"Victor M. Martinez" wrote in message
...

Can someone please explain to me exactly what redox is and how it relates
to
plants?

In a redox chemical reaction there is an exchange of electrons...

But I have no idea how this relates to aquatic plant keeping.

I'm not a chemist either, but as I remember, redox potential has a lot to do
with plant biochemistry.
There is such a term as "redox potential of aquarium water (substrate?)"
which concerns the rate of oxydation - the more unoxidyzed organic residues
are in the tank (the "older" the tank is), the less redox it has.
Different plants (not only higher ones, algae also) prefer different levels
of redox. For example, most fast growing stem plants prefer high levels,
echinodoruses - medium, cryptocorines - low. For algae this continuity looks
like following: blue green red brown. That is the order in which this
ones would flourish in the tank whilst it becomes "older", of course if the
tank owner won't interfere the natural processes with continuous water
changes, substrate syphoning and fertilization.
--
~SP~