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Lippold E, Schlüter S, Mueller CW, Höschen C, Harrington G, Kilian R, Gocke MI, Lehndorff E, Mikutta R, Vetterlein D. Correlative Imaging of the Rhizosphere─A Multimethod Workflow for Targeted Mapping of Chemical Gradients. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:1538-1549. [PMID: 36626664 DOI: 10.1021/acs.est.2c07340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Examining in situ processes in the soil rhizosphere requires spatial information on physical and chemical properties under undisturbed conditions. We developed a correlative imaging workflow for targeted sampling of roots in their three-dimensional (3D) context and assessed the imprint of roots on chemical properties of the root-soil contact zone at micrometer to millimeter scale. Maize (Zea mays) was grown in 15N-labeled soil columns and pulse-labeled with 13CO2 to visualize the spatial distribution of carbon inputs and nitrogen uptake together with the redistribution of other elements. Soil columns were scanned by X-ray computed tomography (X-ray CT) at low resolution (45 μm) to enable image-guided subsampling of specific root segments. Resin-embedded subsamples were then analyzed by X-ray CT at high resolution (10 μm) for their 3D structure and chemical gradients around roots using micro-X-ray fluorescence spectroscopy (μXRF), nanoscale secondary ion mass spectrometry (NanoSIMS), and laser-ablation isotope ratio mass spectrometry (LA-IRMS). Concentration gradients, particularly of calcium and sulfur, with different spatial extents could be identified by μXRF. NanoSIMS and LA-IRMS detected the release of 13C into soil up to a distance of 100 μm from the root surface, whereas 15N accumulated preferentially in the root cells. We conclude that combining targeted sampling of the soil-root system and correlative microscopy opens new avenues for unraveling rhizosphere processes in situ.
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Affiliation(s)
- Eva Lippold
- Department of Soil System Science, Helmholtz Centre for Environmental Research - UFZ, Theodor-Lieser-Straße 4, 06120 Halle (Saale), Germany
| | - Steffen Schlüter
- Department of Soil System Science, Helmholtz Centre for Environmental Research - UFZ, Theodor-Lieser-Straße 4, 06120 Halle (Saale), Germany
| | - Carsten W Mueller
- Department of Life Science Systems, Soil Science, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Straße 2, 85354 Freising, Germany
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Carmen Höschen
- Department of Life Science Systems, Soil Science, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Straße 2, 85354 Freising, Germany
| | - Gertraud Harrington
- Department of Life Science Systems, Soil Science, TUM School of Life Sciences, Technical University of Munich, Emil-Ramann-Straße 2, 85354 Freising, Germany
| | - Rüdiger Kilian
- Mineralogy and Geochemistry, Martin Luther University Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany
| | - Martina I Gocke
- Soil Science and Soil Ecology, Institute of Crop Science and Resource Conservation, University of Bonn, Nussallee 13, 53115 Bonn, Germany
| | - Eva Lehndorff
- Soil Ecology, Bayreuth University, Dr.-Hans-Frisch-Straße 1-3, 95448 Bayreuth, Germany
| | - Robert Mikutta
- Soil Science and Soil Protection, Martin Luther University Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany
| | - Doris Vetterlein
- Department of Soil System Science, Helmholtz Centre for Environmental Research - UFZ, Theodor-Lieser-Straße 4, 06120 Halle (Saale), Germany
- Soil Science and Soil Protection, Martin Luther University Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany
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Speckert TC, Petibon F, Wiesenberg GLB. Late-season biosynthesis of leaf fatty acids and n-alkanes of a mature beech ( Fagus sylvatica) tree traced via 13CO 2 pulse-chase labelling and compound-specific isotope analysis. FRONTIERS IN PLANT SCIENCE 2023; 13:1029026. [PMID: 36684794 PMCID: PMC9853289 DOI: 10.3389/fpls.2022.1029026] [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: 08/26/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Leaf cuticular waxes play an important role in reducing evapotranspiration via diffusion. However, the ability of mature trees to regulate the biosynthesis of waxes to changing conditions (e.g., drought, light exposition) remain an open question, especially during the late growing season. This holds also true for one of the most widely distributed trees in Central Europe, the European beech tree (Fagus sylvatica L.). In order to investigate the ongoing formation of wax constituents like alkanes and fatty acids, we conducted a 13CO2 pulse-chase labelling experiment on sun-exposed and shaded branches of a mature beech tree during the late summer 2018. The 13C-label was traced via compound-specific δ13C isotope analysis of n-alkanes and fatty acids to determine the de-novo biosynthesis within these compound classes. We did not observe a significant change in lipid concentrations during the late growing season, but we found higher n-alkane concentrations in sun-exposed compared to shaded leaves in August and September. The n-alkane and fatty acid composition showed ongoing modifications during the late growing season. Together with the uptake and following subsequent decrease of the 13C-label, this suggests ongoing de-novo biosynthesis, especially of fatty acids in European beech leaves. Moreover, there is a high variability in the 13C-label among individual branches and between sun-exposed and shaded leaves. At the same time, sun-exposed leaves invest more of the assimilated C into secondary metabolites such as lipids than shaded leaves. This indicates that the investigated mature beech tree could adjust its lipid production and composition in order to acclimate to changes in microclimates within the tree crown and during the investigated period.
