plant defense compound assays

Ross Koning Koning at ECSUC.CTSTATEU.EDU
Tue Oct 8 15:27:31 EST 1996

At  9:58 AM 10/8/96 -0700, Christopher T. Cole wrote:
>Does anyone on this bulletin board know of relatively simple assays for
>plant defense compounds, suitable for an undergraduate interested in
>questions about what can cause a plant to increase the production of
>defense compounds?  Assaying plant secondary compounds is not my line of

I'm guessing that the instrumentation needed for
rigorous identification of such compounds is beyond
typical budgets.  However, there are some simple
bioassays such as feeding rates of hornworm larvae
and behavioral responses in hissing roaches.  The
plant called pyrethrum produces pyrethroids that
can be assayed with roaches.  Cecil Still in the
Plant Science Department of Cook College at Rutgers
University in New Brunswick, NJ could give you
some particulars on how he assays these chemicals
in pyrethrum using the roaches.

I'm not sure who to refer you to for the Manduca
sexta feeding procedure, but my recollection is that
you can use Petri dishes with young larvae and place
the plant material to be tested in with the larvae.
Then you observe feeding rates (grams per hour per
gram of larva, or some such).  You'd be doing more
of a "taste test" than perhaps a toxicity assay,
but then that is what determines what is palatable
to herbivores.  This kind of test does not allow
food discrimination, however, and is probably a
design flaw.

Perhaps someone knows of an entomology list that
this request could go to for further information?


Ross Koning                 | Koning at
Biology Department          |
Eastern CT State University | Phone: 860-465-5327
Willimantic, CT  06226  USA | Fax: 860-465-5213

                Plant Physiology is Phun!

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|  |  |  |    |  |  ||       //\___     \CH3     /\|/\\/\\COOH
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 /\ | |__|=        NH       |  || ||           //\//\
  | COOH                    \\ /\ /            O
  COOH        H2C=CH2         N  NH

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