Question

Set up an experiment to demonstrate root pressure.

Answer 1

Hint: Root pressure is defined as hydrostatic pressure developed in the root due to the accumulation of absorbed water. The pressure exerted on the liquid contents of the cortical cells of the roots, under fully turgid condition this root pressure pushes the water up the xylem vessels to the aerial parts. So the water absorption is an active process.

Complete answer:
Aim: To demonstrate root pressure.
Apparatus: A planted plant with stem cut, rubber tube, glass tube, knife, colored water, and clamp.
Procedure:
> Take a well-watered organized potted plant and slash the stem portion a few centimeters above the ground level.
> Then join a glass tube by means of a strong rubber tubing.
> The dimension of the glass tube should be equal to the size of the stem.
> Pay attention while joining tube and stem being bound strictly, water cannot breakout
from the tube.
> Now pour little colored water in the glass tube till the water plane can be seen above the rubber tube.
> Spot the level of water (S1) in the tube.
> Keep your arrangement aside for some hours.
> Then observe and spot the water level (S2) in the tube.
> The difference between S2 and S1 indicates the level of water raised.
Observation: There is growth in the water level which is raised in the stem.
Result: The uprise in the water level is due to the root pressure generated in the plant.

Note: Root pressure is caused by active diffusion of mineral nutrient ions into the root xylem. The emitting of water from the cut end of the stem is called bleeding. The flow of water from the cut surface or bleeding is measured by the mercury manometer.