noun, plural: phytoalexins
Phytoalexins refer to different chemicals involved in plant immune defense mechanism. Plants produce phytoalexins to combat plant pathogens and pests. Examples include terpenoids, alkaloids, and glycosteroids. These chemicals accumulate immediately in areas where there is 'stress', such as those caused by infections, diseases, and parasitism. Some of these chemicals have antimicrobial properties, such as the ability to disrupt the cell wall or the metabolism of an invading microorganism.
Word origin: Greek phuton (plant) + Greek alexein (to ward off)