Diseases In Plants

Question 1

Effect of tobacco mosaic virus

Answer 1

Causes leaves to discolour in a mosaic pattern
= rate of photosynthesis reduced
= growth of plant also reduced

Question 2

Fungus disease in plants

Answer 2

Rose black spot

Question 3

Effects of rose black spot

Answer 3

Causes leaves to develop purple or black spots
= leaves turn yellow and fall off
= causes rate of photosynthesis reduce
= reduces rate of growth

Question 4

How is rose black spot spread

Answer 4

spread by water or by wind

Question 5

How to treat rose black spot

Answer 5

Spray plants with fungicides
Remove infected leaves and destroy them

Question 6

How to check plants for diseases

Answer 6

Discolouration
Spots on leaves
Stunted growth
Decay or rot
Growths
Malformed stems or leaves

Question 7

How to identify disease

Answer 7

• use a garden manual or website
• take infected plant to lab
• use testing kits containing monoclonal antibodies

Question 8

Effect of lack of nitrate ion

Answer 8

Stunted growth
= as nitrate is needed for protein synthesis and therefore growth

Question 9

Effect of lack of magnesium ion

Answer 9

• condition chlorosis
  = as magnesium required to make chlorophyll

Question 10

Describe chlorosis

Answer 10

Leaves loose their green colour

Question 11

Describe a plants physical response

Answer 11

Leaves covered in layer of waxy cuticle
= difficult for microorganisms to penetrate
= protects plant from attack
Bark
= layer of dead cells
= barrier to entry of microorganisms

Question 12

Describe chemical responses

Answer 12

Plants release antibacterial chemicals
= kill bacteria and prevent them attacking the plant
Plants can release poisons
= deter herbivores from grazing on the plant

Question 13

Describe mechanical defence system

Answer 13

Sharp throne
= directly protect a plant from being eaten
Plants have hairs
= irritate mouth of herbivores
= make plant difficult to eat
Leaves that droop or curl when touched
= might scare herbivores
Mimicry
= white dead nettle looks similar to stinging nettle
= herbivores less likely to eat it as they make mistake it for a stinging nettle

Question 14

Effect of TMV

Answer 14

Lack of chlorophyll
= less photosynthesis
= less glucose made
= less energy released for growth as less glucose needed for respiration
= less proteins made for growth as glucose needed for making proteins