Ask A Scientist© Botany Archive

  
name        Karina
status      student
age         18

Question -  I'm brazilian. Sorry for my english, I don't know to speak
and to write in english. But I can to read, then you can to answer that
I know to understand.

My question: "Why havem't blue leafs?"
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Dear Karina,

Blue is possible:
http://www.sigmaxi.org/amsci/articles/97articles/Lee.html

Sincerely,

Anthony R. Brach, Ph.D.
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I think you mean why are there no blue leaves?  Plants get their energy for
food by the process of photosynthesis.  The chloroplasts in the leaves
contain pigments (colors) that absorb red and blue light and reflect green
and yellow light.  Since leaves depend on photosynthesis and since the blue
light is needed, then a plant would die without using the blue light.  So no
blue light is reflected and so you don't see any blue light coming from any
leaves.  Sometimes leaves are red, but underneath the red there is green.

Van Hoeck
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Hi Karina!
I am brazilian too and so it is an extra pleasure to answer to you.
And you write nicely in English.
The reason why there are no blue leaves is exactly because
all leaves (oh almost all) are green... And they are green
due to the presence of a green pigment named  chlorophyll.
The chlorophylls (there are 2 different types) have the most
important role for the vegetals and also for all the Earth,
the photosynthesis.
All free energy consumed by biological systems arises from
solar energy that is trapped by the process of photosynthesis.
The basic equation of photosynthesis is:
H2O + CO2  + light =  (CH2O) + O2

((CH2O) represents a carbohydrate)

Photosynthesis occurs in  green plants and its mechanism is quite
complex. The first step is the absortion of light by a chlorophyll molecule.
The energy is transferred from one chlorophyll to another until it
reaches a chlorophyll with special properties at a site called the reaction
center. There light is converted  into chemically useful energy at 2
kinds of reaction centers that are both required for photosynthesis to
happen.
I hope you followed well my (broken) english... if not ask again and
i'll try to put it in portuguese, OK?
And... it is a pity that so few brazilians know and use NEWTON...
Tell your friends..
Mabel
(Dr. Mabel Rodrigues).
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