Question

Transpiration from plants would be most rapid when

• A. There is lot of humidity in atmosphere.
• B. The air is more humid.
• C. There is excess rain fall.
• D. Environmental conditions are dry.

Answer 1

Answer: (D)

Environmental conditions are dry.

Transpiration is loss of water in vapour form through stomata. Rate of transpiration depends on a number of factors, like carbon dioxide concentration, temperature, light, humidity etc. The most important factor which governs rate of transpiration is the vapour pressure gradient, which exists between leaf mesophyll and atmosphere. Thus, more the humidity lesser the rate of transpiration and vice versa. When environmental conditions are dry there will be more transpiration and at higher rates water will be lost from aerial parts.