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Spores are formed in the sporangiophore by encasing each haploid nucleus and cytoplasm in a tough outer membrane. During asexual reproduction, these spores are dispersed via wind and germinate into haploid hyphae. [4] Although sexual reproduction in fungi varies between phyla, for some fungi the sporangium plays an indirect role in sexual ...
A hypha consists of one or more cells surrounded by a tubular cell wall. In most fungi, hyphae are divided into cells by internal cross-walls called "septa" (singular septum). Septa are usually perforated by pores large enough for ribosomes, mitochondria, and sometimes nuclei to flow between cells.
Mucoralean fungi are typically fast-growing, and their wide hyphae (long, filamentous structures) lack septa (multi-perforate septa are present only in sporangiophores and gametangia). The hyphae grow mostly within the substrate. Sporangiophores are upright (simple or ramified) hyphae, that support sac-like sporangia filled with asexual ...
This relationship is supported by a number of observed differences between the characteristics of oomycetes and fungi. For instance, the cell walls of oomycetes are composed of cellulose rather than chitin [12] and generally do not have septations. Also, in the vegetative state they have diploid nuclei, whereas fungi have haploid nuclei.
An extension of the sporangiophore called the columella protrudes into the sporangium. The sporangium walls are easily ruptured to release the spores, which germinate readily to form a new mycelium on appropriate substrates. During sexual reproduction, compatible strains form short, specialized hyphae called gametangia. At the point where two ...
Rhizopus species grow as filamentous, branching hyphae that generally lack cross-walls (i.e., they are coenocytic). They reproduce by forming asexual and sexual spores. In asexual reproduction, spores are produced inside a spherical structure, the sporangium. Sporangia are supported by a large apophysate columella atop a long stalk, the ...
The sexual cycle is thought to occur by the following steps. Two hyphae of different mating type encounter each other, and their tips undergo a septation event to produce gametangia. Gametangia are haploid multinuclear cells equivalent to gametes. The two gametangia fuse to form an immature zygospore.
For instance, the zygomycota use light as signal to promote vegetative reproduction and growth of aerial hyphae to facilitate spore dispersal. Fungal phototropism has been investigated in detail using the fruiting body, sporangiophore, of Phycomyces as a model. Phycomyces has a complex photoreceptor system. It is able to react to different ...