Hi Charles,

Many of the pigments in plants and algae fluoresce. In particular -
chlorophyll. As a test for water quality, chloropyll fluorescence is
used to detect certain parameters. (Chlorophyll fluorescence detected,
must mean there is algae in the water). To see the fluorescence you
need to excite the pigment with the correct frequency of light. In
most cases, the amount of fluorescence is not easily detected by the
unaided eye. Instruments made to detect the fluorescence utilize photo
diodes, avalanche diodes and photo multiplyer devices (for extreme low
level detection). You can however use a filter set to allow the
fluoresced light frequence pass through while blocking other
frequencies thus enabling you to "see" it. You are probably most
familiar with UV or black light being the excitation source at
non-visable wavelengths and then seeing the fluoresced result at
visible wavelengths. Chlorophyll is excited by light in the visible
spectrum as well as many other pigments. You can look up the
excitation frequencies of these compounds and see for yourself. Many
may have a number of excitation wavelengths, some stronger than others.
I hope this is of help.

Larry T.

Charles wrote:
I've been reading a book about algae, several places it mentions
fluorescence from the accessory pigments.

what would be required to see this fluorescence? I have a microscope,
and believe I could get somewhat narrow band light using a light
source and a prism.