Biology · BIOLOGICAL CLASSIFICATION

In members of Basidiomycetes (such as mushrooms and puffballs), traditional sex organs are completely absent. How is the initial dikaryotic stage accomplished during their sexual cycle?

1. By transformation of asexual conidia under high temperature conditions
2. By direct absorption of diploid nuclei from adjacent plant tissue cells
3. By endogenous spore germination inside a protected coenocytic sporangium
4. By plasmogamy brought about by fusion of two vegetative or somatic cells of different strains or genotypes