Re: Re: OT: Pigments & green

Christian,

You have asked several questions.  I'll try to respond to most.

The "Y" (for yellow) is for the pigments that include carotene, and if I am
not mistaken, some closely allied yellow, oil-soluble pigments.  Pink is the
result of a separate recessive gene "t" for "tangerine" that modifies carotene
into lycopene, the same pigment that makes tomatos red. Beta-carotene is
Vitamin A, by the way.

"I" stands for "inhibitor."

Y and the modified Y that make pink *do* definitely show dosage effects.  One
dose is pale ivory to cream (or equally pale pink, orange, etc.).  Two doses
light yellow, three full yellow and four perhaps a more saturated yellow.
Pinks don't build up to tomato red (drats!) but there's hope that breeding
deeper and deeper pinks or oranges that there may be some future limit beyond
what we have seen so far.

Mixing blue-violet (iris blue is not "blue"--check it against a spectrum blue
color reference and you will see just how violet the bluest iris really is)
with Y yellow at any level results in grey, or dull greenish grey at best, and
as the dosages of one or the other pigment build up, tan, brown, bronze, brick
red.

The Lycopene (Y-plus-t) colored flowers when overlain by violanin (blue violet
pigment) produce orchid pinks, rose colors to vivid majenta rose, all with
orange-red to tomato red beards in some degree or other.

The "green" iris aren't really green--just greenish if you want badly enough
to see them as green.  The pigments just don't show up that way to the human
eye.

I suggest you do some reading on "Additive" and "Subtractive" color mixing.
Iris colors combine both kinds of color mixes because they are translucent and
light coming *through* the petals tends to give some "additive" color effects,
but also some subtractive..  Light reflected from the surface gives a mix of
the two types also, simply because the Y (and y-plus t) are not in the same
layers of an otherwise nearly transparent medium.  As Keith Keppel pointed
out, the Y makes a canvas of color --the yellow is in minute dots inside the
cells in structures designed to hold oil-soluble materials in place, and the
violet or blue violanin is a liquid, water soluble ink throughout the cells.
This does wierd things to human color perception and produces the rainbow
range of colors we see in iris.

As to *Progenitor,* this is a named iris and the ultimate ancestor of all or
nearly all standards-inhibitor varieties.  It is a hybrid between a TB blue
and a plant Paul Cook grew from seed received as "reichenbachii" but which may
not have been pure species.  I. mellita (aka suaveolens) at least in one
clone, has been demonstrated to contain the same inhibitor, as witness the
registration of the iris "Melamoena.."

There is a picture of *Progenitor* in the HIPS site I mentioned in a previous
post.  You may find it interesting.  It took the genius of a Paul Cook to see
the potential people like Fred Kerr have unfolded from its decendants.

Do go to the AIS website and look at the AIS Storefront.offerings.
Registrations and Introductions of 2000 to the present and the Iris Check
Lists 99.89. 79 etc back to 1939 are VERY worth your while with the interest
you show and questions you ask.  They will tell you more than you could ever
dream you could know.  Buy them one at a time if you need to, but do buy them.
They are invaluable as the "tools of the trade."

Neil Mogensen  z 6b/7a near Asheville, NC

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