Geometric Diversity in the Plant Epidermis

Specialized cell geometries in the plant epidermis optimize important biochemical and mechanical functions. For example, epidermal pavement cells, which help maintain the mechanical stability of leaves and petals, develop from convex, smooth-polygonal cells to highly lobed "puzzle-piece" cells. In addition, gas exchange through pores is regulated by stomatal guard cells, often found in elongated crescent shapes. We propose a novel computational model for the plant epidermis that incorporates both cell types and reproduces the observed diverse tissue structure during development. Two mechanisms for pavement-stomata interactions are tested: rigid stomatal growth and pavement-stomata adhesion. We quantify the cell shape and spatial distribution of the cell type as a function of the mechanical properties and growth rates of the cells. We then validate the simulation results against high resolution microcomputed tomography scans of the epidermis of plant leaves of several species at different developmental stages.