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Compound-specific dual isotope analysis for the investigation of plant response to environmental change

Applicant Saurer Matthias
Number 166162
Funding scheme Project funding (Div. I-III)
Research institution Swiss Federal Research Inst. WSL Direktion
Institution of higher education Swiss Federal Institute for Forest, Snow and Landscape Research - WSL
Main discipline Climatology. Atmospherical Chemistry, Aeronomy
Start/End 01.08.2016 - 31.07.2018
Approved amount 231'220.00
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All Disciplines (3)

Discipline
Climatology. Atmospherical Chemistry, Aeronomy
Geochemistry
Environmental Research

Keywords (5)

biochemistry; tree rings; sugars; stable isotopes; tree physiology

Lay Summary (German)

Lead
Die Untersuchung stabiler Isotope in Pflanzen ist eine vielseitige Methode in Klima- und Oekosystemforschung. Dabei wird die natürliche Variabilität des seltenen Kohlenstoffs mit Atomgewicht 13 zum häufigen Kohlenstoff mit Atomgewicht 12 untersucht, sowie auch das Isotopenverhältnis beim Sauerstoff (Sauerstoff-18 zu Sauerstoff-16). Wenn nun bei Pflanzen gleichzeitig Kohlenstoff- und Sauerstoff-Isotope analysiert werden, ergibt das die Möglichkeit, wichtige Prozesse der Photosynthese (CO2-Aufnahme) und der Transpiration (Wasserverlust) besser zu verstehen.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Das Ziel des Projektes ist es, den Zusammenhang zwischen Umweltfaktoren und der Isotopenzusammensetzung in Pflanzen besser zu verstehen. Bei Untersuchung von gemahlenen Blättern als Ganzes ergeben sich jedoch Nachteile, da verschiedene Substanzen wie Zellulose, Zucker und Lipide zusammen analysiert werden. In diesem Projekt wollen wir deshalb eine neue, kürzlich entwickelte Methode anwenden, mit der Isotopenverhältnisse von einzelnen Substanzen bestimmt werden können, z.B. von Saccharose. Wir werden sowohl Pflanzen im Labor unter kontrollierten Bedingungen wie auch Bäume im Freiland untersuchen. Eine besondere Aufmerksamkeit liegt dabei auf der Auswirkung von Trockenstress auf die Physiologie der Pflanzen und daraus resultierende Veränderungen in den Isotopenverhältnissen diverser Pflanzenkomponenten.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Mit dem Projekt möchten wir neue Indikatoren entwickeln, die anzeigen, wie Pflanzen mit den gegenwärtigen Umweltveränderungen, wie etwa der Erwärmung und zunehmenden Trockenheit, umgehen und darauf reagieren. Dies soll helfen, die Gefährdung respektive Anpassungsfähigkeit von verschiedenen Pflanzen zu erkennen.
Direct link to Lay Summary Last update: 25.07.2016

Responsible applicant and co-applicants

Employees

Publications

Publication
Influence of starch deficiency on photosynthetic and post-photosynthetic carbon isotope fractionations
Lehmann Marco M, Ghiasi Shiva, George Gavin M, Cormier Marc-André, Gessler Arthur, Saurer Matthias, Werner Roland A (2019), Influence of starch deficiency on photosynthetic and post-photosynthetic carbon isotope fractionations, in Journal of Experimental Botany, 70(6), 1829-1841.
Drought induced tree mortality – a tree-ring isotope based conceptual model to assess mechanisms and predispositions
Gessler Arthur, Cailleret Maxime, Joseph Jobin, Schönbeck Leonie, Schaub Marcus, Lehmann Marco, Treydte Kerstin, Rigling Andreas, Timofeeva Galina, Saurer Matthias (2018), Drought induced tree mortality – a tree-ring isotope based conceptual model to assess mechanisms and predispositions, in New Phytologist, 219(2), 485-490.
The effect of18O-labelled water vapour on the oxygen isotope ratio of water and assimilates in plants at high humidity
Lehmann Marco M., Goldsmith Gregory R., Schmid Lola, Gessler Arthur, Saurer Matthias, Siegwolf Rolf T.W. (2018), The effect of18O-labelled water vapour on the oxygen isotope ratio of water and assimilates in plants at high humidity, in New Phytologist, 217(1), 105-116.
Oxygen isotope analysis of levoglucosan, a tracer of wood burning, in experimental and ambient aerosol samples
Blees Jan, Saurer Matthias, Siegwolf Rolf T.W., Ulevicius Vidmantas, Prevôt André S.H., Dommen Josef, Lehmann Marco M. (2017), Oxygen isotope analysis of levoglucosan, a tracer of wood burning, in experimental and ambient aerosol samples, in Rapid Communications in Mass Spectrometry, 31(24), 2101-2108.
Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species δ 18 O of individual leaf carbohydrates
Lehmann Marco M., Gamarra Bruno, Kahmen Ansgar, Siegwolf Rolf T.W., Saurer Matthias (2017), Oxygen isotope fractionations across individual leaf carbohydrates in grass and tree species δ 18 O of individual leaf carbohydrates, in Plant, Cell & Environment, 40(8), 1658-1670.

