koning at ECSUC.CTSTATEU.EDU
Mon Jul 12 21:02:47 EST 1999
At 9:19 PM -0400 7/12/99, A. Cary wrote:
>But a young Cauliflower head is meristematic tissue.
Andy is right...the key word is YOUNG!
At the risk of getting boring, I'll reiterate
that we have to be careful about development...
How OLD are we talking? The head of cauliflower
has a range of primoridal stages depending on
its AGE. I think, making a few assumptions about
responses, that EVERYONE has been basically right
on this question but that various writers are
talking about portions of a head that are at
quite different developmental stages.
Those who say...it is flowers... are talking
about cauliflower that you are growing and allowing
to continue to develop. Indeed from base to tip
and from outer to inner, these primordial structures
develop into flowers. As someone has said, they
make an impressive inflorescence...eventually.
Humans happen to harvest this inflorescence when
it is very YOUNG and so, while some of the peripheral
primorida may be fully developed into flower buds,
the central tissues within the floret, and certainly
the central florets in the head are STILL MERISTEMATIC.
So those who say...it is meristem...are right too,
depending on how fully developed this head is. If
you probe for meristematic RNA later (at a time beyond
normal harvest!!!!) it will no longer show that
gene expression...even in the central florets of the
So, if you focus on the end product or are letting
your plants grow, the final product is INDEED flowers.
If you get your cauliflower in the grocery, or if
a technician cuts it in the field to bring it in for
your physiology/genetics/histology at the usual harvest
stage, then what you think of as the final product is
How "committed" this meristem is to flower production
is probably open to test...and an important criterion
for this test would have to be the developmental stage
(plastochron?) for each bud. I haven't a clue as to
how you would develop an index to identify each bud in
such a vast inflorescence in order to attach a developmental
frame to state when it is "canalized" into floral development.
So I think we are going to be wallowing in chaos without
an essential frame for discussion.
Ross Koning | koning at ecsu.ctstateu.edu
Biology Department | http://koning.ecsu.ctstateu.edu/
Eastern CT State University | phone: 860-465-5327
Willimantic, CT 06226 USA | fax: 860-465-4479
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