Here is a term paper on the ‘Mineral Nutrition in a Plant’ for class 9, 10, 11 and 12. Find paragraphs, long and short term papers on the ‘Mineral Nutrition in a Plant’ especially written for school and college students.
Term Paper # 1. The Importance of Nitrogen-Containing Ions:
Living organisms need proteins for growth and repair. Plants have to manufacture (‘synthesise’) their own proteins. To do this, they convert their carbohydrates into amino acids, and then link the amino acids together to form proteins.
Nitrogen is another element plants need to be able to convert carbohydrate into amino acid. Plants absorb nitrogen, as the nitrate ion (NO3_), from the soil through root hairs. Nitrogen makes up about 79% of the atmosphere, but plants cannot make direct use of it in this form.
Experiment:
To Show the Effects of a Lack of Nitrogen on the Growth of a Plant:
Apparatus:
i. Two small cuttings or seedlings
ii. Two containers
iii. Cotton wool
iv. Black paper or black polythene
v. Culture solutions (available from suppliers)
Method:
Two seedlings (e.g. sorghum), or small cuttings with the same number of leaves are selected from a quick-growing plant and held in the top of two containers (A and B) using cotton wool, as shown in Fig. 27.
Container A contains a ‘complete culture solution’, i.e. a solution comprising all the necessary salts dissolved in distilled water (supplying the following ions- potassium, calcium, magnesium, iron, nitrate, sulphate and phosphate). A complete culture solution can be made by dissolving 1 g calcium nitrate, 0.25 g each of potassium nitrate, magnesium sulphate and potassium phosphate, and a trace of ferric chloride in 1 litre of distilled water.
Container B contains a similar solution, but lacking in nitrate ions. (Use calcium and potassium chlorides instead of nitrates when making up the solution.)
The two containers are left in light and at a suitable temperature. It is advisable to blow air into the solutions each day, using a small glass tube.
Results:
Container A (the Control)- Seedling grows tall and healthy, with vigorous root growth.
Container B: Seedling fails to grow, leaves begin to die and root system fails to develop.
Conclusion:
Nitrogen (present in nitrates) is needed for the healthy growth of plants.
Term Paper # 2. The Importance of Magnesium Ions:
Magnesium ions, like nitrates and other ions are absorbed from the soil through the root hairs. Magnesium is the central atom in a chlorophyll molecule. Plants grown in soils deficient in magnesium ions develop yellow leaves (a condition called chlorosis).
Insufficient chlorophyll can be made so photosynthesis is restricted. Insufficient carbohydrates are manufactured, the respiration rate is slow and few proteins can be made. Growth is therefore limited.
Term Paper # 3. The Use of Nitrogen-Containing Ions in Agriculture:
Normally, plants obtain their nitrates from decaying organic materials in the soil. However, agricultural land often lacks this organic matter. To increase the amount of nitrates available to crops, a farmer may add artificial nitrogen- containing fertilisers (e.g. nitrate or ammonium salts, which soil bacteria will convert into nitrates – see the section on the nitrogen cycle, below). The fertiliser boosts the growth of the crop, and the farmer can get a quick and high yield.
The Dangers of the Overuse of Artificial Fertilisers:
Although better crops are produced by using artificial fertilisers, there is a danger that the readily soluble nitrates will be washed into streams, rivers and lakes.
This can cause:
(i) An abundant growth of water plants (eutrophication).
(ii) When these plants eventually die, they are decayed by bacteria which use up the oxygen in the water resulting in the death of the water animals such as fish.
(iii) If this water is used as drinking water by humans, the high levels of nitrate may lead to cancer of the stomach.