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David Hershey dh321 at excite.com
Tue Nov 30 21:54:54 EST 1999

That site gives the standard chlorophyll absorption spectrum showing
absorption peaks in the red and blue wavelengths. However, that is for
chlorophyll extracted from leaves in a test tube of organic solvent such
as acetone. The photosynthesis action spectrum for an intact leaf shows
much smaller peaks in the red and blue and shows that 60%-plus of the
green and yellow wavelengths are used in photosynthesis. The text 'Plant
Physiology' by Salisbury and Ross explains that the greater use of green
and yellow wavelengths in an intact leaf is due to the complex geometry
which repeatedly reflects the green or yellow photons if a chlorphyll
molecule does not absorb them. That gives the chlorophyll repeated
chances to absorb them and increases the overall rate of absorption over
that seen in a test tube of chlorophyll extract. Thus, the low rate of
yellow and green absorption by a chlorophyll extract is not
representative of the behavior in an intact leaf.

David Hershey
dh321 at excite.com

Stephen M Jankalski wrote:
> Ahoy there! How are the rest of the Argonauts?
> The answer to your question can be found here.
> http://photoscience.la.asu.edu/photosyn/education/photointro.html
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> Jason H <chunky at wantree.com.au> wrote in article
> <8200ij$lr1$1 at centipede.wantree.com.au>...
> > Hi.
> >
> > I was curious to know the wavelength(s) of the electromagnetic spectrum
> that
> > plants use in the photosynthesis?
> >
> > Thanks.
> >
> > Regards,
> > Jason.
> >
> >
> >

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