Allelochemicals and Phytoalexins?

Question

What is the difference between Allelochemicals and Phytoalexins?I know that they are both produced by plants as a defense mechanism but what is the actual difference between them?
Thanks

Answer 1

Allelochemicals influence the growth and development of neighbouring plants by adding chemical compounds to the environment. Normally they cause the inhibition of seed germination and/or seedling growth, which means that around the plant that's releasing the allelochemicals there will be very few plants growing. This prevents the plant from having to "fight" for resources.

Phytoalexins are antibiotics produced by plants that are under attack and act as toxins to the attacking organism. They may puncture the cell wall, delay maturation, disrupt metabolism or prevent reproduction of the organism. Usually they are targeted at specific predators and won't be able to repel insects as well as fungi for example.