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Lirette AO, Despland E. Defensive Traits during White Spruce ( Picea glauca) Leaf Ontogeny. INSECTS 2021; 12:insects12070644. [PMID: 34357304 PMCID: PMC8306798 DOI: 10.3390/insects12070644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 07/05/2021] [Accepted: 07/11/2021] [Indexed: 11/23/2022]
Abstract
Simple Summary Leaves can only toughen after they have finished growing and, as a result, many herbivorous insects specialize in newly developing leaves because softer leaves are easier to chew. The foliage of conifer trees is particularly tough, and so one would expect conifers to invest more defensive chemicals into soft vulnerable growing needles than into tough mature ones. We summarize the literature describing how chemical defenses of foliage change during the growing season in white spruce, an economically important conifer tree. We next report measurements of the toughness of white spruce buds as they swell, burst, and grow into young needles. As expected, buds soften as they swell in spring, but after budburst, needles become tougher until they are similar to previous-year foliage in mid-summer. Leaves grown in the sun are slightly tougher than leaves grown in the shade. However, there was no indication that trees invest more in chemical defense of growing leaves than of mature leaves. Abstract Changes during leaf ontogeny affect palatability to herbivores, such that many insects, including the eastern spruce budworm (Choristoneura fumiferana (Clem.)), are specialist feeders on growing conifer leaves and buds. Developmental constraints imply lower toughness in developing foliage, and optimal defense theory predicts higher investment in chemical defense in these vulnerable yet valuable developing leaves. We summarize the literature on the time course of defensive compounds in developing white spruce (Picea glauca (Moench) Voss) needles and report original research findings on the ontogeny of white spruce needle toughness. Our results show the predicted pattern of buds decreasing in toughness followed by leaves increasing in toughness during expansion, accompanied by opposite trends in water content. Toughness of mature foliage decreased slightly during the growing season, with no significant relationship with water content. Toughness of sun-grown leaves was slightly higher than that of shade-grown leaves. However, the literature review did not support the expected pattern of higher defensive compounds in expanding leaves than in mature leaves, suggesting that white spruce might instead exhibit a fast-growth low-defense strategy.
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Vieira J, Nabais C, Campelo F. Extreme Growth Increments Reveal Local and Regional Climatic Signals in Two Pinus pinaster Populations. FRONTIERS IN PLANT SCIENCE 2021; 12:658777. [PMID: 34220886 PMCID: PMC8248814 DOI: 10.3389/fpls.2021.658777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
Tree rings are valuable proxies of past climate that allow inferring past growth responses to climate variability and extreme events, which is only possible considering that the relationship between tree growth and environmental conditions is linear and stable over time. However, in the last decades, divergent growth patterns have been observed in trees from the same forest stand, while unprecedented growth convergence was observed between trees from distant locations. Here, we use a new approach that considers convergent and divergent event years in two populations of Pinus pinaster Aiton in an altitudinal and oceanic-continental gradient to investigate what is triggering divergence and convergence in tree growth. The two study sites are Tocha (TCH), a plantation on sand dunes at low altitude near the ocean, and Serra da Estrela (SdE), a mountain plantation located at 1,100 m altitude, 100 km away from the ocean. The analysis of the climatic conditions in convergent growth years revealed that positive convergent growth was related to above average precipitation in previous winter and that negative convergent growth was related to below average precipitation during the growing season. Divergent growth revealed a temperature signal with warmer temperatures in spring promoting growth in SdE and growth reduction in TCH. Convergent growth was associated with a regional climatic signal, reinforcing the importance of precipitation in the Mediterranean region, and divergent growth to site conditions, revealing local adaptation. The information gathered in this study gives valuable insights on the response of P. pinaster to extreme climatic events, allowing for more adjusted management strategies of Mediterranean pine forests.
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Tracing plant–environment interactions from organismal to planetary scales using stable isotopes: a mini review. Emerg Top Life Sci 2021; 5:301-316. [DOI: 10.1042/etls20200277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 01/09/2023]
Abstract
Natural isotope variation forms a mosaic of isotopically distinct pools across the biosphere and flows between pools integrate plant ecology with global biogeochemical cycling. Carbon, nitrogen, and water isotopic ratios (among others) can be measured in plant tissues, at root and foliar interfaces, and in adjacent atmospheric, water, and soil environments. Natural abundance isotopes provide ecological insight to complement and enhance biogeochemical research, such as understanding the physiological conditions during photosynthetic assimilation (e.g. water stress) or the contribution of unusual plant water or nutrient sources (e.g. fog, foliar deposition). While foundational concepts and methods have endured through four decades of research, technological improvements that enable measurement at fine spatiotemporal scales, of multiple isotopes, and of isotopomers, are advancing the field of stable isotope ecology. For example, isotope studies now benefit from the maturation of field-portable infrared spectroscopy, which allows the exploration of plant–environment sensitivity at physiological timescales. Isotope ecology is also benefiting from, and contributing to, new understanding of the plant–soil–atmosphere system, such as improving the representation of soil carbon pools and turnover in land surface models. At larger Earth-system scales, a maturing global coverage of isotope data and new data from site networks offer exciting synthesis opportunities to merge the insights of single-or multi-isotope analysis with ecosystem and remote sensing data in a data-driven modeling framework, to create geospatial isotope products essential for studies of global environmental change.
