Integrated modeling and observational analysis of light-saturated electron transport rates in four C3 species

Currently, there is still a lack of systematic comparison between the light-saturated maximum electron transport rate ( J max ) predicted by the Farquhar-von Caemmerer-Berry (FvCB) model and the empirically observed whole-chain electron transport rate ( J f−max ) measured directly through experiments, which is essential for validating the reliability and predictive capability of the photosynthesis model. This study presents a comparative evaluation of the FvCB model’s ability to estimate the J max in four C 3 species: Ipomoea batatas , Pachyrhizus erosus , Capsicum annuum , and Abelmoschus esculentus . By integrating gas exchange measurements and chlorophyll fluorescence data, we analyzed A n – C i curves under saturating irradiance to derive J max values using two FvCB sub-models (I and II) and compared these estimates with J f−max . Results revealed significant discrepancies: Sub-model II consistently overestimated J max relative to J f−max in three species ( I. batatas , P. erosus , and C. annuum ), while Sub-model I showed no statistical deviation. Notably, A. esculentus exhibited anomalous overestimations by both sub-models, with J max exceeding J f−max —a contradiction of theoretical stoichiometry. These findings highlight limitations in the universal applicability of FvCB sub-models, particularly regarding assumptions of electron partitioning among assimilatory and non-assimilatory pathways. However, the empirical model developed by Ye et al. could accurately and reliably estimate J f−max values for all four C 3 species. The study underscores the need for model refinements to better account for species-specific electron transport dynamics and environmental interactions, advancing the accuracy of photosynthetic predictions in ecological and agricultural contexts.