In angiosperm wood (hardwoods):
Vessels (pores) are the specialized, open-ended tube-like conductive cellular elements primarily responsible for the vertical conduction of sap (water and dissolved mineral salts).
In gymnosperm wood (softwoods), vessels are absent, and conduction is performed by tracheids.
Medullary rays function in radial conduction and storage, while tyloses are balloon-like outgrowths that block old vessels.

In gymnosperm timber (softwoods such as pines, firs, and deodar):
True vessels (pores) and specialized libriform fibers are completely absent.
Instead, Tracheids constitute more than 90–95% of the total wood volume and perform dual functions: the earlywood (thin-walled) tracheids conduct water, while the thick-walled latewood tracheids provide mechanical support.

Detailed analysis of options:

• Tylosis: Ingrowth of adjacent ray or axial parenchyma cells through pit cavities into the lumina of xylem vessels (pores) during heartwood formation, blocking fluid conduction.
• Ring porous woods: A pattern where large earlywood pores form a distinct concentric ring.
• Tracheids: Elongated, tapering xylem conducting and supporting cells.
• Fibres: Thick-walled mechanical supporting cells in angiosperm wood.