Dictionary Definition

microsporophyll n : in non-flowering plants, a sporophyll that bears only microsporangia

Extensive Definition

A sporangium (pl., sporangia) is a plant or fungal structure producing and containing spores. Sporangia occur in angiosperms, gymnosperms, ferns, fern allies, bryophytes, algae, and fungi. Their spores are sometimes called sporangiospores.
Microsporangia are the structures on the stamens of flowers called anthers, and the pollen-producing structures on the microsporophylls of male conifer cones or cycad cones.
Megasporangia are the comparable "female" structures on these plants, associated with the flower carpel and the megasporangial cone.
On ferns, the mature plant is a sporophyte that develops sporangia, tiny, stalked sacs which contain meiospores, on all or just certain leaves (called sporophylls if sporangia are present). The spores are usually on the underside of the leaves.
In mosses, the little case that rises above the vegetative growth on a thin stalk is a sporangium often called a capsule that, as in ferns, produces meiospores. This sporophytic (diploid) growth arises out of the gametophytic (haploid) archegonium after the ovum is fertilized. The sporophyte initially has some chlorophyll, but later turns brown and becomes dependent upon the gametophyte for nutrition, which is absorbed through the foot (base of the stalk), embedded in the archegonial tissues.
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.
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.

See also

microsporophyll in Afrikaans: Sporangium
microsporophyll in Czech: Mikrosporangium
microsporophyll in German: Sporangium
microsporophyll in Spanish: Esporangio
microsporophyll in Persian: هاگدان
microsporophyll in French: Sporange
microsporophyll in Icelandic: Gróhirsla
microsporophyll in Italian: Sporangio
microsporophyll in Hebrew: מנבג
microsporophyll in Dutch: Sporangium
microsporophyll in Japanese: 胞子嚢
microsporophyll in Polish: Zarodnia
microsporophyll in Portuguese: Esporângio
microsporophyll in Russian: Спорангий
microsporophyll in Chinese: 孢子囊
Privacy Policy, About Us, Terms and Conditions, Contact Us
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2
Material from Wikipedia, Wiktionary, Dict
Valid HTML 4.01 Strict, Valid CSS Level 2.1