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4 Protective Tissues

Protective tissues are divided into two parts:

  • Epidermis
  • Cork/Phellem


It is usually present in the outermost layer of the plant body such as leaves, flowers, stem and roots.

  • Epidermis is one cell thick and is covered with cuticle.
  • Cuticle is a water proof layer of a waxy substance called cutin.
  • It forms a continuous layer without intercellular spaces.
  • Most epidermal cells are relatively flat.


  • The main function of epidermis is to protect the plant from desiccation and infection.
  • Cuticle of epidermis helps to reduce water loss by evaporation from the plant surface.
  • This aids in protection against loss of water, mechanical injury and invasion by parasitic fungi.
  • In some plants living in very dry habitats, the epidermis may be thicker since protection against water loss is critical.


  • Epidermis of a leaf is not continuous at some places due to the presence of small pores, called stomata.
  • Each stoma is bounded by a pair of specialised epidermal cells or two kidney-shaped cells called guard cells.
  • Function of Stoma: The stoma allows gaseous exchange to occur during photosynthesis and respiration.


  • As plants grow older, the outer protective tissue undergoes certain changes.
  • A strip of secondary meristem, replaces epidermis of stem.
  • Ultimately becomes several layered thick cork (bark) of trees.
  • The cork cells do not contain protoplasm but are filled with resin or tannins.


  • Cells of cork are dead and compactly arranged without intercellular spaces
  • Suberin: Suberin deposits are organic, fatty substances which form the heavily thickened walls of cork cells. Suberin makes the plants impervious to gases and water.

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