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Temperature‐sensitive biochemical $^{18}$O‐fractionation and humidity‐dependent attenuation factor are needed to predict δ $^{18}$O of cellulose from leaf water in a grassland ecosystem

Hirl, Regina T.; Ogée, Jérôme; Ostler, Ulrike 1,2; Schäufele, Rudi; Baca Cabrera, Juan C.; Zhu, Jianjun; Schleip, Inga; Wingate, Lisa; Schnyder, Hans
1 Institut für Meteorologie und Klimaforschung – Atmosphärische Umweltforschung (IMK-IFU), Karlsruher Institut für Technologie (KIT)
2 Institut für Meteorologie und Klimaforschung (IMK), Karlsruher Institut für Technologie (KIT)


We explore here our mechanistic understanding of the environmental and physiological processes that determine the oxygen isotope composition of leaf cellulose (δ$^{18}$O$_{cellulose}$) in a drought‐prone, temperate grassland ecosystem.
A new allocation‐and‐growth model was designed and added to an $^{18}$O‐enabled soil–vegetation–atmosphere transfer model (MuSICA) to predict seasonal (April–October) and multi‐annual (2007–2012) variation of δ$^{18}$O$_{cellulose}$ and $^{18}$O‐enrichment of leaf cellulose (Δ$^{18}$O$_{cellulose}$) based on the Barbour–Farquhar model.
Modelled δ$^{18}$O$_{cellulose}$ agreed best with observations when integrated over c. 400 growing‐degree‐days, similar to the average leaf lifespan observed at the site. Over the integration time, air temperature ranged from 7 to 22°C and midday relative humidity from 47 to 73%. Model agreement with observations of δ$^{18}$O$_{cellulose}$ (R$^{2}$ = 0.57) and Δ$^{18}$O$_{cellulose}$ (R$^{2}$ = 0.74), and their negative relationship with canopy conductance, was improved significantly when both the biochemical $^{18}$O‐fractionation between water and substrate for cellulose synthesis (ε$_{bio}$, range 26–30‰) was temperature‐sensitive, as previously reported for aquatic plants and heterotrophically grown wheat seedlings, and the proportion of oxygen in cellulose reflecting leaf water $^{18}$O‐enrichment (1 – p$_{ex}$p$_{x}$, range 0.23–0.63) was dependent on air relative humidity, as observed in independent controlled experiments with grasses.
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Verlagsausgabe §
DOI: 10.5445/IR/1000129335
Veröffentlicht am 05.02.2021
DOI: 10.1111/nph.17111
Zitationen: 5
Web of Science
Zitationen: 5
Zitationen: 6
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Atmosphärische Umweltforschung (IMK-IFU)
KIT-Zentrum Klima und Umwelt (ZKU)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 03.2021
Sprache Englisch
Identifikator ISSN: 0028-646X, 1469-8137
KITopen-ID: 1000129335
HGF-Programm 12.02.01 (POF III, LK 01) Effects of land use and climate change
Erschienen in The new phytologist
Verlag John Wiley and Sons
Band 229
Heft 6
Seiten 3156-3171
Vorab online veröffentlicht am 30.12.2020
Schlagwörter canopy conductance; grassland; isotope‐enabled soil–vegetation–atmosphere transfer model (MuSICA); 18O‐enrichment of cellulose oxygen isotope composition of cellulose; perennial ryegrass (Lolium perenne); relative humidity temperature
Nachgewiesen in Dimensions
Web of Science
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