Plant cell parenchyma cells, that covers the external surfaces of leaves, stems and roots. Several cell types may be present in the epidermis. Notable among these are the stomatal guard cells that control the rate of gas exchange between the plant and the atmosphere, glandular and clothing hairs or trichomes, and the root hairs of primary roots. In the shoot epidermis of most plants, only the guard cells have chloroplasts. Chloroplasts contain the green pigment chlorophyll which is needed for photosynthesis. The epidermal cells of aerial organs arise from the superficial layer of cells known as the "tunica" (L1 and L2 layers)
Cell-based models Cell-based models Cell-based models are mathematical models that represent biological cells as a discrete entities. They are used in the field of computational biology for simulating the biomechanics of multicellular structures such as tissues. Their main advantage is the easy integration of cell level processes such as cell division, intracellular processes and single-cell variability within a cell population. Cell-based models can be divided into on- and off-lattice models. On-lattice models such as cellular automata or cellular potts restrict the spatial arrangement of the cells to a fixed grid. The mechanical interactions are then carried out according to literature-based rules (cellular