Macronutrients – Class 11 | Chapter – 12 | Biology Short Notes Series PDF

Macronutrients: Macronutrients are elements that are found in enormous levels in plant tissues. They exceed 10 moles per kilogram of dry materials. The macronutrients are carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur, potassium, calcium, and magnesium.

List of Important Macronutrients 

  • Nitrogen: It is important for plant growth as it is used in protein synthesis and energy metabolism. The plant absorbs nitrogen in the form of nitrate, which is essential for plant growth. It is also required for photosynthesis and the creation of chlorophyll.
  • Phosphorus
  • Potassium: It is involved in water control and the transport of reserve chemicals in plants. It improves photosynthesis, strengthens cell tissue, and promotes nitrate absorption. Potassium also promotes blooming as well as glucose and enzyme synthesis. 
  • Calcium: Calcium is crucial for developing strong plants. Calcium helps create cell walls around plant cells. Plants don’t have bones to hold them up, so they rely on rigid cell walls to help keep them upright. Strong cell walls also help to protect the plant from disease. Calcium is also required for plant metabolism. Interestingly, plants also use calcium to help them absorb nitrogen from the soil. Without calcium, plants may not be able to take in enough nitrogen.
  • Sulphur: It plays several roles in plant health. It can help the plant be more resistant to diseases. It is also involved in plant growth through the production of amino acids, proteins, enzymes, and vitamins. Sulfur is actively involved in the process of seed formation.
  • Magnesium: It is required for photosynthesis since it is the core of the chlorophyll molecule. As a result, it is a necessary component for plant growth. Phosphorus absorption and transportation are aided by magnesium. It aids in the storage of sugars inside the plant. It acts as an enzyme activator, activating more enzymes than any other mineral. 

Deficiency Symptoms of Essential Macronutrients Elements

  • The critical concentration of an essential element is the level below which plant growth is slowed.
  • When the element is present below the critical concentration, it is said to be deficient.
  • Plants exhibit distinct morphological changes in the absence of a specific element, known as deficiency symptoms and are diagnostic of particular element deficits.
  • The deficiency symptoms differ from element to element, but they always go away once the lacking mineral nutrient is given to the plant.
  • When elements are generally stationary and are not moved out of the mature organs, deficiency symptoms emerge first in the young tissues.
  • Sulphur and calcium, for example, are part of the cell’s structural components and hence are difficult to release.
  • Chlorosis, necrosis, stunted plant growth, premature fall of leaves and buds, and suppression of cell division are examples of deficient symptoms seen in plants.
  • Chlorosis is a yellowing of the leaves produced by a lack of chlorophyll due to a lack of the elements N, K, Mg, S, Fe, Mn, Zn, and Mo. 
  • Necrosis is the loss of tissue, especially leaf tissue, caused by a lack of Ca, Mg, Cu, and K.
  • Cell division is inhibited by a lack of or low N, K, S, and Mo levels.
  • Some elements, such as N, S, and Mo, can cause flowering to be delayed if their concentration in plants is low.

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By Team Learning Mantras