From: Steve Marak samarak at arachne.uark.edu> on 2000.11.29 at 21:18:10(5725)
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Sender: "Jay Vannini"
Subject: Apomicts
Dear Jim:
Sorry for muddying the waters even further on this issue, but I was trying
to clarify that apomicts "spontaneously" generate ovules, ergo, may generate
seed without having been self-pollinated, cross-pollinated, etc. I accept
that my post was less than clear on this.
Again, I find it interesting that, in Anthurium papillilaminum at least, one
may cross-pollinate two presumably unrelated plants and that the plant in
stigmatic phase will accept pollen from its conspecific, and that, in my
experience, manual pollination appears to "short-circuit" apomictic seed set
further up the spadix. The morphological variation amongst individual plants
suggests that this trait is far from being able to be described in absolute
terms. I'm afraid one might easily fall into the "what constitutes a
species" trap with this.
And in another, "DUH!" yesterday, hopefully the product of sleep
deprivation, I overlooked a number of well-known apomictic indigenous
Anthurium, i.e. A. bakeri, A. gracile, etc. in my mail.
Regards,
Jay
-----Original Message-----
To: Multiple recipients of list AROID-L
Date: Mi?rcoles, 29 de Noviembre de 2000 08:44 a.m.
Subject: Re: Apomicts
>In a message dated 11/28/2000 11:19:20 PM Eastern Standard Time,
>interbnk@terra.com.gt writes:
>
><< Indeed, my understanding of these plants is that they CAN generate
viable
> seed without manual fertilization. I am aware of at least two Anthurium
spp.
> that often generate seed thusly - A. clarinervium & A. papillilaminum.
> Surely, there are many more.
>
> With regard to Claude Sweet's comment - it is worth noting that both of
> these Anthuriums have been utilized by aroid hybridizers for some time,
and
> that the former species is suspected of being one of the parents of A.
> leuconeurum. I have manually pollinated both of the above, and have
> generated viable seed either way. >>
>
>Jay,
>
>Apomixis is a very complicated subject with many variations in natural
>manifestation. Typically the subject species/clone can create viable ovules
>without "outside" genetic influence. One of the best studied and classic
>examples is Hosta ventricosa. The seed-grown offspring are essentially
clones
>of the mother.
>
>If I read your posting correctly, you emphasize dependency on "manual
>fertilization" which has nothing to do with apomixis. Most will have heard
of
>"parthenogenesis" and it is typically apomixis from an unreduced gamete
>identical to the mother's tissue. There are many variations and the subject
>has an interesting bibliography.
>
>The reason the apomicts in question could in fact have been used in
>hybridization is that their pollen is usually fertile and the apomict can
be
>used as the pollen parent. If the cross is attempted in reverse, GENERALLY
>the apomict's ovule would not accept the pollen's genetic contribution (be
>warned; exceptions are known!).
>
>Hope this slightly clears the murky water". :-)
>
> Jim Langhammer
>
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