Auxin

• Auxins are useful for controlling plant growth
• Killing weeds:

  • more weeds growing in fields of crops or in a lawn are broad-leaved, in contrast to grasses and cereals which have very narrow leaves
  • selective weedkillers have been developed using auxins, which only affect the broad-leaved plants
  • they totally disrupt their normal growth patterns, which soon kills them, whilst leaving the grass and crops untouched
• Growing from cuttings with rooting powder:

  • a cutting is part of a plant that has been cut off it, like the end of a branch with a few leaves on it
  • normally, if you stick cutting in the soil they won't grow, but if you add rooting powder, which contains auxins, they will produce roots rapidly and start growing as new plants
  • this enables growers to produce lots of clones of a really good plant very quickly
• Growing cells in tissue culture:

  • tissue culture can be used to grow clones of a plant from a few of its cells
  • to do this, hormones such as auxins need to be added to the growth medium (along with nutrients) to stimulate the cells to divide to form both roots and shoots