3.3.2 Plant Defence Responses

What is the role of a plant's waxy cuticle in defence?

It acts as a physical barrier to stop microorganisms entering the leaves.

How do cellulose cell walls defend against pathogens?

They form a physical barrier into the cells, preventing invasion.

What are chemical defences in plants?

Poisons from plants like foxgloves, tobacco plants, deadly nightshades and yew deter herbivores, while antibacterial compounds such as mint and witch hazel kill bacteria.

What are mechanical defences in plants?

Thorns and hairs make it painful for animals to eat them, some leaves droop or curl when touched to move insects away, and some plants use mimicry to trick animals.

How does mimicry protect plants?

Some plants droop to look unhealthy so animals avoid them, others have patterns that resemble butterfly eggs to deter egg-laying, and species like the ice plant family mimic stones or pebbles to avoid predation.