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Wieloch, Thomas
Alternative names
Publications (10 of 12) Show all publications
Wieloch, T. (2019). Intramolecular isotope analysis reveals plant ecophysiological signals covering multiple timescales. (Doctoral dissertation). Umeå: Umeå Universitet
Open this publication in new window or tab >>Intramolecular isotope analysis reveals plant ecophysiological signals covering multiple timescales
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Intramolekylär isotopanalys avslöjar växtekofysiologiska signaler som täcker multipla tidsskalor
Abstract [en]

Our societies' wellbeing relies on stable and healthy environments. However, our current lifestyles, growth-oriented economic policies and the population explosion are leading to potentially catastrophic degradation of ecosystems and progressive disruption of food chains. Hopefully, more clarity about what the future holds in store will trigger stronger efforts to find, and adopt, problem-focused coping strategies and encourage environmentally friendly lifestyles.

Forecasting environmental change/destruction is complicated (inter alia) by lack of complete understanding of plant-environment interactions, particularly those involved in slow processes such as plant acclimatisation and adaptation. This stems from deficiencies in tools to analyse such slow processes. The present work aims at developing tools that can provide retrospective ecophysiological information covering timescales from days to millennia.

Natural archives, such as tree-rings, preserve plant metabolites over long timescales. Analyses of intramolecular isotope abundances in plant metabolites have the potential to provide retrospective information about metabolic processes and underlying environmental controls. Thus, my colleagues and I (hereafter we) analysed intramolecular isotope patterns in tree rings to develop analytical tools that can convey information about clearly-defined plant metabolic processes over multiple timescales. Such tools might help (inter alia) to constrain plants' capacities to sequester excess amounts of anthropogenic CO2; the so-called CO2 fertilisation effect. This, in turn, might shed light on plants' sink strength for the greenhouse gas CO2, and future plant performance and growth under climate change.

In the first of three studies, reported in appended papers, we analysed intramolecular 13C/12C ratios in tree-ring glucose. In six angiosperm and six gymnosperm species we found pronounced intramolecular 13C/12C differences, exceeding 10‰. These differences are transmitted into major global C pools, such as soil organic matter. Taking intramolecular 13C/12C differences into account might improve isotopic characterisation of soil metabolic processes and soil CO2 effluxes. In addition, we analysed intramolecular 13C/12C ratios in a Pinus nigra tree-ring archive spanning the period 1961 to 1995. These data revealed new ecophysiological 13C/12C signals, which can facilitate climate reconstructions and assessments of plant-environment interactions at higher resolution; thus providing higher quality information. We proposed that 13C/12C signals at glucose C-1 to C-2 derive from carbon injection into the Calvin-Benson cycle via the oxidative pentose phosphate pathway. We concluded that intramolecular 13C/12C measurements provide valuable new information about long-term metabolic dynamics for application in biogeochemistry, plant physiology, plant breeding, and paleoclimatology.

In the second study, we developed a comprehensive theory on the metabolic and ecophysiological origins of 13C/12C signals at tree-ring glucose C-5 and C-6. According to this theory and theoretical implications of the first study on signals at C-1 to C-3, analysis of such intramolecular signals can provide information about several metabolic processes. At C-3, a well-known signal reflecting CO2 uptake is preserved. The glucose-6-phosphate shunt around the Calvin-Benson cycle affects 13C/12C compositions at C-1 and C-2, while the 13C/12C signals at C-5 and C-6 reflect carbon fluxes into downstream metabolism. This theoretical framework enables further experimental studies to be conducted in a hypothesis-driven manner. In conclusion, the intramolecular approach provides information about carbon allocation in plant leaves. Thus, it gives access to long-term information on key ecophysiological processes, which could not be acquired by previous approaches.

