New
New
Year 11
OCR
Foundation

Plant defences against disease

I can describe physical, chemical and mechanical plant defences against pathogens and pests.

New
New
Year 11
OCR
Foundation

Plant defences against disease

I can describe physical, chemical and mechanical plant defences against pathogens and pests.

Lesson details

Key learning points

  1. Plants can be infected by pathogens, such as viruses, bacteria and fungi, that cause diseases.
  2. Pests, including insects, can damage plants by feeding on them, and can spread pathogens that cause diseases.
  3. Plants have physical, chemical and mechanical defences against pathogens.
  4. Examples of physical, chemical and mechanical defences in plants.

Common misconception

Plants have no defence against pests or pathogens.

Plants have physical, chemical and mechanical defences against pathogens.

Keywords

  • Pathogen - A virus, bacterium or other microorganism that causes disease.

  • Pest - An insect or other animal that damages plants and can spread plant pathogens.

  • Waxy cuticle - Waterproof coating on the surface of a leaf.

  • Cell wall - Structure made of cellulose that surrounds plant cells.

  • Antimicrobial - A substance that kills microorganisms or stops their growth.

The lesson includes a video clip of the "sensitive plant" (Mimosa pudica) curling up, as an example of a mechanical defence. Demonstrating this effect in a real plant such as this one or any others that respond to touch can help to increase engagement and really bring the idea to life.
Teacher tip

Equipment

None required.

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Which of the following can be pathogens?
antibiotics
Correct answer: bacteria
Correct answer: fungi
Correct answer: viruses
plants
Q2.
Pathogens can causes disease in plants.
Correct answer: True
False
Q3.
The image below shows the cross section of a leaf. What is being shown by label A?
An image in a quiz
palisade mesophyll cells
chlorophyll
Correct answer: waxy cuticle
epidermal cells
spongy mesophyll cells
Q4.
Label this plant cell.
An image in a quiz
Correct Answer:A,cell wall

cell wall

Correct Answer:B,cell membrane

cell membrane

Correct Answer:C,chloroplast

chloroplast

Correct Answer:D,vacuole

vacuole

Q5.
What are plant cell walls made from?
Correct Answer: Cellulose, cellulose
Q6.
Which organism in this food chain is a herbivore?
An image in a quiz
oak leaf
Correct answer: aphid
ladybird
blue tit
wildcat
Q6 UYSEG

6 Questions

Q1.
Match the disease to the pathogen that causes it.
Correct Answer:TMV,virus

virus

Correct Answer:crown gall disease,bacteria

bacteria

Correct Answer:chalara ash dieback,fungus

fungus

Q2.
Which of the following are physical defences?
Correct answer: tree bark
production of poisons
Correct answer: waxy cuticle
Correct answer: cell wall
production of antimicrobial substances
Q3.
Insects can transfer pathogens.
Correct answer: True
False
Q4.
What substance in the phloem of a plant do some insects feed upon?
An image in a quiz
Correct Answer: sap, cell sap
Q5.
Which plants produce poisons that deter herbivores from eating them?
Correct answer: foxglove
clover
mint
Correct answer: stinging nettles
Q6.
Which plants demonstrate mechanical defences?
Correct answer: mimosa pudica
lettuce
Correct answer: thistles
grasses