Why are aquatic plants placed both the reacted and unreacted phenol solution?

Aquatic plants are placed in both reacted and unreacted phenol solutions to assess their ability to tolerate or bioaccumulate phenolic compounds. This comparison helps researchers evaluate the impact of phenols on plant health and growth, as well as the potential for using these plants in bioremediation processes. By observing the differences in plant responses, scientists can better understand how phenol pollution affects aquatic ecosystems.