Question

Which one among the following is correct?

• A. Tracheids are unicellular with a wide lumen
• B. Vessels are multicellular with a wide lumen
• C. Tracheids are multicellular with narrow lumen
• D. Vessels are unicellular with narrow lumen

Answer 1

The correct option is B Vessels are multicellular with a wide lumen

Tracheids and vessels are the components of xylem. Xylem is a conducting tissue for water and minerals. It also provides mechanical support to the plants.

Tracheids are unicellular, elongated, tube-like cells with tapering ends. They have thick lignified walls. Their cells lack protoplasm.

Vessels are multicellular, long cylindrical tube-like structures. They are formed of individual units known as vessel members. They have lignified walls with pits and a large central cavity. They are also devoid of protoplasm. The vessel members are stacked end to end to form the vessel. There are perforations in the common walls of the two adjacent vessel members or endplates which allow the vessels to work as a pipeline.


Both tracheids and vessels have pores in the lignified cell walls which are known as pits. But they both have several differences which are listed below:

$\begin{array}{ccc}\text{S.No}& \text{Tracheids}& \text{Vessels}\\ 1.& \text{They are present in all vascular plants}& \text{They are present only in angiosperms}\\ 2.& \text{They have a narrow lumen}& \text{They have a wider lumen}\\ 3.& \text{Walls are highly thickened}& \text{Walls are less thickened than traceids}\\ 4.& \text{They do not have endplates}& \text{They have perforated endplates}\end{array}$