How does 2,4-D move within plant tissue to exert its effect?

• A. It moves to reproducing areas of roots, stems, and leaves and causes unsustainable growth
• B. It stays only at site of application
• C. It moves to old leaves
• D. It remains in the root

Answer: (A)

2,4-D is a systemic herbicide, meaning it moves within the plant after absorption. It travels through the phloem to actively growing tissues—root tips, shoot tips, and developing leaves. There, it acts as an auxin mimic, triggering uncontrolled, abnormal growth that damages meristematic cells and eventually kills the plant. This mobility explains why the herbicide doesn’t stay at the application site or only affect old tissues; it targets new growth points throughout the plant.