Gas transport is considered as a two-dimensional flow.
A submodel describes the effects of external factors on stomatal aperture. The model purpose is to predict the leaf photosynthesis and transpiration for various environmental conditions for plants adapted and non-adapted to elevated CO2 atmosphere. Modeling gas diffusion within a leaf and in the boundary layer adjacent to a leaf surface seems to be a promising approach that excludes lumped transport parameters and uses the measurable geometric parameters of leaf anatomy. The governing equations of gas transport are solved numerically to obtain spatial distributions of the gas contents within the leaf cross-section domain. The Galerkin finite element method with linear basis functions and triangular elements is used.