From: nospam@sonic.net   
      
   sgoptics wrote:   
   >   
   > We are planning experiments with plant leaves.   
   > We'ld like to begin in the lab, rather than in a greenhouse.   
   > Therefore, we need a paint with optical reflectivity very similar to   
   fhlorophyll, including in the NIR   
   > Any idea?   
      
   Green paint?  Chlorophyll absorbs rather strongly   
   across the visible spectrum except for a notch   
   in the green.  I once took a course which included   
   a few lectures from Ephriam Racker, who did a lot   
   of the early research on _Halobacterium_halobium_,   
   a photosynthetic bacterium that lives in the Dead Sea.   
   Its photosensitive pigment is bacteriorhodopsin,   
   which absorbs strongly in a narrow band right on   
   top of the notch in the chlorophyll absorbance   
   spectrum.  He had a hypothesis that the precursor   
   of the chloroplast arose in the presence of   
   _H._halobium_, so it used the light that was left   
   over.   
      
   > alternatively, how fcan we preserve leavs so that the reflectivity will be   
   almost unchanged.   
      
   That probably won't work.  Dead leaves bleach   
   pretty quickly.  The problem is that chlorophyll   
   converts light energy into chemically reactive   
   molecules.  If you don't provide a sink for that   
   chemical energy, they'll just tear stuff apart.   
      
   Paints used for military camouflage might be best.   
   If their reflectance didn't match foliage, you   
   could use filters to make them stand out against   
   foliage.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)