🌸 Why Double Fertilization Happens Only in Angiosperms? | NEET 2025 Biology

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🔑 Introduction

Have you ever wondered why flowering plants (angiosperms) dominate our planet while gymnosperms, ferns, and mosses are limited in distribution?
The secret lies in a unique process called double fertilization – a phenomenon found only in angiosperms. This process not only ensures reproduction but also guarantees efficient food storage for the embryo. And here’s the best part – NEET 2025 always asks questions from this topic.

In this blog, we’ll decode double fertilization step by step, link it to NCERT, and solve some high-yield NEET questions.


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🌺 Structure of the Flower – A Quick Recap

Before jumping into fertilization, let’s recall the essential parts of a flower:

Androecium (Male Reproductive Organ): Produces pollen grains in anthers.

Gynoecium (Female Reproductive Organ): Consists of stigma, style, and ovary.

Ovule: Located inside the ovary, contains the female gametophyte (embryo sac).


👉 The embryo sac is haploid and usually 7-celled, 8-nucleate:

1 egg cell

2 synergids

3 antipodals

2 polar nuclei


This structure plays a key role in double fertilization.


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🌸 Pollination & Pollen–Pistil Interaction

1. Pollination – Transfer of pollen grains from anther to stigma.

Self-pollination (Autogamy, Geitonogamy)

Cross-pollination (Xenogamy)



2. Pollen–Pistil Interaction – If the pollen is compatible, stigma secretes fluids that allow pollen germination.


3. Pollen Tube Growth – The pollen tube emerges, carrying two male gametes toward the ovule.




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🧬 Fertilization Process in Angiosperms

1. Entry into Ovule: Pollen tube enters through the micropyle.


2. Guidance: Synergids help guide the tube to the egg cell.


3. Release of Male Gametes: Two sperm cells are released inside the embryo sac.



Now comes the magical part – double fertilization!


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🌟 Double Fertilization – The Unique Process

First Fertilization (Syngamy):

One male gamete (n) fuses with the egg cell (n).

Forms a zygote (2n) → develops into the embryo.


Second Fertilization (Triple Fusion):

The other male gamete (n) fuses with two polar nuclei (n + n).

Forms a primary endosperm nucleus (3n) → develops into endosperm.



👉 Since fertilization occurs twice in the same embryo sac, it is called double fertilization.


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🌍 Significance of Double Fertilization

1. Resource Efficiency: Endosperm forms only after fertilization, so no wastage of food.


2. Embryo Nourishment: Endosperm supplies nutrition during development.


3. Evolutionary Advantage: This process gives angiosperms dominance over other plants.



💡 Fun Fact: This process is absent in gymnosperms (they form haploid endosperm before fertilization).


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📒 Quick Revision Notes for NEET

Embryo sac = 7-celled, 8-nucleate.

Two male gametes are carried by pollen tube.

Syngamy → Zygote (2n).

Triple Fusion → Endosperm (3n).

Double fertilization = Syngamy + Triple Fusion.

Unique to angiosperms.



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📝 NEET Previous Year Questions (PYQs)

Q1. Double fertilization is:
a) Fusion of two eggs with one male gamete
b) Fusion of two polar nuclei with one male gamete
c) Fertilization occurring twice in the same embryo sac ✅
d) Fusion of zygote with polar nuclei

Q2. (NEET 2017) Triple fusion in angiosperms results in:
Answer: Primary Endosperm Nucleus (3n) ✅

Q3. (AIIMS 2014) How many male gametes are discharged in embryo sac during fertilization?
Answer: Two male gametes ✅


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💡 Practice MCQs (with Answers)

Q1. The ploidy of endosperm after double fertilization is:

a) Haploid

b) Diploid

c) Triploid ✅

d) Tetraploid


Q2. Which of the following is absent in gymnosperms but present in angiosperms?

a) Pollination

b) Fertilization

c) Double fertilization ✅

d) Seed formation


Q3. Double fertilization ensures:

a) Twin embryos

b) Food supply for embryo ✅

c) Fruit formation

d) Cross-pollination



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🏆 Conclusion

Double fertilization is a masterstroke of nature – a process that ensures both zygote and endosperm formation simultaneously. This resource-saving mechanism is why angiosperms became the most successful plants on Earth

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