How Are Plant Hormones Used Commercially?

Plant hormones are used commercially to control plant growth and fruit ripening. In AQA GCSE Biology, the examples are auxins, ethene and gibberellins. This is Higher Tier, biology-only content, so this answer assumes you are studying separate GCSE Biology at Higher Tier.

How are auxins used?

Auxins are plant hormones involved in growth responses. Growers use them in three ways:

• Weed killers: auxins can be used to control unwanted plants.
• Rooting powders: these encourage cuttings to grow roots. A cutting is a piece taken from a parent plant to grow into a new plant.
• Tissue culture: auxins can promote growth when small groups of plant cells are grown to produce new plants.

For example, a gardener might apply rooting powder to a cutting before planting it. Encouraging root growth helps the cutting establish itself as a new plant. Tissue culture is another way to produce plants: it starts with small groups of cells rather than a cutting. In both cases, the commercial aim is to grow more plants with useful characteristics.

What about other plant hormones?

Ethene is used in the food industry to control when fruit ripens during storage and transport. Controlling ripening helps suppliers manage when fruit is ready for sale. Gibberellins can be used to end seed dormancy, promote flowering and increase fruit size. Seed dormancy is a period when a seed does not germinate; ending it allows germination to begin. Promoting flowering or increasing fruit size can also be useful to growers producing crops for sale.

The key is to link each hormone to its particular use, rather than simply saying that plant hormones make plants grow. An easy exam mistake is to give every use to auxins. Keep the examples distinct: auxins for weed killers, rooting powders and growth in tissue culture; ethene for fruit ripening; and gibberellins for seed dormancy, flowering and fruit size.