Tissue may be defined as a group or layer of similarly specialized cells which together performs certain special functions. On the basis of the types of cells found in tissues, they are classified as animals and plants tissues.
A group of plant cells performing essentially the same function and common to the similar structure is a plant tissue. On the basis of the stages of development, plant tissues are divided into two types:
The group of young cells which have the capacity of active cell division is called meristem. On the basis of origin, they are classified as primary and secondary meristems.
They are made up of cells that have lost the power of division and are differentiation to carry out various functions. The permanent tissues are of following types:
The tissue is a group of similar cells, which performs the specific function. E.g. blood, muscle etc.
The differences between meristematic tissue and permanent tissue are as follows:
|Meristematic tissue||Permanent tissue|
|i) It is classified into primary meristem and secondary meristem.||i) It is classified into simple, complex and special.|
|ii) It is of different shapes without intercellular space.||ii) It is of different shapes with an intercellular space.|
|iii) It undergoes mitosis cell division.||iii) It loses the power of division.|
Apical meristematic tissues help in increasing length so if these tissues stop functioning the plant cannot grow further through the root, as well as shoot.
Simple permanent tissues are of three types:
i) Parenchyma: In all the living areas of the plant body.
ii) Collenchyma: It occurs in the peripheral portions of young stems and leaves.
iii) Sclerenchyma: It is found in stems and roots as well as with the veins of leaves, a hard outer covering of seeds and nuts.
Complex tissues are a group of different kinds of cells, some of which may differ from each other in structure but work together.
It is mainly of two types:
Parenchyma tissues are made up of thin-walled cells, which are living and having shapes like oval or spherical.
Phloem is the storage tissue made by vascular bundle and other components. So, it is called as complex tissue.
A type of complex tissue called xylem transport water from the root to other parts of the plant.
Phloem tissue helps in transportation of prepared food materials from the leaf to storage organs and growing regions too. So, if all these tissues are removed from plant body, energy supply to every cell is stopped and no further activities can perform by plant cell. Ultimately, the cell dies which result in the death of the plant.