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18 O enrichment of sucrose and photosynthetic and non-photosynthetic leaf water in a C 3 grass -- atmospheric drivers and physiological relations
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  • Juan C. Baca Cabrera,
  • Regina T. Hirl,
  • Jianjun Zhu,
  • Rudi Schäufele,
  • Jérôme Ogée,
  • Hans Schnyder
Juan C. Baca Cabrera
Technische Universitat Munchen Forschungsdepartment Pflanzenwissenschaften

Corresponding Author:j.baca.cabrera@fz-juelich.de

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Regina T. Hirl
Technische Universitat Munchen Forschungsdepartment Pflanzenwissenschaften
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Jianjun Zhu
Technische Universitat Munchen Forschungsdepartment Pflanzenwissenschaften
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Rudi Schäufele
Technische Universitat Munchen Forschungsdepartment Pflanzenwissenschaften
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Jérôme Ogée
Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement
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Hans Schnyder
Technische Universitat Munchen Forschungsdepartment Pflanzenwissenschaften
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Abstract

The 18O enrichment (Δ 18O) of leaf water affects the Δ 18O of photosynthetic products such as sucrose, generating an isotopic archive of plant function and past climate. However, uncertainty remains regarding how leaf water compartmentation between photosynthetic and non-photosynthetic tissue affects the relationship between Δ 18O of bulk leaf water (Δ 18O LW) and leaf sucrose (Δ 18O Sucrose). We grew Lolium perenne (a C 3 grass) in mesocosm-scale, replicated experiments with daytime relative humidity (RH 50 or 75%) and CO 2 level (200, 400 or 800 μmol mol -1) as factors, and determined Δ 18O LW, Δ 18O Sucrose and morpho-physiological leaf parameters, including transpiration ( E leaf), stomatal conductance ( g s) and mesophyll conductance to CO 2 ( g m). The Δ 18O of photosynthetic medium water (Δ 18O SSW) was estimated from Δ 18O Sucrose and the equilibrium fractionation between water and carbonyl groups (ε bio). Δ 18O SSW was well predicted by theoretical estimates of leaf water at the evaporative site (Δ 18O e) with adjustments that correlated with gas exchange parameters ( g s or total conductance to CO 2). Isotopic mass balance and published work indicated that non-photosynthetic tissue water was a large fraction (~0.53) of bulk leaf water. Δ 18O LW was a poor proxy for Δ 18O Sucrose, mainly due to opposite Δ 18O responses of non-photosynthetic tissue water (Δ 18O non-SSW) relative to Δ 18O SSW, driven by atmospheric conditions.
27 Feb 2023Submitted to Plant, Cell & Environment
01 Mar 2023Submission Checks Completed
01 Mar 2023Assigned to Editor
05 Mar 2023Review(s) Completed, Editorial Evaluation Pending
13 Mar 2023Reviewer(s) Assigned
28 Apr 2023Editorial Decision: Revise Minor
20 May 20231st Revision Received
20 May 2023Submission Checks Completed
20 May 2023Assigned to Editor
21 May 2023Review(s) Completed, Editorial Evaluation Pending
24 May 2023Reviewer(s) Assigned
14 Jun 2023Editorial Decision: Accept