|MadSci Network: Botany|
Yes, there is a difference in transpiration between the top and bottom of a leaf. Stomata are the tiny pores in the cutical of the leaf which can be opened and closed to regulate the air and water vapor movement out of the cell. Generally, there are more stomata on the bottom of the leaf then on the top. Therefore, there is more transpiration from the bottom surface. I was just thinking about a neat little experiment we did in my college plant physiology class a couple of years ago. Get a few glass slides, several different species of plants, and a tube of superglue. Place a drop single drop of glue on the slide, let it dry for ten seconds, then press and hold a leaf to the drop of glue for a minute or so. When you pull the leaf away from the slide, the cutical will stay on the silde. Put the slide under a microscope and you can see for yourself how many stomta are on the top compared to the bottom!! A good biology or plant physiology text book should have photos of stomata to help you see what you are looking for. One more note, the slides will be ruined by the glue. I hope this helps! Eric J. Biddinger Graduate Student Department of Horticulture Penn State University firstname.lastname@example.org
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