In the life bicycle of a sexually reproducing fungus, a haploid phase alternates v a diploid phase. The haploid step ends v nuclear fusion, and also the diploid phase starts with the formation of the zygote (the diploid cabinet resulting from combination of two haploid sex cells). Meiosis (reduction division) restores the haploid variety of chromosomes and initiates the haploid phase, which produces the gametes. In the majority of fungi, all structures room haploid other than the zygote. Nuclear blend takes location at the time of zygote formation, and also meiosis adheres to immediately. Only in Allomyces and a few related genera and in part yeasts is alternation that a haploid thallus with a diploid thallus definitely known.
You are watching: The diploid phase of the life cycle is shortest in which of the following
In the higher fungi a 3rd condition is interspersed between the haploid and also diploid phases that the life cycle. In these fungi, plasmogamy (fusion the the cellular contents of two hyphae but not the the two haploid nuclei) results in dikaryotic hyphae in which every cell has two haploid nuclei, one from each parent. Eventually, the nuclear pair fuses to form the diploid nucleus and thus the zygote. In the Basidiomycota, binucleate cells division successively and give climb to a binucleate mycelium, which is the key assimilative phase of the life cycle. It is the binucleate mycelium that eventually forms the basidia—the stalked fruiting bodies in i beg your pardon nuclear combination and meiosis take place prior come the development of the basidiospores.
Despite their gelatinous appearance, jelly mushroom (Tremella mesenterica; additionally known together witch"s butter) contain longitudinally septate basidia, i beg your pardon are formed from binucleate mycelia.
Fungi typically reproduce both sexually and also asexually. The asexual cycle produces mitospores, and also the sex-related cycle produces meiospores. Also though both varieties of spores are created by the very same mycelium, they are an extremely different in form and easily distinguished (see above Sporophores and also spores). The asexual phase usually precedes the sexual phase in the life cycle and may be repeated frequently before the sexual phase appears.
See more: 11039 East Freeway B Houston Tx 77029, Texas Department Of Public Safety
Some mushroom differ from rather in their lack of one or the other of the reproductive stages. Because that example, part fungi reproduce only sexually (except for fragmentation, i m sorry is common in many fungi), whereas others reproduce just asexually. A number of fungi exhibit the phenomenon that parasexuality, in which processes comparable to plasmogamy, karyogamy, and meiosis take it place. However, these processes execute not occur at a mentioned time or at specified points in the life bicycle of the organism. As a result, parasexuality is identified by the pervasiveness of heterokaryosis in a mycelium—i.e., the presence, next by side, the nuclei of various genetic composition.