Sexual reproduction of fungi carries out very differently in different groups of fungi. Sexual reproduction in lower fungi In lower fungi sexual repr

Sexual reproduction of fungi [propagation, mating]

Sexual reproduction of fungi carries out very differently in different groups of fungi.

Sexual reproduction in lower fungi

In lower fungi sexual reproduction is similar to algae’s. Here we have the isogamy and oogamy and finally zigogamy — a sexual process that resembles conjugation in Zygnematophyceae. Content of copulating cells usually is not differentiated into separate sexual elements. The first division of the zygote in lower fungi is meiosis.

Sexual reproduction in higher fungi (Dikarya)

Higher fungi (Dikarya) can be divided into two groups:

  • Ascomycetes (Ascomycota), in which there are more or less clear indications of the sexual process.
  • Basidiomycetes (Basidiomycota), which do not have even a hint of the existence of the sexual organs.

Sporulation in the form of asci is typical for ascomycetes; for basidiomycetes — as basidia (diagram 263). The first stages of the asci and basidia are the same. Ascus, as well as basidium, is binuclear at first. Then follows fusion of two nuclei, that causes the ascus and basidium to become single-nucleus again with a double set of chromosomes. The resulting cell divides with reducing method (meiosis). This is followed by the second (in the case of basidia) and often the third (in the case of asci) division, thereby producing 4 or 8 spores. Spores in ascomycetes occur within the cavity of the ascus, i.e. endogenously; in basidiomycetes they are on the surface and occur exogenously (diagram 263).

The development of asci and basidia with the fusion of the cells indicates their importance as sporophores of sexual origin. In contrast to the lower fungi, zygote of higher fungi that is a result of two cell’s protoplast fusion, does not go into a state of rest, and begins to germinate immediately. The nuclei in the zygote do not merge and come together in paired groups (dikaryons). Both dikaryons nucleus divide further on their own. The nuclear fusion occurs later — during the formation of ascus or basidium. Taken from http://worldofschool.org

Diagram 263. Structure of asci and basidia: 1 — development of ascus; 2 — development of basidium; s — spores

Loss of sexual function

In different groups of fungi could be traced trails of loss of sexual function. Lower fungi have sexual organs; many higher fungi have complexly organized sexual organs, often reduced. In this case, their scraps remain, usually no longer functioning.

In the most organized fungi — Basidiomycetes (Basidiomycota) sexual organs never form. The sexual process carries out in the form of a fusion of two cells, i.e. there is zigogamy.

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