Re: cells and chloroplasts (depicted on the color wheel)
Your statement "Just curious as to where the third colors (yellow) could
be coming from" could be taken to be a broad philosophical question that
touches on the existential nature of not just yellow pigments but on
all of the Universe as we observe it.
I think you meant to ask is yellow (distinct from white as a color
characterisitic in hosta leaves) caused by mutations? IMO, it is at one
point in time. This opinion has been artfully expressed in the Hosta
Color Wheel designed by Bill Meyer. This graphic color wheel, a tool to
more accurately define colors on hostas, has three pie-shaped segments
with shades of green, white and yellow, which are the colors of
representative tissues as determined by the presence of green
chloroplasts, colorless leucoplasts and carotenoid pigments associated
with plastids. The basic concept of the color wheel is that the
proportions of the populations of various plastids and their mix in
cells and tissues determines their colors as we perceive them.
If three colors exist in a leaf, it is a tri-colored chimera with
distinct tissues comprised of cells with specific plastid attributes.
H.'Summer Music' and H.' Lakeside Meter Maid' come to mind as does an
un-named white centered sport of H.'Fascination' in my garden with dark
green margins and a bright yellow transition area between the white
center and the dark green margin. The bright yellow tissue is probably
caused by a mutation within the L1 tissue, allowing for the presence
of two colors of L1 tissue (white and yellow) and the one color of
unmutated green tissue in the L2 area of the leaf. This mutation in
'Summer Music' obviously occurred after a chimeral rearrangement (tissue
transfer sport) occurred in the tissue culture lab in Lake Placid,
Florida (owned by Klehm's man in Florida) which found and propagated
the 'Summer Music'. Your 'Lakeside Meter Maid' is a modified version of
H. 'Fascinator', a sister mediovariegated sport of 'Fascination', has an
all yellow center (with no white involved) which is somewhat darker
than the above mentioned colors because it probably has more green
chloroplasts in the color mix of plastids in the cells of the involved
tissues. These examples are somewhat analogous to mixing paint on an
artist's palette as described previously in a Journal article.
I think your question was an excellent one. All of this is getting to be
very heady, stimulating stuff, isn't it?
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