The abundance of the hydrogen isotope deuterium, δD, is important for linking the water cycle with plant ecophysiology. The main factors affecting δD in plant organic matter are commonly assumed to be the δD in source water and leaf-level evaporative enrichment. Current δD models incorporate biochemical D fractionations as constants. In the third study we showed that biochemical D fractionations respond strongly to low ambient CO2 levels and low light intensity. Thus, models of δD values in plant organic matter should incorporate biochemical fractionations as variables. In addition, we found pronounced leaf-level δD differences between α-cellulose and wax n-alkanes. We explained this by metabolite-specific contributions of distinct hydrogen sources during biosynthesis.

Overall, this work advances our understanding of isotope distributions and isotope fractionations in plants. It reveals the immense potential of intramolecular isotope analyses for retrospective assessment of plant metabolism and associated environmental controls.

Place, publisher, year, edition, pages
Umeå: Umeå Universitet, 2019. p. 33
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 2004
Keywords
NMR spectroscopy, tree ring, isotope ratio, isotope effect, intramolecular 13C/12C signal, carbon allocation, acclimation, plant performance, climate reconstruction, plant ecophysiology
National Category
Cell Biology Biochemistry and Molecular Biology Biophysics Other Biological Topics Climate Research Geosciences, Multidisciplinary Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-154968 (URN)978-91-7855-001-2 (ISBN)
Public defence
2019-01-23, N440, Naturvetarhuset, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2019-01-09 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Cormier, M.-A., Werner, R. A., Sauer, P. E., Gröcke, D. R., Leuenberger, M. C., Wieloch, T., . . . Kahmen, A. (2018). 2H-fractionations during the biosynthesis of carbohydrates and lipids imprint a metabolic signal on the δ2H values of plant organic compounds. New Phytologist, 218(2), 479-491
Open this publication in new window or tab >>2H-fractionations during the biosynthesis of carbohydrates and lipids imprint a metabolic signal on the δ2H values of plant organic compounds
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2018 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 218, no 2, p. 479-491Article in journal (Refereed) Published
Abstract [en]

Hydrogen (H) isotope ratio (δ2H) analyses of plant organic compounds have been applied to assess ecohydrological processes in the environment despite a large part of the δ2H variability observed in plant compounds not being fully elucidated.

We present a conceptual biochemical model based on empirical H isotope data that we generated in two complementary experiments that clarifies a large part of the unexplained variability in the δ2H values of plant organic compounds.

The experiments demonstrate that information recorded in the δ2H values of plant organic compounds goes beyond hydrological signals and can also contain important information on the carbon and energy metabolism of plants. Our model explains where 2H‐fractionations occur in the biosynthesis of plant organic compounds and how these 2H‐fractionations are tightly coupled to a plant's carbon and energy metabolism. Our model also provides a mechanistic basis to introduce H isotopes in plant organic compounds as a new metabolic proxy for the carbon and energy metabolism of plants and ecosystems.

Such a new metabolic proxy has the potential to be applied in a broad range of disciplines, including plant and ecosystem physiology, biogeochemistry and palaeoecology.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
Keywords
alkanes, biomarker, cellulose, hydrogen isotopes, plant metabolism
National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-145979 (URN)10.1111/nph.15016 (DOI)000428070100011 ()29460486 (PubMedID)
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2019-01-07Bibliographically approved
Schleucher, J., Wieloch, T., Serk, H., Immerzeel, P., Ehlers, I., Nilsson, M. & Zuidema, P. (2018). Intramolecular stable isotope variation: Consequences for conventional isotope measurements and elucidation of new ecophysiological signals. In: Geophysical Research Abstracts: . Paper presented at EGU General Assembly 2018. , 20, Article ID EGU2018-5511.
Open this publication in new window or tab >>Intramolecular stable isotope variation: Consequences for conventional isotope measurements and elucidation of new ecophysiological signals
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2018 (English)In: Geophysical Research Abstracts, 2018, Vol. 20, article id EGU2018-5511Conference paper, Oral presentation with published abstract (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-145981 (URN)
Conference
EGU General Assembly 2018
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2018-06-09
Wieloch, T., Ehlers, I., Yu, J., Frank, D., Grabner, M., Gessler, A. & Schleucher, J. (2018). Intramolecular 13C analysis of tree rings provides multiple plant ecophysiology signals covering decades. Scientific Reports, 8, Article ID 5048.
Open this publication in new window or tab >>Intramolecular 13C analysis of tree rings provides multiple plant ecophysiology signals covering decades
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 5048Article in journal (Refereed) Published
Abstract [en]

