plant hormones

auxin controls plant growth in response to

phototropism and gravitropism

auxin controls growth at the

tips of roots and shoots of a plant

auxin gets produced in … and moves to..

tips and moves backward to stimulate cell elongation

if a tip of a shoot is removed

no auxin is produced and the shoot may stop growing

extra auxin promotes… but inhibits…

shoot growth / root growth

shoots grow towards light how

shoot exposed to light

more auxin accumulates on shaded side causing that side to elongate and grow faster- as light causes it to accumulate there

the shoot curves up maximising photosynthesis

shoot grows away from gravity how

due to gravity auxin is unequally distributed more on lower side

this causes lower side to elongate faster and curve up

root grows towards gravity how

again unequal distribution causes more auxin on lower side

but extra auxin inhibits root growth

the top will elongate faster causing curve down

gibberellins

starting germination of seeds

ethene

controls cell division and ripening of fruit