There are 3 known mechanisms by which plants develop resistance to herbicides. The first and most common mechanism is an altered site of action. Most herbicides have a specific site of action in the plant and any change in this site will cause the herbicide to be inactive (more information in slide 5). The second mechanism is enhanced metabolism. Simply put, enhanced metabolism means that the plants have the natural ability to degrade or metabolize the herbicide into a non-active compound. The third and least common mechanism for resistance is called sequestration. With sequestration, the plant has the ability to prevent the herbicide from reaching its site of action by limiting its movement. This mechanism is also called compartmentalization.