Sexual Reproduction in
Basidiomycota Fungi
Step-by-step explanation with
diagrams
Step 1: Spore Germination
• Basidiospores are released from the mushroom.
• A spore lands on a suitable surface and germinates.
• It grows into haploid mycelium (vegetative part of the fungus).
Step 2: Plasmogamy
• Two compatible haploid mycelia fuse their cytoplasm.
• This forms a heterokaryotic cell (contains two or more different nuclei).
• The nuclei remain separate at this stage.
Step 3: Fruiting Body Formation
• The heterokaryotic mycelium grows and forms a mushroom (fruiting body).
• Basidia structures form on the gills under the mushroom cap.
Step 4: Karyogamy
• Inside each basidium, the two nuclei fuse.
• This forms a diploid nucleus with a complete set of chromosomes.
Step 5: Meiosis
• The diploid nucleus undergoes meiosis.
• Four haploid nuclei are produced and become basidiospores.
• The cycle restarts when spores are released.
Summary of the Sexual Life Cycle
1. Spore → haploid mycelium
2. Plasmogamy → heterokaryotic mycelium
3. Fruiting body (mushroom) forms
4. Karyogamy → diploid nucleus
5. Meiosis → basidiospores