B2 : Factors affecting transpiration

Question 1

What factors effect transpiration

Answer 1

Temperature, humidity, air movement and light intensity
Anything that increases rate of photosynthesis will increase transpiration because more stomata have to open to allow CO2 to enter meaning more water is lost through stomata by evaporation
Therefore, an increase in light intensity will increase the rate of transpiration

Question 2

High humidity

Answer 2

High humidity decreases rate of transpiration as there is a smaller concentration gradient between the leaves and the atmosphere thus decreased rate of evaporation

Question 3

Wind conditions

Answer 3

Windy conditions with lots of air movement will increase rate of transpiration and help to maintain a steep concentration gradient

Question 4

Temperature

Answer 4

Temperature will increase rate of transpiration as water molecules will move faster increasing rate of evaporation.
Additional rate of photosynthesis also increase therefore more stomata will be open causing an increase rate of transpiration

Question 5

Xerophytes

Answer 5

Plants adapted to dry environments. They can be adapted by having stomata that only open at night or having rolled leaves that trap air making the environment very humid. High humidity means lower rate of transpiration

Question 6

Wilt

Answer 6

If plants don’t have enough water, they wilt (protective measure). This reduces surface area available for water loss by evaporation.

Question 7

Potometer

Answer 7

Rate of transpiration can be measured using a potometer to show how uptake of water by a plant changes in different conditions