Question

Vessel elements differ from other elements of xylem in having

• A. Simple and bordered pits on end walls
• B. Simple perforation on their end walls
• C. Simple pits on their radial walls
• D. Bordered pits on their lateral walls

Answer 1

The correct option is B Simple perforation on their end walls

The xylem tissues are complex permanent tissue composed of heterogeneous cells which coordinate to perform several functions. It mainly helps in conduction. It consists of two conducting cell known as tracheids and vessel elements. Both of these cell types are elongated and dead at maturity so that water moves through them without crossing any lipid membranes. In tracheids, the cell wall remains intact but the secondary wall does not develop in particular areas so that there are pits through which water can move more readily than elsewhere. In vessel elements, end walls break down, so that there is an open tube through which water can move unimpeded. Many individual cells can form a vessel that can be several centimeters long.
As in the tracheids, there are pits in the side walls so that lateral movement of water is possible as well as longitudinal. So, vessel elements differ from other elements of xylem in having simple perforation on their end walls and not by simple pits on their radial walls, bordered pits on their lateral walls or simple and bordered pits on end walls.
Thus, the correct answer is option B.