3.2 Plant defence responses

Physical defence responses

• Cellulose cell walls.
• Tough waxy cuticle on leaves.
• Layers of dead cells around stems (bark on trees) which fall off.

Chemical plant defence responses.

• Antibacterial chemicals
• Poisons to deter herbivores.

Mechanical adaptations

• Thorns and hairs deter animals.
• Leaves which droop or curl when touched.
• Mimicry to trick animals.

how do physical defences prevent infections

create a barrier to resist microorganisms