NIOS Biology Chapter 09 Nutrition in plants – Mineral Nutrition

NIOS Class 12 Biology Intext Solutions Chapter 9

INTEXT QUESTIONS 9.1

1. What are nutrients?

Ans: Nutrients are the chemical substances in food, such as CO2, water, minerals, proteins, carbohydrates, fats, etc.

2. Define aeroponics.

Ans: A technique of growing plants with roots supplied with moisture present in the atmosphere.

3. Why is it necessary to aerate nutrient solution in water culture?

Ans: To supply oxygen in sufficient quantity for the roots.

INTEXT QUESTIONS 9.2

1. In which form do plants get oxygen?

Ans: Molecular form from air or water

2. Molybdenum is a micronutrient. Give reason.

Ans: Required by the plant in very small quantities. 0.1 mg per gram of dry matter or less.

3. Why are carbon, oxygen, potassium, and sulphur called macronutrients?

Ans: They are required in large quantities, 1-10 mg per gram of dry matter.

INTEXT QUESTIONS 9.3

1. State any two metabolic processes for which mineral nutrition is required.

Ans: Membrane permeability, turgidity of cell, transport of electrons, enzyme activity (any two)

2. Which element is provided by NO2 and NH4 when taken up by plants?

Ans: Nitrogen

3. State any two functions of Ca²⁺ in plants.

Ans:

Present as calcium pectate in the middle lamella of cell walls that joins the adjacent cells together.
Activates enzymes needed for the growth of the root and shoot tips.
Needed for normal cell wall development.
Required for cell division, cell enlargement.

INTEXT QUESTIONS 9.4

1. What is meant by ‘passive absorption’ of minerals by plants?

Ans: It is the initial and rapid phase wherein ions are absorbed into the “outer space” of the cells, through the apoplast without the use of any metabolic energy.

2. Name the minerals whose deficiency affects normal cell division.

Ans: N, K, S, Mo (any two)

3. “Deficiency of K, Ca and Mg causes necrosis of leaves”. What does this statement mean?

Ans: The deficiency causes the death of leaf tissues.