Seed Germination and Seed Dormancy in Plants
NCERT-Based NEET Biology Notes for NEET 2027
📚 Quick Summary
Seed germination and seed dormancy are important concepts in plant biology. Germination begins when a viable seed resumes growth under suitable environmental conditions and develops into a seedling.
For NEET Biology preparation, remember the major requirements of germination, the stages of germination, epigeal and hypogeal germination, and the causes and significance of seed dormancy.
🎯 Preparing for NEET Biology?
Study the relevant NCERT concepts first. Then revise the differences, examples and important terms before practising NEET-style questions.
Explore NEET Biology Resources →Seed Germination and Seed Dormancy in Plants
A seed contains a developing embryo along with stored food reserves. Under suitable conditions, the embryo resumes growth and the seed develops into a seedling. This process is called seed germination.
However, a viable seed may sometimes fail to germinate even when some external conditions appear favourable. This temporary state is known as seed dormancy.
1. What Is Seed Germination?
Seed germination is the process by which a viable seed resumes growth and develops into a seedling when suitable conditions are available.
Germination involves water uptake, metabolic activation, mobilisation of stored food and growth of the embryo.
2. Conditions Required for Seed Germination
A viable seed generally requires suitable environmental conditions for successful germination.
| Condition | Importance |
|---|---|
| Water | Initiates imbibition and activates metabolic processes. |
| Oxygen | Required for aerobic respiration and energy production. |
| Suitable temperature | Supports enzyme activity and metabolic reactions. |
| Viable seed | The seed must contain a living embryo capable of growth. |
Think of the basic requirements as: Water + Oxygen + Suitable Temperature + Viable Embryo.
3. Imbibition – The First Step
Imbibition is the absorption of water by dry hydrophilic materials such as seed coats and cell walls.
Water absorption causes the seed to swell and helps initiate metabolic activity during germination.
Dry seed → Water absorption → Imbibition → Metabolic activation
4. Major Stages of Seed Germination
Stage 1: Imbibition
The dry seed absorbs water and swells. This hydration helps activate enzymes and cellular metabolism.
Stage 2: Metabolic Activation
Enzymes become active and stored food reserves begin to be mobilised. Respiration increases to provide energy for growth.
Stage 3: Radicle Emergence
The radicle, which develops into the primary root, emerges from the seed.
Stage 4: Shoot Development
The developing shoot grows upward and eventually forms the young seedling.
5. Types of Seed Germination
Based on the position of the cotyledons during seedling development, germination is commonly described as epigeal or hypogeal.
5.1 Epigeal Germination
In epigeal germination, the cotyledons are brought above the soil surface because of elongation of the hypocotyl.
Examples: Bean and castor.
5.2 Hypogeal Germination
In hypogeal germination, the cotyledons remain below the soil surface while the epicotyl elongates.
Examples: Pea and maize.
6. Epigeal vs Hypogeal Germination
| Feature | Epigeal | Hypogeal |
|---|---|---|
| Cotyledons | Come above soil | Remain below soil |
| Main elongating region | Hypocotyl | Epicotyl |
| Example | Bean, castor | Pea, maize |
7. What Is Seed Dormancy?
Seed dormancy is a state in which a viable seed does not germinate even when apparently favourable conditions are available.
Dormancy allows seeds to delay germination until environmental conditions are more suitable for successful establishment.
8. Causes of Seed Dormancy
- Hard seed coat: may restrict water uptake or gas exchange.
- Immature embryo: the embryo may require further development before germination.
- Germination inhibitors: chemical substances can prevent or delay germination.
- Environmental factors: unsuitable temperature, moisture or other conditions can prevent germination.
Role of Abscisic Acid
Abscisic acid (ABA) is an important plant hormone associated with seed dormancy and inhibition of germination.
ABA → Maintains seed dormancy
9. Importance of Seed Dormancy
- Prevents germination during unfavourable conditions.
- Helps seeds survive adverse environmental periods.
- Allows germination to occur at a more suitable time.
- Contributes to the survival and distribution of plant species.
10. Seed Germination vs Seed Dormancy
| Feature | Germination | Dormancy |
|---|---|---|
| Meaning | Resumption of seed growth | Temporary failure to germinate |
| Condition | Suitable conditions | Germination is delayed |
| Outcome | Seed develops into seedling | Seed remains viable but does not germinate |
🔥 NEET High-Yield Points
- Germination begins with water uptake by the seed.
- Imbibition is the absorption of water by hydrophilic substances.
- Oxygen is required for respiration during germination.
- A suitable temperature is necessary for proper enzyme activity.
- The radicle is the first embryonic root structure to emerge.
- Epigeal germination → cotyledons come above the soil.
- Hypogeal germination → cotyledons remain below the soil.
- Bean and castor are examples of epigeal germination.
- Pea and maize are examples of hypogeal germination.
- ABA is associated with maintenance of seed dormancy.
- A viable seed may remain dormant even under apparently favourable conditions.
11. NEET Practice MCQs
1. The first step in seed germination after water becomes available is:
A. Flowering
B. Imbibition
C. Pollination
D. Fertilisation
✅ Answer: B. Imbibition
2. Which of the following is essential for aerobic respiration during seed germination?
A. Oxygen
B. Carbon dioxide only
C. Nitrogen
D. Ethylene only
✅ Answer: A. Oxygen
3. In epigeal germination, the cotyledons:
A. Remain below the soil
B. Come above the soil
C. Develop into roots
D. Always remain inside the seed
✅ Answer: B. Come above the soil
4. Which is an example of epigeal germination?
A. Pea
B. Maize
C. Bean
D. Both A and B
✅ Answer: C. Bean
5. Which is an example of hypogeal germination?
A. Bean
B. Castor
C. Pea
D. Cotton
✅ Answer: C. Pea
6. The radicle develops into the:
A. Primary root
B. Primary shoot
C. Leaf
D. Flower
✅ Answer: A. Primary root
7. Seed dormancy refers to:
A. Death of the embryo
B. Failure of a viable seed to germinate under apparently favourable
conditions
C. Permanent loss of viability
D. Seed formation
✅ Answer: B. Failure of a viable seed to germinate under apparently favourable conditions
8. Which plant hormone is strongly associated with maintenance of seed dormancy?
A. Auxin
B. Gibberellin
C. Abscisic acid
D. Cytokinin
✅ Answer: C. Abscisic acid
9. In hypogeal germination, the region that elongates is mainly the:
A. Hypocotyl
B. Epicotyl
C. Radicle only
D. Root cap
✅ Answer: B. Epicotyl
10. Which combination is correct?
A. Epigeal – pea
B. Hypogeal – bean
C. Epigeal – bean
D. Hypogeal – castor
✅ Answer: C. Epigeal – bean
📌 One-Minute Revision
Germination → Seed resumes growth
First step → Imbibition
Essential factors → Water + Oxygen + Suitable temperature
First visible root → Radicle
Epigeal → Cotyledons above soil
Hypogeal → Cotyledons below soil
Epigeal examples → Bean, Castor
Hypogeal examples → Pea, Maize
Dormancy → Viable seed does not germinate under apparently favourable conditions
Hormone associated with dormancy → ABA
🌿 NEET Biology for Odisha Students
Students preparing for NEET in Odisha can use these NCERT-based Biology notes for systematic revision of Plant Physiology and other important Class 11 and Class 12 topics.
For better preparation, combine NCERT reading with short notes, chapter-wise revision and regular MCQ practice.
Explore NEET Biology for Odisha Students →📖 Related Biology Resources
NCERT-focused Biology notes, diagrams, MCQs and NEET preparation resources for Class 11, Class 12 and NEET Biology students.