Microsporogenesis and Megasporogenesis – NEET Notes with Diagrams

🌿 What Is Sporogenesis?

Sporogenesis is the process of formation of spores (which later become gametophytes). In angiosperms, it occurs inside reproductive structures:

Microsporogenesis → In anthers

Megasporogenesis → In ovules

🧠 Trick: “Micro = Male, Mega = Female”

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🔹 Microsporogenesis – Formation of Male Gametophyte

📍Location: Anther (Pollen Sac)

🔬 Steps:

1. Microspore Mother Cell (MMC) inside pollen sacs undergoes meiosis

2. Forms a tetrad of 4 haploid microspores

3. Microspores develop into pollen grains

📌 Key Points:

Each pollen grain is 2-celled (generative + vegetative)

Microspores arranged in a tetrad

Happens in microsporangia

🧠 Mnemonic: “MMC → Meiosis → Microspores → Male Pollen”

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🔹 Megasporogenesis – Formation of Female Gametophyte

📍Location: Ovule (Nucellus)

🔬 Steps:

1. Megaspore Mother Cell (MMC) undergoes meiosis

2. Produces 4 haploid megaspores, but only one survives

3. That one megaspore undergoes 3 mitotic divisions → Embryo sac (female gametophyte)

📌 Key Points:

Embryo sac is 7-celled, 8-nucleated

Occurs in nucellus part of ovule

MMC = diploid → megaspore = haploid

🧠 Mnemonic: “MMC → 1 Megaspore → 3 Mitosis → Embryo sac”

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🧬 Comparison Table

Feature Microsporogenesis Megasporogenesis

Occurs in Anther (microsporangium) Ovule (nucellus)

Initial Cell Microspore Mother Cell (MMC) Megaspore Mother Cell (MMC)

Type of Division Meiosis Meiosis

Product 4 Microspores 4 Megaspores (1 survives)

Resulting Gametophyte Male gametophyte (Pollen grain) Female gametophyte (Embryo sac)