4.1.1 Communicable Disease and Prevention – Defence in Plants Flashcards
(12 cards)
What type of defences in plants prevent pathogens from entering the plant and spreading?
Passive defences.
Why do plants close their stomata when a pathogen is detected?
The stomata are possible points of entry for pathogens.
List some physical passive defences in plants and state specifically where they are found.
- Cellulose cell wall (in the plant cell)
- Lignin (in the wall of the xylem)
- Waxy cuticle (of the leaf)
- Bark (stem/trunk)
How do waxy cuticles prevent pathogens from entering and spreading?
The waxy cuticle prevents water from collecting on the leaf. Pathogens collect water and need it to survive.
When a pathogen infects a plant what does it bind onto in the plant cells?
Receptors.
What does the binding stimulate?
Signalling molecules are released and they switch on genes in the nucleus.
What type of cellular response is triggered?
Active defences such as producing defensive chemicals.
What type of molecule is callose?
It is a polysaccharide.
Why is callose deposited between the cell wall and cell membrane in cells next to infected cells?
It acts as a barrier to prevent pathogens entering from the site of infection.
Where is callose deposited in the phloem?
In blocks the sieve plates (preventing spread of the pathogen).
Which structure is callose deposited in, to prevent pathogens moving from cell to cell?
The plasmodesmata.
State some chemicals that plants can produce to repel vectors or kill pathogens.
Pyrethrin, phenols, defensins, lysosomes.
