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New insights into the mechanisms of plant isotope fractionation from combined analysis of intramolecular ¹³C and deuterium abundances in Pinus nigra tree-ring glucose 2024 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137Article in journal (Refereed) Epub ahead of print

Abstract [en]

• Understanding isotope fractionation mechanisms is fundamental for analyses of plant ecophysiology and paleoclimate based on tree-ring isotope data.
• To gain new insights into isotope fractionation, we analysed intramolecular ¹³C discrimination in tree-ring glucose (Δ_i', i = C-1 to C-6) and metabolic deuterium fractionation at H¹ and H² (ε_met) combinedly. This dual-isotope approach was used for isotope-signal deconvolution.
• We found evidence for metabolic processes affecting Δ₁' and Δ₃', which respond to air vapour pressure deficit (VPD), and processes affecting Δ₁' and Δ₃', and ε_met, which respond to precipitation but not VPD. These relationships exhibit change points dividing a period of homeostasis (1961–1980) from a period of metabolic adjustment (1983–1995). Homeostasis may result from sufficient groundwater availability. Additionally, we found Δ₅' and Δ₆' relationships with radiation and temperature, which are temporally stable and consistent with previously proposed isotope fractionation mechanisms.
• Based on the multitude of climate covariables, intramolecular carbon isotope analysis has a remarkable potential for climate reconstruction. While isotope fractionation beyond leaves is currently considered to be constant, we propose significant parts of the carbon and hydrogen isotope variation in tree-ring glucose originate in stems (precipitation-dependent signals). As basis for follow-up studies, we propose mechanisms introducing Δ₁', Δ₂', Δ₃', and ε_met variability.

Place, publisher, year, edition, pages

John Wiley & Sons, 2024.

Keywords [en]

carbon stable isotopes, hydrogen stable isotopes, intramolecular isotope analysis, isotope fractionation mechanisms, leaf water status, plant–environment interactions, stem water status, tree rings

National Category

Botany

Identifiers

URN: urn:nbn:se:umu:diva-230106DOI: 10.1111/nph.20113ISI: 001318897800001PubMedID: 39314055Scopus ID: 2-s2.0-85204714005OAI: oai:DiVA.org:umu-230106DiVA, id: diva2:1901673

Funder

Swedish Research Council Formas, 2022-02833Available from: 2024-09-29 Created: 2024-09-29 Last updated: 2024-10-16

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Wieloch, ThomasYu, JunNiittylä, Totte

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Wieloch, ThomasYu, JunNiittylä, Totte

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Umeå Plant Science Centre (UPSC)Department of Mathematics and Mathematical Statistics

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New Phytologist

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Botany

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