HYB: Lycopene color(s)
Linda Mann, asking about the contrast between Lycopene colors in extract and
*in vivo,* asks about the apparent difference:
":Stuff in the cytoplasm? Stuff in the 'wrapper' around the plastid?
Chemical form of the pigment in the plastid? Physical characteristics
of the flower cuticle? [Linda, do you mean epidermis?] Other pigments in the
arrangement of the plastids inside the cell (are the vacuoles and their
pigments layered on "top" of the plastids inside the cell) [No]?"
Linda, the main difference is a known--you're looking at a solution dispersed,
diluted in the kitchen chemistry extraction.
In the cell the pigment is concentrated in plastids. There's a radical
difference due to concentration. Even if the plastids are discrete dots, they
are numerous in any one cell. From the illustrations I have seen of how cells
are arranged, <some>of the plastids are between the viewer's eye and the
pigments in the vacuole. Others <may> be on the opposite (interior) side of
Cells typically are so nearly transparent over-all that pigments can be
considered as embedded in glass, so to speak. At least that is what I
There are co-pigment effects that may be in place. It may have been Clarence
Mahan, if I remember correctly, who reminds us that the parenchymal cells of
the internal support layer of the petal DO contain pigments that appear
colorless in daylight, but floresce under ultra-violet. They may affect how
our other pigments appear.
Also, there may well be co-pigments, mixes of pigments (such as the potential
alpha-Carotene appearing as Lycopene, but the beta-Carotene expressed), and so
on. Most of your speculations apply, except for the one "are the vacuoles and
their pigments layered on 'top' of the plastids....?" To that one I can say
no--or at least, half-no.
Do you remember that deep orange-red solution in the Easter Egg coloring set?
Soak an egg in it, take out and you have yellow? Pigment colors seem heavily
dependent on solution/solid dilution levels or lack thereof.
Your questions, however, need to be addressed to microscope studies. Ask on
the list next spring when things are in bloom. At least two folk have said
they intend to do some looking at several pigment questions with high powered
optical microscopes and sharp tools for slicing through petals.
I wish I could be one of them, but I neither have the equipment, nor would
dare try to use it, considering the state of my vision. I'm doing well to
just do things "the way we've always done them," quoting the excuse people
give for stubborn conservatism flying in the face of plain evidence.
Neil Mogensen z 7 western NC mountains
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