4.3.3.1 Detection and Identification of Plant Diseases

Question 1

Mineral deficiency:

Answer 1

• Situation where a plant cannot get enough of a particular mineral from the soil for healthy growth
• Different minerals are needed for different reasons as each one provides different symptoms of mineral deficiency

Question 2

How can mineral deficiencies be stopped (externally) in plants?

Answer 2

Extra minerals can be provided through fertilisers to stop mineral deficiencies

Question 3

What are the different mineral deficiencies in plants?

Answer 3

• Nitrate deficiency
• Phosphate/Phosphorous deficiency
• Potassium deficiency
• Magnesium deficiency

Question 4

Symptoms of nitrate deficiency in plants:

Answer 4

• Poor growth
• Yellow leaves

Question 5

Symptoms of phosphate/phosphorous deficiency in plants:

Answer 5

• Poor root growth
• Discoloured leaves

Question 6

Symptoms of potassium deficiency in plants:

Answer 6

• Poor growth of fruit and flowers
• Discoloured leaves

Question 7

Symptoms of magnesium deficiency in plants:

Answer 7

Yellow leaves - as magnesium is needed to make chlorophyll and a deficiency of it means the leaves won’t be green as chlorophyll is a green pigment and needs magnesium to be made

Question 8

How do plants absorb minerals?

Answer 8

• Plants can only absorb soluble minerals (those that can dissolve in water)
• They absorb minerals dissolved in solution from the soil through their root hair cells
• The concentration of minerals in the soil is very low
• Minerals can’t be absorbed by osmosis as this is the movement of only water molecules
• Cannot be absorbed by diffusion, because minerals are in very low concentration
• Active transport used to absorb mineral
• Root hair cells have carrier molecules on their cell membrane
• The carrier molecules pick up the mineral ions and move them across the membrane into the cell going against the concentration gradient

Question 9

How can the identification of plant diseases be made?

Answer 9

• Reference to gardening manual or website
• Taking infected plants to a laboratory to identify the pathogen
• Using testing kits that contain monoclonal antibodies

Question 10

How can plants be infected?

Answer 10

By a range of viral, bacterial, and fungal pathogens as well as by insects

Question 11

Plants can be damaged by a range of iron deficiency conditions, which are:

Answer 11

• Stunted growth caused by nitrate deficiency
• Chlorosis caused by magnesium deficiency