Question

The most important factor affecting transpiration is?
A. Light
B. Temperature
C. Wind
D. Atmospheric humidity

Answer 1

Hint: Transpiration is the process of loss of water in gaseous or vapor form through stomata. Transpiration is mainly governed by the vapor pressure gradient between the internal environment of leaf mesophyll tissue and the environment. Thus, the most important factor that affects the process of transpiration is the atmospheric humidity.

Complete answer:
> Option (A)- light
As the Light increases, the rate of transpiration increases. This is because with the increase in lights, the rate of water absorption, and the resulting turgidity of the two guard cells increases. This forms the boundary of each stoma and brings about the opening of the stomates, which increases the transpiration rate.

> Option (B)- Temperature
Transpiration rates increase with the increase in temperature. This happens especially during the growing season when the air is warmer due to stronger sunlight.

> Option (C) - wind
A widespread perception is that transpiration from plant leaves increases, with increasing wind speed. However, evidence also suggests that increasing wind speed enhances carbon dioxide uptake which reduces transpiration because of more efficient convective cooling (under high solar radiation loads).

> Option (D) - Atmospheric humidity
As the relative humidity of the air around the plant rises, the transpiration rate falls. Water is easily evaporated into dryer air than into more saturated air.

Hence, The correct answer is option (D).

Note: Transpiration is the process of water movement through a plant. It also involves evaporation from aerial parts, such as leaves, stems, and flowers. Water is necessary for plants. The water taken in by plants through roots is used for growth and metabolism and the rest is lost by transpiration and guttation.