Chlorophyll Fluorescence
    Plant chlorophyll fluorescence technology was developed in the 1990s. The 
    variation in fluorescence can be shown by false color images or as numerical 
    values  from  the  photochemical  reaction  kinetics  (quantum  yield, 
    fluorescence decline, non-photosynthetic quenching).
   Chlorophyll Fluorescence
     Photosynthesis  belongs  to  ones  of  the  oldest  photo-physical and biochemical 
     processes on Earth. A  large progress in the research of photosynthesizing  organisms 
     was achieved at the end of 20th century by  the   introduction of modern optical 
     methods and techniques allowing to study photosynthetic processes ranging from the 
     subcellular up to the plant canopy level.
    Chlorophyll (Chl) fluorescence: 
    These techniques appeared to be a very powerful tool for studying of photochemical and 
    non-photochemical processes within thylakoid membranes, chloroplasts, plant tissues, or 
    whole plants.
         Chlorophyll Fluorescence
          Photosynthesis is the primary process by which plants synthesize food and maintain energy. As 
             part  of  that  process  some  energy  is  released  as  light  or  fluorescence,  commonly  in  the 
             chlorophyll pigment areas in the leaf. 
          This chlorophyll fluorescence can be measured using the Chlorophyll Fluorescence meter to 
             provide an inside look at the efficiency of the photosynthetic process or its disruption due to 
             stress related factors.
          Applications:
         •   Photosynthesis research
         •   Plant ecology
         •   Stress physiology
         •   Terrestrial / aquatic plants
         •   Information from whole leaf to single cells
         •   Detecting phytotoxic compounds
    Chlorophyll fluorescence measurements in plants
    by : J. Leipner
      Light energy that is absorbed by chlorophyll in a leaf can undergo three 
       fates: 
     a) It can be used to drive photosynthesis (photochemistry). 
     b) It can be dissipated as heat. 
     c) It can be re-emitted as red fluorescence.
      
    Absorption and emission spectrum of 
    chlorophyll
   Chlorophyll fluorescence measurements in plants
   by : J. Leipner
    These three process occur in competition. 
    Any increase in the efficiency of one process will result in a decrease in the 
    yield of the other two. 
    Therefore, determining the yield of chlorophyll fluorescence will give 
    information about changes in the efficiency of photochemistry and heat 
    dissipation.
    
                Possible fates of excited chlorophyll