Question

Tracheids are less efficient than vessels due to

• A. absence of closed-end walls
• B. uneven thickenings
• C. casparian strips
• D. presence of tapering end walls

Answer 1

The correct option is D presence of tapering end walls

Tracheids are elongated cells and are wide in appearance and have large pits without any perforations. Tracheids differ in many ways from vessels. Tracheids have narrow lumen while vessels lumen is wide. Tracheids have less number of large pits while vessels have a large number of small pits.
Tracheids are imperforated with thin cell wall while vessels are perforated with thick cell wall.
Tracheids have tapering ends while vessels have diagonal or transverse end walls, so vessels can have better water conduction by means of transverse end walls. Tapering ends will make the tracheids less efficient than vessels.