Are there "Identical Twin" plants?

Cereoid CEREOID at prodigy.net
Mon Dec 18 08:07:19 EST 2000


You're arguing semantics of the different interpretations of the word
"spore". So you would call seeds megaspores and pollen microspores? That's
what happens when your botany gets too basic. Their actual morphology is a
bit more complex than that. The reproductive sperm and egg cells themselves
are not spores. A seed is not a spore either.

"Wayne Parrott" <wparrott at uga.edu> wrote in message
news:3A3D2092.6C565AC4 at uga.edu...
>
>
> Cereoid wrote:
>
> > Sorry dude but flowering plants produce seeds not spores.
> >
> > You need to study up on your basic botany then get back to us.\
>
> Sorry dude, but flowering plants do produce spores.  Study your basic
botany and
> then get back to us.
>
> Flowering plants do not release spores like ferns do, but they still
produce
> them.  The spores divide mitotically to form the sperm and egg cells,
which fuse
> to form the zygote, which, together with maternal tissues, forms the seed.
>
> >
> >
> > "George Hammond" <ghammond at mediaone.net> wrote in message
> > news:3A3C13B6.D8241A58 at mediaone.net...
> > > Cereoid wrote:
> > > >
> > > > Sorry but you are mistaken. The "Dandelion" is not an asexually
clonally
> > > > propagated species. It reproduces from seeds. Seeds are propagated
> > sexually
> > > > by definition.
> > >
> > > GH:  That's what i was asking.. i got the impression Dandelion "seeds"
> > >      were actually "spores"... thanks for the info.
> > >
> > >
> > > > An asexually propagated species is one propagated from offsets,
division
> > or
> > > > tissue culture.
> > >
> > > GH:  I'm aware of the definition.
> > >
> > > [Hammond]
> > >    Elsewhere you have asked what the BOTTOM LINE of this discussion
> > > is.  well, here it is.  Perhaps you can answer the fundamental
question
> > > which is posed below:
> > >
> > > > > GH:  You've totally missed the point. I DON'T WANT TO CONTROL
> > ANYTHING.
> > > > >      What I want to know is, what is the Standard Deviation of
plant
> > > > >      growth in the "real environment" when we are talking strictly
> > about
> > > > >      a crop of geneetically identical plants?
> > > > >        Now, somebody in agriculture must KNOW the answer to this,
say
> > > > >      for potatoes, or onions or some other asexual crop plant.
> > > >
> > > > It depends on the variety and on the trait, and it depends if you
are
> > talking
> > > > about the SD within a field or between fields.  For something like
> > flower color,
> > > > the SD would be close to zero.
> > >
> > > GH: Right, I understand that.
> > >
> > > > For something like height or yield, it would
> > > > fairly uniform within a field (barring spots which are overly
wet/dry,
> > or
> > > > otherwise inappropropriate),
> > >
> > > GH: YES, this is what I'm talking about, "gross overall size",
> > >     I'm NOT concerned with "specific traits".
> > >       I argue that there is such a thing as a "growth curve" for
> > >     ALL plants and animals and the "plateau" of this
> > >     curve represents what we call "maturity", or
> > >     "terminal growth".
> > >       However, there is reason to believe that there is such
> > >     a thing as a "theoretical growth curve" for any given
> > >     genetic species, and that in fact, since a large cloned
> > >     plant population has a "terminal growth variance"; that very
> > >     few plants EVER achieve this "theoretical growth curve".
> > >       Would you agree with this speculation?
> > >
> > >  but could be quite large between fields, depending
> > > > on how distant they are.  Breeders generally call this genotype x
> > environment
> > > > interactions.  Genotypes are known which are more stable across
> > environments than
> > > > others.  In the end, the SD is difficult to predict without
measuring
> > it.
> > >
> > > GH:  Yes, it is the "between fields" VARIANCE that I am talking about.
> > >      You apparently agree that such a thing exists and can be
> > >      measured.
> > >
> > > >
> > > > Keep in mind that plants need not reproduce vegetatively to be
> > genetically
> > > > identical.  Hybrids from inbred parents (as in a field of corn) are
> > genetically
> > > > identical.  So are inbred plants (as in a field of soybean) and
> > apomictic plants
> > > > (as in dandelions).
> > >
> > > GH:    You see; the question here is nothing but the old
NATURE-NURTURE
> > >      discussion.... with a NEW TWIST.
> > >        It is now hypothesized that higher animals, and probably
plants,
> > >      have something which we could call a "nominal maximum genetic
> > >      size", and that in the natural environment, very few IF ANY
> > >      individual specimens EVER ACHIEVE IT.
> > >        The object then, becomes the task of PROVING THIS CONJECTURE.
> > >      That is, proving from existing data, that there is such a
> > >      thing as a "terminal growth deficit" that exists for all
> > >      plants and animals, and naturally we would want to eliminate
> > >      "genetic variation" from the measurements, which is why the
> > >      question has come up explicitly concerning "clonal" plants.
> > >
> > >
> > > --
> > > BE SURE TO VISIT MY WEBSITE, BELOW:
> > > -----------------------------------------------------------
> > > George Hammond, M.S. Physics
> > > Email:    ghammond at mediaone.net
> > > Website:  http://people.ne.mediaone.net/ghammond/index.html
> > > -----------------------------------------------------------
>







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