Commercial uses of plant hormonesSpec 6.16B
In short
Plant hormones are used commercially to control how plants grow. Auxins are used as selective weedkillers, which make broad-leaved weeds grow uncontrollably, and in rooting powders for cuttings. Gibberellins end seed dormancy, make flowers and fruits develop and produce seedless fruit. Ethene is used to ripen fruit that was picked unripe for transport.
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 |
Learn every use in the table: two for auxins, three for gibberellins and one for ethene. A good answer states the hormone, the use and the effect.
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.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026