auxin
/ˈɔksɪn/
noun
- A plant hormone that controls growth, especially by making cells longer. It helps plants grow toward light and roots grow downward.
- Gardeners sometimes use synthetic auxin to help cuttings develop roots.
- When the tip of a plant is cut off, the flow of auxin is disrupted and growth changes.
- Auxin is responsible for the way a plant bends toward the sun.