Seed Germination and Dormancy in Plants – NEET-Focused Guide

🌱 What is Seed Germination?

Germination is the process by which a seed develops into a seedling under suitable conditions.

✳️ Key Conditions Required:

Water: Activates enzymes

Oxygen: Needed for aerobic respiration

Temperature: Optimum range for enzyme activity

Viable seed: Healthy, living embryo

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🔍 Types of Seed Germination

Type Description Example

Epigeal Cotyledons come above soil Bean, Castor

Hypogeal Cotyledons remain underground Maize, Pea

🧠 Trick: “Epi = Up, Hypo = Hidden”

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🧬 Phases of Germination

1. Imbibition: Water absorption by seed

2. Activation: Enzyme activation and respiration

3. Radicle Emergence: First visible sign of growth

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⏸️ What is Seed Dormancy?

Dormancy is a period when a viable seed does not germinate, even under favorable conditions.

🌿 Reasons for Dormancy:

Hard seed coat (mechanical barrier)

Immature embryo

Presence of germination inhibitors (e.g., abscisic acid)

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🔓 Breaking Dormancy – Techniques

Method Purpose

Scarification Scratching seed coat (mechanical)

Stratification Chilling treatment (cold + moist)

Chemical GA₃ or H₂SO₄ treatment

🧠 NEET Tip: “GA₃ breaks dormancy in barley seeds”