#3.3.1
Detection and identification of plant diseases
Plant diseases can be detected by:
- stunted growth
- spots on leaves
- areas of decay (rot)
- growths
- malformed stems or leaves
- discolouration
- the presence of pests.
Identification can be made by:
- reference to a gardening manual or website
- taking infected plants to a laboratory to identify the pathogen
- using testing kits that contain monoclonal antibodies.
#3.3.2
Plant defence responses
Students should be able to describe physical and chemical plant defence responses.
Physical defence responses to resist invasion of microorganisms.
- Cellulose cell walls.
- Tough waxy cuticle on leaves.
- Layers of dead cells around stems (bark on trees) which fall off.
Chemical plant defence responses.
- Antibacterial chemicals.
- Poisons to deter herbivores.
Mechanical adaptations.
- Thorns and hairs deter animals.
- Leaves which droop or curl when touched.
- Mimicry to trick animals.