1. Introduction

Meristematic tissue (meristos = divisible)

A group of identical cells which are in a continuous state of cell division. Some of the cells from the meristematic tissue stops dividing and exhibit certain changes to become permanent tissues of the plant. This change from meristematic to permanent state is called as differentiation. The rest of the cells in the meristematic tissues persists their meristematic activity. The meristematic tissues are self-perpetuating.

Features of meristematic cells

The meristematic cells may be round, oval, polygonal or rectangular in shape. These cells are arranged closely without intercellular spaces. They have dense cytoplasm with large nucleus. They have smaller vacuoles scattered throughout the cytoplasm. Their cell walls were thin, elastic and made up of cellulose.

 

2.  Classification of meristems

Based on its position (Figure 7.1), meristematic tissues are classified into three types:

•  I. Apical meristem

 II. Intercalary meristem

 III. Lateral meristem

Figure 7.1: Longitudinal section of shoot- showing the positions of meristems