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Temperature‐sensitive biochemical 18O‐fractionation and humidity‐dependent attenuation factor are needed to predict δ 18O 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)

Abstract:

We explore here our mechanistic understanding of the environmental and physiological processes that determine the oxygen isotope composition of leaf cellulose (δ18Ocellulose) in a drought‐prone, temperate grassland ecosystem.
A new allocation‐and‐growth model was designed and added to an 18O‐enabled soil–vegetation–atmosphere transfer model (MuSICA) to predict seasonal (April–October) and multi‐annual (2007–2012) variation of δ18Ocellulose and 18O‐enrichment of leaf cellulose (Δ18Ocellulose) based on the Barbour–Farquhar model.
Modelled δ18Ocellulose 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 δ18Ocellulose (R2 = 0.57) and Δ18Ocellulose (R2 = 0.74), and their negative relationship with canopy conductance, was improved significantly when both the biochemical 18O‐fractionation between water and substrate for cellulose synthesis (εbio, 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 18O‐enrichment (1 – pexpx, range 0.23–0.63) was dependent on air relative humidity, as observed in independent controlled experiments with grasses.
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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 Scopus
Web of Science
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Verlagsausgabe §
DOI: 10.5445/IR/1000129335
Veröffentlicht am 05.02.2021
Originalveröffentlichung
DOI: 10.1111/nph.17111
Scopus
Zitationen: 18
Web of Science
Zitationen: 16
Dimensions
Zitationen: 19
Seitenaufrufe: 145
seit 06.02.2021
Downloads: 160
seit 06.02.2021
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