Measurements of carbon isotope contents of plant organic matter provide important information in diverse fields such as plant breeding, ecophysiology, biogeochemistry and paleoclimatology. They are currently based on 13C/12C ratios of specific, whole metabolites, but we show here that intramolecular ratios provide higher resolution information. In the glucose units of tree-ring cellulose of 12 tree species, we detected large differences in 13C/12C ratios (>10‰) among carbon atoms, which provide isotopically distinct inputs to major global C pools, including wood and soil organic matter. Thus, considering position-specific differences can improve characterisation of soil-to-atmosphere carbon fluxes and soil metabolism. In a Pinus nigra tree-ring archive formed from 1961 to 1995, we found novel 13C signals, and show that intramolecular analysis enables more comprehensive and precise signal extraction from tree rings, and thus higher resolution reconstruction of plants’ responses to climate change. Moreover, we propose an ecophysiological mechanism for the introduction of a 13C signal, which links an environmental shift to the triggered metabolic shift and its intramolecular 13C signature. In conclusion, intramolecular 13C analyses can provide valuable new information about long-term metabolic dynamics for numerous applications.

National Category
Other Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-145978 (URN)10.1038/s41598-018-23422-2 (DOI)000428033900002 ()29567963 (PubMedID)
Funder
Knut and Alice Wallenberg Foundation, 2015.0047
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2019-01-07Bibliographically approved
Wieloch, T., Ehlers, I., Yu, J., Frank, D., Grabner, M., Gessler, A. & Schleucher, J. (2018). Tree-ring cellulose exhibits several interannual 13C signals on the intramolecular level. In: Geophysical Research Abstracts: . Paper presented at EGU General Assembly 2018. , 20, Article ID EGU2018-17509-2.
Open this publication in new window or tab >>Tree-ring cellulose exhibits several interannual 13C signals on the intramolecular level
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2018 (English)In: Geophysical Research Abstracts, 2018, Vol. 20, article id EGU2018-17509-2Conference paper, Poster (with or without abstract) (Refereed)
Abstract
National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-145982 (URN)
Conference
EGU General Assembly 2018
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2018-06-09
Wieloch, T., Ehlers, I., Frank, D., Gessler, A., Grabner, M., Yu, J. & Schleucher, J. (2017). Tree-ring cellulose exhibits several distinct intramolecular 13C signals. In: Geophysical Research Abstracts: . Paper presented at EGU General Assembly 2017. , 19, Article ID EGU2017-14723.
Open this publication in new window or tab >>Tree-ring cellulose exhibits several distinct intramolecular 13C signals
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2017 (English)In: Geophysical Research Abstracts, 2017, Vol. 19, article id EGU2017-14723Conference paper, Oral presentation with published abstract (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-145983 (URN)
Conference
EGU General Assembly 2017
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2018-06-09
Ehlers, I., Augusti, A., Köhler, I., Wieloch, T., Zuidema, P., Robertson, I., . . . Schleucher, J. (2016). Detecting plant-climate interactions over decades-millennia using NMR isotopomer analysis. In: Geophysical Research Abstracts: . Paper presented at EGU General Assembly 2016. , 18, Article ID EGU2016-9141-2.
Open this publication in new window or tab >>Detecting plant-climate interactions over decades-millennia using NMR isotopomer analysis
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2016 (English)In: Geophysical Research Abstracts, 2016, Vol. 18, article id EGU2016-9141-2Conference paper, Oral presentation with published abstract (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-145985 (URN)
Conference
EGU General Assembly 2016
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2018-06-09
Ehlers, I., Wieloch, T., Groenendijk, P., Vlam, M., van der Sleen, P., Zuidema, P. A., . . . Schleucher, J. (2014). Enhanced photosynthetic efficiency in trees world-wide by rising atmospheric CO2 levels. In: Geophysical Research Abstracts: . Paper presented at EGU General Assembly 2014. , 16, Article ID EGU2014-12587-1.
Open this publication in new window or tab >>Enhanced photosynthetic efficiency in trees world-wide by rising atmospheric CO2 levels
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2014 (English)In: Geophysical Research Abstracts, 2014, Vol. 16, article id EGU2014-12587-1Conference paper, Oral presentation with published abstract (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-145986 (URN)
Conference
EGU General Assembly 2014
Available from: 2018-03-24 Created: 2018-03-24 Last updated: 2018-06-09
Thomas, W., Helle, G., Heinrich, I., Voigt, M. & Schyma, P. (2011). A novel device for batch-wise isolation of a-cellulose from small-amount wholewood samples. Dendrochronologia, 29(2), 115-117
Open this publication in new window or tab >>A novel device for batch-wise isolation of a-cellulose from small-amount wholewood samples
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2011 (English)In: Dendrochronologia, ISSN 1125-7865, E-ISSN 1612-0051, Vol. 29, no 2, p. 115-117Article in journal (Refereed) Published
Abstract [en]

