Commercial uses of plant hormones

• How can auxins be used in farming?

  • Sprayed onto developing fruits to prevent abscission
  • Sprayed onto flowers to initiate fruit growth without fertilisation
  • applied to the cut end of the shoot to stimulate root production
  • Synthetic auxins are used as selective herbicides
  • can be used for the production of seedless fruit
• What are gibberellins mainly used for in farming or manufacture?

  • Seed germination
  • delay ripening and aging
  • improving the size and shape of fruits
  • speed up the malting process in beer brewing
• State the role of cytokinins in farming and manufacture of plants

  • Delay leaf senescence- can be sprayed on lettuce leaves to prevent them from yellowing
  • Can be used in tissue culture to mass produce plants
• State the role of ethene in farming and manufacture

  Promotes fruit ripening
• what do rooting powders contain and how are they used in micropropagation?

  • auxins- affect the growth of roots and shoots
  • used to propagate new plants from plant cuttings
  • rooting powder increases the chances of roots forming and successful propagation
• what are cuttings?

  • small pieces of the stem of a plant, usually with some leaves on.
  • When placed in the soil, roots may appear and a new plant forms.
  • Dipping this cutting into rooting powder increases the chance of it developing roots
  • used in horticulture and agriculture
• how do weeds affect the growth of plants?

  competition- they compete for light, space, water and minerals
• how are hormones used as weedkillers and how do weedkillers work?

  • synthetic auxins used as weedkillers
  • most weeds are broad leaved dicots
  • if these auxin containing weedkillers are applied to the dicots, they are absorbed by the leaves and affect the metabolism of the weeds
  • the growth rate increases and becomes unsustainable- so they die.
  • narrow leaved plants aren't affected and continue to grow normally, free from competition
• what are the advantages of using weedkillers containing synthetic auxins?

  • simple and cheap to produce
  • low toxicity to animals
  • selective