AP BIOLOGY

Detailed explanation-1: -Lignin provides mechanical strength and resistance against pathogens, and makes the cell walls impermeable to water, thus enabling the transport of solutes via tracheids in the xylem tissue.

Detailed explanation-2: -The chemical composition of lignin varies from species to species, but lignin is traditionally considered to be formed from the oxidative coupling of three monolignols: p-coumaryl, coniferyl, and sinapyl alcohols (Boerjan et al., 2003; Ralph et al., 2004).

Detailed explanation-3: -Xylem vessels transport water and minerals upwards through the plant stem. It comprises dead and empty cells. Its walls are lignified which permits it to endure pressure changes as water moves. Lignin, which is a complicated natural polymer that offers primary help to the tissues of vascular plants.

Detailed explanation-4: -In Sclerenchyma tissue, lignin is present. Lignin is a group of complex organic polymers that make up important structural elements in most plants’ support tissues.