Mineral Nutrition

Question 1

What are the 3 roles of inorganic nutrients?

Answer 1

• structural: calcium in middle lamella of walls
• synthesis of compounds needed for growth eg enzyme activators, such as Mg2+ needed for ATPase and DNA polymerase
• form an integral part of a molecule eg mg2+ in chlorophyll, iron in protein carriers of ETC, and manganese in ps11

Question 2

Where do plants get nitrogen from and how?

Answer 2

Nitrogen in humus in soil, in inorganic molecules of decaying organisms. It occurs as NO3- and NH4+. Taken up by roots as nitrates, but rhizobium In root nodules delivers NH4+ to the plant.

Question 3

How does nitrogen travel through the plant and get used?

Answer 3

Transported in the xylem to cells where nitrate is converted to ammonia which then becomes the amino group of amino acids.

Question 4

How are amino acids transported and what are they used for?

Answer 4

In the phloem

Used for synthesis of proteins, chlorophylls and nucleotides

Question 5

What are symptoms of nitrogen deficiency?

Answer 5

Reduced growth in the whole plant

Chlorosis - yellowing of the plant because it is part of chlorophyll

Question 6

How is magnesium transported in the plant?

Answer 6

Absorbed as MG2+ and transported in the xylem.

Question 7

What is magnesium used for?

Answer 7

Required by all tissues but especially leaves
Constituent of chlorophyll
Enzyme activator for ATPase

Question 8

What is the main symptom of magnesium deficiency?

Answer 8

Chlorosis