Plant Disease Flashcards

All 12 cards in this deck

List the signs by which a plant disease can be detected.

Stunted growth, spots on leaves, areas of decay (rot), growths, malformed stems or leaves, discolouration, and the presence of pests.

Give three ways a plant disease can be identified.

Using a gardening manual or website; sending an infected plant to a laboratory; using monoclonal antibody testing kits.

Name the required example of a viral, a fungal and an insect infection of plants.

Viral: tobacco mosaic virus. Fungal: rose black spot. Insect: aphids.

Which ion deficiency causes stunted growth in a plant?

Nitrate ion deficiency — nitrate ions are needed for protein synthesis and therefore growth.

What is chlorosis, and which ion deficiency causes it?

Yellowing of the leaves through lack of chlorophyll; caused by magnesium ion deficiency, as magnesium ions are needed to make chlorophyll.

True or false? Yellow leaves on a plant are always caused by infection with a pathogen.

False. Discolouration can also be caused by an ion deficiency, e.g. chlorosis from a lack of magnesium ions.

Give three physical defence responses of plants.

Cellulose cell walls; a tough waxy cuticle on leaves; layers of dead cells around stems (bark on trees) which fall off.

Give two chemical defence responses of plants.

Antibacterial chemicals, and poisons to deter herbivores.

Give three mechanical adaptations that defend plants.

Thorns and hairs to deter animals; leaves which droop or curl when touched; mimicry to trick animals.

True or false? Sharp thorns on a plant are a chemical defence response.

False. Thorns are a mechanical adaptation, which deters herbivores from damaging the plant.

How does mimicry defend a plant?

The plant looks like another organism, so animals are tricked or deceived and avoid eating it.

What does the tough waxy cuticle on leaves do to protect the plant?

Acts as a physical barrier that resists invasion by microorganisms (pathogens) entering the leaf.