What is Nutrition in Plants? – Complete NCERT Notes

Introduction

Nutrition is the process by which living organisms obtain food and utilize it for growth, energy, repair, and maintenance of the body. Plants also require nutrition to survive and grow.

Unlike animals, most plants prepare their own food through a process called photosynthesis. Therefore, plants are known as autotrophs (self-feeding organisms).

Definition of Nutrition in Plants

Nutrition in plants is the process by which plants obtain and utilize nutrients and prepare their own food using carbon dioxide, water, sunlight, and chlorophyll.

Key Points

Plants make their own food.
Green plants are called autotrophs.
The food-making process is known as photosynthesis.
Sunlight is the primary source of energy.
Chlorophyll helps absorb sunlight.

Why Do Plants Need Nutrition?

Plants need nutrition for:

Purpose	Importance
Growth	Development of roots, stems, leaves, and flowers
Energy	Performing life processes
Repair	Replacing damaged cells and tissues
Reproduction	Formation of flowers, fruits, and seeds
Storage	Storing food for future use

Modes of Nutrition in Plants

Plants show different modes of nutrition.

Mode of Nutrition	Description
Autotrophic Nutrition	Plants prepare their own food
Heterotrophic Nutrition	Plants depend on other organisms for food

Types of Heterotrophic Nutrition

Parasitic Nutrition
Saprotrophic Nutrition
Symbiotic Nutrition
Insectivorous Nutrition

Autotrophic Nutrition

Autotrophic nutrition is the mode of nutrition in which green plants synthesize their own food from simple inorganic substances.

Characteristics

Requires sunlight
Requires chlorophyll
Uses carbon dioxide and water
Produces glucose

Examples

Mango plant
Neem plant
Grass
Rose plant

Photosynthesis

Photosynthesis is the process by which green plants prepare food in the presence of sunlight and chlorophyll.

Definition

Photosynthesis is the process of converting carbon dioxide and water into glucose using sunlight energy in the presence of chlorophyll.

Requirements for Photosynthesis

Plants need the following:

Requirement	Function
Sunlight	Source of energy
Chlorophyll	Traps solar energy
Water	Raw material absorbed by roots
Carbon dioxide	Taken from atmosphere through stomata

Photosynthesis Equation

The photosynthesis reaction can be represented as:

6CO₂ + 6H₂O -> C₆H₁₂O₆ + 6O₂

Meaning of the Equation

Carbon dioxide + Water → Glucose + Oxygen
Sunlight provides energy.
Chlorophyll captures solar energy.

Steps of Photosynthesis

1. Absorption of Sunlight

Chlorophyll absorbs sunlight.
Leaves act as food factories.

2. Absorption of Water

Roots absorb water from soil.
Water moves through xylem vessels.

3. Intake of Carbon Dioxide

Carbon dioxide enters through stomata.
Stomata are tiny pores on leaves.

4. Food Formation

Chemical reactions produce glucose.
Food is stored as starch.

5. Release of Oxygen

Oxygen is released into the atmosphere.
This oxygen supports life on Earth.

Role of Chlorophyll

Chlorophyll is the green pigment present in leaves.

Functions

Gives green color to plants.
Absorbs sunlight.
Initiates photosynthesis.

Important Fact

Without chlorophyll, photosynthesis cannot occur.

Role of Stomata

Stomata are tiny pores present mainly on the lower surface of leaves.

Functions

Exchange of gases.
Entry of carbon dioxide.
Exit of oxygen.
Helps in transpiration.

Heterotrophic Nutrition in Plants

Some plants cannot prepare their own food completely.

Reasons

Absence of chlorophyll.
Growth in nutrient-poor environments.

Parasitic Nutrition

A parasite obtains food from another living organism called the host.

Characteristics

Depends on host plant.
May harm the host.

Examples

Cuscuta (Amarbel)
Dodder plant

Saprotrophic Nutrition

Saprotrophic plants obtain food from dead and decaying organic matter.

Characteristics

Secrete digestive enzymes.
Absorb dissolved nutrients.

Examples

Mushroom
Bread mold
Fungi

Symbiotic Nutrition

In symbiosis, two organisms live together and both benefit.

Example: Lichen

Organism	Benefit
Alga	Makes food
Fungus	Provides shelter and water

Both organisms benefit from each other.

Insectivorous Nutrition

Some plants trap insects to obtain nutrients, especially nitrogen.

