Auxin
AWK-sin🔬 Anatomy●● Intermediate
Also known as: growth hormone, IAA
Auxins are the master growth hormones of plants, controlling directional growth toward light (phototropism), stimulating root formation on cuttings, and maintaining apical dominance. Synthetic auxins like IBA and NAA are the active ingredients in rooting hormones. When the apical bud is removed (pinching), auxin flow is disrupted, triggering lateral branching.
Etymology
Greek auxein meaning to grow