Uses of plant hormonesSpec 4.5.4.2
In short
Plant hormones are used in agriculture and horticulture to control plant growth. Auxins are used as weed killers, as rooting powders and to promote growth in tissue culture. Ethene is used to control the ripening of fruit during storage and transport. Gibberellins are used to end seed dormancy, promote flowering and increase fruit size.
Plant growth hormones are used in agriculture and horticulture to control plant growth.
| Hormone | Use |
|---|---|
| Auxins | As weed killers; as rooting powders; for promoting growth in tissue culture |
| Ethene | In the food industry to control ripening of fruit during storage and transport |
| Gibberellins | To end seed dormancy; to promote flowering; to increase fruit size |
Using hormones as weed killers can affect biodiversity. Killing weeds helps the crop grow, but it also reduces the number of other plant species in the area, and so the animals that depend on them.
Match the hormone to its use: auxin for weed killer, rooting powder and tissue culture; ethene for ripening; gibberellins for dormancy, flowering and fruit size.
Quick check
Which hormone causes unequal growth in roots and shoots?
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Auxin.
Why does a shoot bend towards light?
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Auxin builds up on the shaded side, so cells there grow more and the shoot bends towards the light.
What do the terms phototropism and gravitropism mean?
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Phototropism is a growth response to light. Gravitropism (geotropism) is a growth response to gravity.
Higher tier Name one use of gibberellins.
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Any one of: ending seed dormancy, promoting flowering, increasing fruit size.
Written and checked against the AQA GCSE Biology (8461) specification · Updated October 2026