plant diseases and defences Flashcards
how do aphids cause damage to plants?
they use their sharp mouthparts to extract sap from plant phloem, weakening the plant, also vectors who transfer pathogens to healthy plants
how can we reduce the number of aphids?
chemical pesticides
biological pest control
why do plants need mineral ions?
so they don’t suffer deficiencies
why do plants need nitrate ions?
they convert sugars to proteins which are required for growth so a lack of them can cause stunted growth
why do plants need magnesium ions?
they are required to synthesise chlorophyll which is needed for photosynthesis as it absorbs light energy so a lack means the leaves can’t photosynthesise properly and get yellow leaves
what is having yellow leaves called?
chlorosis
7 symptoms of disease
-stunted growth
-spots on leaves
-areas of decay
-growths
-malformed stems/leaves
-discolouration
-presence of pests
3 ways to identify the disease
-reference to a gardening manual or website
-laboratory testing
-mAbs testing kits
what does a nitrate deficiency cause?
stunted growth
what does a magnesium deficiency cause?
chlorosis/yellow leaves
3 physical defences
-waxy cuticle
-cell walls made from cellulose
-layers of dead cells (bark) which fall off
what do physical defences act as and why?
a barrier to stop pathogens from entering
2 chemical defences and why
-antibacterial chemicals: kill bacteria
-poisons: deter herbivores
3 mechanical defences and why
-thorns and hairs: stop animals from touching and eating them
-leaves that droop/curl: prevent from being eating by knocking insects off them
-mimicry: trick animals
