Plant Defences-passive

Question 1

Passive

Answer 1

Defences present before infection and their role is to prevent entry and spread of pathogens.

Question 2

Cellulose cell wall

Answer 2

Physical barrier- may also contain chemical defences that are activated when a pathogen is detected

Question 3

Lignin thickening of cell wall

Answer 3

Lignin us waterproof and is completely indigestible.

Question 4

Waxy cuticles

Answer 4

Prevents water from collecting on the cell surface. As pathogens need water to survive, this is a passive defence.

Question 5

Bark

Answer 5

Bark contains chemical defences that work against pathogenic organisms.

Question 6

Stomata closure

Answer 6

The stomata acts as a point of entry for pathogens. Stomata closure is controlled by guard cells. Closed when pathogenic organisms are detected.

Question 7

Callose

Answer 7

Callose is a large polysaccharide deposit that blocks old phloem sieve tubes. This blocks the flow in phloem sieve tubes preventing pathogens spreading.

Question 8

Tylose formation

Answer 8

Tylose is a balloon like swelling that fills the xylem vessel. When the tylose has fully formed it plugs the vessel and the vessel can no longer carry water. Blocks the xylem vessel and prevents spread of pathogens.