HYB: orange
- To: i*@egroups.com
- Subject: HYB: orange
- From: a*@cs.com
- Date: Wed, 22 Nov 2000 16:18:44 EST
To save some newcomers time spent plowing through the archives:
THE WORLD OF IRIS provides a detailed explanation of the carotenes. Its
discussion of chemical pathways gets pretty deep, but the most important
thing to remember is that this is an entire family of pigments of varying
colors from yellow through yellow-orange to orange-red. They can, and do,
appear both together and separately -- which provides the potential for many
different shades of yellow and orange.
On page 426, there is a table showing the occurence of these, and other,
pigments in 28 varieties of TBs. You may have to consult checklists for some
you don't recognize, but I found comparing this analysis with photos and
descriptions to be VERY enlightening. [Linda -- another of your dreaded
"homework assignments"!]
Dr. Werckmeister described these as plastids within the cell wall of the
epidermal layer and his model does explain why oranges produced by a mixture
of carotenes appear to be smooth, rather than striated or washed. If you are
interested only in TBs, this model is the most useful I've found. Browns are
explained as the combination of violet-colored cell sap, seen through the
yellow plastids in the cell wall -- the depth of the brown depending, of
course, on the intensity of the violet and yellow components. So:
pale-violet + yellow-orange = deeper orange
This can also explain the pixelated effect found in some arilbreds [and, I
suspect, in some older TBs] because it treats each cell as a separate entity.
PIXILATED is a good example, not a true orange, but on portions of the
flower the mixture of pink and deep yellow is so intense that it does look
orange from a distance. Early hybridizers of pink TBs worked so hard to get
the yellow out of the pink-and-yellow blends that I wonder if some of those
cultivars did not also have this pixelated pattern.
Werckmeister's model does not, however, explain the barber-pole effects
apparent in so many arilbreds. These have changeable color, depending on
the angle at which the flower is viewed. Such oranges are produced by a
surface layer of reddish-violet overlaying a yellow base. Some can be as
intense as the orange of a robin's breast.
If you include apricots and peaches in the "orange" group, there are even
more routes to explore -- but I'd rather save than until another day.
Sharon McAllister
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