NEET BIOLOGY

Detailed explanation-1: -The sapwood is the living and functional part of the wood. It is the outermost layer that is present after the bark of the tree. It is usually light in color and is made up of secondary xylem. The sapwood is helpful in the transportation of the water and sap from the roots to the other parts of the tree.

Detailed explanation-2: -Thus, in the trunk and older branches of a large tree, only the outer secondary xylem (sapwood) serves in water conduction, while the inner part (heartwood) is composed of dead but structurally strong primary xylem.

Detailed explanation-3: -Only sapwood is involved in the conduction of water because heartwood is blocked with accumulation of aromatic compounds. But both sapwood and heartwood are the part of secondary xylem.

Detailed explanation-4: -Sapwood is the innermost secondary xylem and is lighter in colourDue to deposition of tannins, resins, oils etc., heart wood is dark in colour. Heart wood does not conduct water but gives mechanical support. Sapwood is involved in conduction of water and minerals from root to leaf.

Detailed explanation-5: -In woody plants secondary xylem comprises the bulk of the tissue in the stems and roots. It is the most important supporting tissue in arborescent dicotyledons and most gymnosperms, and the major tissue for the transport of water and essential minerals in woody plants.