LEAFC3-N photosynthesis, stomatal conductance, transpiration and energy balance model: Finite mesophyll conductance, drought stress, stomata ratio, optimized solution algorithms, and code

A new, upgraded version of the LEAFC3-N model of combined photosynthesis, stomatal conductance, transpiration, and leaf energy balance is presented. The paper focuses mainly on simulating the effects of drought stress on diurnal time courses of leaf gas exchange by considering a finite variable mesophyll conductance. Further recent improvements are: (1) a model function accounting for the effect of different stomata frequencies at each leaf side on leaf conductance, (2) an accompanying dynamic model of plant water transport and storage to account for drought stress, (3) advanced solution algorithms, (4) clearly structured and well documented program code, (5) a user interface and simulation tool, and (6) a detailed documentation. The current model version was successfully re-calibrated against data of the diurnal time courses of net photosynthesis rate, stomatal conductance, and transpiration rate measured on wheat and barley leaves in the field and proved to account correctly for the reduction of these characteristics during midday and afternoon hours (midday depression) based on introducing a finite mesophyll conductance. With the current development we intend to provide a platform facilitating application and further improvement of the model. Documentation and source code may be provided by email request to the first author.