B3/ Further additional science

Plant defences

Lupin
This is a plant which produces poisonous chemicals called alkaloids. The production of these follow a circadian rhythm- the production starts early in the morning and stops at night. The chemicals make the leaves very poisonous to insect pests or larger herbivores that may want to eat it.

Plants make chemicals to defend themselves against pathogens. Pathogens are micro organisms that cause disease. For example:

Potatoes are often attacked by a fungus- like organism called potato blight, that destroys their leaves killing the plant. A few varieties of potatoes counteract this by producing chemicals that kill it. Scientists hope to produce potatoes that can make chemicals to kill blight so they can produce more yield for the growing population.

It is important to remember that as humans are not able to make food internally, we rely on other animals and plants for food. If pathogens destroy or damage a crop, it would mean that our food supply would be at risk. This happened in Ireland in 1845, when the famine caused by potato blight occurred.

Uses of plant poison:
1) Digoxin-
Found: In foxgloves
Usage: Treat heart disorders by improving how the heart beats.

2) Quinine-
Found: Cinchona trees
Usage: Treat malaria

3) Aspirin-
Found: Willow tree
Usage: Treat symptoms of a disease such as fever and pain.