Question on Coloring in Flowers
majordude
I have a question that my Daughter posed to me and I could not answer: What
makes any flower have color? In a short way, please explain how this
occurs in a genral sense and perhaps examples from one or 2 type of plants.
If this sounds too long to answer, please include links for us.
Thanks in advance.
Ed
Iris Cohen
It is genetically determined. In the case of anthocyanins, the blue, red, &
purple pigments, there are 2 or 3 genes involved, which cause the production of
enzymes which convert sugar to pigment. If any one of these genes is missing or
defective, the result is white flowers. There are other genes which control
spots & patterns. The flavonoids, the yellow & orange colors, at least in some
families, are not controlled by genes, but by other bodies in the nucleus.
These are passed on by the seed-bearing parent.
In some cases, the exact shade or depth of color is influenced by temperature
and/or light.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"It is forbidden to live in a town which has no greenery." Jerusalem Talmud,
Kiddushin 4:12.
Beverly Erlebacher
majordude <ham...@p3.net> wrote:
>
>I have a question that my Daughter posed to me and I could not answer: What
>makes any flower have color? In a short way, please explain how this
>occurs in a genral sense and perhaps examples from one or 2 type of plants.
>If this sounds too long to answer, please include links for us.
Iris mentioned anthocyanins, which provide most of the colors in the
pink/purple/blue range. One interesting aspect of these chemicals is
that they are pH indicators, i.e. the color changes with changes in
acidity. The purple color of beets and red cabbage is caused by anthocyanins,
and you and your daughter may enjoy observing the color change of cooking
water from these vegetable when you add vinegar or baking soda.
Many plants produce anthocyanins in their leaves and stems, and the intensity
of color may depend on light exposure. Plants may increase the amount of
pigment as protection against light that is too intense, or reduce it when
they are growing in dimmer light. Some plants also produce a purple color
in leaves and stems in reaction to other stresses like cold, drought or
nutrient deficiencies, notably phosphorous. Tomato plants are a good example
of this. I don't know if there is any adaptive value to this, or whether
it is just a generalized stress response. The point is that many plants
have the machinery to make anthocyanins available anyway, so can adapt it
for coloring their flowers.
Btw, the technique of chromatography was originally developed by someone
who wanted to investigate flower colors by separating the pigments. You
can extract most flower pigments with rubbing alcohol, and use filter paper
strips (coffee filter paper should work) to separate them. I don't know
how old your daughter is, but projects like this can give a child a lasting
interest in science and technology.
Alan Justice
"Beverly Erlebacher" <b...@cs.toronto.edu> wrote in message
news:2001May12.1...@jarvis.cs.toronto.edu...<snip>
> Btw, the technique of chromatography was originally developed by someone
> who wanted to investigate flower colors by separating the pigments. You
> can extract most flower pigments with rubbing alcohol, and use filter
paper
> strips (coffee filter paper should work) to separate them. I don't know
> how old your daughter is, but projects like this can give a child a
lasting
> interest in science and technology.
>
Sounds like fun to me (and I'm in my 40's)!
-Alan Justice