The thin layer of plant epidermis tissue is known as dermal tissue.
Dermal tissue protects the soft parts of the plant.
The dermal tissue helps to protect the plant by reducing water loss.
It also protects the plant from microorganisms and pests.
Periderm:
Periderm is known as the secondary dermal tissue.
In older stems it replaces the roots of the plant.
It helps in protecting from mechanical injury, diseases, heat, freezing, and desiccation.
It consists of phellem (protective layer of dead cells), phellogen (meristematic tissue responsible for the production of cork cambium), and phelloderm (thin-walled tissue present on the inner side of cork cambium.
During secondary growth the cork cambium (lateral meristem) produces phellem, phellogen, and phelloderm.