Why plants use 400-700 nm

Wed Oct 1 15:59:15 EST 1997

The question that Joe Berry raised as to why plants are pretty much restricted
to 400-700 nm is one that I ask my biology students, but I broaden it to includ
e animals. The eye uses essentially the same small region of the electromagneti
c spectrum.  My answer would be similar to Winslow Briggs:too much photochemist
ry at short wavelengths and too little at longer wavelengths.  However, I wonde
r if Chl's restricted range is that much of a problem. Chl does absorb, althoug
h poorly, in the green and many plants exist in canopy situations. This means t
hat in a closed canopy I understand that over 90% of the photons in the 400-700
 nm region can be absorbed.  If this is so, the antenna pigments are doing a pr
etty good job.  Or am I being naive?

George Bowes
Dept Botany, University of Florida
Gainesville, Fl 32611

Tel +1 352 392 7919    Fax:  +1 352 392 3993

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