Plant disease

Plant diseases can be detected due to physical symptoms a plant displays, these symptoms can be directly linked to certain diseases. Two communicable plant diseases are rose black spot and tobacco mosaic virus, in plants non-communicable diseases are mineral deficiencies. Two of these minerals and their deficiency symptoms are:

Nitrate

Use: making amino acids, proteins, chlorophyll, DNA and other things

Deficiency symptom: stunted growth, older leaves turn yellow

Magnesium

Use: needed to make chlorophyll

Deficiency symptom: chlorosis (this means inability to produce chlorophyll), therefore leaves turn yellow

Identification of these symptoms can be made by referencing a gardening manual/website or using testing kits containing monoclonal antibodies.

Plant defence response

Like humans, plants have some very effective defences against infection by pathogens, these can be physical barriers, chemical responses or mechanical adaptations. These include:

PHYSICAL

• Cellulose cell walls

• Tough waxy cuticle on leaves

• Layers or dead cells around stems ( bark on trees ) which fall off

CHEMICAL

• Antibacterial chemicals released

• Poisons to deter herbivores

MECHANICAL

• Thorns and hairs deter animals

• Leaves which droop or curl when touched

• Mimicry to trick animals