Plant tissue & tissue system

•A group of cells performing a particular function is collectively called as tissue.

•A tissue may be defined as ‘a group of similar or dissimilar cells having, common origin

and performing a specific function’.

Classification of tissue Classification of tissue

Tissue are mainly divided in to three Tissue are mainly divided in to three categoriescategories

Meristematic tissue Meristematic tissue Permanent tissuePermanent tissue Secretary tissueSecretary tissue

Tissue

permanent tissueMeristematic tissue

Permanent tissuePermanent tissue1.1. Simple tissueSimple tissue

parenchyma tissueparenchyma tissueCollenchyma tissueCollenchyma tissueSclerenchyma tissueSclerenchyma tissueEpidermisEpidermiscorkcork

2.2. Complex tissueComplex tissueXylemXylemphloemphloem

Meristematic tissue

The word meristem “originated from meristos” (Greek =Continous division).

A group of cells which are much active and capable of showing continuous divisions & redivisions is called as meristematic tissue.

Cells are very small and isodiametric in nature.

Meristematic tissue

Intercellular spaces are not present. Vacuoles in Meristematic tissues are

very small or even may be absent.

Permanent tissue

Permanent tissue are made up of mature cells which have lost the capacity to divided and have attained a permanent shape, size& function due to division and differentiation in meristematic tissue.

(1) Parenchyma

Parenchyma is a living tissue. Parenchymatous cells are thin

cellulosic walled polyhedral in shape. It contain large central vacuole in many

cases. it contain intercellular spaces. Present in all the plant organs e.g. roots, stems, leaves, fruits,

seeds, etc.

Parenchymatous functions

It helps storage of food material & water.

e.g.-carrot. It also helps food manufacture excretion,

secretion. Chlorenchyma helps in photosynthesis.

(2) Collenchyma(2) Collenchyma

The cells of this tissue contain protoplasm and The cells of this tissue contain protoplasm and are living.are living.

It is the typical supporting tissue found It is the typical supporting tissue found underneath the epidermis of many stems, leaf-underneath the epidermis of many stems, leaf-stalks.stalks.

Collenchyma may or may not intercellular Collenchyma may or may not intercellular spaces.spaces.

Collenchyma (function)Collenchyma (function)

They provide They provide mechanical mechanical strength to strength to younger part younger part where xylem is where xylem is less developed.less developed.

(3) Sclerenchyma(3) Sclerenchyma

It consist of thick walled dead cells.It consist of thick walled dead cells. It is very hard and is responsible for It is very hard and is responsible for

strengthening of the organs in which it strengthening of the organs in which it is present due to uniforms deposition of is present due to uniforms deposition of ligninlignin