HORTICULTURE

Detailed explanation-1: -The xylem wall should contain gaps (pits), which enable the exchange of water molecules. Lignin can be represented by either a spiral (coiled) or annular (rings) arrangement.

Detailed explanation-2: -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-3: -Bordered pits are cavities in the lignified cell walls of xylem conduits (vessels and tracheids) that are essential components in the water-transport system of higher plants.

Detailed explanation-4: -It is present in vascular and supporting tissues such as xylem tracheids, vessel elements and sclereids cells. Lignin helps in the transportation of water in stems. Hence, it is present in xylem cells, that’s why they are heavily lignified and make up the wood of woody plants.