Kinds of Meristematic Tissue

Meristems

• The plant tissues in which cells are constantly dividing are called meristems. These are the regions that produce new cells, and are responsible for plant growth. These newly made cells typically are small, six-sided, box-looking cells with many tiny vacuoles -- small cavities in a cell's cytoplasm, which contain food, water or metabolic waste -- and a large nucleus. There are three kinds of meristems: the apical meristems, the lateral meristems and the intercalary meristems.

Apical Meristems

• Primary growth occurs in this part of the plant. The apical meristems are located at or about the tips of the plant's roots and shoots. As new cells form in the meristematic tissue, the roots and shoots expand, increasing in length. Tree growth is a prime example of this form of cell enlargement.

Lateral Meristems

• Lateral meristems make new cells that cause the stems and roots to become thicker. This type of growth is known as secondary growth. A good example of secondary growth is when tree trunks increase in girth. Secondary growth begins in a plant's second year and continues with each subsequent year.

Intercalary Meristems

• Intercalary meristems are found in grasses and other such plants that do not have lateral meristems, meaning they don't increase in girth. These plants do, however, possess apical meristems. Intercalary meristems actively produce new cells and are responsible for these plants growing in height. A good example of the type of growth for which intercalary meristems are responsible is the regrowth of cut grass.