Re: HYB: color (was Cult: lets talk about browns and brokens)

Christian, 

Were answering the post in bits and pieces, 
and I dont think anyone commented on the 
colors yet.  I havent seen CHOCOLATE MARMALADE 
but Ill try to answer at least part of your 
question.  Im not very good yet at translating 
the written descriptions into a mental picture 
(I seem to have a particularly female brain 
when it comes to that sort of thing.)  Mind 
you, I dont for a minute pretend to be an 
expert.  This comes mostly from what I have 
read in The World of Irises, catalogs and prior 
posts to this forum (Feb 03).

There are three layers of cells in the petal 
(the beard too, Im pretty sure.)  The pigments 
for yellows, pinks and oranges are found in the 
center layer of cells.  The outer layers are 
where the purple, blue, lavender, and orchid 
pink pigments are found.   The cell composition 
of the different layers is different, the outer 
layers are made up of mostly vacuoles (a 
vacuole is loosely defined as a membrane 
holding fluid which functions to produce 
pressure against the cell wall, which helps it 
hold its shape).  The center layer of cells is 
made up of mostly plastids.  (Plastids are 
defined as granules or particles found in the 
protoplasm of plant cells)  The 
yellow/pink/orange pigments are contained 
within the plastids.  The cells in plants have 
fairly significant walls which are to some 
extent permeable by gases and fluids, but the 
pigment molecules are relatively large compared 
to water or gas molecules and are held within 
the cell walls.

When you see the browns, it is not an actual 
mixture of the pigments as the yellows, pinks 
and oranges are oil soluble and the purple, 
blue, lavender, and orchid pink  
(anthocyanidins) are water soluble, and 
therefore do not mix.  It works more like a 
transparency.  If you lay a purple/blue layer 
over the yellow/pink/orange layer, the visual 
effect will be something like wine reds to 
shades of brown depending on a lot of factors, 
such as pigment concentrations, dosages, 
presence of other pigments, etc.

The distribution of the yellows/pinks/oranges 
does not follow the same genetic expression as 
the plicata pattern.  The plicata pattern is 
expressed through the 
purple/blue/lavender/orchid pink water-based 
pigment in the outer cell layers only and is a 
genetically recessive trait.   They certainly 
look similar, but the yellow plicata looking 
distribution is most commonly referred to as 
the Joyce Terry pattern.   I honestly dont 
know much about the heredity of Joyce Terry 
pattern or the amoena and reverse amoena 
patterns in the yellow and pink pigments.  I 
havent found much written on the subject so 
far.  

If I messed any of this up, corrections are 
always appreciated.  And anyone having any tips 
on good reading material, let me know.  The 
winters here are long and cold and I need 
something to do to keep me out of trouble <g>

Robin Shadlow
Zone 5 NE

where OVER AND OVER is sending up a stalk !!



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