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Werner C, Fasbender L, Romek KM, Yáñez-Serrano AM, Kreuzwieser J. Heat Waves Change Plant Carbon Allocation Among Primary and Secondary Metabolism Altering CO 2 Assimilation, Respiration, and VOC Emissions. FRONTIERS IN PLANT SCIENCE 2020; 11:1242. [PMID: 32922421 PMCID: PMC7456945 DOI: 10.3389/fpls.2020.01242] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 07/29/2020] [Indexed: 05/17/2023]
Abstract
Processes controlling plant carbon allocation among primary and secondary metabolism, i.e., carbon assimilation, respiration, and VOC synthesis are still poorly constrained, particularly regarding their response to stress. To investigate these processes, we simulated a 10-day 38°C heat wave, analysing real-time carbon allocation into primary and secondary metabolism in the Mediterranean shrub Halimium halimifolium L. We traced position-specific 13C-labeled pyruvate into daytime VOC and CO2 emissions and during light-dark transition. Net CO2 assimilation strongly declined under heat, due to three-fold higher respiration rates. Interestingly, day respiration also increased two-fold. Decarboxylation of the C1-atom of pyruvate was the main process driving daytime CO2 release, whereas the C2-moiety was not decarboxylated in the TCA cycle. Heat induced high emissions of methanol, methyl acetate, acetaldehyde as well as mono- and sesquiterpenes, particularly during the first two days. After 10-days of heat a substantial proportion of 13C-labeled pyruvate was allocated into de novo synthesis of VOCs. Thus, during extreme heat waves high respiratory losses and reduced assimilation can shift plants into a negative carbon balance. Still, plants enhanced their investment into de novo VOC synthesis despite associated metabolic CO2 losses. We conclude that heat stress re-directed the proportional flux of key metabolites into pathways of VOC biosynthesis most likely at the expense of reactions of plant primary metabolism, which might highlight their importance for stress protection.
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Affiliation(s)
- Christiane Werner
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
- *Correspondence: Christiane Werner,
| | - Lukas Fasbender
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
| | | | - Ana Maria Yáñez-Serrano
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
- Center of Ecological Research and Forest Applications (CREAF), Universitat Autònoma de Barcelona, Barcelona, Spain
- Global Ecology Unit CREAF-CSIC-UAB, Cerdanyola del Vallès, Barcelona, Spain
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Cartenì F, Deslauriers A, Rossi S, Morin H, De Micco V, Mazzoleni S, Giannino F. The Physiological Mechanisms Behind the Earlywood-To-Latewood Transition: A Process-Based Modeling Approach. FRONTIERS IN PLANT SCIENCE 2018; 9:1053. [PMID: 30079078 PMCID: PMC6063077 DOI: 10.3389/fpls.2018.01053] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/28/2018] [Indexed: 05/24/2023]
Abstract
In extratropical ecosystems, the growth of trees is cyclic, producing tree rings composed of large-lumen and thin-walled cells (earlywood) alternating with narrow-lumen and thick-walled cells (latewood). So far, the physiology behind wood formation processes and the associated kinetics has rarely been considered to explain this pattern. We developed a process-based mechanistic model that simulates the development of conifer tracheids, explicitly considering the processes of cell enlargement and the deposition and lignification of cell walls. The model assumes that (1) wall deposition gradually slows down cell enlargement and (2) the deposition of cellulose and lignin is regulated by the availability of soluble sugars. The model reliably reproduces the anatomical traits and kinetics of the tracheids of four conifer species. At the beginning of the growing season, low sugar availability in the cambium results in slow wall deposition that allows for a longer enlargement time; thus, large cells with thin walls (i.e., earlywood) are produced. In late summer and early autumn, high sugar availability produces narrower cells having thick cell walls (i.e., latewood). This modeling framework provides a mechanistic link between plant ecophysiology and wood phenology and significantly contributes to understanding the role of sugar availability during xylogenesis.
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Affiliation(s)
- Fabrizio Cartenì
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
| | - Annie Deslauriers
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
| | - Sergio Rossi
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, Chinese Academy of Sciences, Guangzhou, China
| | - Hubert Morin
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
| | - Veronica De Micco
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Stefano Mazzoleni
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Francesco Giannino
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
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