The epidermal tissue system has a variety of functions:-
(i) It protects the inner tissues.
(ii) It reduces the rate of transpiration due to cuticularisation of the outer layer. It also reflects the light to some extent, reducing heating.
(iii) It helps in gaseous exchange due to presence of stomata.
(iv) The epidermis also stores water and metabolic products.
(v) The bulliform cells help in inrolling and unrolling of leaves and thus, reduce transpiration.
(vi) Trichomes help in protection of parts and help in retention or moisture on the plant body.
(vii) Root hairs help in absorption of water and minerals.
(viii) Glandular hairs help in secretion of substances used for protection of plants and digestion as in insectivorous plants.
(ix) Epidermal cells sometimes with chloroplast help in photosynthesis.
(x) Epidermal hairs on seeds help in dispersal.