Commercial uses of plant hormonesSpec 6.16B
Growers and farmers use plant hormones, or chemicals that act like them, to control how plants grow.
| Hormone | Use | Effect |
|---|---|---|
| Auxins | Weedkillers | Selective weedkillers make broad-leaved weeds grow too fast and uncontrollably, which kills them. Narrow-leaved crops such as cereals are not affected. |
| Auxins | Rooting powders | Cuttings dipped in the powder grow roots quickly, so new plants can be produced |
| Gibberellins | Germination | Used to end seed dormancy and make seeds germinate |
| Gibberellins | Fruit and flower formation | Used to make flowers and fruits develop |
| Gibberellins | Seedless fruit | Fruits form without being fertilised, so they contain no seeds |
| Ethene | Fruit ripening | Unripe fruit is picked, transported, and then ripened using ethene when it is needed |
Quick check
What is a tropism?
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A growth response of a plant to a stimulus.
Which hormone is involved in phototropism and gravitropism?
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Auxin.
Why does a shoot bend towards light?
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Auxin moves to the shaded side and makes those cells elongate more, so that side grows faster.
Are roots positively or negatively gravitropic?
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Positively gravitropic: they grow downwards, in the direction of gravity.