3.3.2 Plant Defence Responses

• What is a physical defence?

  A defence that physically prevents the entry of pathogens.
• What is a chemical defence?

  Chemicals that plants can secrete to destroy pathogens.
• What is a mechanical defence?

  Structures that reduce the chance of being attacked.
• What are some examples of physical plant defences?

  • Strong cellulose cell walls.
  • Layers of dead cells around the trunk (bark).
  • A waxy cuticle on the leaves and stems.
• What are some examples of chemical plant defences?

  Production of antimicrobial substances & production of poisons that kill insects.
• What are some examples of mechanical plant defences?

  • Hairs and thorns.
  • Leaves that curl or droop when insects land on them.
  • Mimicking other organisms to trick animals.