Plants defence responses 4.3.3.2

Question 1

What are the 3 physical defence systems plant have and explain?

Answer 1

• Cellulose cell wall - waterproof and indigestible
• Waxy cuticle – prevents water from collecting on the surface ( pathogens need water!)
• Layer of dead cells on stems that act as a barrier to protect against pathogens and that fall off. (bark on trees)

Question 2

Can you name any plants with antibacterial properties?

Answer 2

Aloe Vera, Mint, tea tree, Witch Hazel, cinnamon

Question 3

What are the 2 chemical defence system a plant has?

Answer 3

• Antibacterial chemicals - some create a scent this is why mint plants smell minty!
• Poisons -This stops herbivores feeding on them. Less grazing means less exposure to pathogens

Question 4

What are the 3 mechanical defence system a plant has?

Answer 4

• Thorns and hairs -deter animals from touching/eating them
• Leaves which droop/ curl -when touched they move away from animal (insects fall off)
• Mimicry- to trick animals from eating them and/or laying their eggs on them