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Watanabe Y, Yamagishi S, Takata N, Tsuyama T, Yasue K, Ohno Y. Formation of xylem tissues and secondary cell walls is diminished by severe and consecutive insect defoliation. AMERICAN JOURNAL OF BOTANY 2023; 110:e16232. [PMID: 37661818 DOI: 10.1002/ajb2.16232] [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: 04/05/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 09/05/2023]
Abstract
PREMISE Insect defoliation of trees causes unusual changes to wood anatomy and slows radial growth that decreases tree value; however, the characteristics of these anatomical changes in hardwoods remain unclear. The aim of this study was to characterize the anatomy and histochemistry of the wood in trunks of Betula maximowicziana trees after severe insect defoliation. METHODS Secondary xylem tissues were sampled from trunks that had been defoliated by Caligula japonica at Naie and Furano in central Hokkaido during 2006-2012, then cross-dated and examined microscopically and stained histochemically to characterize anatomical and chemical changes in the cells. RESULTS White rings with thin-walled wood fibers and greatly reduced annual ring width in the subsequent year were observed in samples from both sites. From these results, the year that the white rings formed was determined, and severe defoliation was confirmed to trigger white ring formation. The characteristics may prove useful to detect the formation year of white rings. Scanning electron microscopy and histochemical analyses of the white rings indicated that the thickness of the S2 layer in the wall of wood fiber cells decreased, but xylan and lignin were still deposited in the cell walls of wood fibers. However, the walls of the fibers rethickened after the defoliation. CONCLUSIONS Our results suggest that B. maximowicziana responds to a temporary lack of carbon inputs due to insect defoliation by regulating the thickness of the S2 layer of the cell wall of wood fibers. For B. maximowicziana, insect defoliation late in the growing season has serious deleterious effects on wood formation and radial growth.
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Affiliation(s)
- Yoko Watanabe
- Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Shohei Yamagishi
- Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
- Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan
| | - Naoki Takata
- Forest Bio-Research Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan
| | - Taku Tsuyama
- Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Koh Yasue
- Institute for Mountain Science, Shinshu University, Minami-minowa, 399-4598, Japan
| | - Yasuyuki Ohno
- Forest Research Institute, Hokkaido Research Organization, Bibai, 079-0198, Japan
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Vitali V, Peters RL, Lehmann MM, Leuenberger M, Treydte K, Büntgen U, Schuler P, Saurer M. Tree-ring isotopes from the Swiss Alps reveal non-climatic fingerprints of cyclic insect population outbreaks over the past 700 years. TREE PHYSIOLOGY 2023; 43:706-721. [PMID: 36738262 PMCID: PMC10177004 DOI: 10.1093/treephys/tpad014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 01/31/2023] [Indexed: 05/13/2023]
Abstract
Recent experiments have underlined the potential of δ2H in tree-ring cellulose as a physiological indicator of shifts in autotrophic versus heterotrophic processes (i.e., the use of fresh versus stored non-structural carbohydrates). However, the impact of these processes has not yet been quantified under natural conditions. Defoliator outbreaks disrupt tree functioning and carbon assimilation, stimulating remobilization, therefore providing a unique opportunity to improve our understanding of changes in δ2H. By exploring a 700-year tree-ring isotope chronology from Switzerland, we assessed the impact of 79 larch budmoth (LBM, Zeiraphera griseana [Hübner]) outbreaks on the growth of its host tree species, Larix decidua [Mill]. The LBM outbreaks significantly altered the tree-ring isotopic signature, creating a 2H-enrichment and an 18O- and 13C-depletion. Changes in tree physiological functioning in outbreak years are shown by the decoupling of δ2H and δ18O (O-H relationship), in contrast to the positive correlation in non-outbreak years. Across the centuries, the O-H relationship in outbreak years was not significantly affected by temperature, indicating that non-climatic physiological processes dominate over climate in determining δ2H. We conclude that the combination of these isotopic parameters can serve as a metric for assessing changes in physiological mechanisms over time.
