Meristematic Tissue  

These are living tissues which are capable of division throughout life. These tissues are found in growing regions of plants. Cells have thin cell wall and are compactly packed with no intercellular space. Cells contain dense cytoplasm and do not have vacuoles. Cells contain prominent and large nucleus.

Function of Meristematic Tissue

Meristematic tissue is responsible for the growth in length and width(girth) of plant body.

Meristematic tissue are free from virus because meristem has continuously and rapidly dividing cells. These cells have a high rate of metabolism and viruses cannot replicate in such cells.

Most of the viruses migrate through vascular elements but at the tip/meristem region, vascular elements are not formed. Thus, viruses cannot reach the meristem region.

1.0Classification of Meristematic Tissue

On the basis of their location, meristematic tissues are of three types:

Apical Meristem

It is present at the growing tips of shoot and roots. They are responsible for increase in the length of shoot and root.

Root apical meristem is covered by root cap which protects it from getting damaged by the rubbing of soil particles.

Intercalary Meristem

These are present at the base of leaf or internode (on either side of the node). They are responsible for the growth in length of plant organs.

Intercalary meristem may be present at the internode as in grasses, bamboo and mints or at the base of Pinus leaves.

Apical and intercalary meristem are responsible for primary growth of plants (growth in length).

Lateral Meristem (Cambium)

It lies on the lateral sides of stem and root or occurs along the sides of the longitudinal axis of the plant. It helps in increasing the diameter (girth) of the plant, hence helps in secondary growth.

Lateral meristem is of two types, vascular cambium and cork cambium. Vascular cambium produces secondary phloem and secondary xylem. Cork cambium (phellogen) produces a protective cork on the outside.

2.0Difference amongst three types of Meristems