1. Introduction and Plant Tissues

Chapter-2

Tissues

Introduction and Plant Tissues

Introduction

As you all know that we have a complex body organization starting from cellular level to a well-developed individual. If we look at the hierarchy of organization we see that:

Cells → Tissue→ organ→ organ system→ organism

As far as cells are concerned, we have studied that cells are structural and functional units of life. The cells, when formed, undergo the process of differentiation according to the functions that they will perform. The cells that have the same structure, features and perform the same functions form a particular type of tissue. Let us start with the chapter where we will learn all about it.

The cells which are specialized in a function are grouped together and form a particular type of tissue. We have different tissues in our body that performs different functions like:

1. They play the role of protection.

2. They help in control and coordination.

3. They help in transportation.

4. They act as insulators.

5. Many more functions are performed.

Let us learn about Plant tissue

Types of plant tissues

They are classified into mainly two types as given below

• Meristematic tissue
• Permanent tissue

Meristematic tissue and its types

You all have seen that plants have a tendency to grow and keep growing throughout their life. This is because of certain cells in it that keep on dividing and they are called meristematic cells. Let us learn about them. They are formed of cells that have the ability to divide continuously throughout their life and help in increasing the length and girth of the plant.

Characteristics of meristematic cells

• They have thin cellulose cell walls.
• The meristematic cells may be spherical, oval, polygonal or rectangular in shape. The meristermatic cells are compactly arranged.
• Each meristematic cell contains dense or abundant cytoplasm and a single large nucleus.
• The meristematic cells contain few vacuoles or no vacuoles at all.

Occurrence

According to their position in the plant, meristems are of three types:

• Apical meristem
• Lateral meristem
• Intercalary meristem

Apical meristems

• It is present at the growing tip of stems and roots. It is at shoot apex and root apex.
• Its function is to increase the height of the plant.

Lateral meristems

• These are found beneath the bark (called cork cambium).
• The function is to help increase in diameter.

Intercalary meristems

• It is located at the base of leaves or at internodes.
• Its function is to increase the number of branches.