Italy
| | - Angela L. Prendin
- Dipartimento Territorio e Sistemi Agro Forestali, Università degli Studi di PadovaPadua, Italy
| | - Katarina Čufar
- Department of Wood Science and Technology, Biotechnical Faculty, University of LjubljanaLjubljana, Slovenia
| | - Marco Carrer
- Dipartimento Territorio e Sistemi Agro Forestali, Università degli Studi di PadovaPadua, Italy
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von Arx G, Arzac A, Olano JM, Fonti P. Assessing Conifer Ray Parenchyma for Ecological Studies: Pitfalls and Guidelines. FRONTIERS IN PLANT SCIENCE 2015; 6:1016. [PMID: 26635842 PMCID: PMC4649045 DOI: 10.3389/fpls.2015.01016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/03/2015] [Indexed: 05/09/2023]
Abstract
Ray parenchyma is an essential tissue for tree functioning and survival. This living tissue plays a major role for storage and transport of water, nutrients, and non-structural carbohydrates (NSC), thus regulating xylem hydraulics and growth. However, despite the importance of rays for tree carbon and water relations, methodological challenges hamper knowledge about ray intra- and inter-tree variability and its ecological meaning. In this study we provide a methodological toolbox for soundly quantifying spatial and temporal variability of different ray features. Anatomical ray features were surveyed in different cutting planes (cross-sectional, tangential, and radial) using quantitative image analysis on stem-wood micro-sections sampled from 41 mature Scots pines (Pinus sylvestris). The percentage of ray surface (PERPAR), a proxy for ray volume, was compared among cutting planes and between early- and latewood to assess measurement-induced variability. Different tangential ray metrics were correlated to assess their similarities. The accuracy of cross-sectional and tangential measurements for PERPAR estimates as a function of number of samples and the measured wood surface was assessed using bootstrapping statistical technique. Tangential sections offered the best 3D insight of ray integration into the xylem and provided the most accurate estimates of PERPAR, with 10 samples of 4 mm(2) showing an estimate within ±6.0% of the true mean PERPAR (relative 95% confidence interval, CI95), and 20 samples of 4 mm(2) showing a CI95 of ±4.3%. Cross-sections were most efficient for establishment of time series, and facilitated comparisons with other widely used xylem anatomical features. Earlywood had significantly lower PERPAR (5.77 vs. 6.18%) and marginally fewer initiating rays than latewood. In comparison to tangential sections, PERPAR was systematically overestimated (6.50 vs. 4.92%) and required approximately twice the sample area for similar accuracy. Radial cuttings provided the least accurate PERPAR estimates. This evaluation of ray parenchyma in conifers and the presented guidelines regarding data accuracy as a function of measured wood surface and number of samples represent an important methodological reference for ray quantification, which will ultimately improve the understanding of the fundamental role of ray parenchyma tissue for the performance and survival of trees growing in stressed environments.
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Affiliation(s)
- Georg von Arx
- Landscape Dynamics Research Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf, Switzerland
| | - Alberto Arzac
- Departamento de Biología Vegetal y Ecología, Facultad de Ciencia y Tecnología, Universidad del País VascoLeioa, Spain
| | - José M. Olano
- Departamento de Ciencias Agroforestales, Escuela Universitaria de Ingenierías Agrarias, Instituto Universitario de Investigación en Gestión Forestal Sostenible-Universidad de ValladolidSoria, Spain
| | - Patrick Fonti
- Landscape Dynamics Research Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSLBirmensdorf, Switzerland
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27
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Anderegg WRL. Spatial and temporal variation in plant hydraulic traits and their relevance for climate change impacts on vegetation. THE NEW PHYTOLOGIST 2015; 205:1008-14. [PMID: 25729797 DOI: 10.1111/nph.12907] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plant hydraulics mediate terrestrial woody plant productivity, influencing global water, carbon, and biogeochemical cycles, as well as ecosystem vulnerability to drought and climate change. While inter-specific differences in hydraulic traits are widely documented, intra-specific hydraulic variability is less well known and is important for predicting climate change impacts. Here, I present a conceptual framework for this intra-specific hydraulic trait variability, reviewing the mechanisms that drive variability and the consequences for vegetation response to climate change. I performed a meta-analysis on published studies (n = 33) of intra-specific variation in a prominent hydraulic trait - water potential at which 50% stem conductivity is lost (P50) - and compared this variation to inter-specific variability within genera and plant functional types used by a dynamic global vegetation model. I found that intra-specific variability is of ecologically relevant magnitudes, equivalent to c. 33% of the inter-specific variability within a genus, and is larger in angiosperms than gymnosperms, although the limited number of studies highlights that more research is greatly needed. Furthermore, plant functional types were poorly situated to capture key differences in hydraulic traits across species, indicating a need to approach prediction of drought impacts from a trait-based, rather than functional type-based perspective.
