A sporangium (; from
Late Latin
Late Latin ( la, Latinitas serior) is the scholarly name for the form of Literary Latin of late antiquity.Roberts (1996), p. 537. English dictionary definitions of Late Latin date this period from the , and continuing into the 7th century in t ...
, ) is an enclosure in which
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...
s are formed. It can be composed of a
single cell Single cell and similar can mean:
Biology
* Single-cell organism
*Single-cell protein
* Single-cell recording, a neuro-electric monitoring technique
* Single-cell sequencing
**Single cell epigenomics
*Single-cell transcriptomics
Other
*Single-cell ...
or can be
multicellular
A multicellular organism is an organism that consists of more than one cell, in contrast to unicellular organism.
All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially ...
. Virtually all
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...
s,
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
, and many other lineages form sporangia at some point in their
life cycle. Sporangia can produce spores by
mitosis
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...
, but in nearly all land plants and many fungi, sporangia are the site of
meiosis
Meiosis (; , since it is a reductional division) is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, such as sperm or egg cells. It involves two rounds of division that ultimately ...
and produce genetically distinct
haploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...
spores.
Fungi
In some phyla of fungi, the sporangium plays a role in
asexual reproduction
Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the ...
, and may play an indirect role in
sexual reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote th ...
. The sporangium forms on the sporangiophore and contains
haploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...
nuclei and
cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...
.
Spores are formed in the sporangiophore by encasing each haploid nucleus and cytoplasm in a tough outer
membrane. During
asexual reproduction
Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the ...
, these
spores are dispersed via wind and
germinate into haploid
hypha
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one or ...
e.
Although
sexual reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote th ...
in fungi varies between phyla, for some fungi the sporangium plays an indirect role in sexual reproduction. For
Zygomycota, sexual reproduction occurs when the haploid hyphae from two individuals join to form a
zygosporangium in response to unfavorable conditions. The haploid nuclei within the zygosporangium then fuse into
diploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectiv ...
nuclei.
When conditions improve the zygosporangium germinates, undergoes meiosis and produces a sporangium, which releases spores.
Land plants
In mosses, liverworts and hornworts, an unbranched
sporophyte
A sporophyte () is the diploid multicellular stage in the life cycle of a plant or alga which produces asexual spores. This stage alternates with a multicellular haploid gametophyte phase.
Life cycle
The sporophyte develops from the zygote ...
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 lycophytes and 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
Marsileaceae () is a small family of heterosporous aquatic and semi-aquatic ferns, though at first sight they do not physically resemble other ferns. The group is commonly known as the "pepperwort family" or as the "water-clover family" because ...
) and some lycophytes (the genera ''
Selaginella
''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses.
This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having ...
'' 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
fern
A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...
s, sporangia are typically found on the