Re: Seed germination

Peter Cole (carnivor@bunyip.demon.co.uk)
Wed, 10 Jan 1996 10:04:52 GMT

> Date: Tue, 9 Jan 1996 07:33:49 +0100
> From: hansmh@sn.no (Hans Martin Hanslin)
> To: cp@opus.hpl.hp.com
> Subject: Re:seed germination
> Message-ID: <199601090633.HAA04253@hasle.sn.no>
>
> >I have some seed from Allen that refuses to germinate
> >even with this high GA3 concentration and some others of which only a few
> >germinate. So I'm not sure if you will succeed with a lower concentration.
>
>
> Could you be more specific about the species that do not respond to your
> treatment. I am awaiting a batch of seeds from Lowrie and have planned
> to experiment with gibberellic acid (1 mg/ml). Do you (or any) know if
> the concentration of GA affects the survival of the seedlings. I applied
> GA (unknown concentration) to seeds of _U. calycifida_. Both control and
> treated seeds germinated (70-80% success), with the germination of the
> control seeds a week delayed. Unfortunately the "treated" seedlings died
> within a week. Just a coincidence - or are there similar observations?

I'd say 1000ppm was way too high a dose - I use 250ppm for seeds,
and have observed this 'overdose' effect on Proboscidea parviflora
when I was first playing with GA3 and didn't know about the dosage
(well, OK, I mostly just wanted to see what would happen :) I
probably had a concentration several times yours. They just burst
open in a mass of cells, and then died. I can't comment on how
they compared to normally germinating ones, as I'm still waiting
for a more sensibly treated batch to sprout, but I believe excess
GA3 will at least inhibit rooting.

I know that some tissue cultured plants require exogenous GA3 for
satisfactory micropropagation (Potato, Dahlia, etc.) but the dosage
used is in the order of 0.1mg/L - does anyone know if any CPs (in
tissue culture,) fall into this category?

And if testament to the power of GA3 was needed, I had a Mimosa
pudica germinate the other day in 2 1/2 days after 24hrs in 250ppm
GA3!! - not bad for last year's seed!

Happy growing,

Peter