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7 Cards in this Set
- Front
- Back
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Cellulose cell wall |
Acts as physical barrier & contains a variety of chemical defences that can be activated when a pathogen is detected |
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Lignin thickening of cell walls |
Waterproof and almost completely indigestible |
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Waxy cuticles |
Prevent water collecting on cell surfaces. Pathogens collect in water and need it to survive; the absence of it is a passive defence |
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Bark |
Most contain a variety of chemical defences that work against pathogenic organisms |
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Stomatal closure |
Stomata are possible points of entry for pathogens. Stomatal aperture is controlled by the guard cells. When pathogenic organisms are detected, the guard cells close the stomata in that part of the plant |
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Callose |
Large polysaccharide that is deposited in the sieve tubes at the end of a growing season. It is deposited around sieve plates and blocks the flow in the sieve tube. This can prevent a pathogen spreading around the plant |
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Tylose formation |
A tylose is a balloon-like swelling or projection that fills the xylem vessel. When a tylose is fully formed, it plugs the vessel and the vessel can no longer carry water. Blocking the xylem vessels prevents spread of pathogens through the heartwood. The tylose contains a high concentration of chemicals such as terpenes that are toxic to pathogens |
