What have we learned so far

1
Lesson 7

• What have we learned so far?

2
The importance of transpiration

• Plants use transpiration to - provides water
• for
• Photosynthesis
• Support
• Cooling
• Movement of minerals

3
Controlling transpiration

• Healthy plants balance the amount of water
• they lose via transpiration with the amount
• they gain from the roots-
• Waxy cuticle on the upper surface of the leaves
• Location of the stomata more on the lower side
  of the leaf
• Guard cells problem stomata need to be open
  during the day

4
Guard cells control the size of the stoma
5
Think about washing on a line.

• What conditions dry clothes quickest?

What condition dry clothes more slowly?
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Our Washing Line
7
Investigating transpiration

• Make a prediction for each leaf and explain your
  
• reason for your answer. Then draw
• Apparatus / method

8
Work to do
References Dobson page 161, Roberts page 245
and Worksheet 3.4

• 1. Give a definition of transpiration and
  transpiration stream.
• 2. List the reasons why Transpiration is
  important?
• 3. Explain How the transpiration stream flows.
• 4. Using Dobson pages 161 and 162 draw open and
  closed guard cells and turgid, flaccid and
  (plasmolysed) cells
• 5. Roberts page249 assignments 1-4
• 6. Exam Q 11 and 13

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Homework

• Exam Q 11, wilting
• Exam Q..3 Describe how a potometer works. (poly
  bag)
• Questions 11 and 13 from worksheet

10
Plan an investigation on the rate of
transpiration

• You could use weight loss and water intake as a
  measure of water
• You could look at the effects of different
  variables on different plants
• You could investigate how different numbers of
  stomata affect the rate