Protective Tissues in Plants
Protective tissues of the plants are the tissues which provides protection They are usually present in the outermost layer of the plant.
Types of protective tissues in plants
There are two types of protective tissues in the plants
- Epidermis is the outermost layer of the plant made up of single layer of cells.
- It protects all parts of the plant.
- On the aerial parts of the plant, epidermal cells often secretes a waxy, water resistant layer on their outer surface.
- This waxy layer provides protection against loss of water mechanical injury and microbial infection.
- Epidermal tissues forms a continuous layer of cells.
- Epidermal tissues have no intercellular spaces due to its protective role.
- Most of epidermal cells are relatively flat.
- The outer wall and side walls of epidermis are thicker than the inner wall.
- Epidermal cells of leaf bear small pores known as stomata.
- They are enclosed by two kidney shaped cells called guard cells.
- Stomata are responsible for the exchange of gases with the atmosphere and for the process of transpiration that is loss of water in the form of water vapors.
- Epidermal cell of the root bear long hair like outgrowths called root hairs.
- The increase the total absorptive surface area and help the roots to absorb water and nutrients from the soil.
- Epidermal cell in desert plant has a thick waxy coating of cutin. Cutin is a chemical substance with waterproof quality.
- Cutin helps to prevent the water loss.
- As the plant grows older the outer protective tissue undergoes certain changes.
- Strip of Secondary Meristem replaces the epidermis of the Stem
- Cells on the outside are cut off from this epidermal layer. This form several layer thick cork or bark with no intercellular spaces.
- Cork helps to prevent loss of water.
- It protects plant from invasion of parasites and other harmful organisms.
Functions Of Protective Tissue in Plant
- It helps the plants by protecting it from external environment.
- Protects the plant from mechanical injury.
- Prevents loss of water.
- Protects plant from microbial infection.