B2.2.6 Transpiration Factors

Question 1

List Factors affecting transpiration

Answer 1

• light intensity
• temperature
• air movement (wind)
• humidity

Question 2

How does light intensity affect transpiration?

Answer 2

Brighter light, greater rate of transpiration (until all stomata open)

-light =stomata opens=more water evaporates

Question 3

How does temperature affect rate of transpiration?

Answer 3

Higher temperature, greater rate of transpiration

-particles have more energy=evaporate and diffuse out of stomata faster

Question 4

How does air movement/wind affect rate of transpiration?

Answer 4

Faster air movement, greater rate of transpiration

-wind blows evaporated water away from leaf= higher concentration gradient between leaf and air=water diffuses out of leaf quicker

Question 5

How does humidity affect rate of transpiration?

Answer 5

Higher humidity, lower rate of transpiration

-more water in air=low concentration gradient between leaf and air=water diffuses out slower

Question 6

How to measure rate of transpiration?

Answer 6

potometer - measures how quickly plant shoot takes up/loses water

1. Air bubble in capillary tube
2. As water moves into shoot, evaporating from leaves, air bubble moves towards plant
3. Measure rate of air bubble movement