20 Growth and Development in Plants

NIOS Biology Intext Solutions Chapter 20

INTEXT QUESTIONS 20.1

1. Distinguish between growth and development.

Ans: 

• Growth: Increase in the number and size of a cell, organ, or organism.
• Development: Series of qualitative & quantitative changes including growth, differentiation, and maturation.

2. What is differentiation?

Ans: Process of change in cells, tissues, or organs to carry out different functions.

3. What role does it play in plant growth and development?

Ans: Similar cells organise to form a group called a tissue to perform a particular function

INTEXT QUESTIONS 20.2

1. Name the plant hormones concerned with the following:

(i) Elongation of cell.

(ii) Shedding of leaves

(iii) Breaking seed dormancy 

Ans: 

• (i) Auxin
• (ii) Ethylene
• (iii) Abscisic acid

2. Mention two functions of auxin

Ans:

• (i) Cell elongation
• (ii) Delays the fall of leaves
• (iii) suppresses the growth of lateral buds (any two)

3. What is the difference between dedifferentiation and redifferentiation?

Ans: 

• Dedifferentiation: Process by which precursor cells become distinct cell types to perform a specific function.
• Redifferentiation: Process by which the plant cells, while undergoing dedifferentiation, lose their capacity to divide once again but mature to perform specific functions.

4. Which two hormones are essential for vascular tissue differentiation?

Ans: Auxin and cytokinin.

INTEXT QUESTIONS 20.3

1. Distinguish between phototropism and geotropism

Ans: 

• Phototropism- Movement induced by light
• Geotropism- Movement induced by gravity

2. Give two examples of turgor movement

Ans: 

• Closure of leaves at the fall of darkness
• Dropping of leaves on touch
• Closing the leaves of the Venus flytrap to catch an insect that lands on it (any two)

Additional Study Materials

• Chapter 14 Respiration and Elimination of Nitrogenous Wastes
• Chapter 15 Circulation of Body Fluids
• Chapter 16 Locomotion and Movement
• Chapter 17 Coordination and Control – The Nervous and Endocrine Systems
• Chapter 18 Homeostasis: The Steady State
• Chapter 19 Reproduction in Plants