Question

Compare sclerenchyma and collenchyma with regards to:
a) structure and composition of cell wall
b) function
c) positions in plants
                                           (8)

Answer 1

Collenchyma	Sclerenchyma
Structure and Composition	Structure and Compostion
It is made up of living cells.	Sclerenchyma cells are generally dead
The cells are filled up with protoplasm.	The cells are empty.
Wall thickening is not uniform	Wall thickening is uniform.
Wall thickening consists of cellulose.	Wall thickening can be of cellulose lignin or both.
Lumen or cell cavity is wide.	Lumen or cell cavity is usually narrow.
Function	Function
Collenchyma provides mechanical strength as well as elasticity	It is only a mechanical tissue.
It allows plant organs to stretch and elongate.	Sclerenchyma occurs in areas which have stopped elongation.
It keeps the organ soft.	It provides hardness to the region where it occurs.
Being living the cells can store food and take part in photosynthesis.	Sclerenchyma has no such function.
Position in plants	Position in plants
They tend to occur as part of vascular bundles or on the corners of angular stems.	Sclerenchyma occur as bundle cap fibers some cells occur in the fruits of Pear. These cells (Sclereids or stone cells) give pears their gritty texture. common type of schlerenchyma cell is the fiber.