Question

Root pressure in a plant is measured by
A. Potometer
B. Manometer
C. Thermometer
D. Barometer

Answer 1

Hint:- Root pressure which is a force or hydrostatic pressure generated in the plants that help to drive fluids and ions from the soil in an upward direction into the plant vascular tissue i.e. xylem. Root pressure can be measured by an instrument filled with mercury in a glass column.

Complete Answer:-
A. Potometer- Potometer is used to measure the rate of transpiration which is proportional to water uptake. As some of the water is used in the process of photosynthesis so transpiration cannot be measure directly.
B. Manometer- Manometer is used to measure the pressure or gases which are exerted in the plants i.e. root pressure. Root pressure is an osmotic pressure inside the cells of the root system which enables fluids or ions to move upward from the plant stem to the leaves.
C. Thermometer- Thermometer is used to measure temperature gradient or temperature.
D. Barometer- Barometer is a scientific instrument used to measure atmospheric pressure it is also known as barometric pressure.
When a stem is cut, exudation or secretion of fluids occurs then the manometer is placed there to measure the root pressure. The stem cutting is done above the ground.

So, as we have discussed above the correct option is B (Manometer) which is used to measure root pressure.

Note:- Theory which is related to the root pressure was discovered by Priestly in the year 1916. In the overall process of water transport root pressure only serves as a pull. Root pressure has no significant role in water transport in tall trees.