Plant defences against Pathogens
- Created by: ebcrankomills
- Created on: 24-05-19 11:24
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- Plant defences against Pathogens
- Physical
- High levels of callose are made
- Deposited in the plasmodesmata between infected cells, sealing them off from healthy ones
- Synthesised and deposited between cells walls and membrane soon after an initial attack
- Large amounts continue to be deposited and lignin is added , this makes the meechanical barrier even stronger.
- Callose papillae acts as barriers stopping pathogens from entering cells
- Blocks seive plates in the phloem, sealing off infected area, stopping it spreading
- Scientists still aren't sure of the functions of callose in the defence mechanism
- High levels of callose are made
- Chemical
- Often powerful chemicals are produced which repel or kill invading insects or pathogens.
- insect repellants- pine resin and citronella
- Insecticides- caffeine and pyrethrins
- Antibacterial compounds (inc. antibiotics)- phenols, defensins. lysosomes
- Antifungal compounds- phenols, antifungal gossypol, saponins chitinases
- Anti-oomycetes- glucananses and P.infestans
- General toxins- cyanide
- Recognising attacks
- Receptors on cells respond to pathogenic molecules
- Signalling molecules are released. They appear to switch on genes in the nuclleus of the cell.
- A cellular response is triggered, this informs unaffected cells.
- Unaffected cells thicken their walls and trigger defence system.
- Physical
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