Question

Why the cells of sclerenchyma and tracheids become dead?

Answer 1

Sclerenchyma cells, which are usually dead at maturity (i.e., have lost their protoplasts). They characteristically contain very thick, hard secondary walls lined with lignin; consequently, sclerenchyma provides additional support and strength to the plant body.

Answer 2

Sclerenchyma- The cells of this tissue are dead. They are rigid, contain thick and lignified secondary walls. Their main function is to provide strength and support to parts of the plant.

Tracheids are dead and lignified cells. The deposition of lignin on cell wall is responsible to form a different type of thickenings.