Mineral Nutrition in Plants – Essential Elements and Their Roles

Introduction

Mineral nutrition means the essential inorganic ionic elements required by plants. These mineral ions are required in either Small or large quantity. The main source of these mineral ions is mailny soil and are absorbed by plants in the form of solution.

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Essential Mineral Elements

Mineral nutrients required by plants are classified into macro elements and micro elements.

1. Macronutrients

These are required in larger amounts.

Nitrogen (N): Major component of amino acids, proteins, nucleic acids, chlorophyll.

Phosphorus (P): Part of ATP, nucleic acids, and phospholipids.

Potassium (K): Maintains osmotic balance, activates enzymes, regulates stomatal movement.

Calcium (Ca): Important for cell wall formation (calcium pectate), stabilizes cell membranes.

Magnesium (Mg): Central atom of chlorophyll, activates enzymes involved in respiration and photosynthesis.

Sulphur (S): Component of amino acids (cysteine, methionine), vitamins, and coenzymes.

2. Micronutrients

Required in trace amounts but vital for plant metabolism.

Iron (Fe): Component of cytochromes, required for chlorophyll synthesis.

Manganese (Mn): Activates enzymes involved in photosynthesis, nitrogen metabolism.

Zinc (Zn): Component of auxin synthesis, activates enzymes.

Copper (Cu): Involved in electron transport chain.

Molybdenum (Mo): Essential for nitrogen fixation and nitrate reduction.

Boron (B): Helps in cell division, pollen germination, and sugar transport.

Chlorine (Cl): Important in photosynthesis, especially in photolysis of water.

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Beneficial Elements

Some elements are not essential but beneficial:

Sodium (Na): Helps in C4 and CAM plants.

Cobalt (Co): Required in nitrogen-fixing bacteria.

Silicon (Si): Provides mechanical strength in grasses.

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Criteria of Essentiality

An element is considered essential if:

1. Its absence prevents the plant from completing its life cycle.

2. It cannot be replaced by another element.

3. It is directly involved in plant metabolism.

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Mineral Deficiency Symptoms

When a nutrient is deficient, plants show specific symptoms:

Nitrogen deficiency: Chlorosis (yellowing of leaves), stunted growth.

Phosphorus deficiency: Poor root growth, anthocyanin accumulation.

Potassium deficiency: Leaf tip necrosis.

Calcium deficiency: Necrosis of young leaves, poor root development.

Magnesium deficiency: Interveinal chlorosis in older leaves.

Iron deficiency: Interveinal chlorosis in young leaves.

Sulphur deficiency: Yellowing of young leaves.

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Hydroponics in Mineral Nutrition

Hydroponics is the technique of growing plants in a nutrient solution without soil.

It helps in studying nutrient requirements of plants.

Essential in commercial crop production (tomato, lettuce, cucumber).

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High-Yield Points for NEET

Macronutrients vs Micronutrients list must be memorized.

Deficiency symptoms are frequently asked in NEET.

Hydroponics experiment is an important application-based question.

Iron (Fe), Magnesium (Mg), Nitrogen (N), and Potassium (K) are commonly asked in MCQs.

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Conclusion

Mineral nutrition is the main focus in plant for metabolism and growth. Deficiency symptoms arise in absence of them. Keeping the importance of minerals in plant life, NEET Aspirants must memorise the roles and deficiency symptoms of all essential elements.