What happens at lightsaturation ?

Shayde Hayes assah2 at uaa.alaska.edu
Tue Dec 22 22:00:10 EST 1998


I'm not sure I understand what exactly it is you are doing.  I presume you
are studying the growth of plants, as this is bionet.plants.

What kind of plants will you be growing?  C3?
What will be your source of radiant energy?  Our sun?  or HID lights?
If you will be using HID lights, what is the PAR (photosynthetically active
radiation) of your source?  Equal wattage high pressure sodium and metal
halide have different PAR outputs.  Or will you be using fusion sulpher?
Will you be measuring in microEinsteins (PAR), lumens, foot-candles?  I
suggest microEinsteins.

As to surplus radiant energy.  Quite obviously (it seems), it will "bounce
around" depending on what kind of environment your light source is in.  Will
you be surrounding your target plants with Mylar?  Fabrifoil?  Tinfoil?
Flat white paint?  Different surfaces have different reflective properties.

Surplus radiant energy will all eventually change form, i.e. transform into
heat, or be absorbed by phytochromes.

I think a lot of your experiment will depend on the accuracy of your light
measuring instruments.  You absolutely must have an acurate spectrometer to
measure light at different wavelengths, especially if you plan to use an
artificial light source. Try:

Good Luck.


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