Final answer:
The epidermal cells are the main cellular component of the dermal tissue system and their function is to protect the plant from environmental stresses.
Step-by-step explanation:
The cellular components of the dermal tissue system in plants are primarily the epidermal cells which form a single layer called the epidermis. The main function of the dermal tissue system is to protect the plant from environmental stresses such as water loss, infections, and damage. The epidermal cells secrete a waxy substance called cuticle that helps to waterproof and protect the plant.