Question

1.of the 16 elements needed for plant growth, state one contribution to the growth of cowpea plant . State also one deficiency symptom of each mineral element

2.What do nodules contribute to the growth of maize in America mid-west

Answer 1

There are 17 essential elements required for proper plant growth
They are grouped into two categories
1. Macroelements:
a. Carbon: Major constituent of all the biomolecules
b. Hydrogen: Major constituent of all the biomolecules
c. Oxygen: Major constituent of all the biomolecules
d. Nitrogen: COmponent of amino acids, proteins, and nucleic acids.
e. Phosphorous: Component of membranes and nucleic acids
f. Potassium: Required anion-cation balance and stomatal opening
g. Calcium: Component middle labellum and required for the photolysis of water
h. Magnesium: Component of chlorophyll and required for the ribosome subunit assembly
i. Sulfur: Component of several cofactors such as biotin and coenzyme A

Microelements:
a. Boron: Required for carbohydrate translocation and pollen germination
b. Copper: Component of electron carriers such as Plastocyanin
c. Chlorine: Anion-cation balance and water-splitting complex
d. Iron: Activator of Catalase and component of Ferredoxin
e. Molybdenum: Required for nitrogen fixation
f. Manganese: Required for photolysis of water and nitrogen fixation
g. Nickel: Activator of urease and provides disease resistance
h. Zinc: Activator of carboxylases and required for auxin biosynthesis

Apart from these, there are four beneficial elements (Na, Se, Si, and Co) required for the enhanced plant growth.

Deficiency symptoms:
1. Chlorosis: Absence of chlorophyll
It is caused by the deficiency of N, K, Mg, S, Fe, Mn, Zn and Mo

2. Necrosis: Tissue damage
It is caused by the deficiency of Ca, Mg, Cu, and K.

3. Inhibition of cell division leading to stunted growth
It is caused by the deficiency of N, K, S, and Mo.

4. Delay in flowering is caused by the deficiency of N, S, and Mo.