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Uses of plant hormones

Uses of plant hormones

Selective weedkillers

  • Artificial auxin is used as a selective weedkiller as it makes plants with broad leaves, like dandelions and daisies grow out of control and die.
  • This means plants with narrow leaves, such as wheat and grass, are unaffected. So farmers can kill all the weeds in a field of cereal crop without affecting their crop.

Rooting Powder

  • Synthetic auxins are used in rooting powders. Plant cuttings are dipped into this rooting powder which makes them develop roots quickly.
  • Large numbers can be grown of the same plants by using cuttings, compared with growing plants from seeds.

Seedless fruits

  • Some seedless fruits are produced using plant hormones. The flowers of the plant are sprayed with plant hormones so the fruit develops but the seeds do not.
  • In the case of fruits which are naturally seedless but small fruits (some varieties of grape), they are sprayed with gibberellins to increase their size.

Fruit ripening

  • Farmers make use of plant hormones as they naturally control the ripening of fruits. For example:
    • Plant hormones are sprayed onto fruit trees to stop the fruits falling off. As a result, the fruits get less damaged as they are not falling and also allow the fruit to get bigger.
    • Plant hormones can speed up the ripening of fruits. If sprayed on a fruit tree, all the fruit is ripened and picked in one go.
    • Plant hormones can ripen unripe fruit so when they reach the supermarket, they are in the ‘just ripe’ stage.