Subtopic: Antheridium Structure
– Antheridia consist of a thin cellular layer holding many sperm inside
– Diagram of a liverwort antheridium depicts the general structure
– Antheridium is a haploid organ producing male gametes called antherozoids or sperm
– Androecium is the term for a structure containing one or more antheridia
– Antheridia are found in the gametophyte phase of bryophytes, ferns, algae, and some fungi
Subtopic: Reduction of Antheridia in Gymnosperms and Angiosperms
– In gymnosperms and angiosperms, male gametophytes are reduced to pollen grains
– Antheridia in these plants are reduced to a single generative cell within the pollen grain
– During pollination, the generative cell divides to produce sperm cells
– Female counterparts to antheridia are archegonium in cryptogams and gynoecium in flowering plants
– Antheridium typically consists of sterile cells and spermatogenous tissue
Subtopic: Antheridium in Bryophytes
– Sterile cells in the antheridium may form a central support structure or a protective jacket
– Spermatogenous cells give rise to spermatids through mitotic cell division
– In some bryophytes, antheridium is borne on an antheridiophore
– Antheridiophore is a stalk-like structure carrying the antheridium at its apex
– Moss flowers have clusters of antheridia, forming an androecium
Subtopic: Gallery of Antheridia
– Oogonium and antheridium of the alga Chara are produced on the plant stem
– Developing antheridia in Hypnum cupressiforme shown in a magnified view
– Sperm of Marchantia polymorpha liverwort are produced on the upper surface of antheridiophores
– Cross-sectional micrograph of antheridia in Marchantia sp. shows spermatogenous tissue
– Antheridium of Equisetum sp. depicted in a micrograph
Subtopic: Related Concepts
– Hornworts have antheridia, sometimes arranged within androecia
– Microsporangia produce spores leading to male gametophytes
– References include studies on hornworts, fern gametophytes, and taxonomy of model systems
– Further reading materials cover developmental physiology of fern gametophytes
– Taxonomy, phylogeny, and morphology of Marchantia polymorpha are detailed in plant and cell physiology studies
An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. Androecium is also the collective term for the stamens of flowering plants.
Antheridia are present in the gametophyte phase of cryptogams like bryophytes and ferns. Many algae and some fungi, for example ascomycetes and water moulds, also have antheridia during their reproductive stages. In gymnosperms and angiosperms, the male gametophytes have been reduced to pollen grains and in most of these the antheridia have been reduced to a single generative cell within the pollen grain. During pollination, this generative cell divides and gives rise to sperm cells.
The female counterpart to the antheridium in cryptogams is the archegonium, and in flowering plants is the gynoecium.
An antheridium typically consists of sterile cells and spermatogenous tissue. The sterile cells may form a central support structure or surround the spermatogenous tissue as a protective jacket. The spermatogenous cells give rise to spermatids via mitotic cell division. In some bryophytes, the antheridium is borne on an antheridiophore, a stalk-like structure that carries the antheridium at its apex.