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Re: apomictic?

Neil wrote in response to Sue:

>>Apomixis is NOT any form of asexual reproduction. Apomixis is asexual
>>reproduction involving flower parts. Seeds without sex.
>other forms of asexual reproduction which are not apomixis are, =
>leaf propagation, tissue culture, offsets, bulbils etc.

Very true.  Also, relying upon literal translations from either the
Greek or Latin is as unreliable as you can get, because these are
invariably considerably distanced from the reality and are only
descriptions in the broadest possible sense.  Defining apomixis in
plants is almost impossible without going into details at cellular
level and I have tried, albeit very ponderously to give a very broad
outline of what takes place in my reply to Sue Zunino.  The immense
problem is that the plant kingdom is so infinitely variable and for
every definition, there are innumerable exceptions.=20

The general consensus appears to be that apomixis is asexual
reproduction involving (almost exclusively) those parts of the ovum
not directly involved with fertilisation.  Lets try to get this into
perspective.  Most of us are familiar with the idea of a placenta and
umbilical cord in animals (including us).  These are the connective
tissues or 'somatic' tissues which remain part of the parent but are
essential in the continued development of the embryo.  Genetically
they are identical to the host parent (mother) and any tissue culture
taken from these, resulting in an offspring, would be clones of the
mother.  In plants there are vaguely similar (connective or
integumental) somatic tissues and it is in these areas that 'budding'
or embryo genesis can take place.

I prefer the term 'apogamic' because it more accurately describes the
'non-gametal'  ie. unfertilised status of these embryos.=20

Dave Poole

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