Multiple isotopic models using various kinetic fractionation coefficients to estimate δ18O of leaf water

Investigation of δ18O of leaf water may improve our understanding of the evapotranspiration partitioning and material exchange between the inside and outside of leaves. In this study, δ18O of bulk leaf water (δL,b) was estimated by both isotopic-steady-state (ISS) and non-steady-state (NSS) assumptions considering the Peclet effect. Specifically, we carefully modified kinetic fractionation coefficients (αk). The results showed that the Peclet effect is required to predict δL,b. On the diel time scale, both NSS assumption + Peclet effect (NSS + P) and ISS assumption + Peclet effect (ISS + P) using modified αk (αk-modified) for δL,b showed a good agreement with observed δL,b (p > 0.05). When using previously proposed αk, however, both NSS + P and ISS + P were not reliable estimators of δL,b (p