Question

Write two basic differences between Parenchyma and Collenchyma tissues?

Answer 1

Parenchyma is the most common type of unspecilalised simple tissue. It is composed of collection of cells which are more or less isodiametric in shape with or without intercellular space. These are the living cells with active protoplast.


Collenchyma The cells of this tissue are living cells with vacuolated protoplast. The most important distinctive character of collenchyma is that either walls are unevenly thickened or these thickenings are confined to the corners of the cells. It is usually absent in monocot.

Parenchyma vs Collenchyma



Parenchyma




Collenchyma




Parenchyma cells are present in the epidermis, cortex, pith and pericycle. Meristematic cells are parenchymatous.

It occurs in the peripheral part of elongating organs like stem and petiole, usually appearing as a continuous ring beneath the epidermis.

Thin cell wall

Unequally thickened cell wall

Intercellular space is present

Intercellular space is absent.

No pectin deposition

Pectin deposition is found at the corners.

Shape - Isodiametric

Shape - Polygonal.

Permanent tissue

Permanent tissue sometimes revives meristematic activity.

Functions:

a) Storage of food materials.

b) Chlorenchyma carries out photosynthesis.

c) Aerenchyma helps aquatic plants in floating and gaseous exchange.

Functions: 

a) It gives mechanical support.

b) It can resist bending and stretching caused by winds.

c) It carries out photosynthesis if chloroplast are present. 

Answer 2

Parenchyma: The cell wall is commonly thin but uniform in thickness  

Collenchyma: The cell wall develops extra thickenings at intracellular spaces.