Re: Differences of volume of transpiration between upside and back of leave.

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
ejb190@psu.edu