Given below is the diagram of an experimental setup to study the process of Transpiration. Cobalt chloride papers are fixed on the upper as well as lower surface of the leaf. Answer the questions that follow: Given below is the diagram of an experimental setup to study the process of Transpiration. Cobalt chloride papers are fixed on the upper as well as lower surface of the leaf. Answer the questions that follow:
The rate of transpiration is less when there is:
Topic: Factors reducing the rate of transpiration
Try it
Pick an option and check your answer. The full worked answer is below either way.
Answer
(a) High humidity in the air and low temperature..
Transpiration slows when the air is HUMID and the temperature is LOW.
WHY EACH WORKS: HIGH HUMIDITY — the air outside the leaf already holds a great deal of water vapour, so the difference in concentration between leaf and air is small and diffusion out is slow. LOW TEMPERATURE — less heat energy for evaporation, so water changes into vapour more slowly.
The four external factors, and note that humidity works in the OPPOSITE direction to the other three: TEMPERATURE up — transpiration UP LIGHT up — transpiration UP (stomata open) WIND up — transpiration UP (vapour carried away) HUMIDITY up — transpiration DOWN
Every wrong option contains at least one factor that INCREASES transpiration — bright sunlight, high temperature, more wind, less humidity — so checking each half against the list eliminates them quickly.
High humidity in the air and low temperature..