Collaboration

Group / person Country
Types of collaboration
Markus Leuenberger, Physics Institute, University of Bern Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Ansgar Kahmen, University of Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
European Geophysical Union General Assembly Poster How does the δ18O of atmospheric water vapour influence the δ18O of water and assimilates in plants? 08.04.2018 Wien, Austria Lehmann Marco; Gessler Arthur; Saurer Matthias;
Isotopes Talk given at a conference Compound-specific δ18O analysis by GC/Pyrolysis-IRMS – an underestimated tool. 09.07.2017 Ascona, Switzerland Lehmann Marco; Saurer Matthias;
American Geophysical Union Fall Meeting Talk given at a conference The δ18O of atmospheric water vapour is recorded in δ18O of leaf water and organic molecules at high relative humidity 12.12.2016 San Francisco, United States of America Gessler Arthur; Saurer Matthias; Treydte Kerstin; Lehmann Marco;
Joint European Stable Isotopes User group Meeting Talk given at a conference The influence of atmospheric water vapour on the oxygen isotope ratio of organic molecules in plants 04.09.2016 Ghent, Belgium Lehmann Marco; Saurer Matthias;


Associated projects

Number Title Start Funding scheme
136295 iTREE-Long-term variability of tree growth in a changing environment - identifying physiological mechanisms using stable C and O isotopes in tree rings. 01.04.2012 Sinergia
175888 Disentangling source water and leaf water signals in highly resolved oxygen isotope data from tree rings 01.05.2018 Project funding (Div. I-III)
150003 Compound-specific oxygen isotope analysis of carbohydrates as a novel tool in ecophysiology and climate research 01.08.2014 Project funding (Div. I-III)
182092 Development of a diagnostic stable isotope tool to elucidate the drought response of trees 01.05.2019 Project funding (Div. I-III)

Abstract

Stable carbon and oxygen isotope ratios of plant materials are versatile tools in climatic and ecophysiological research. The combined use of the two isotope ratios has great potential because the fundamental processes of carbon uptake and water loss can be partly disentangled due to different isotope fractionations for carbon and oxygen during photosynthesis and transpiration. This method has been applied already in many studies, but has some limitations related to the use of bulk plant matter which consists of a complex mixture of different compounds with different history regarding time of production, chemical pathway and pool turnover time. Compound-specific isotope analysis therefore provides a more detailed view on the biochemical fractionation processes involved and should enable a better mechanistic understanding of the important steps of isotope fractionation during photosynthesis and downstream metabolism. So far, however, only techniques for compound-specific carbon isotope analysis have been available. Recently, we have now successfully developed a new method for GC-pyrolysis-isotope-ratio-MS of d18O based on methylation for a range of carbohydrates (including the most common sugars such as sucrose, fructose, glucose and sugar alcohols). This opens for the first time the possibility of compound-specific dual isotope analysis for the investigation of fractionation processes in plants. We will build upon these promising advances by conducting a dual-isotope labelling in the greenhouse and by studying natural carbon and oxygen isotope variations in the field, with a focus on the effect of drought. In the greenhouse experiment, we will expose tree saplings to a drought treatment, while another group of trees will be well watered, and then apply a puls-labelling. We will then follow the isotope signal in individual compounds by multiple sampling from the leaves, phloem and the stem. In the field studies, we will measure natural isotope variations during the growing season in mature forests. By analyzing the relationship between weather conditions and the isotope ratios in different plant parts, we will be able to detect the response of both isotope ratios in leaf sugars to the actual environmental conditions as well as the changes later on in other tissues related to post-photosynthetic fractionation and exchange processes.By extending the dual isotope method from the bulk level to the level of individual molecules, we will improve the quantification of isotope fractionation in plants and therefore contribute to a more reliable application of stable isotopes in various fields of the environmental sciences.
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