Half-seed assay

Ross Koning koning at ECSUC.CTSTATEU.EDU
Tue Nov 25 14:38:58 EST 1997

At 12:14 PM -0500 11/25/97, Dr. David Starrett wrote:
>  I was planning to do the Braley seed half assay for GA next week.  I have
>done it before, but somehow cannot come up with the formulations.  Does
>anyone know the concentration of starch that goes in the agar plates (1%?)
>and more importantly, the concentration of GA in the agar test plates?


I recommend a range covering 10-8 M to 10-4 M GA3.
If you want to be SURE, guess high...GA is not
particularly toxic as are auxins at high concentrations.

BTW, it is really tough to get surface sterility
and you really do need the plate to be axenic...most
fungi that attack half-seeds can digest starch and
infected seeds routinely get haloes under them because
of fungal amylase.  I have never been happy with the
assay because of this dependency.


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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