factors affecting the rate of transpiration

how does light intensity affect the rate of transpiration?

• Light is needed for photosynthesis

• As light intensity increases, more stomata open to let carbon dioxide in (and oxygen out), the rate of transpiration increases

how does temperature affect the rate of transpiration?

• Higher temperature increases the kinetic energy of water molecules

• Water molecules diffuse and evaporate faster

• So transpiration rate increases

how does wind affect the rate of transpiration?

Wind will blow away water molecules near the stomata, maintaining a steep concentration gradient and causing the rate of evaporation to increase.

how does humidity affect the rate of transpiration?

• As humidity increases the rate of transpiration decreases.

• The higher the humidity the more water there is in the air (lower concentration gradient)

how is rate of transpiration measured and how does this device work?

using a potometer

why does a potometer not give an accurate measure of transpiration rate?

as it assumes all water uptake is due to transpiration