Plant Hormones Flashcards
Why are gibberellins important?
They initiate seed germination
Why is ethene important?
Controls cell division and RIPENING of FRUITS
What are tropisms?
Tropisms are a directional growth response, triggered by a stimulus
Why do plants respond to stimuli?
- Avoid stress
- Avoid being eaten
- Enhance survival
- Improve chances of having offspring
What controls growth in plants?
Hormones
What are 3 examples in a plant whose growth is affected by hormones?
- Roots and shoots
- Seed germination
- Fruit ripening
What are the 4 tropisms in plants?
- Phototropism
- Gravitropism
- Chemotropism
- Hydrotropism
What is phototropism?
Where plants grow in direction of light
What is gravitropism?
Where plant ROOTS grow in direction of gravity pull
What is chemotropism?
Where plant roots grow towards the chemicals in the ground
What is hydrotropism?
Where roots grow towards WATER
What is auxin?
- Auxin is a plant hormone which promotes growth in plants
- Found in both roots and shoots of plants
How does auxin work in the shoots?
- Sunlight breaks down auxin on side with higher light intensity
- So there is more auxin on shaded side
- Auxin in shoots causes INCREASED growth
- So the shaded side with more auxin GROWS FASTER than the side in direct sunlight
- So the plant leans and grows in direction of sunlight (phototropism)
How do auxins work in the roots?
- In the roots, auxins accumulate on the darker side
- However the hormone causes a decrease in growth
- Meaning the side with the MOST direct sunlight bends downwards
- And root grows downwards (gravitropism)
How can ethene be used in the farming industry?
Ethene can be used to control the ripening times of fruits
