Class 11 Biology Chapter 12 Mineral Nutrition Notes

Mineral Nutrition

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 (NH3) into nitrite and then to nitrate.

Denitrification : A process of conversion of nitrate into nitrous oxide and nitrogen gas (N2).

Leg-hemoglobin : Pinkish pigment found in the root nodules of legumes.

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 elements.

Essential Elements

Macronutrients Micro-nutrients Macronutrients are present in Micro-nutrients are needed in very low plant tissues in concentrations amounts : 0.1 mg per gram of dry

of 1 to 10 mg per gram of dry matter. matter.

C, H, O, N, P, K, S, Ca, Mg. Fe, Mn, Cu, Mo, Zn, B, Cl, Si.

Chlorosis : Yellowing of leaves due to loss of chlorophyll.

Active Transport : Absorption occuring at the expense of metabolic energy.

Passive Transport : Absorption of minerals with concentration gradient by the process of diffusion without the expense of metabolic energy.

Role of Minerals Elements in Plants

MICRO-NUTRIENTS

Element	Obtained as	Functions	Deficiency symptoms
Iron (Fe)	Fe+++	Constituent of Ferredoxin	Chlorosis
		and cytochrome; needed
		for synthesis of chlorophyll.
Manganese	Mn+++	Activates certain enzymes involved	Chlorosis, grey spots
(Mn)		in photosynthesis,	on leaves.
		respiration and
		nitrogen metabolism.
Zinc (Zn)	Zn++	Activates various enzymes	Malformation of leaves.
		like carbo-xylases. Required	Dieback of shoots.
		for synthesis of auxins.
Copper (Cu)	Cu+++	Activates certain enzymes.
Boron (B)	BO3- or B4O72-	Required for uptake of water and	Death of stem and root
		Ca, for membrane functioning,	apex.
		pollen germination, cell
		elongation carbohydrate
		translocation.
Molybdenum	MoO22+	Activates certain enzymes in
(Mo)	(molybdate)	nitrogen metabolism.
Chlorine (Cl)	Cl-	Maintains solute concentration
		along with Na+ & K+; maintain
		anioncation balance in cells;
		essential for oxygen evolution in photosynthesis.