Question

Sol. Key concept: Heartwood accumulates pigments and other secondary substances.

Duramen is heartwood: the older, inner secondary xylem that has largely ceased conducting water. During heartwood formation, substances such as tannins, resins and pigments accumulate and often give it a darker colour and greater resistance to decay.

Santalin from red sandalwood, brazilin from brazilwood or sappanwood, and haematoxylin from logwood are examples of dyes associated with heartwood. Therefore, the correct option is (c), duramen.

Alburnum means the younger, outer, water-conducting sapwood. Rhytidome refers to outer bark, while phelloderm is tissue produced inward by cork cambium. These are not the intended dye-bearing wood region.