Re: HYB: pigments/gray?

Linda,

Be careful not to confuse the "t" dosage level with dosage level of the
yellow(s) present.  They are two quite different things.  All the "t" does,
when present in three or four doses, is to divert some of the yellow synthesis
into a slightly different chemical sequence, in the case of Tttt diverting a
very small amount of one (or more?) of the yellows to lycopene "carrot" or
"orangish tomato" pigment, and with tttt diverting much of the Y synthesis
into lycopene.  The "t" factor is not a pigment itself--it is a *modifier* of
a pigment only--a diversion of the synthesis of the chemical carotene to the
somewhat different chemical lycopene.  Just think of "t" as the fork in a
factory manufacturing line.  Go left, get pink; go straight ahead, continue
getting yellow..

All of the above goes on without any reference whatsoever to what is happening
in the blue/violet set of pigments.  The inhibitor in the Progenitor/Whole
Cloth type bicolors works from top down in the flower, also by a diversion of
the chemical sequence that produces the pigment, just like the "t" doe, but
into colorless forms in this case.  The symbol isn't "I", it is "I" with a
subscript "s", meaning, of course, "Inhibitor, standards."

Keep the two processes of synthesizing pigments separate.  They only mix in
our perception of color, not in the flower itself.

There are a potful of various pigments, differing in various ways, such as
which sugars--dextrose or rhamnose, if I remember correctly--attach to which
two (and sometimes three) different spots on the anthocyanin basic molecule,
giving different color tones.  Then there are chelates of metal ions that
affect color values as well, and the presence of various "co-pigments" also
varying the appearance of the basic *violanin* of TB irises.  Then, some other
variations are the result of switching "-H" and "-OH" in two or three other
spots on the basic molecule.  The number of possible variations on simple
anthocyanin is fairly large.

The list of pigments *present,* not absent, in the white iris WINTER OLYMPICS,
( as shown in the Appendix A of TWOI ) is all by itself an education about how
complex TB pigments are.

In anyones seedling patch the color values of the seedlings tend to vary over
a fairly wide range from grayed, somewhat dull, tones to bright, sparkly clean
ones.  Naturally, we tend to pick the bright, clean, well-washed and Chloroxed
ones to name.  Some of the dull siblings hit the compost pile rather quickly.
Others have a certain charm *because* they have a somewhat smoked-color look.
It just depends on the flower.

Just why your seedling has the degree of smokey (that's a nice way of saying
"gray") tones in its colors has to do with the particular forms of pigments
that seedling's internal biochemistry cooks up.  In different soils, different
temperatures and pH values the seedling might look quite different.

What fun it would be to have a "Color Tricorder" (a practical, inexpensive
derivitive of that gizmo Dr. McCoy uses on StarTrek, of course) that we could
wave over the blossom and have an instant readout of just what is going on in
the flower's color chemistry.  The device might give us some concrete
understanding of how pigments and colors actually work---then, on the other
hand, its readings might raise more questions than answers.

Neil Mogensen   z  7  western NC

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