Which method describes the movement of herbicides through a plant's vascular system?

The movement of herbicides through a plant's vascular system is best described by translocation. This term specifically refers to the process by which substances, such as nutrients or chemicals, are transported within the plant's vascular tissues. In the case of herbicides, once absorbed by the plant, they move through the xylem and phloem, effectively reaching various parts of the plant, including leaves, stems, and roots. This system allows for a widespread distribution of the herbicide, ultimately enhancing its effectiveness in controlling unwanted vegetation.

In contrast, absorption refers to the initial uptake of herbicides through plant tissues, which is the first step before translocation occurs. Contact describes a method where the pest or weed is affected by direct contact with the herbicide, impacting only the area where the herbicide lands. Retention involves how well a herbicide stays on the plant surface after application, which affects its effectiveness but does not address its movement within the plant.