16.3 Plant responses to herbivory

Question 1

what are the physical defences of plants

Answer 1

• thorns
• spiny/hairy leaves
• spikes
• inedible tissue

Question 2

what are the chemical defences of plants

Answer 2

• tannins
• alkaloids
• terpenoids
• pheromones

Question 3

how to tannins defend plant

Answer 3

its bitter and toxic to insects it binds to digestive enzymes and inactivates them

Question 4

how do alkaloids defend plants

Answer 4

it acts as a drug affecting metabolism and poisoning organism

Question 5

how do terpenoids defend plants

Answer 5

insect repellants/toxins

Question 6

how do pheromones defend plants

Answer 6

pheromones can be released when a plant is being attacked by insects, the release of pheromones causes neighbouring leaves to produce callose this increases defence against insects

Question 7

what are VOC’s

Answer 7

volatile organic compounds
similar to pheromones but they facilitate communication between organisms (rather than within different parts of an organism
apple trees produce them to attract predatory mites when attacked by spider mites
wheat seedling use them to repel aphids