In article .com,
"Mike Lyle" writes:
|
| Thanks, both. It was the general selective advantage of sexual
| reproduction that interested me: since so few species (of those known
| to me, at any rate) do this trick, it presumably isn't a highly
| adaptive character. ...

There is good evidence that the selective advantage of sexual reproduction
is fairly small in plants, because of the number of times that it has been
lost or reduced to a minor role. I have some suspicion that this may be
associated with the totipotency - the genetic resetting that occurs only
in the gonads of vertebrates occurs to a great extent in the apical tissue
of the vascular plants[+], and I suspect that it is associated with some
genetic shuffling.[*]

While I have precisely no formal education in biology etc. etc., my
record at such guesses is good. But the chances of my guesses being
right in detail are zilch.

| Perhaps somebody can point me toward a good article somewhe I'm
| getting fascinated.

I have never seen one. The reproductive biology of plants is very poorly
understood, not so much because it has had less attention than that of
vertebrates, but because it is a lot more complicated.

[+] Old plant cells often get old and die, just as mammalian ones do, but
there is no equivalent of the Hayflick limit for apical cells (at the
very least). Don't ask me to explain bush ivy etc. :-)
[*] Think of how food crops that can reproduce only vegetatively have as
many forms as those that reproduce sexually, and how common it is for
viable varieties to arise as natural sports on new shoots.


Regards,
Nick Maclaren.