12.4 Plant defences to pathogens Flashcards
how do plant cells recognise an attack?
receptors in cells respond to pathogen molecules or to the chemicals produced when a plant cell wall is attacked
what is callose?
a polysaccharide which is involved in a plant’s defence system
what is the function of callose?
it is synthesised and deposited in the plasmodesmata linking cells together
the callose acts as a barrier by preventing the pathogen from entering
what is added after callose?
lignin which makes the barrier thicker and stronger
what tissue does callose block?
the phloem tissue which stops pathogens spreading
by blocking sieve tube plates
how are pathogens prevented from spreading between cells?
callose is deposited in the plasmodesmata which seals the healthy cells from the infected cell
what are chemical defences a plant deploys?
- insect repellents
- insecticides
- antibacterial compounds
- anti-fungal compounds
- anti-oomycetes
- general toxins
what closes when a plant is under attack from a pathogen?
the Stomata
what causes a hypersensitive responses?
caused by bacteria, viruses, fungi
what is a hypersensitive response?
apoptosis
stops any nutrient and water supply to the pathogen
what are the primary defences to pathogens in plants?
waxy cuticle
bark
cellulose cell wall
what do plants do with infected tissue?
seal it off and sacrifice it
plants are able to replace the damaged parts with the meristematic tissue