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28
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Fleta-Soriano E, Fernández-Marín B, Olano JM, Míguez F, Molinero J, Camarero JJ, García-Plazaola JI. Tocochromanols in wood: a potential new tool for dendrometabolomics. TREE PHYSIOLOGY 2014; 34:1411-1418. [PMID: 25430882 DOI: 10.1093/treephys/tpu090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Tocochromanols are the most abundant lipid-soluble antioxidants in plants. Among them, α-tocopherol (α-Toc) shows a particularly high sensitivity to environmental stressors and its content is used as a stress biomarker even in non-photosynthetic tissues. Nevertheless, the presence of tocochromanols has not been described yet in the xylem of woody plants, even when their functions regarding cell membrane protection and the transport of photoassimilates may be crucial in this tissue and despite its potential utility in dendrometabolomics. Considering all these, we aimed to determine the presence and distribution of tocochromanols in the xylem of woody plants, to examine their responsiveness to high temperature and to evaluate their potential as environmental bioindicators. The analysis of 29 phyllogenetically diverse species showed that α-Toc is the most abundant and frequent tocochromanol in the xylem and is ubiquitously present in all the studied species, with a concentration ranging from 0.5 to 39.3 μg g(-1) of dry weight. α-Tocopherol appeared to be mainly located in the parenchyma rays and was found in both the sapwood and the heartwood, suggesting that it is present even in dead parenchyma cells. The levels of α-Toc in the xylem did not change in response to locally induced xylem heating, but responded positively to the 3-year moving average of annual precipitation. The present findings suggest that α-Toc may be linked to changes in climatic stress. This should enhance further research on the environmental controls of α-Toc variation in the xylem as a first step towards a deeper understanding of dendrometabolomics.
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Affiliation(s)
- Eva Fleta-Soriano
- Departament of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo 644, E-48080 Bilbao, Spain
| | - Beatriz Fernández-Marín
- Departament of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo 644, E-48080 Bilbao, Spain Institute of Botany and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Sternwartestraße 15, Innsbruck A-6020, Austria
| | - José Miguel Olano
- Departamento de Ciencias Agroforestales, EU de Ingenierías Agrarias, Universidad de Valladolid, Los Pajaritos s/n, E-42004 Soria, Spain
| | - Fátima Míguez
- Departament of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo 644, E-48080 Bilbao, Spain
| | - Jon Molinero
- Departament of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo 644, E-48080 Bilbao, Spain
| | - Jesús Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda Montañana 1005, E-50192 Zaragoza, Spain
| | - José Ignacio García-Plazaola
- Departament of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo 644, E-48080 Bilbao, Spain
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29
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Gimeno TE, Escudero A, Valladares F. Different intra- and interspecific facilitation mechanisms between two Mediterranean trees under a climate change scenario. Oecologia 2014; 177:159-69. [PMID: 25354713 DOI: 10.1007/s00442-014-3115-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/14/2014] [Indexed: 10/24/2022]
Abstract
