EVERYDAY SCIENCE

Detailed explanation-1: -Mature sclerenchyma cells are usually dead cells that have heavily thickened secondary walls containing lignin. The cells are rigid and nonstretchable and are usually found in nongrowing regions of plant bodies, such as the bark or mature stems.

Detailed explanation-2: -Sclerenchyma cells are dead, without nucleus and cytoplasm. Their cell wall is formed of cellulose and hemicellulose. It is thickened due to the secondary deposition of lignin (i.e., have lignified cell walls). Lignin acts as a cement and hardens the cell wall.

Detailed explanation-3: -The sclerenchyma is called the dead tissue because it lack protoplasm and has thick secondary walls which do not elongate during cell growth. Hence, mature cells get destroyed inside the sclerenchyma tissues.

Detailed explanation-4: -Unlike parenchyma and collenchyma, sclerenchyma cells are nonliving when mature.

Detailed explanation-5: -Like parenchyma cells, collenchyma is living at maturity. Collenchyma cells have thick primary walls composed of cellulose. (Note that you can distinguish collenchyma cells from sclerenchyma cells because of the chemical composition of their cell walls.