Transpiration And Evaporation

Question 1

What is transpiration?

Answer 1

The process where plants lose water vapour through the cells lining the air spaces in the stomata. This loss of water vapour is known as transpiration. As water evaporates from the surface of the leaves, more water is pulled up through the xylem to take its place. This constant movement of water molecules through the xylem from the roots to the leaves is known as the transpiration stream.

Question 2

What are factors that affect the rate of transpiration?

Answer 2

1. Temperature
2. Humidity
3. The amount of air movement
4. Light intensity

Question 3

Why does increase light intensity increase the rate of transpiration?

Answer 3

Because the stomata open more, meaning there is more loss of water vapour.

Question 4

What are some adaptations that plants have to help them photosynthesise as much as possible while losing as little water as possible?

Answer 4

1. Waxy cuticle
2. Wilting - leaves collapse and hang down, reducing surface arra available for water loss by evaporation.
3. Stomata close - stops photosynthesis and risks overheating. However, this prevents most water loss and any further wilting.