Herbicides can be classified based on their mode of action. For example: - Contact Herbicides: These affect only the tissues they come into contact with. Under the microscope, tissue necrosis is evident in the treated areas. - Systemic Herbicides: These are absorbed and transported throughout the plant. Histological examination can show disruptions in vascular tissues, such as the phloem and xylem, which are crucial for nutrient and water transport.
