Biology · BIOLOGICAL CLASSIFICATION

In Ascomycetes and Basidiomycetes, fusion of haploid cells does not immediately result in diploid cells; instead, an intervening dikaryotic stage (\( n + n \)) occurs. What is the ultimate developmental fate of these dikaryotic hyphae in fruiting bodies?

1. They undergo immediate mitotic cleavage without nuclear fusion to form conidia
2. They remain permanently in the \( n + n \) state and directly transform into asexual sporangia
3. The cells lose both nuclei and undergo apoptosis to form hollow structural stalks
4. The parental nuclei fuse to form diploid cells, which subsequently undergo reduction division to form haploid spores