Experiments on Mineral Nutrition in Plants | Botany

List of top two experiments on mineral nutrition in plants:- 1. Detection of Essentiality of Mineral Elements 2. Determination of Ionic Accumulation (Chloride) in Plant Cells.

Experiment # 1. Detection of Essentiality of Mineral Elements:

On the basis of various experimental observations it has been noticed that a number of mineral elements are necessary for plant growth and development. They are called “essential elements”.

Again, various essential elements are required by the plants in different amounts: some are required in large quantities while others are required in small quantities — the former are designated as macro or major, and the latter as micro or trace elements.

Among approximately 40 essential mineral elements, nine elements like N, P, K, C, H, O, Ca, Mg, S are macro elements, while others like Fe, Mn, Zn, Cu, Ni, Bo, Co, Al, Vd, Na etc. are micro elements.

Each and every essential elements has its characteristic physiological functions. Deficiency of any such element produces their characteristic deficiency symptoms.

By nutrient culture (sand or water cul­ture) techniques it is possible to study the deficiency symptom of essential elements without much difficulty. The deficiency symptoms are expressed principally in leaves as characteristic foliar changes.

(A) Water Culture Technique:

Materials Required:

1. Inorganic nutrient solution (any one)

(i) Knop’s solution (1860),

(ii) Hoagland solution (1920)

2. Wide-mouthed bottles with cork

3. Black paper etc.

4. Rooted plants

Procedure:

1. Take a few wide-mouthed bottles and fill them with the nutrient solutions of desired types. In each bottle a specific element is lacking except the control one. Mark the deficient element on the bottle.

2. Place rooted plants through the corks in the bottles and cover all the bottles with black paper to protect the roots from light.

3. Allow the plants to grow for 10-15 days.

4. Change the nutrient solutions every 3-4 days.

5. Note the deficiency symptoms from each experimental set.

Observations:

The various deficiency symptoms as expressed as foliar systems, growth of stems and roots are also noted against each treatments.

Report:

(B) Sand Culture Technique:

Materials Required:

1. Washed sand or crushed quartz or vermiculite

2. Earthen pots (20 cm × 15 cm)

3. Rooted plants

4. Inorganic nutrient solutions of desired types

5. Glass marker etc.

Procedure:

1. Fill the earthen pots with washed sand or vermiculite.

2. Moisten the sand with water and one of the desired nutrient solutions (except control set, each set is efficient in one particular element).

3. Place one rooted plant in each pot and mark the deficient element.

4. Cover the upper surfaces of the pots to check evaporation of water vapour.

5. Allow the plants to grow for 2 weeks and then record the deficiency symptoms.

Observations:

The deficiency symptoms against treatment condition is recorded.

Report:

Experiment # 2. Determination of Ionic Accumulation (Chloride) in Plant Cells:

Different mineral ions (anions or cations) are absorbed by actively growing plants — either by passive or active mechanism. Then the ions are accumulated in cell sap either in organic or inorganic combinations for a considerable period.

The ions can then be extracted from plant tissues and quantified by suitable titration methods.

Materials and Equipment’s Required:

1. Hydrilla plants

2. Mortar and pestle

3. Sand, water, activated charcoal

4. 0.02N AgNO₃ soln. (0.34 gm. of AgNO₃ per 100 ml soln.)

5. 5% K₂CrO₄ solution as indicator

6. Standard NaCl soln. (329.6 mg of dry NaCl per 1,000 ml solutions).

Procedure:

1. Weigh 10 gms of Hydrilla plants and crush them with neutral sand and distilled water in a mortar.

2. Dilute extract up to 50 ml by dist. water and then filter.

3. Remove chlorophyll by absorption with activated charcoal and subsequent filtering.

4. Titrate 10 ml of extract against 0.02N AgNO₃ solution using a drop of 5% K₂Cr₂O₄ soln. as indicator. The end point of titration is indicated by the appearance of a permanent faint reddish brown colour (due to formation of silver chromate AgCrO₄).

5. Standardize the 0.02 N AgN0₃ against standard NaCl soln. using K₂CrO₄ indicator solution as mentioned above.

Results:

Let X ml of 0.02 N AgNO₃ be standardized by Y ml of standard NaCl soln.

Now, 1 ml of standard NaCl contains 0.02 mg of chlorine

Therefore, Y ml of standard NaCl = 0.02 × Y mg of chlorine

Hence, X ml of 0.02 N AgNO₃ = 0.02 × Y mg of chlorine

Now, 1 ml of 0.02 N AgNO₃ = 0.03 × Y/X mg of chlorine

If the volume of 0.02 N AgNO₃ to titrate 10 ml of plant extract be Z, then the amount of chlorine ion is

0.02 × Y × Z/X mg per 10 ml of the sap

The amount of chlorine ion per gm. of plant material

0.02 × Y × Z /X × 10 × 5 mg