NEET BIOLOGY

Detailed explanation-1: -Xylem is a tissue consisting of dead, hollowed-out cells that form a system of pipes. The walls of xylem cells are lignified (strengthened with a substance called lignin ). This allows the xylem to withstand pressure changes as water moves through the plant.

Detailed explanation-2: -All tissues in the xylem except the xylem parenchyma are dead. Their cytoplasm is highly reduced and they only perform the function of conduction. The xylem tissues also lack cell organelles. Therefore, they are considered dead.

Detailed explanation-3: -Xylem consists of tracheids, vessels, parenchyma, and fibers. Vessels consist of vessel elements joined together in files by large perforation plates, large gaps in the end walls between successive vessel elements, while tracheids have tapering ends that overlap with adjacent cells, and lack perforation plates.

Detailed explanation-4: -Tracheids and vessels are the main water-conducting components of the xylem. They are dead cells as they do contain any protoplasm. They are elongated tube-like structures having a lignified wall.