Soil-applied herbicides move upward in what plant tissue?

Soil-applied herbicides move upward in what plant tissue?

• A. Phloem
• B. Xylem
• C. Cortex
• D. Epidermis

Answer: (B)

Upward movement of soil-applied herbicides happens through the xylem, the plant tissue that transports water and dissolved minerals from the roots up to the shoots. When these herbicides are taken up by the roots, they ride along with the water pulled upward by transpiration, traveling through the xylem to the leaves and growing points. The phloem moves mainly sugars and other nutrients from sources to sinks and can carry substances in multiple directions, not just upward from the roots. Cortex and epidermis are protective or storage tissues and don’t serve as the long-distance transport highway for upward chemical movement.

Upward movement of soil-applied herbicides happens through the xylem, the plant tissue that transports water and dissolved minerals from the roots up to the shoots. When these herbicides are taken up by the roots, they ride along with the water pulled upward by transpiration, traveling through the xylem to the leaves and growing points. The phloem moves mainly sugars and other nutrients from sources to sinks and can carry substances in multiple directions, not just upward from the roots. Cortex and epidermis are protective or storage tissues and don’t serve as the long-distance transport highway for upward chemical movement.