B3.3. Plant disease

Question 1

Name three ways of visually detecting a plant disease.

Answer 1

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

Question 2

Name three ways to identify a plant disease.

Answer 2

“1. Look symptoms up in a gardening manual or website

2. Taking the infected plant to a laboratory
3. Using a testing kits that contains monoclonal antibodies”

Question 3

Name four possible causes of plant diseases.

Answer 3

Viruses; bacteria; fungi; insects.

Question 4

How do aphids damage plants?

Answer 4

Pierce stems with their mouthparts to drink sugary liquid in phloem, introduce pathogens and deprive plants of sugars.

Question 5

Name two problems caused in plants by an ion deficiency.

Answer 5

Stunted growth caused by nitrate deficiency AND chlorosis caused by magnesium deficiency.

Question 6

Why does a lack of nitrate ions affect plant growth?

Answer 6

Nitrate ions are used to make proteins.

Question 7

Why does a lack of magnesium ions affect plant growth?

Answer 7

Magnesium ions are used to make chlorophyll.

Question 8

Name three physical defences of plants.

Answer 8

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

Question 9

Name two chemical defences of plants.

Answer 9

Antibacterial chemicals, poisons to deter herbivores,

Question 10

Name three mechanical defences of plants.

Answer 10

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