Stomata And Transpiration

Question 1

What are stomata?

Answer 1

They are tiny pores on the surface of the plant. They allow CO2 and oxygen to diffuse directly in and out of a leaf,also allow water vapour to escape during transpiration.

Question 2

What are stomata surrounded by and what effect does this have?

Answer 2

They are surrounded by guard cells and this allows them to change shape to control the size of the pore.

Question 3

Light intensity

Answer 3

The brighter the light the greater the transpiration rate. Stomata begin to close as it gets darker. When they close very little water can escape.

Question 4

Temperature

Answer 4

The warmer it is the faster transpiration happens, when it is warm the water particles have more energy to evaporate and diffuse out of the stomata

Question 5

Air flow

Answer 5

The better the air flow around a leaf the greater the transpiration rate. If the air flow is poor the water vapour just surrounds the leaf and doesn’t move away = high concentration of water particles around the leaf.

Question 6

How to estimate the transpiration rate

Answer 6

You can use a potometer to estimate transpiration rate, measures water uptake by a plant
Set up the apparatus, record the starting position of the air bubble.
Stop the stopwatch and record the distance moved by the bubble per unit time.
Calculating the speed of air bubble movement gives an estimate of the transpiration rate.