Geissorhiza radians

Paul Tyerman
Mon, 05 Aug 2002 05:39:45 PDT
>We are doing a research project on above mentioned bulb.  We are trying
>to germinate the seeds of Geissorhiza in vitro (tissue culture).  Has
>this ever been done or is germination only done in soil?  The seeds seem
>to posess a internal dormancy that only time can break! True?  Please
>give any suggestions, guidelines or contact numbers regarding this


I have sown 8 species of Geissorhiza over the last couple of years,
including G. radians twice (the 7 were..... aspera, corrugata, heterostyla,
inflexa, unknown yellow/green, radians (twice) and tulbaghensis).  These
were all sown in either April or June of two different years.  All those
that were sown in April germinated within 4-5 weeks, while those sown in
late June took around 8-9 weeks.  I think that the temps around early May
and late August must be fairly similar, thereby triggering the germination
at these times, rather than a "fixed" time after sowing.  By June the temps
are lower, and obviously they stay that way until late August, which must
be when the ideal temperatures are again achieved.  I can't give you
average temps here for these times, but it should give you some idea of the
type of temperature required.  It is apparently a certain temperature
range, rather than a time basis as your enquirer is assuming.  

For reference, my two sowings of G. radians occured in both of the time
frames.  One was sown April 1st, 2002 and appeared on the 11th May
2002...... the other was sown on June 24th, 2001 and appeared on the 30th
August 2001.  These were very similar results to other species sown at the
same times.

I haven't, however, sown any during summer to see if they wait until autumn
to germinate.  I have pretty much always sown any non-ephemeral seeds in
Autumn and get pretty good germination that way.

I stress these are just my own observations.  I hope this is of some help.


Paul Tyerman
Canberra, Australia.  USDA equivalent - Zone 8/9

Growing.... Galanthus, Erythroniums, Fritillarias, Cyclamen, Crocus,
Cyrtanthus, Liliums, Hellebores, Aroids, Irises plus just about anything
else that doesn't move!!!!!

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