Question

If in a tree, a cut end is put in eosin solution then

• A. Leaves will quickly die because ascent of sap stops.
• B. Leaves remain fresh but ascent of sap stops.
• C. Phloem gets coloured because of ascent of sap.
• D. Xylem elements get stained showing ascent of sap through them.

Answer 1

The correct option is D Xylem elements get stained showing ascent of sap through them.

Eosin is a red or pink coloured stain, which can be used to track the movement of water inside the plants. As phloem is not involved in water transport, the phloem cells will not be stained in this experiment. The ascent of sap occurs through nonliving xylem tracheids and vessels. Hence, xylem elements will be coloured due to stain in this procedure. The force responsible for the pull of water to great heights is the transpiration pull. The properties of adhesion, cohesion and capillarity help in the ascent of sap through nonliving tracheids and vessels.

So, the correct answer is option D.