Growth inhibitors Flashcards
Define a growth inhibitor
A growth inhibitor is a chemical that causes a reduction in growth of plants
GIve two examples of growth inhibitors
Ethene and abscisic acid are examples of growth inhibitors in plants
What is ethene also known as?
formerly called ethylene
What is the only growth regulator that is a gas?
Ethene (formerly called ethylene) is the only growth regulator that is a gas.
Where is ethene made in a plant?
It is made by plants in stem nodes, ripe fruits and decaying leaves.
List the functions of ethene (5)
The functions of ethene include:
1. Ripening fruits
2. Causing fruit colour to form, fruit flavour to develop and fruit tissues to soften
3. Stimulating leaves to fall in autumn
4. Ageing of plants
5. Stimulating more ethene production (.e. ethene stimulates more ethene).
What is ethene used commercially to do?
Ethene is used commercially to ripen bananas.
When are bananas harvested?
Bananas are harvested while they are still green and are exported to consumer countries.
Why are bananas exposed to ethene?
They are exposed to ethene to stimulate ripening (i.e. they turn yellow and soften) just before distribution to shops
Where is abscisic acid produced in a plant?
Abscisic acid is produced in leaves, stems and root caps.
What is abscisic acid often called?
It is often called the stress regulator of plants.
What are the functions of abscisic acid? (4)
The functions of abscisic acid include:
1. Causing plants to respond to harmful conditions
2. Causing stomata to close in dry conditions (to retain water)
3. Causing the production of bud scales, which protect the buds in winter
4. Inhibiting seed germination, which allows the seeds to remain dormant in the sol during winter.
What causes leaf fall (abscission) in autumn?
Although it was thought that abscisic acid caused leaf fall (abscission) in autumn, this is now known to be caused by ethene (in combination with auxins).
what is abscission?
leaf fall in autumn
What is leaf fall in autumn called scientifically?
abscission
