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hardy  Aroids)" <ARISAEMA-L at NIC.SURFNET.NL> Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>
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From: pbruggeman at TISCALI.NL
Subject: Betr: Re: Arisaema dilatatum germination quandary
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Oeps...., "trade" should of course be "trait"......

>-- Oorspronkelijk bericht --
>Date:         Thu, 27 Jan 2005 12:38:00 +0100
>Reply-To:     "Arisaema Enthusiast Group (AEG) Discussion List (and othe==
r
>hardy              Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>
>From:         pbruggeman at TISCALI.NL
>Subject: Betr: Re: Arisaema dilatatum germination quandary
>To:           ARISAEMA-L at NIC.SURFNET.NL
>
>
>Dear Adam,
>
>As far as I know what causes an Arisaema species to show this behavior s==
till
>remains a little bit of a mystery and the behavior is not always a stabl==
e
>characteristic within a species. Some species can be induced to show thi==
s
>behavior. Older seed of A. nepenthoides for instance sometimes shows a m==
ixture
>of hypogeal and epigeal germination for a species that usually produces
a
>seedleaf in the first season. It is however closely related to a species==

>that has several clones that exclusively produce a seedleaf only in thei==
r
>second season (A. lobatum). It therefore might be influenced by ecologic==
al
>circumstances which would make the production of the seedleaf unfavourab==
le
>in the first year. One might think, for instance, that high altitude spe==
cies
>with a relatively short growing season, would prefer this type of germin==
ation
>more but I have tried to analyze the species that show this type of germ==
ination
>and the habitat they come from and thusfar I have not been able to make
any
>correlation. It seems to occur random throughout the genus and, at best,==

>would suggest it is a trade aquired by species independant from one anot==
her
>(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 s==
ame
>ancestor. The species that do show a certain characteristic can be relat==
ed
>to eachother but only because the common ancestor has developed the trad==
e.
>The possibility of this type of germination is there but only few actual==
ly
>have developed it.
>
>Also what the small tuber is is hard to say. The use of the term "protoc==
orm"
>is strictly speaking false because that only applies to the relatively u==
nstructured
>mass of cells formed by orchids after germination that have interaction
with
>mycorrhiza. There seems to be some structure in the small Arisaema tuber==
s
>and usually the size of the little tuber at the the end of the first sea==
son
>is twice the size of the initial seed but can they already take up nutri==
ents
>without photosynthesis? Would it be an advantage to store nutrients the
first
>year and produce bigger growth the next year? 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. Fasci==
nating
>stuff but I am afraid more questions than answers.
>
>Pascal
>>-- Oorspronkelijk bericht --
>>Date:         Wed, 26 Jan 2005 18:04:15 -0600
>>Reply-To:     "Arisaema Enthusiast Group (AEG) Discussion List (and oth==
er
>>hardy              Aroids)" <ARISAEMA-L at NIC.SURFNET.NL>
>>From:         Adam Fikso <irisman at AMERITECH.NET>
>>To:           ARISAEMA-L at NIC.SURFNET.NL
>>Subject: Re: Arisaema dilatatum germination quandary
>>
>>
>>OK, one person's experience (yours) was  enough to certainly confirm th==
at
>>something unusual was going on.  Maybe there's no data in the literatur==
e
>>on
>>how this was established as fact.  Sort of lost in the mists of history==
?
>>
>
>
>_____________________________________________________________________
>
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