A plant hormone that promotes stem and
root growth in plants.  Auxins influence many
aspects of plant growth and development,
including cell enlargement, inhibition of
development of axillary buds, tropisms, and
the initiation of roots.  Synthetic auxins
are used in rooting powders for cuttings, and
in some weedkillers, where the high
concentrations cause such rapid growth that
the plants die. They are also used to prevent
premature fruit-drop in orchards.  The most
common naturally occuring auxin is known as
indoleacetic acid, or IAA.  It is synthesized
in the shoot apex and transported to other
parts of the plant.

Subject by: Russell Webb