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A sporangium (from Late Latin, from Ancient Greek σπορά (sporá) 'seed' and ἀγγεῖον (angeîon) 'vessel'); pl.: sporangia) [1] is an enclosure in which spores are formed. [2] It can be composed of a single cell or can be multicellular .
In meiotic sporogenesis, a diploid spore mother cell within the sporangium undergoes meiosis, producing a tetrad of haploid spores. In organisms that are heterosporous, two types of spores occur: Microsporangia produce male microspores, and megasporangia produce female megaspores. In megasporogenesis, often three of the four spores degenerate ...
Spores form part of the life cycles of many plants, algae, fungi and protozoa. [2] They were thought to have appeared as early as the mid-late Ordovician period as an adaptation of early land plants. [3] Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. [4]
The sporophyte produces spores (hence the name) by meiosis, a process also known as "reduction division" that reduces the number of chromosomes in each spore mother cell by half. The resulting meiospores develop into a gametophyte. Both the spores and the resulting gametophyte are haploid, meaning they only have one set of chromosomes.
In addition to the chlamydospore, P. cactorum also produces another asexual spore called a sporangium. A sporangia is a multinucleate dispersal structure with a thin wall and papilla that is formed on a sporangiophore. Although the size may vary based on the environmental conditions in which they are formed, the width of a sporangia is always ...
An annulus in botany is for ferns an arc or a ring of specialized cells on the sporangium. These cells are arranged in a single row, and are associated with the release or dispersal of spores. In mosses it is a ring of cells around the tip of the sporangium. In flowers it is a ring of hairs within the flower tube.
[1] [2] These products then reproduce by mitotic divisions leading to the formation of a sporangium structure (germosporangium) that develops out from the zygospore. The germosporangium contains spores (germspores) that have one to six haploid nuclei like those in the vegetative sporangium.
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 sporangiophore. Sporangiophores arise among distinctive, root-like rhizoids. In sexual reproduction, a dark zygospore is produced at the point where two compatible mycelia fuse ...