Plant defences Flashcards
Dangers of plant diseases
Kills or reduces growth of plants
Reduces biodiversity
Can cause famine if in crops
What is the Tobacco mosaic virus?
Plant virus that infects tomatoes and tobacco
Causes a mosaic discolouration on their leaves
How does the tobacco mosaic virus work?
Infects other plants through contact
Infects the chloroplasts of the leaves
Turns the green into a mosaic yellow colour
Limits ability to photosynthesise = stunted growth
How to stop tabaco mosaic virus?
No cure
Stop crops from being infected by removing contact
What is the rose black spot fungus?
Caused by a fungus
Caused black or purple discolouration on leaves
How does rose black spot work?
Transmitted in air/ water and direct contact between gardeners
Caused purple spots on the leaf and the rest turns yellow/drops off
Limits ability to photosynthesise
So kills/stunts growth
How to stop rose black spots?
Using fungicides
Destroying infected leaves
Aphids
Feed on the phloem of plants and their sap
Can kill or damage the plant
How to stop aphids?
Cultivate more ladybirds as they eat them
Deficiency diseases
Diseases in a plant caused by a lack of mineral ions
Nitrate and magnesium deficiency
Without these minerals = less chlorophyll made
Leaves turn yellow = less photosynthesis = less growth
Chlorosis
Lack of chlorophyll in a plant
Could be caused by lack of mineral ions
Turns leaf yellow
How can you detect plant infections?
Internet/ book guides
Take cutting to a garden centre
Take cutting to a lab to use monoclonal antibodies to detect it
Physical defences against infection
Bark
Cellulose wall
Waxy cuticle
Chemical defences examples
Producing antibacterial chemicals to limit bacteria spread if physical defences fail
In mint and witch hazel
