GCSE BIOLOGY - Plant Structures and their Functions 6.4.2

• Plant hormones can be extracted or artificially made and used by gardeners and farmers in horticulture and agriculture to control plant growth for larger yields
• The use of auxins, ethene, and gibberellins commercially has been beneficial in producing food and plants for decoration
• Everyday use of hormones as weed killers can negatively affect biodiversity by inhibiting the growth of natural plants like weeds, which serve as food sources and habitats for other organisms
• Auxins:

  • Can be used as selective weed killers, negatively affecting the growth of broad-leaved plants (weeds) compared to narrow-leaved grasses and cereals grown as crops
  • Control the growth of weeds to prevent competition with crops for space and nutrients
  • Once applied to a crop, their spread cannot be controlled and may negatively affect other plant species
  • Used by gardeners and farmers to produce clones of desirable plants by taking cuttings and dipping the tips in auxins ('rooting powders') to encourage root development
  • Used in tissue culture to promote growth in cloned plants
• Ethene:

  • Used in the food industry to control ripening of fruit during storage and transport
  • Inhibiting ethene production can delay fruit ripening, preventing damage and spoilage
  • Ethene gas can be released to speed up ripening when needed, such as in supermarkets
• Gibberellins:

  • End seed dormancy by promoting germination
  • Promote flowering regardless of weather conditions
  • Increase fruit size by promoting development and growth
  • Produce seedless fruit by applying gibberellins to unpollinated flowers