Plant hormones

Auxin

• Used in weed killer
• rooting powder
• tissue culture

Roots

• In roots auxin causes less growth thus inhibits growth
• Auxin accumulates on lower side of root
• Cells on lower side grows less and cells on upper side grow more
• Root bends in direction of gravity to get more water/nutrients

Shoots

• In shoots auxin causes more growth
• Area that is more shaded will have more auxin so will grow more than the non-shaded side
• This causes shoot to bend towards the light