B1 - Controlling plant growth Flashcards Preview

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Flashcards in B1 - Controlling plant growth Deck (18):

What processes do plant hormones control?

- growth of shoots towards light
- growth of roots downwards
- growth of flowers
- ripening of fruits


Do plant shoots grow towards or away from light?

Plant shoots grow towards light.


Which part of the plant responds to the force of gravity by growing downwards?

The roots.


What are the two responses to a stimuli?

- negative: the plant grows away from a stimulus
- positive: the plant grows towards a stimulus


Where is auxin made?

Auxin is made in the tips of roots and shoots of a plant.


What is phototropism?

Phototropism is when a plant responds to light.


What is geotropism?

Geotropism is when a plant responds to gravity.


What is negative phototropism?

Negative phototropism is when the roots grow away from light.


What is positive phototropism?

Positive phototropism is when plant shoots grow towards light.


What is positive geotropism?

Positive geotropism is when plant roots grow with the pull of gravity.


What is negative geotropism?

Negative geotropism is when plant shoots grow away from the pull of gravity.


Why does the removal of the tip stop the plant growing?

It gets rid of auxin which is needed for plant growth.


Suggest why farmers need to slow down the growth of fruit on their trees.

This is because it stops the fruit from falling off the tree before the harvest.


What are selective weedkillers?

Selective weedkillers contain synthetic auxin and only kill certain weeds.


How do selective weedkillers work?

These work by making the weeds grow too fast so that they die.


How does synthetic auxin help farmers to grow roots?

This works by taking cuttings from existing plants and dipping them in auxin where the powder stimulates the roots to grow.


What is gibberellic acid?

Gibberellic acid is a hormone found in plants that causes seeds to germinate.


Bananas are picked when they are green, but when we buy them they are yellow and ripe. Why is this?

This is because they are sprayed with ethene which causes them to ripen while they are being transported.