Question

Transpiration pull will be maximum under which of the following conditions:

• A. Open stomata, dry atmosphere and moist soil
• B. Open stomata, highly humid atmosphere and well irrigated soil
• C. Open stomata, highly humid atmosphere and dry soil
• D. Close stomata, dry atmosphere and dry soil

Answer 1

The correct option is A

Open stomata, dry atmosphere and moist soil

The correct option is A:

Explanation of the correct option:

1. Transpiration is the process of loss of water from the stomatal opening of the aerial parts of the plant in the form of water vapor.
2. The maximum rate of transpiration will be observed when the atmosphere is dry or less humid.
3. It creates a negative pressure known as transpiration pull that depends on several factors.
4. Transpiration pull is maximum when the stomata are open, and the atmosphere is humid.
5. If the soil is moist, then plants can absorb more water, and the rate of transpiration is high, which maximizes the transpiration pull.

Explanation of the incorrect options:

Option B:

A humid atmosphere decreases the rate of transpiration; therefore, maximum transpiration pull is not observed.

Option C:

A humid atmosphere reduces the rate of transpiration.

Option D:

Closed stomata do not allow the loss of water through transpiration.

Final answer: Transpiration pull will be maximum if the stomata are open, the atmosphere is dry, and the soil is moist.