Internal Leaf Structure

Do Now Collect some parts tags from the front Cut out the tags and attach some string then tie to the proper place on the plant Place the parts on a plant outside and check to see that they’re correct

Cuticle and upper epidermis- allows light to shine on the leaf and the wax helps to keep water in Palisade cells -main site of photosynthesis

Mesophyll- contains the chloroplasts and has air spaces for carbon dioxide and oxygen to diffuse around the cell

Stomata- pore where gas enters and exits the leaf Guard cell- opens and closes the stomata

Function of the stomata Where do we find stomata? What is the role of the guard cell?

Gas Exchange Plants rely on Carbon dioxide to create sugars during photosynthesis How do the Stomata help with the absorption of CO 2 ?

Water vapour Plants rely on water for growth and structure. If there is a opening on the leaf what effect might this have on water in the leaf? When would you need to keep the stomata closed to stop to much water vapour being lost?

Lets look closer at the stomata Click on the picture to see an animation of the stomata and water vapour

Leaf Pull Practical We can see stoma if we strip a single layer of cells from the underside of a leaf Equipment: 1. Clear nail polish 2. Waxy leaf 3. Microscope and glass slides 4. Iodine solution to stain the leaf

Method Paint a strip of nail polish on the underside of the leaf – allow to dry Tear the leaf across the strip of nail polish

Peel off the strip of nail polish Place on a glass slide Add two drops of iodine solution Now observe under a microscope

To Do Sketch what you see in the microscopes Can you tell if the stomata are open or closed? What else can you see?