AP BIOLOGY

Detailed explanation-1: -Sclerenchyma tissue possesses long, narrow cells with thickened walls. They possess secondary walls made of lignin. Lignin is a chemical substance, which acts as cement and hardens them.

Detailed explanation-2: -The sclerenchyma cells are long and narrow and their walls are thickened due to a chemical substance lignin. This type of tissue is found in the stem and the veins of the leaf.

Detailed explanation-3: -Lignin is a component of the cell walls of sclerenchymatous cells. Two types of sclerenchyma cells exist-fibres and sclereids. Their walls consist of cellulose, hemicellulose, and lignin. Sclerenchyma cells are the dead cells in plant tissues that play a vital role in providing mechanical support to the plants.

Detailed explanation-4: -Lignin is an organic substance belonging to a group of aromatic alcohols. It is naturally produced by certain plants (especially woody plants and certain algal species). It is found in the secondary cell walls of plants where it serves as a binder for cellulose fibers and provides stiffness to the cell walls.

Detailed explanation-5: -Lignin is deposited in the cell wall of sclerenchyma.