photosynthesis lab

[Jon Monroe]

Beverly et al.,

The book by Carol Reiss, "Experiments in Plant Physiology" has a 
number of good exercises that could be adapted for first year bio 
courses.  One of them that I tried for the first time this semester 
in Plant Phys involves taking photographs of the students (probably 
not feasible for big intro courses), then taping the negative to a 
bean leaf that was depleted of starch, exposing the leaf to light 
then clearing the leaf and staining with iodine.  When it works it is 
spectacular but we had troubles getting good prints.

For my daughter's 4th grade class a few weeks ago we did this but 
instead of using negatives they cut out shapes from black paper and 
paper-clipped them to the leaves.  After staining the contrast 
between shaded and lighted parts of the leaf was wonderful :-) but 
after pressing the leaves in paper towels over night all of the 
iodine stain disappeared. :-(  Does anyone know why this happened and 
how to prevent it?

Jon


>Does anyone have a photosynthesis lab of which they are particularly
>proud?  We have two labs, one for non-majors and one for majors.  They
>include variations on watching spinach disks rise in varying light
>intensities, varying wavelength intensities, and the old Coleus leaf,
>boiled, with iodine, etc.  This series of experiments is prone to great
>failure and we would like to revamp it entirely!
>
>Thanks!
>
>Beverlyl
>
>
>--
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>Beverly J. Brown, Ph.D.                Phone:  716-389-2555
>Nazareth College of Rochester       Fax:      716-586-2452
>Biology Department                      E-mail: bjbrown at naz.edu
>4245 East Avenue
>Rochester, NY 14618-3790
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  Jonathan D. Monroe           	    Associate Professor
  Department of Biology, MSC 7801   office: 540-568-6649
  James Madison University	      fax: 540-568-3333
  Harrisonburg, VA 22807   	email: monroejd at jmu.edu
     http://csm.jmu.edu/biology/monroejd/jmonroe.html
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