In harsh environments facilitation alleviates biotic and abiotic constraints on tree recruitment. Under ongoing drier climate change, we expect facilitation to increase as a driver of coexistence. However, this might not hold under extreme abiotic stress and when the outcome depends on the interaction with other drivers such as altered herbivore pressure due to land use change. We performed a field water-manipulation experiment to quantify the importance of facilitation in two coexisting Mediterranean trees (dominant Juniperus thurifera and coexisting Quercus ilex subsp. ballota) under a climate change scenario. Shifts in canopy dominance favouring Q. ilex could be based on the extension of heterospecific facilitation to the detriment of conspecific alleviation. We found that saplings of both species transplanted under the canopy of nurse trees had greater survival probability, growth and photochemical efficiency. Intra- and interspecific facilitation mechanisms differed: alleviation of abiotic stress benefited both species during summer and J. thurifera during winter, whereas browsing protection was relevant only for Q. ilex. Facilitation was greater under the dry treatment only for Q. ilex, which partially agreed with the predictions of the stress gradient hypothesis. We conclude that present rainfall availability limits neither J. thurifera nor Q. ilex establishment. Nevertheless, under current global change scenarios, imposing increasing abiotic stress together with altered herbivore browsing, nurse trees could differentially facilitate the establishment of Q. ilex due to species-specific traits, i.e. palatability; drought, heat and cold tolerance, underlying species differences in the facilitation mechanisms and eventually triggering a change from pure juniper woodlands to mixed formations.
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Affiliation(s)
- Teresa E Gimeno
- Hawkesbury Institute for the Environment, University of Western Sydney, Locked Bag 1797, Penrith, Sydney, NSW, 2751, Australia,
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Drought-induced increase in water-use efficiency reduces secondary tree growth and tracheid wall thickness in a Mediterranean conifer. Oecologia 2014; 176:273-83. [PMID: 24958369 DOI: 10.1007/s00442-014-2989-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/29/2014] [Indexed: 10/25/2022]
Abstract
In order to understand the impact of drought and intrinsic water-use efficiency (iWUE) on tree growth, we evaluated the relative importance of direct and indirect effects of water availability on secondary growth and xylem anatomy of Juniperus thurifera, a Mediterranean anisohydric conifer. Dendrochronological techniques, quantitative xylem anatomy, and (13)C/(12)C isotopic ratio were combined to develop standardized chronologies for iWUE, BAI (basal area increment), and anatomical variables on a 40-year-long annually resolved series for 20 trees. We tested the relationship between iWUE and secondary growth at short-term (annual) and long-term (decadal) temporal scales to evaluate whether gains in iWUE may lead to increases in secondary growth. We obtained a positive long-term correlation between iWUE and BAI, simultaneously with a negative short-term correlation between them. Furthermore, BAI and iWUE were correlated with anatomical traits related to carbon sink or storage (tracheid wall thickness and ray parenchyma amount), but no significant correlation with conductive traits (tracheid lumen) was found. Water availability during the growing season significantly modulated tree growth at the xylem level, where growth rates and wood anatomical traits were affected by June precipitation. Our results are consistent with a drought-induced limitation of tree growth response to rising CO2, despite the trend of rising iWUE being maintained. We also remark the usefulness of exploring this relationship at different temporal scales to fully understand the actual links between iWUE and secondary growth dynamics.
