Auxin (pronounced Ox Inn)
Auxin is a hormone that controls growth by stimulating or restricting growth in plant cells. Auxin in shoots stimulates growth but has the opposite effect in roots.
Auxin - Stimulates in the Shoots and
Restricts in the Roots
The start letters S and R help you remember which is which.
Auxin (pronounced Ox Inn) – Growth hormone
The Ox ingested (auxin) too much growth hormone.
In a shoot
The shaded side contains more auxin and grows longer, causing the shoot to bend towards the light.
In a root
If a root is placed horizontally, the bottom contains more auxin than the top side. This makes the bottom side of the root grow less than the top side, causing the root to bend in the direction of gravity. This is the opposite of auxin in the shoot.