4.3.3.2 Plant defence responses

What are the plant defence response types?

Physical, chemical, mechanical

Why do plants have physical defences?

To prevent the invasion of microorganisms

Why do plants have chemical defences?

To deter predators or kill bacteria

What physical defences do plants have?

Tough waxy layer stops entry into leaves, cellulose cell walls form a physical barrier into the cells, plants have layers of dead cells around stems which stop pathogens entering

What chemical defences do plants have?

Poisons that deter herbivores, antibacterial compounds kill bacteria such as mint plant and witch hazel

What mechanical defences do plants have?

Thorns and hairs make it difficult and painful for animals to eat them, some leaves can droop or curl when touch which allows them to move away and move insects off their leaves, they have a mimicry to trick animals