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Affiliation(s)
- Valentina Vitali
- Stable Isotope Research Centre (SIRC), Ecosystem Ecology, Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
| | - Richard L Peters
- Physiological Plant Ecology, Department of Environmental Sciences, University of Basel, Schönbeinstrasse 6, Basel CH-4056, Switzerland
| | - Marco M Lehmann
- Stable Isotope Research Centre (SIRC), Ecosystem Ecology, Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
| | - Markus Leuenberger
- Climate and Environmental Physics Division and Oeschger Centre for Climate Change Research, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland
| | - Kerstin Treydte
- Department of Dendrosciences, Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
| | - Ulf Büntgen
- Department of Dendrosciences, Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
- Department of Geography, University of Cambridge, Downing Place, Cambridge CB2 3EN, UK
- Global Change Research Institute (CzechGlobe), Czech Academy of Sciences, Brno 603 00, Czech Republic
- Department of Geography, Faculty of Science, Masaryk University, Brno 611 37, Czech Republic
| | - Philipp Schuler
- Stable Isotope Research Centre (SIRC), Ecosystem Ecology, Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
| | - Matthias Saurer
- Stable Isotope Research Centre (SIRC), Ecosystem Ecology, Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf CH-8903, Switzerland
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Oberhuber W, Landlinger-Weilbold A, Schröter DM. Triggering Bimodal Radial Stem Growth in Pinus sylvestris at a Drought-Prone Site by Manipulating Stem Carbon Availability. FRONTIERS IN PLANT SCIENCE 2021; 12:674438. [PMID: 34122490 PMCID: PMC8193578 DOI: 10.3389/fpls.2021.674438] [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: 03/01/2021] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
A bimodal radial growth (RG) pattern, i.e., growth peaks in spring and autumn, was repeatedly found in trees in the Mediterranean regions, where summer drought causes reduction or cessation of cambial activity. In a dry inner Alpine valley of the Eastern Alps (Tyrol, Austria, 750 m asl), Pinus sylvestris shows unimodal RG with onset and cessation of cambial activity in early April and late June, respectively. A resumption of cambial activity after intense summer rainfall was not observed in this region. In a field experiment, we tested the hypothesis that early cessation of cambial activity at this drought-prone site is an adaptation to limited water availability leading to an early and irreversible switch of carbon (C) allocation to belowground. To accomplish this, the C status of young P. sylvestris trees was manipulated by physical blockage of phloem transport (girdling) 6 weeks after cessation of cambial cell division. Influence of manipulated C availability on RG was recorded by stem dendrometers, which were mounted above the girdling zone. In response to blockage of phloem flow, resumption of cambial activity was detected above girdling after about 2 weeks. Although the experimentally induced second growth surge lasted for the same period as in spring (c. 2 months), the increment was more than twice as large due to doubling of daily maximum RG rate. After girdling, wood anatomical traits above girdling no longer showed any significant differences between earlywood and latewood tracheids indicating pronounced effects of C availability on cell differentiation. Below girdling, no reactivation of cambial activity occurred, but cell wall thickness of last formed latewood cell was reduced due to lack of C supply after girdling. Intense RG resumption after girdling indicates that cessation of cambial activity can be reversed by manipulating C status of the stem. Hence, our girdling study yielded strong support for the hypothesis that belowground organs exert high C sink strengths on the drought-prone study site. Furthermore, this work highlights the need of in-depth experimental studies in order to understand the interactions between endogenous and exogenous factors on cambial activity and xylem cell differentiation more clearly.
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Affiliation(s)
- Walter Oberhuber
- Department of Botany, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
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Escobar‐Sandoval M, Pâques L, Fonti P, Martinez‐Meier A, Rozenberg P. Phenotypic plasticity of European larch radial growth and wood density along a-1,000 m elevational gradient. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2021; 2:45-60. [PMID: 37284284 PMCID: PMC10168074 DOI: 10.1002/pei3.10040] [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: 08/24/2020] [Revised: 01/19/2021] [Accepted: 02/03/2021] [Indexed: 06/08/2023]
Abstract
Phenotypic plasticity is a key mechanism for sedentary long-living species to adjust to changing environment. Here, we use mature Larix decidua tree-ring variables collected along an elevational transect in the French Alps to characterize the range of individual plastic responses to temperature. Stem cores from 821 mature Larix decidua trees have been collected from four plots distributed along a 1,000-m elevational gradient in a natural forest to build up individual linear reaction norms of tree-ring microdensity traits to temperature. The sign, magnitude and spread of variations of the slopes of the individual reaction norms were used to characterize variation of phenotypic plasticity among plots and traits. Results showed a large range of phenotypic plasticity (with positive and negative slopes) at each elevational plot and for each tree-ring variable. Overall, phenotypic plasticity tends to be larger but positive at higher elevation, negative at the warmer lower sites, and more variable in the center of the elevation distribution. Individual inter-ring reaction norm is a valuable tool to retrospectively characterize phenotypic plasticity of mature forest trees. This approach applied to Larix decidua tree-ring micro-density traits along an elevation gradient showed the existence of large inter-individual variations that could support local adaptation to a fast-changing climate.
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Affiliation(s)
| | - Luc Pâques
- INRAEUMR 0588 BIOFORAOrléans Cedex 2France
| | - Patrick Fonti
- Swiss Federal Institute for Forest Snow and Landscape Research WSLBirmensdorfSwitzerland
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