Flashcards · Biology · Plant Disease
Plant Defence Responses
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What are the three groups of plant defences?
Physical, chemical and mechanical.
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Name a physical defence of a plant.
Cellulose cell walls, a waxy cuticle or layers of dead cells.
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How does the waxy cuticle protect a leaf?
It is a tough barrier that microorganisms cannot easily get through.
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How do layers of dead cells protect a stem?
They form a barrier, then fall off, taking pathogens with them.
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What is the bark of a tree made from?
Layers of dead cells.
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Name two chemical defences.
Antibacterial chemicals and poisons to deter herbivores.
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What is a herbivore?
An animal that eats plants.
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Name a mechanical adaptation.
Thorns, hairs, leaves that droop or curl, or mimicry.
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How do thorns protect a plant?
They deter animals from eating it.
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Why do some leaves curl when touched?
It makes them harder to eat, and may scare animals away.
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What is mimicry in plants?
A plant looks like something else, to trick animals.
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Give an example of plant mimicry.
A passion flower leaf has markings that look like butterfly eggs, so butterflies avoid laying eggs on it.
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Why do plants need defences?
They cannot move away from pathogens or animals that eat them.
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Which defence stops microorganisms entering through the leaf surface?
The waxy cuticle.
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Are plant cell walls made of cellulose?
Yes.
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Name the type of defence marked X and say how it protects the plant. A mechanical adaptation, thorns. They deter animals from eating the plant.
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Label the three types of plant defence and each example. 
Physical: cellulose cell wall, waxy cuticle, dead cells (bark). Chemical: antibacterial chemicals, poisons. Mechanical: thorns, hairs, leaves that curl.