Stomata Structure and Function

A few days ago we painted the underside of leaves in clear nail polish to see if we could see the stomata once we peeled them off. The nail varnish coated the underside of the leaf and sank into the stomata and formed "dips"  We then painted the nail varnish with blue food colouring which sank into the diops showing there the stomata are on the leaf.  Although this project didn't work very well it gave us the idea to look at leaves and red onions through a microscope. 

Stomata are little pores on the underside of leaves that play a crucial role in photosynthesis, they are where waste is expelled from the plant (oxygen, excess water and carbon dioxide ect.) Each stoma (singular form of stomata) can be opened and closed when necessary. This is because of the guard cells either side of the stoma. The guard cells are two cells either side of the stoma and act as doors that open and close, when the guard cells are turgid (firm) the stoma stays open, when they become flaccid (limp or floppy) the stoma is closed. You can think of the guard cells like a bouncy castle: when inflated it stands upright, when deflated it falls in on itself. 

The stomata are placed on the underside of the leaf to shelter them from direct sunlight which would cause the stomata to open too much and the plant to wilt.