A novel device for the chemical isolation of α-cellulose from wholewood material of tree rings was designed by the Potsdam Dendro Laboratory. It allows the simultaneous treatment of up to several hundred micro samples. Key features are the batch-wise exchange of the chemical solutions, the reusability of all major parts and the easy and unambiguous labelling of each individual sample. Compared to classical methods labour intensity and running costs are significantly reduced.

National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-58211 (URN)10.1016/j.dendro.2010.08.008 (DOI)
Available from: 2012-08-27 Created: 2012-08-27 Last updated: 2018-06-08Bibliographically approved
Laumer, W., Andreu, L., Helle, G., Schleser, G. H., Wieloch, T. & Wissel, H. (2009). A novel approach for the homogenization of cellulose to use micro-amounts for stable isotope analyses. Rapid Communications in Mass Spectrometry, 23(13), 1934-1940
Open this publication in new window or tab >>A novel approach for the homogenization of cellulose to use micro-amounts for stable isotope analyses
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2009 (English)In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 23, no 13, p. 1934-1940Article in journal (Refereed) Published
Abstract [en]

Climate reconstructions using stable isotopes from tree-rings are steadily increasing. The investigations concentrate mostly on cellulose due to its high stability. In recent years the available amount of cellulose has steadily decreased, mainly because micro-structures of plant material have had to be analyzed. Today, the amounts of cellulose being studied are frequently in the milligram and often in the microgram range. Consequently, homogeneity problems with regard to the stable isotopes of carbon and oxygen from cellulose have occurred and these have called for new methods in the preparation of cellulose for reliable isotope analyses. Three different methods were tested for preparing isotopically homogenous cellulose, namely mechanical grinding, freezing by liquid nitrogen with subsequent milling and ultrasonic breaking of cellulose fibres. The best precision of isotope data was achieved by freeze-milling and ultrasonic breaking. However, equipment for freeze-milling is expensive and the procedure is labour-intensive. Mechanical grinding resulted in a rather high loss of material and it is also labour-intensive. The use of ultrasound for breaking cellulose fibres proved to be the best method in terms of rapidity of sample throughput, avoidance of sample loss, precision of isotope results, ease of handling, and cost.

National Category
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-58209 (URN)10.1002/rcm.4105 (DOI)
Available from: 2012-08-27 Created: 2012-08-27 Last updated: 2018-06-08Bibliographically approved
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