Question

How are the terms ‘critical concentration’ and ‘deficient’ different from each other in terms of concentration of an essential element in plants?

How will you find the values of ‘critical concentration’ and ‘deficient’ for minerals – Fe & Zn?

Answer 1

a. Critical concentration:

The concentration of the element below which the plant growth gets retarded is referred to as critical concentration.

Deficiency:

Deficiency refers to the condition in which the concentration of an element is below the critical concentration. It causes signs of deficiency in the plant.

b. Technique to determine critical concentration and deficiency:

Hydroponics can be used to find out the values of both the critical concentration and deficient elements.



To find critical concentration and deficient concentration of iron:

● Different hydroponic setups can be used.

● The nutrient solution of these setups must be in increasing concentrations of iron, keeping the concentrations of other elements constant.

● The other conditions of light, aeration and the type of plant used must remain the same.

● The growth of the plants in the different set ups with respect to a particular parameter must be recorded every day.

After a set period of time, the specific concentration of iron in the hydroponic set up with plants first showing stunted growth must be recorded. Let that value be ‘x’. This ‘x’ gives the deficient concentration value. The concentration just above this particular concentration (x), let ‘y’, is the critical concentration value.