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31
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Esteban R, Fernández-Marín B, Olano JM, Becerril JM, García-Plazaola JI. Does plant colour matter? Wax accumulation as an indicator of decline in Juniperus thurifera. TREE PHYSIOLOGY 2014; 34:267-274. [PMID: 24591236 DOI: 10.1093/treephys/tpu006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The photosynthesis in evergreen trees living in Mediterranean ecosystems is subjected to multiple climatic stresses due to water shortage and high temperatures during the summer and to low temperatures during the winter. Mediterranean perennials deploy different photoprotective mechanisms to prevent damage to the photosynthetic system. Wax accumulation in leaves is a primary response which by enhancing light scattering in the leaf surface reduces incident radiation in the mesophyll. The existence of high variability in wax accumulation levels between coexisting individuals of a species has a visual effect on colour that provides distinguishable green and glaucous phenotypes. We explored this variability in a Mediterranean evergreen tree Juniperus thurifera (L.) to evaluate the impact of epicuticular wax on optical and ecophysiological properties and on the abundance of photoprotective pigments throughout an annual cycle. Because of light attenuation by waxes, we expected that glaucous phenotypes would lower the need for photoprotective pigments. We evaluated the effect of phenotype and season on reflectance, defoliation levels, photochemical efficiency and photoprotective pigment contents in 20 green and 20 glaucous junipers. Contrary to our expectations, the results showed that glaucous trees suffered from a diminution in photochemical efficiency, but there was no reduction in photoprotective pigments. Differences between glaucous and green phenotypes were greater in winter, which is the most stressful season for this species. Glaucous individuals also showed the highest levels of leaf defoliation. The lower photochemical efficiency of glaucous trees, together with higher defoliation rates and equal or greater number of physiological photoprotective mechanisms, suggests that in spite of wax accumulation, glaucous trees suffer from more severe stress than green ones. This result suggests that changes in colouration in Mediterranean evergreens may be a decline indicator.
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Affiliation(s)
- R Esteban
- Department of Plant Biology and Ecology, University of Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
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32
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Schollaen K, Heinrich I, Helle G. UV-laser-based microscopic dissection of tree rings - a novel sampling tool for δ(13) C and δ(18) O studies. THE NEW PHYTOLOGIST 2014; 201:1045-1055. [PMID: 24219751 DOI: 10.1111/nph.12587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/02/2013] [Indexed: 06/02/2023]
Abstract
UV-laser-based microscopic systems were utilized to dissect and sample organic tissue for stable isotope measurements from thin wood cross-sections. We tested UV-laser-based microscopic tissue dissection in practice for high-resolution isotopic analyses (δ(13) C/δ(18) O) on thin cross-sections from different tree species. The method allows serial isolation of tissue of any shape and from millimetre down to micrometre scales. On-screen pre-defined areas of interest were automatically dissected and collected for mass spectrometric analysis. Three examples of high-resolution isotopic analyses revealed that: in comparison to δ(13) C of xylem cells, woody ray parenchyma of deciduous trees have the same year-to-year variability, but reveal offsets that are opposite in sign depending on whether wholewood or cellulose is considered; high-resolution tree-ring δ(18) O profiles of Indonesian teak reflect monsoonal rainfall patterns and are sensitive to rainfall extremes caused by ENSO; and seasonal moisture signals in intra-tree-ring δ(18) O of white pine are weighted by nonlinear intra-annual growth dynamics. The applications demonstrate that the use of UV-laser-based microscopic dissection allows for sampling plant tissue at ultrahigh resolution and unprecedented precision. This new technique facilitates sampling for stable isotope analysis of anatomical plant traits like combined tree eco-physiological, wood anatomical and dendroclimatological studies.
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Affiliation(s)
- Karina Schollaen
- GFZ - German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473, Potsdam, Germany
| | - Ingo Heinrich
- GFZ - German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473, Potsdam, Germany
| | - Gerhard Helle
- GFZ - German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473, Potsdam, Germany
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33
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Eckstein D. 'A new star'--but why just parenchyma for dendroclimatology? THE NEW PHYTOLOGIST 2013; 198:328-330. [PMID: 23510184 DOI: 10.1111/nph.12229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Affiliation(s)
- Dieter Eckstein
- Department of Wood Science, Wood Biology, University of Hamburg, Leuschnerstr, 91, 21031, Hamburg, Germany
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