TOW: Dormancy, Seed and Bulb

Mary Sue Ittner msittner@mcn.org
Tue, 13 Jan 2004 08:31:19 PST
Hi everyone,

Roy had thought it would be very interesting to have a topic about dormancy 
in seeds and bulbs so I asked him to introduce it. He has spent some time 
looking through the literature on this and I hope we'll have some 
contributions from others too.

Many of us attempt to grow bulbs from seed and understanding what the 
requirements are for good germination is really helpful. I'd like to throw 
out some questions that came to mind while reading his introduction and see 
if any of you can answer them.


>After-ripening is the time between the formation of a mature seed and its 
>ability to germinate;

In the past people have talked about how some seeds will continue to ripen 
if you cut the scape and put it in water. Do we have any idea of which 
genera this applies to? I often wonder if I can cut pods off and let them 
dry somewhere else or if I need to leave them on the plant until the pod 
opens to ensure the seeds will be viable. Anyone care to tell us what they 
have observed about this?

>Impermeable/Mechanically Resistant Seed Coats.

Which geophytes do we think have seed coats that need to be nicked or sand 
papered?

>Chilling.

I assumed that chilling was necessary for species that come from very cold 
climates and would regularly get cold temperatures they would have adapted 
to. But Roy has found chilling helpful for alstroemeria. Remembering Jane's 
discussion of the many habitats she observed for this genus, they wouldn't 
all grow where it would be cold. So what do we think is happening in this 
situation?

Roy has talked about soaking alstroemeria before you sow it. I always soak 
my Cyclamen seed too. Are there other seeds that people have found from 
their experience benefit from this?

Have any of you done any experiments using smoke water to help break 
dormancy and ensure good germination?

Many years ago Diana Chapman told us about her fire method that had worked 
for Veltheimia germination. If I recall what happened was that after her 
burning, seeds came up in great numbers all at the same time.

What about the seeds that come up in later years (like Romulea). What has 
happened to make this happen?

Finally I am once again struggling with Aristea seed. Rachel sent me some 
extra seed to experiment with and I have tried soaking them in smoke water 
and sowing them as I usually do. I have about 5 different species. So far I 
have one seed up in 10 pots. I kept back some seed to start in the spring. 
Does anyone have any suggestion for other things I might try with the rest 
of the seed. One of my Aristea pots from last year (0 germination then) 
that I have left outside to be rained on has 2 shoots.

Thanks.

Mary Sue


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