Question

The chemical substance present in the thickening wall of collenchyma is:
A. Lignin
B. Cellulose
C. Pectin
D. Both B and C

Answer 1

Hint: Collenchyma is responsible for the elastic nature of pedicles and small branches and leaves. Basically, Collenchyma cells are simple permanent tissue that is composed of cells that are of similar types. The cell wall is irregularly thick and provides support and structure.

Complete answer:
1. Collenchyma is a supporting tissue composed of relatively elongated living cells with unevenly thickened edges and non-lignified primary walls. It is present/ seen in the regions of primary growth in stems and leaves.
2. It provides support, structure, mechanical strength, and flexibility to the petiole, leaf veins, and the stem of young plants, allowing them to bend easily without breakage and tear.
3. Their thick, non- lignified, and uneven cell walls are composed of the cellulose and pectin
Cellulose is a homopolymer of glucose composed of numerous branches at the 6th position of glucose and linkages at its 4th position. Pectin is a heteropolysaccharide that occurs naturally in the cell walls of fruits and vegetables to give them structure and strength. It consists of partial methyl esters of polygalacturonic acid and their salts (sodium, potassium, calcium, and ammonia).
4. Following are some of the characteristic features of collenchyma:
A. They have a living protoplasm.
B. Their basic function is to provide flexibility and elasticity to the plants.
C. The cells are isodiametric.
D. They have relatively axially elongated cells.
E. They have thin cells with thickened corners.
F. The intracellular space is generally absent.
G. They often contain chloroplasts eccentrically.

So, the correct answer is “Option 4 Both B and C”.

Note:
1. Sclerenchyma is a fibrous tissue that provides the skeletal framework for plants and rough structure to seeds and pines.
2. Parenchyma is the abundant tissue that is typically soft and succulent, found chiefly in the softer parts of leaves, the pulp of fruits, bark, and pith of the stems, etc.