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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/05/02 00:45:04」(JST)

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Mature sporangium of an Absidia mold

Moss sporangia

Sporangia (sori) on a fern leaf

Scanning electron micrograph of fern leptosporangia

Equisetum arvense strobilus cut open to reveal sporangia

A sporangium (pl., sporangia^[1]) (modern Latin, from Greek σπόρος (sporos) ‘spore’ + αγγείον (angeion) ‘vessel’) is an enclosure in which spores are formed.^[2] It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle. Sporangia can produce spores by mitosis, but in nearly all land plants and many fungi, sporangia are the site of meiosis and produce genetically distinct haploid spores.

Fungi

Structure containing the spores in fungal species.

Land plants

In mosses, liverworts and hornworts, an unbranched sporophyte produces a single sporangium, which may be quite complex morphologically. Most non-vascular plants, as well as many lycophytes and most ferns, are homosporous (only one kind of spore is produced). Some bryophytes, most lycophytes, and some ferns are heterosporous (two kinds of spores are produced). These plants produce microspores and megaspores, which give rise to gametophytes that are functionally male or female, respectively. In some cases, both kinds of spores are produced in the same sporangium, and may even develop together as part of a spore tetrad. However, in most heterosporous plants there are two kinds of sporangia, termed microsporangia and megasporangia. A few ferns (Salviniaceae and Marsileaceae) and some lycophytes (the genera Selaginella and Isoetes and the extinct lepidodendrids) are heterosporous with two kinds of sporangia, as are all the seed plants.

Sporangia can be terminal (on the tips) or lateral (placed along the side) of stems or associated with leaves. In ferns, sporangia are typically found on the abaxial surface (underside) of the leaf and are densely aggregated into clusters called sori. Sori may be covered by a structure called an indusium. Some ferns have their sporangia scattered along reduced leaf segments or along (or just in from) the margin of the leaf.

Lycophytes, in contrast, bear their sporangia on the adaxial surface (the upper side) of leaves or laterally on stems. Leaves that bear sporangia are called sporophylls. If the plant is heterosporous, the sporangia-bearing leaves are distinguished as either microsporophylls or megasporophylls. In seed plants, sporangia are typically located within strobili or flowers.

Cycads form their microsporangia on microsporophylls which are aggregated into strobili. Megasporangia are formed within ovules, which are borne on megasporophylls, which are aggregated into strobili on separate plants (all cycads are dioecious). Conifers typically bear their microsporangia on microsporophylls aggregated into papery pollen strobili, and the ovules, are located on modified stem axes forming compound ovuliferous cone scales. Flowering plants contain microsporangia in the anthers of stamens (typically four microsporangia per anther) and megasporangia inside ovules inside ovaries. In all seed plants, spores are produced by meiosis and develop into gametophytes while still inside the sporangium. The microspores become microgametophytes (pollen). The megaspores become megagametophytes (embryo sacs).

Eusporangia and leptosporangia

Categorized based on developmental sequence, eusporangia and leptosporangia are differentiated in the vascular plants.

In a leptosporangium, found only in ferns, development involves a single initial cell that becomes the stalk, wall, and spores within the sporangium. There are around 64 spores in a leptosporangium.
In a eusporangium, characteristic of all other vascular plants and some primitive ferns, the initials are in a layer (i.e., more than one). A eusporangium is larger (hence contain more spores), and its wall is multi-layered. Although the wall may be stretched and damaged, resulting in only one cell-layer remaining.

Synangium

A cluster of sporangia that have become fused in development is called a synangium. This structure is most prominent in Psilotum and Marattiaceae such as Christensenia, Danaea and Marattia.

Internal structures

A columella (pl. columellae) is a sterile (non-reproductive) structure that extends into and supports the sporangium. In fungi, the columella, which may be branched or unbranched, may be of fungal or host origin. Secotium species have a simple, unbranched columella, while in Gymnoglossum species, the columella is branched. In some Geastrum species, the columella appears as an extension of the stalk into the spore mass (gleba).^[3]

References

^ http://oxforddictionaries.com/definition/sporangium
^ Rost, Barbour, Stocking, Murphy, 2006Plant Biology, 2nd EditionThompson Brooks/Cole
^ Kirk PM, Cannon PF, Minter DW, Stalpers JA (2008). Dictionary of the Fungi. (10th ed.). Wallingford: CABI. p. 161. ISBN 978-0-85199-826-8.

English Journal

Mycelial Mattress from a Sporangia Formation-Delayed Mutant of Rhizopus stolonifer as Wound Healing-Enhancing Biomaterial.

Chien MY1, Chen LC2, Chen YC2, Sheu MT3, Tsai YC4, Ho HO2, Su CH5, Liu DZ6.
PloS one.PLoS One.2015 Aug 14;10(8):e0134090. doi: 10.1371/journal.pone.0134090. eCollection 2015.
A mycelial mattress of Rhizopus stolonifer obtained from a liquid static culture was utilized for wound dressing and biomedical use. Following screening of mutants induced by UV radiation, F6, exhibiting delayed sporangium formation was selected because its sporangium maturation exhibited a 5-day de
PMID 26275241

Update on mucormycosis pathogenesis.

Ibrahim AS1, Kontoyiannis DP.
Current opinion in infectious diseases.Curr Opin Infect Dis.2013 Dec;26(6):508-15. doi: 10.1097/QCO.0000000000000008.
PURPOSE OF REVIEW: Mucormycosis is an increasingly common fungal infection with unacceptably high mortality. The recent sequencing genome projects of Mucorales and the development of gene manipulation have enabled significant advances in understanding the pathogenesis of mucormycosis. Therefore, we
PMID 24126718

Effect of Potassium Ions on Protoplast Generation during Yeast Induction from Mucor circinelloides Tieghem.

Omoifo CO1.
ISRN biotechnology.ISRN Biotechnol.2012 Nov 11;2013:734612. doi: 10.5402/2013/734612. eCollection 2013.
Mucor circinelloides aerobically exhibits coenocytic thallic growth habit with straight and circinate sporangiophores which culminate in globose or pyriform columellae enclosed within sporangial walls. It undergoes dimorphic switch with its conversion to multipolar budding yeast-like cells or thalli
PMID 25969779

Japanese Journal

Variations in the morphology of Rhizomucor pusillus in granulomatous lesions of a Magellanic penguin (Spheniscus magellanicus)

, , , , , ,
Journal of Veterinary Medical Science advpub(0), 2015
This report presents a new case of mucormycosis encountered in penguin characterized by morphological variation of hyphae and presence of sporangia with numerous sporangiospores. A 4.5-year-old Magell …
NAID 130005064936

Intraspecific groups of Umbelopsis ramanniana inferred from nucleotide sequences of nuclear rDNA internal transcribed spacer regions and sporangiospore morphology

Ogawa Yoshio,Suda Atsuhiro,Kusama-Eguchi Kuniko [他],WATANABE Kazuko,TOKUMASU Seiji
Mycoscience 46(6), 343-351, 2005-12-25
NAID 10017160426

Two ultrastructural aspects of the trichospore of Pennella angustispora (Harpellales) : canals in the sporangiospore cell wall and appendage formation

Sato Hiroki
Mycoscience 43(1), 33-36, 2002-02-15
NAID 10013886020

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