B2.2.6 - Factors affecting transpiration

Question 1

What factors affect the rate of transpiration?

Answer 1

Light intensity, temperature, air movement and humidity

Question 2

What does a potometer do?

Answer 2

It measures how quickly a plant shoot takes up and loses water

Question 3

What is the equation for rate of movement?

Answer 3

Rate of movement is equal to distance (mm) over time (s)

Question 4

How can light intensity increase the rate of transpiration?

Answer 4

If you increase the light intensity it allows the stomata to open wider allowing more CO2 in the leaf for photosynthesis

Question 5

How can temperature increase the rate of transpiration?

Answer 5

If you increase the temperature, water evaporates more quickly from leaf cells. The diffusion of water vapour out of the leaf becomes faster.

Question 6

How can humidity increase the rate of transpiration?

Answer 6

If you decreased the humidity, the concentration gradient between the leaf and the air increases. This means that water diffuses more quickly out of the leaf

Question 7

How does air movement increase the rate of transpiration?

Answer 7

The faster the air movement is, the faster water molecules are moved. This increases the concentration gradient between the leaf and the air