6.12 - Environmental Factors and Rate of Water Uptake

Question 1

What effect does an increase in temperature have on the rate of water uptake?

Answer 1

The molecules move faster, resulting in evaporation happening at a faster rate and therefore the rate of transpiration increases. The rate of photosynthesis increases, meaning more stomata are open for gaseous exchange, so more water evaporates and the rate of transpiration increases.

Question 2

How does an increase in relative humidity affect transpiration?

Answer 2

If the relative humidity is high, then there will be a reduced concentration gradient between the concentrations of water vapour inside and outside the leaf, resulting in a slower rate of diffusion. This will decrease the rate of transpiration.

Question 3

What is the effect of increased air movement on transpiration?

Answer 3

If more air is moving away from the leaf, the concentration of water vapour surrounding the leaf will be lower. This will mean there will be a steeper concentration gradient, resulting in diffusion happening faster and increasing the rate of transpiration.

Question 4

How does an increase in light intensity influence the rate of transpiration?

Answer 4

This leads to an increased rate of photosynthesis, so more stomata open to allow gaseous exchange to occur. This means more water can evaporate, leading to an increased rate of transpiration.