These notes for CBSE Class 11 Biology, Chapter 12, focus on Mineral Nutrition. They define autotrophs and heterotrophs, and explain terms like necrosis, biological nitrogen fixation, nitrification, and denitrification. The notes highlight leg-hemoglobin's role as an oxygen scavenger in legume root nodules and define flux as ion movement. Mineral nutrition is explained as the plant's requirement and utilization of mineral elements for growth. Hydroponics, a soil-less culture method, is introduced as a technique to identify deficiency symptoms. Essential elements are categorized into macronutrients (needed in larger amounts, e.g., C, H, O, N, P, K, S, Ca, Mg) and micronutrients (needed in trace amounts, e.g., Fe, Mn, Cu, Mo, Zn, B, Cl, Si). These notes provide a concise overview for effective exam revision.
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Autotroph : An organism that synthesize its required nutrients from simple
and inorganic substances.
Heterotroph : An organism that cannot synthesise its own nutrients and
depend on others.
Necrosis : Death of cells and tissues.
Biological nitrogen fixation : Conversion of atmospheric into organic com-
pounds by living organisms.
Nitrification : Conversion of ammonia (NH
) into nitrite and then to
nitrate. 3 Denitrification : A process of conversion of nitrate into nitrous oxide and
nitrogen gas (N ). Leg-hemoglobin : Pinkish pigment found in the root nodules of legumes. 2 It acts as oxygen scavenger and protects the nitrogenase.
Flux : The movement of ions is called flux.
Necrosis : Death of tissues particularly leaf tissue due to deficiency of Ca,
Mg, Cu, K.
Mineral
Nutrition : Plants require minerall elements for their growth and
development. The utilization of various absorbed ions by a plant for growth and
development is called mineral nutrition of the plant.
Hydroponics : Soil-less culture of plants, where roots are immersed in
nutrient solution without soil is called hydroponics. The result obtained from
hydroponics may be used to determine deficiency symptoms of essential ele-
ments.
Essential Elements
Macronutrients
Micro-nutrients
Macronutrients are present in
Micro-nutrients are needed in very low
plant tissues in concentrations of 1 to 10 mg per gram of dry matter
amounts : 0.1 mg per gram of dry
matter.
C, H, O, N, P, K, S, Ca, Mg
Fe, Mn, Cu, Mo, Zn, B, Cl, Si.
Mineral nutrition refers to the requirement and utilization of mineral elements by plants for their growth and development.
The two main categories are macronutrients, needed in larger amounts, and micronutrients, needed in trace amounts.
Hydroponics is a method of growing plants without soil, where their roots are immersed in a nutrient solution.
Leg-hemoglobin is a pigment found in legume root nodules that acts as an oxygen scavenger, protecting the nitrogenase enzyme.
Nitrification is the process of converting ammonia into nitrite and then into nitrate.
Macronutrients include C, H, O, N, P, K, S, Ca, and Mg.
Micronutrients include Fe, Mn, Cu, Mo, Zn, B, Cl, and Si.
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