6.15B **Biology Only** - Plant Hormones and Growth Flashcards
(16 cards)
What do plants need to coordinate and control growth?
Plants need hormones to coordinate and control growth.
What are tropisms?
Tropisms are responses of plants to environmental stimuli.
What is phototropism?
Phototropism is the response of plants to light.
What is gravitropism (or geotropism)?
Gravitropism is the response of plants to gravity.
How do hormones move in plants?
Hormones move from the place they are made to where they are needed to produce the appropriate response.
What is auxin?
Auxin is a growth hormone that plays a key role in plant growth responses.
What is positive phototropism?
Positive phototropism is when most plants grow towards the light source.
What happens when a plant is exposed to light on one side?
Auxin moves to the shaded side of the shoot, stimulating cells to grow more there, causing the shoot to bend towards the light.
What is negative gravitropism?
Negative gravitropism is when most shoots grow away from gravity.
What happens when a shoot is horizontal?
Auxin moves to the lower side, stimulating cells to grow more on that side, causing the shoot to bend away from the ground.
What is positive gravitropism?
Positive gravitropism is when most roots grow towards gravity.
What happens when a root is horizontal?
Auxin moves to the lower side, stimulating cells to grow on the upper side, causing the root to bend downwards.
Why is positive gravitropism beneficial for roots?
It provides stability and increases the likelihood of accessing water and nutrients.
What happens when auxin distribution is equal on both sides?
The plant grows straight in that direction.
How can you investigate the effect of light on seedlings?
By placing them in a cardboard box and shining light from one side.
How can you investigate the effect of gravity on seedlings?
By attaching a petri dish containing the seedlings to a wall.
