differential growth

David W. Kramer kramer.8 at OSU.EDU
Mon Oct 12 16:12:19 EST 1998

I'm eager to see the responses to your inquiry!  When I explain the opening
of stomata due to the unequal enlargement of guard cells, I draw an oblong
balloon on the board and ask the students what shape it would have when
inflated.  They know, of course!  Then I ask what would happen if you put a
piece of duct tape on one side of the balloon before inflating it.  They
are able to figure it out.  HOWEVER, it just occurred to me that I never
actually did it... so I don't know if it works!  I'm going to try it!
Before I sent this Al Ruesink wrote to say it works!  If Al says it works,
it works!!

You mentioned twining and I'm reminded of David Attenborough's "Private
Life of Plants" which is a book (Princeton U. Press.  1995.  ISBN:
0691006393) but also a videotape of the BBC TV program that aired in 1995.
I haven't looked at the videotape in some time but I recall there was
magnificent time lapse photography of vines (lianas) twining on trees in
the rainforest.  Our campus library has the book and tape and most public
libraries have it, too.


>Dear Colleagues,
>Does anyone have a good physical demonstration of how unequal growth in a
>stem can result in growth towards or away from something?  I have 2-D
>pictures, but I was trying to come up with some analogy, or demo, that
>shows clearly how such unequal growth can cause bending in the phototropic
>response, or in twining for vines.
>Thanks for any ideas you have.  Again, I'm looking for a physical or visual
>demo, not a static, 2-D picture.
>Kath Archer

Dr. David W. Kramer
Department of Evolution, Ecology,
        and Organismal Biology
Ohio State University at Mansfield
1680 University Drive
Mansfield, OH  44906-1547
(419) 755-4344  FAX:  (419) 755-4367
e-mail:  kramer.8 at osu.edu

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