Plant Hormones Flashcards
What is Auxin?
A plant growth hormone
Where is auxin found?
Near the tips of shoots and roots
What does auxin control the growth in response to?
Gravity (geotropism)
Light (phototropism)
Moisture
Where does the cell elongation process take place?
In the cells just behind the tips
What happens if the tip of a plant is removed?
No auxin is available so the shoot may stop growing
Why does the shoot grow towards the light?
When a shoot tip is exposed to light more auxin goes to the side in the shade to the shaded side grows and the shoot bends towards the light
Why do the shoots grow away from gravity?
When a shoot grows sideways gravity causes there to be move auxin on the lower side so the lower side grown faster and it grows upwards
Why do roots grow towards gravity?
A root growing sideways will have more auxin in its lower side. Extra auxin restrains growth in the root so cells on top grow faster causing the root to bend down
What happens when both shoots and roots have extra auxin?
Shoot- promotes growth
Roots- inhibits growth
Why do roots grow towards moisture?
If there is an uneven amount of moisture on either side of a root then the side with more moisture produces more auxin which inhibits growth causing the root to bend towards the moisture
Why are plant hormones used in agriculture?
Most weeds In crop fields are broad leaved whereas most crops have narrow leaves
Selective weed killers are made of plant growth hormones that only affect broad leaved plants
Is disrupts their growth patterns and kills them but Leaves crops untouched
Why is auxin useful when plant cuttings won’t grow?
You can add rooting powder (containing auxin) they’ll produce rapidly and start growing as new plants
This helps growers produce a lot of clones of a good plant very quickly
