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From: Adam Fikso <irisman at AMERITECH.NET>
Subject: Re: Arisaema dilatatum germination quandary
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Good Morning,  Pascal,  Thanks for your extended response.  I understood
"trade" to be "trait"--I had no trouble with it, just read it with a Dutc=h
accent, and it made sense.

Because of my fingers (too big and clumsy) and eyes, (lack of binocular
convergence), I have to proofread everything and still miss some of my
errors.

I note that we again have this group's communication button turned to the
"ON" position , maybe because even though the exchange is not, strictly
speaking, an arisaema matter, it is relevant, interesting, and when there='s
snow and ice on the ground, something worth doing.  I know that I learn f=rom
it, because I can't find everyting on the Internet, not even from  Botany=on
Line.






It therefore might be influenced by ecological
circumstances which would make the production of the seedleaf unfavourabl=e
in the first year.

This occurred to me as something that might be true in the species' histo=ry


One might think, for instance, that high altitude species
with a relatively short growing season, would prefer this type of
germination
more but I have tried to analyze the species that show this type of
germination
and the habitat they come from and thusfar I have not been able to make a=ny
correlation.

But you analyzed it

It seems to occur random throughout the genus and, at best,
would suggest it is a trade aquired by species independant from one anoth=er
(convergent evolution) in a similar way that members of section Tortuosa
all have the same spadix appendix type but do not all seem to have the sa=me
ancestor. The species that do show a certain characteristic can be relate=d
to eachother but only because the common ancestor has developed the trade.
The possibility of this type of germination is there but only few actuall=y
have developed it.

As I noted above, I was thinking of a hypothetical common ancestor

Also what the small tuber is is hard to say. The use of the term "protoco=rm"
is strictly speaking false

OK, But what else should one call it ?

because that only applies to the relatively unstructured
mass of cells formed by orchids after germination that have interaction w=ith
mycorrhiza.


There seems to be some structure in the small Arisaema tubers
and usually the size of the little tuber at the the end of the first seas=on
is twice the size of the initial seed but can they already take up nutrie=nts
without photosynthesis?


I would not be too sure  that there is NO photosynthesis.  I recall some
experiments many years ago, but cannot recall a reference  (not even in m=y
own field for some things)  which showed that light could be detected as =far
down as a couple of inches in the soil, depending, of course on the
structure.   In loose leaf litter, there might be quite a bit of light
available to a germinating seed, and one should not forget the possible
effect of symbiotic organisms assisting in germination, e.g., aspergillus=in
seeds of some palms.

Would it be an advantage to store nutrients the first
year and produce bigger growth the next year?

Of course this seems reasonable.

It definitely is not meant
to place the young tuber deeper in the soil because the roots formed by
species
that produce a seedleaf in the first season do that job much better than
the distance the young tuber   is formed away form the initial seed.

How big a distance is this, say, in diameters of the seed?  I've never se=en
it , so would like to know, "just to send it around in the roulette wheel=of
my mind"    <:-)  (pointy-headed intellectual theorizing type) Regards, A=dam





Fascinating
stuff but I am afraid more questions than answers.

There are always more questions than answers:  and  this provides us
direction for observations.  Regards, Adam



Pascal
>-- Oorspronkelijk bericht --
>Date:         Wed, 26 Jan 2005 18:04:15 -0600
>Reply-To:     "Arisaema Enthusiast Group (AEG) Discussion List (and othe=r
>hardy              Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>