Q.What is meant by plasmogamy?

Plasmogamy and Karyogamy

Sexual reproduction always ends with two parents' genetic material combining in one cell. But this combining is not a single instant event — it happens in stages. Two of the most important stages, especially clear in fungi, are plasmogamy and karyogamy. Understanding them separately explains a puzzling feature of fungal life cycles.

The sequence of fusion

• Plasmogamy is the fusion of the cytoplasm of two gametes (or two mating cells). The two cells merge their contents, so now a single cell contains two nuclei brought close together — but these nuclei have not yet fused.
• Karyogamy is the fusion of the two nuclei. When the two haploid nuclei unite, their chromosomes combine to form a single diploid (2n) zygote nucleus.

So the order is: cytoplasm fuses first (plasmogamy), nuclei fuse afterwards (karyogamy).

Why the delay matters — the dikaryotic stage …