aquatic plant chemicals

I am in fifth grade.
I am working on a science project on the chemicals in aquatic plants that
could affect the growth of bacteria.  The plants I  am studying are
Ludwigia, Hygrophilia, Anacharis, Anubias, Hornwort, and Java Fern.  I am
having trouble finding out what types of chemicals are in these plants that
would affect bacteria. I would appreciate any information.
Thank-you for your help.

Meghan McPhee