Characteristics

Grow in nitrogen-deficient soils.
Capture and digest insects.

Examples

Pitcher plant
Venus flytrap
Sundew

Difference Between Autotrophic and Heterotrophic Nutrition

Feature	Autotrophic Nutrition	Heterotrophic Nutrition
Food Source	Self-prepared	Obtained from others
Chlorophyll	Present	Usually absent
Sunlight Required	Yes	No
Dependency	Independent	Dependent
Example	Green plants	Cuscuta, Mushroom

Importance of Photosynthesis

Ecological Importance

Produces oxygen.
Maintains atmospheric balance.
Supports food chains.
Stores solar energy as chemical energy.

Economic Importance

Source of food crops.
Provides wood and fibers.
Supports agriculture.

NCERT Summary

Nutrition is essential for plant growth and survival.
Most plants show autotrophic nutrition.
Photosynthesis is the food-making process in green plants.
Chlorophyll, sunlight, water, and carbon dioxide are required for photosynthesis.
Some plants exhibit parasitic, saprotrophic, symbiotic, or insectivorous nutrition.
Photosynthesis releases oxygen and supports life on Earth.

Practice Questions with Answers

Short Answer Questions

1. What is nutrition in plants?

Answer: Nutrition in plants is the process by which plants obtain nutrients and prepare food for growth, energy, and maintenance.

2. What is photosynthesis?

Answer: Photosynthesis is the process by which green plants prepare food using carbon dioxide, water, sunlight, and chlorophyll.

3. Why are green plants called autotrophs?

Answer: Green plants prepare their own food and hence are called autotrophs.

4. What is the role of chlorophyll?

Answer: Chlorophyll absorbs sunlight required for photosynthesis.

5. Give two examples of insectivorous plants.

Answer: Pitcher plant and Venus flytrap.

Fill in the Blanks

Plants that make their own food are called autotrophs.
The green pigment in leaves is chlorophyll.
Carbon dioxide enters leaves through stomata.
Food prepared during photosynthesis is glucose.
Cuscuta is a parasitic plant.
Oxygen is released during photosynthesis.
Mushrooms show saprotrophic nutrition.
Lichen is an example of symbiosis.
Roots absorb water from the soil.
Photosynthesis occurs mainly in leaves.

MCQs (Multiple Choice Questions) for practice

1. Which process helps plants prepare food?

A) Respiration
B) Digestion
C) Photosynthesis
D) Excretion

Answer: C) Photosynthesis

2. Which pigment absorbs sunlight?

A) Hemoglobin
B) Chlorophyll
C) Keratin
D) Melanin

Answer: B) Chlorophyll

3. Carbon dioxide enters through:

A) Roots
B) Flowers
C) Stomata
D) Stem

Answer: C) Stomata

4. Which gas is released during photosynthesis?

A) Nitrogen
B) Carbon dioxide
C) Oxygen
D) Hydrogen

Answer: C) Oxygen

5. Which plant is parasitic?

A) Mango
B) Neem
C) Cuscuta
D) Rose

Answer: C) Cuscuta

6. Which is an insectivorous plant?

A) Wheat
B) Rice
C) Pitcher Plant
D) Pea

Answer: C) Pitcher Plant

7. Which is the main site of photosynthesis?

A) Root
B) Leaf
C) Flower
D) Fruit

Answer: B) Leaf

8. Mushrooms obtain food through:

A) Autotrophic nutrition
B) Saprotrophic nutrition
C) Parasitic nutrition
D) Symbiotic nutrition

Answer: B) Saprotrophic nutrition

9. What is the food produced during photosynthesis?

A) Protein
B) Fat
C) Glucose
D) Vitamin

Answer: C) Glucose

10. Which of the following is required for photosynthesis?

A) Oxygen
B) Sunlight
C) Nitrogen gas
D) Helium

Answer: B) Sunlight

Quick Revision Points

✅ Nutrition is the process of obtaining and utilizing food.
✅ Green plants are autotrophs.
✅ Photosynthesis occurs in chlorophyll-containing leaves.
✅ Sunlight, water, carbon dioxide, and chlorophyll are essential for photosynthesis.
✅ Oxygen is released during photosynthesis.
✅ Cuscuta is a parasitic plant.
✅ Mushroom shows saprotrophic nutrition.
✅ Lichen is an example of symbiosis.
✅ Pitcher plant is insectivorous.
✅ Photosynthesis is the foundation of life on Earth.