Botany lecture notes

Sclerenchyma: Structure, Classification and Functions with PPT


sclerenchymatous tissue ppt

Sclerenchyma
(Structure, Types and Functions of Sclerenchymatous Cells in Plants)

What are Sclerenchymatous Cells?

Ø  Sclerenchyma is a simple permanent tissue in plants.

Ø  Sclerenchymatous cells are dead at their maturity.

Ø  Cells do not have protoplast when they completely developed.

Ø  They have thick secondary cell wall.

Ø  The secondary cell wall is lignified and very hard.

Ø  Most of the sclerenchymatous cells show intrusive growth.

Different Types of Sclerenchymatous Cells in Plants:

Ø  Based on size, two types of sclerenchyma are described.

  (I).   Sclereids

(II).    Fibres

(I). Sclereids:

Ø  Sclereids are short sclerenchymatous cells.

Ø  They are also called as stone cells.

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Botany lecture notes

Collenchyma Cells in Plants: Structure, Classification and Functions with PPT

Functions of collechyma

Collenchyma
(Structure, Types and Functions of Collenchymatous Cells in Plants)

What is collenchyma?

Ø  Collenchyma is a simple permanent tissue in plants.

Ø  They are living cells with prominent nucleus and all the cell organelles.

Ø  Each collenchymatous cell is with a large and prominent vacuole in the centre.

Ø  The vacuole is filled with many secondary metabolites.

Ø  Unlike parenchyma, the collenchyma cells possess thick primary cell wall.

Ø  Thick walls are NOT lignified.

Ø  The thick wall is due to the deposition of hemicellulose and pectin along with cellulose.

Ø  Wall thickening in collenchyma is greatly affected by the extent of mechanical stress.

Ø  A plant part which in severe stress or motion due to high wind are more likely to possess more thickened collenchyma.

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Botany lecture notes

Parenchyma Cells in Plants: Structure, Classification and Functions (PPT)


functions of parenchyma

Parenchyma
(Structure, Classification and Function of Parenchyma)

What is simple tissue?

Ø  The tissue (a group of cells with particular function) composed of single type of cells.

Ø  Three types of simple tissue system in plants:

(1).  Parenchyma

(2).  Collenchyma

(3).  Sclerenchyma

What are the characteristics of Parenchyma (Parenchymatous Cells)?

Ø  Parenchyma is a simple permanent tissue.

Ø  They are living cells which contains plenty of water.

Ø  Cells are nucleated with prominent nucleus.

Ø  They are thin walled cells.

Ø  Cell wall composed of cellulosic primary cell wall only.

Ø  No lignin deposition in the cell wall of parenchyma.

Ø  Parenchymatous cells are relatively undifferentiated

Ø  Parenchyma is the least specialized along simple permanent tissues in plants.

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