At 5:49 PM -0500 2/12/98, Mary Williams wrote:
>Dear plant ed folks,
> We have a vegan student who won't participate in our animal
>physiology module in Intro Bio lab. I said I'd be willing to come up with a
>"vegetarian alternative" for her. The lab deals with cell signalling and
>response. Off the top of my head, I decided to have her investigate how the
>embryo triggers starch degradation in barley. The problem is, I've torn my
>office and the internet apart and can't find the protocol I thought I had
>for this lab (I've never done it, but I thought I had it!)
>> Can anyone help out? I've got a pretty good idea of what to expect,
>but need to know such things as - how long does it take to go from dry
>seeds to a enough starch breakdown to detect by IKI? Can I see a loss of
>starch by staining seeds, or do I need to look at breakdown of starch in
>petri dishes? What concentration of GA will stimulate non-embryo seed
>halves to produce amylase? etc etc etc.
The GA effect is supposed to be detectable
down to 10-8 M, but I would use some higher
concentrations...up to 10-4 M just to be sure
she sees a nice response in those embryoless
halves.
The problem with this whole exercise in my hands
is that you have to be axenic with everything!
Any fungal spores on the seeds or other equipment
produce amylase without any signals and confuse
everything...controls often are producing as much
amylase as any treatment.
I think for an intro lab I would do it in Petri Dishes
poured shallow with a starch agar...then flood with I2KI
after incubation. Not too much starch, though or it
takes forever to get haloes around the seed halves.
>Thanks in advance to anyone who responds!
>>As an aside, I wonder how most schools respond to student such as this one
>- we had quite a debate about her in our department meeting! If your
>department has a policy for "conscientious objectors" in the lab classes
>I'd like to hear about it,
Some of our students have used multimedia dissections;
there are videos and computer simulations available.
I don't think the experience is particularly equivalent
but we have tried to be sensitive to these students.
We have stepped away from our farming roots so far that
this is increasingly a situation in our classrooms...back
in the old days....well I'll tell you my chicken dinner
story another time.
ross
________________________________________________________________
Ross Koning | koning at ecsu.ctstateu.edu
Biology Department | http://koning.ecsu.ctstateu.edu/
Eastern CT State University | phone: 860-465-5327
Willimantic, CT 06226 USA | fax: 860-465-4479
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