1. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 1 Transpiration

2. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 2 Learning objectives KQ: How do plants transpire and what affects its rate? Know that Plants carry out transpiration.Plants carry out transpiration. Different factors can affect the rate at which transpiration is carried out.Different factors can affect the rate at which transpiration is carried out. Know how to read graphs and measure the rate of transpiration.Know how to read graphs and measure the rate of transpiration.

3. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE Plants take in water through their roots in the soil… Transpiration

4. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 4 Transpiration …it moves up through the plant…

5. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 5 Transpiration …..and is lost through the leaves in the transpiration stream. Corel 178(NT)

6. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 6 Stomata There are small openings called stomata in the leaves of a plant.

7. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 7 These open to allow gases in and out for photosynthesis and respiration. But at the same time water is lost by evaporation. Stomata

8. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 8 Rate of transpiration When it is hot and dry, photosynthesis and respiration take place quickly. As a result, plants also very quickly lose water.

9. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE The potometer A potometer can be used to measure the rate of transpiration.

10. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 10 Rate of transpiration As the leaf loses water, so the air bubble moves. The distance moved over a time period is measured.

11. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 11 Transpiration rate Graph of bubble movement against time.

12. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 12 Transpiration rate The steeper the graph, the faster the transpiration rate!

13. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 13 Which potometer experiment was run in drier air? Transpiration rate

14. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 14 The drier the air, the faster the transpiration rate! Transpiration rate

15. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 15 Adaptations for plants growing in a dry environment Curled leaves. Moist air trapped inside the curl. Thick waxy cuticle. Stomata on the curled side only.

16. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 16 Adaptations for plants growing in a dry environment Marram grass leaves will even uncurl slightly in the wet and curl up more in the dry. Corel 46(NT)

17. B1b 5.2 Adaptation in plants Biology 1b Evolution and Environment GCSE CORE AQA Science © Nelson Thornes Ltd 2006 17 Learning objectives KQ: How do plants transpire and what affects its rate? Know that Plants carry out transpiration.Plants carry out transpiration. Different factors can affect the rate at which transpiration is carried out.Different factors can affect the rate at which transpiration is carried out. Know how to read graphs and measure the rate of transpiration.Know how to read graphs and measure the rate of transpiration.