Each plant organ (roots, stems, leaves) contains all three tissue types: Dermal tissue covers and protects the plant, and controls gas exchange and water absorption (in roots). Dermal tissue of the stems and leaves is covered by a waxy cuticle that prevents evaporative water loss.
Main function of stomata is exchange of gases between the internal tissues and the external atmosphere. Cuticle is present on the outer wall of epidermis to check evaporation of water. Epidermis forms a Protective layer in leaves, young roots, stem, flower, fruits etc
