1. Do Now 1. List the four factors that affect the rate of transpiration in plants 2. Choose the correct ending to this statement: On a cloudy day when the temperature is cool and there is no wind the a) rate of transpiration will be slow b) rate of transpiration will be fast

2. PLANT PROCESSES Transpiration review Photosynthesis introduction

3. Rate of transpiration - review The speed at which water is lost at the leaves depends upon: 1. Humidity in the air around the leaf - If the humidity is high the rate will be slow - If the humidity is low the rate will increase 2. Wind speed around the leaf The faster the wind the faster the rate of transpiration 3. Temperature The hotter the temperature the faster the water evaporates 4. Amount of sunlight The more sunlight the more photosynthesis that happens which means the stomata are wide open so more water is lost

4. Effect of light intensity Light intensity = how much sunlight there is On a sunny day photosynthesis is occurring at a high rate in the leaves Photosynthesis needs Carbon dioxide from the air around the leaf – this means the stomata are wide open This lets water escape faster so the rate of transpiration increases

5. What rate do we want The rate of transpiration is important for plant growth The rate should be fast enough to - Provide enough water to the leaves for photosynthesis - Provide water to cool the plant - Deliver minerals and nutrients to the plant from the roots If it is too fast the plant will wilt and shut down If it is not fast enough the plant will not be able to carry out photosynthesis and produce food for itself

6. NCEA Questions You will be asked to explain how the rate of transpiration can be increased or decreased to allow for the perfect conditions for plant growth Example: Explain how the humidity level inside a greenhouse can be changed to increase the rate of transpiration. You would need to explain that the level should be reduced to allow more water to evaporate into the air around the plant. High humidity slows the rate of transpiration because the air already contains a large amount of water vapour

7. Do Now Answer the questions in your book on p.139

8. Plant Processes There are three plant processes  Photosynthesis  Respiration  Transpiration These work in conjunction to ensure the plant grows

9. Photosynthesis the process uses light as an energy source to make glucose from carbon dioxide in the air & water from the soil. Photosynthesis occurs in the leaves of a plant

10. 10 Carbon Dioxide & Water Chlorophyll & Light Glucose & Oxygen Process for Photosynthesis

11. 11 Water is taken up through the roots Plants use chlorophyll (the green pigment) in their leaves to obtain energy from light The product of photosynthesis is glucose. Glucose is stored as starch Carbon dioxide is taken up through the Stomata on the underside of the leaves.

12. Do Now Complete Questions 1 and 2 on pages 140-141 of your workbook