B1 AQA - human biology plant hormones

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  • Plant hormones
    • Auxin
      • Auxins a plant hormone
        • Auxin is a plant hormone that controls groth near the tips of shoots and roots
        • Controls growth of plant in response to ,,,
          • Light ( Phototropism)
          • Gravity ( gravitropism or geotropism)
          • Moisture
        • Ausin produced in tips, moves backwards to stimulate cell elongation (enlargement process) that occors in cells behind tips.
        • If tip of shoot removed, no auxin produced so shoot may stop growth.
        • Extra auxin promotes growth in shoot inhibits growth in shoot- produce desired result
      • shoot grows towards light
        • when shoot tip exposed to light, more auxin on side thats in shade
        • Makes cells grow (elongates) faster on shaded side, so shoot bends towards the light.
      • Shoot grow away from gravity
        • when shoot growing sideways, gravity produces equal distribution in tip, with more auxin on lower side.
        • Causes lower side to grow faster, bending the shoot upwards.
      • Roots grow towards gravity
        • Root growing sideways have more auxin on lower side.
        • In root the extra auxin inhibits growth, that means cells ontop elongate faster, root bends downwards.
      • Roots grow towards moisture.
        • An uneven amount of moisture either side of root produces more auxin on side with more moisture.
        • Inhibits growth on that side cause root to bend in that direction towards the moisture .
    • Uses in agriculture
      • plant hormones can be extracted + used by people or artificial versions can be made - useful
      • Weeds in crop feilds broad-leaved, unlike grass + cereals have narrow leaves
        • slelective weedkillers made from plant growth hormones
        • Only affect broad leaved plants
          • Disrupt normal growth patterns , soonb kills  them but leaves crops untoched.
      • plant cuttings wont always grow in soil. Add rooting powder, contains auxin, they'll produce roots rapidly + start growing as new plants
        • helps growers produce lots of clones of really good plants very quickly.
  • Auxin
    • Auxins a plant hormone
      • Auxin is a plant hormone that controls groth near the tips of shoots and roots
      • Controls growth of plant in response to ,,,
        • Light ( Phototropism)
        • Gravity ( gravitropism or geotropism)
        • Moisture
      • Ausin produced in tips, moves backwards to stimulate cell elongation (enlargement process) that occors in cells behind tips.
      • If tip of shoot removed, no auxin produced so shoot may stop growth.
      • Extra auxin promotes growth in shoot inhibits growth in shoot- produce desired result
    • shoot grows towards light
      • when shoot tip exposed to light, more auxin on side thats in shade
      • Makes cells grow (elongates) faster on shaded side, so shoot bends towards the light.
    • Shoot grow away from gravity
      • when shoot growing sideways, gravity produces equal distribution in tip, with more auxin on lower side.
      • Causes lower side to grow faster, bending the shoot upwards.
    • Roots grow towards gravity
      • Root growing sideways have more auxin on lower side.
      • In root the extra auxin inhibits growth, that means cells ontop elongate faster, root bends downwards.
    • Roots grow towards moisture.
      • An uneven amount of moisture either side of root produces more auxin on side with more moisture.
      • Inhibits growth on that side cause root to bend in that direction towards the moisture .

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