TY  - JOUR
AU  - Baca Cabrera, Juan C.
AU  - Hirl, Regina T.
AU  - Zhu, Jianjun
AU  - Schäufele, Rudi
AU  - Ogée, Jérôme
AU  - Schnyder, Hans
TI  - 18 O enrichment of sucrose and photosynthetic and nonphotosynthetic leaf water in a C 3 grass—atmospheric drivers and physiological relations
JO  - Plant, cell & environment
VL  - 46
IS  - 9
SN  - 0140-7791
CY  - Oxford [u.a.]
PB  - Wiley-Blackwell
M1  - FZJ-2023-02623
SP  - 2628-2648
PY  - 2023
AB  - The 18O enrichment (Δ18O) of leaf water affects the Δ18O of photosynthetic products such as sucrose, generating an isotopic archive of plant function and past climate. However, uncertainty remains as to whether leaf water compartmentation between photosynthetic and nonphotosynthetic tissue affects the relationship between Δ18O of bulk leaf water (Δ18OLW) and leaf sucrose (Δ18OSucrose). We grew Lolium perenne (a C3 grass) in mesocosm-scale, replicated experiments with daytime relative humidity (50% or 75%) and CO2 level (200, 400 or 800 μmol mol−1) as factors, and determined Δ18OLW, Δ18OSucrose and morphophysiological leaf parameters, including transpiration (Eleaf), stomatal conductance (gs) and mesophyll conductance to CO2 (gm). The Δ18O of photosynthetic medium water (Δ18OSSW) was estimated from Δ18OSucrose and the equilibrium fractionation between water and carbonyl groups (εbio). Δ18OSSW was well predicted by theoretical estimates of leaf water at the evaporative site (Δ18Oe) with adjustments that correlated with gas exchange parameters (gs or total conductance to CO2). Isotopic mass balance and published work indicated that nonphotosynthetic tissue water was a large fraction (~0.53) of bulk leaf water. Δ18OLW was a poor proxy for Δ18OSucrose, mainly due to opposite Δ18O responses of nonphotosynthetic tissue water (Δ18Onon-SSW) relative to Δ18OSSW, driven by atmospheric conditions.
LB  - PUB:(DE-HGF)16
C6  - 37376738
UR  - <Go to ISI:>//WOS:001017555500001
DO  - DOI:10.1111/pce.14655
UR  - https://juser.fz-juelich.de/record/1009075
ER  -