Question

Root pressure can be measured by
A. Attaching a barometer to the cut end of the stem
B. Attaching a manometer to the cut end of the stem
C. Attaching a thermometer to the cut end of the stem
D. Attaching a potometer to the cut end of the stem

Answer 1

Root pressure can be measured by an instrument with mercury-filled glass columns. It is used by placing the instrument on a cut at the stem of the plant to measure root pressure.

Complete Answer:
Manometer is the instrument used for measuring the root pressure. Root pressure is the osmotic pressure inside the cells of a root system which enables the sap or fluid to rise through the plant stem to the leaves. When the stem is cut, exudation of fluids occurs. Manometer is placed there to measure the root pressure. Cutting of the stem is made just above the ground.

Let's look at the options for finding the correct answer.
- Option A: Barometer is a scientific instrument, which is used to measure the atmospheric pressure at a certain environment. Barometer cannot be used to measure the root pressure of a plant. Therefore, this is the incorrect option.
- Option B: Manometer is the instrument used to measure the pressure acting on a column of fluid. Manometers can be used to measure root pressure in plants. Therefore, this is the correct option.
- Option C: A thermometer is a device that can measure the temperature or temperature gradient. Thermometer is not used to measure root pressure. Therefore, this is the incorrect option.
- Option D: Potometer is used to measure the rate at which a plant draws water. It is not used to measure root pressure. Therefore, this is the incorrect option.

Thus, the correct option is B) Attaching a manometer to the cut end of the stem.

Note: The theory related to root pressure was founded by Priestly in 1916. Root pressure only provides a push in the overall process of water transport. They don't have a major role in water transport in the tall trees.