5.4.2: Use of plant hormones (HT only)
Not started yet — this one needs some love.
Plant growth hormones are used in agriculture and horticulture.
Auxins are used to:
act as weed killers
work as rooting powders
promote growth in tissue culture
Ethene is used in the food industry to control fruit ripening during storage and transport.
Gibberellins can:
end seed dormancy
promote flowering
increase fruit size
Hormone weedkillers can affect biodiversity because they change which plant species survive.
Common exam mistakes
Do not confuse commercial hormone uses: auxins for weed killers, rooting powders and tissue culture; ethene for fruit ripening; gibberellins for dormancy, flowering and fruit size.
Herbicides kill plants or weeds, not insects, bacteria or herbivores.
Ethene is linked to fruit ripening, not seed germination.
Gibberellins end seed dormancy; do not give this as an auxin use.
If asked about weed killers and biodiversity, link the loss of plant species to effects on food chains or habitats.