B1 Control in plants Flashcards
How do plants respond to gravity?
shoots grow against the force of gravity.
roots grow in the direction of the force of gravity.
What is the name of the “action of plant response to gravity”?
Gravitropism/geotropism.
How do plants respond to light?
Their shoots grow towards light.
How do plants respond to moisture?
Their roots grow towards moisture.
What is the name of the “action of plant response to light”?
Phototropism.
What is auxin?
A hormone that controls phototropism + gravitropism
What are “the responses of plant roots and shoots to light, gravity and moisture” caused by?
Unequal distribution of hormones.
What does unequal distribution or hormones cause?
Unequal growth rates.
What are “plant growth hormones” used in agriculture and horticulture as?
Weed killers and rooting hormones.
Explain how shoot X bends towards light as it grew
OR
Describe phototropism
unequal distribution of auxin
more hormones on dark side
causes growth on dark side
Where is the detection of light stimulus?
tip
Where in the shoot the response to light takes place?
behind tip
Describe gravitropism (stem)
redistribution of auxin on lower side of stem
stimulate growth on lower side
stem grows upwards
Gravitropism (roots)
Uneven distribution/redistribution auxin on lower side of roots
lower side of roots grow less quick
roots grows downwards
What are plants sensitive to?
Light, moisture, gravity
