Question

Instrument that can be used to demonstrate transpirational pull due to vaporization of water is
A)Potometer
B)Atmometer
C)Auxanometer
D)Anemometer

Answer 1

Hint: When transpiration takes place in water that evaporates from intercellular spaces into the atmosphere, a negative pressure gets established in the xylem which is transmitted down to the roots. As a result, the whole water column is taken upside down in a apoplast pathway. The mass flow of water occurs, largely due to the transpiration pull.

Complete answer:
Plants absorb water from the soil and move it into the vascular tissue through apoplast or simplest pathways. We now have to try and understand how this water is transported to various parts of the plant. Water has to move up a stem and leaves against gravity. Root pressure and transpiration pull play an important role in upward movement of water.

Now let us collect information about given options :
Potometer : it is also known as a transpirometer. It is used to measure the amount of water that is uptake by the leafy shoot. The amount of water uptake is equal to amount of water loss through transpiration.
Atmometer : it is also known as an evaporimeter. It is used to measure the amount of water that gets evaporated through the wet surfaces due to transpiration pull as the major factor.
Auxanometer : It was invented by Sir Jagdish Chandra Bose. It is used to measure the amount of growth that takes place in a plant.
Anemometer : It is the most commonly used weather Instrument it is used to measure The speed and direction of the wind. It is also used to measure the pressure of the wind.

Hence, the correct answer is option (B)

Note: Despite the absence of a heart or circulatory system in plants, the flow of water upward through the xylem in plants can achieve fairly high rates up to 15 metres per hour. Most researchers believe that water is mainly bullied through the plant and the driving force for this process is transpiration from the leaves. This model which explains translocation of water by the process of transpiration, is known as Cohesion-tension- transpiration pull model (Dixon and Jolly) of water transport.