Plant Respones Flashcards
Where is auxin located and what does it control
A plant hormone that controls the growth near the tips of the shoots and roots
It controls the growth of the plant in response to light (phototropism) and gravity (gravitropism)
What does Auxin stimulate ?
The cell elongation in the tip of shoots
Why do shoots grow towards the light ?
When a shoot tip is exposed to light more auxin accumilates on the side that is shaded .
This means that the distribution of Auxin is unequal on either side
The side with the plant now has less Auxin so cell elongation does not occur as much
However the shaded side has more of the hormone so more growth occurs making it bend towards the light
Why do shoots grow away from gravity ?
When a shoot grows sideways gravity causes an unequal distribution of auxin in the tip. With more Auxin in the lower side . This causes the shoot to bend upwards
Why do roots grow towards gravity ?
A root growing sideways will have more auxin on its lower side .
In a root extra auxin INHIBITS growth this means cells on top grow faster and bend downwards into the ground
What are Gibberellins?
hormones that initiate seed germination
What does ethene control ?
Cell division and ripening of fruit
Define tropism
A growth response of a plant in response to stimuli
What is Auxin used for in agriculture
Weed killers
Rooting powders
Promotion of growth in tissue cultures
What is ethene used for in agriculture
Used to control the ripening in fruit when it is in storage so it does not go out soon after being put in the shelves
What are Gibberellins used for in agriculture
End seed dormancy
Promote flowering
Increase fruit size
