Search results
Results From The WOW.Com Content Network
In bryophytes and other cryptogams, sperm reach the archegonium by swimming in water films, whereas in Pinophyta and angiosperms, the pollen are delivered by wind or animal vectors and the sperm are delivered by means of a pollen tube. [citation needed] Gene expression pattern determined by histochemical GUS assays in Physcomitrella patens
Archegoniatae was a higher taxonomic term that indicated those embryophytes having a female sexual organ in the form of an archegonium.The term was first introduced by the Russian botanist Ivan Nikolaevich Gorozhankin (1848–1904) in 1876 to indicate a division including bryophytes, pteridophytes and gymnosperms in contrast to the Gynoeciatae (Angiosperms) with a more complex female organ.
When (as is almost always the case) the sperm and eggs are produced in different kinds of gametangia, the sperm-producing ones are called antheridia (singular antheridium) and the egg-producing ones archegonia (singular archegonium). Gametophyte of Pellia epiphylla with sporophytes growing from the remains of archegonia
Some bryophytes, such as the liverwort Marchantia, create elaborate structures to bear the gametangia that are called gametangiophores. Sperm are flagellated and must swim from the antheridia that produce them to archegonia which may be on a different plant. Arthropods can assist in transfer of sperm. [14]
Antheridia producing non-motile sperm (spermatia) are called spermatangia. Some antheridia do not release their sperm. Some antheridia do not release their sperm. For example, the oomycete antheridium is a syncytium with many sperm nuclei and fertilization occurs via fertilization tubes growing from the antheridium and making contact with the ...
The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. [1] The 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. [2]
In dioicous mosses, male and female sex organs are borne on different gametophyte plants. In monoicous (also called autoicous) mosses, both are borne on the same plant. In the presence of water, sperm from the antheridia swim to the archegonia and fertilisation occurs, leading to the production of a diploid sporophyte. The sperm of mosses is ...
A cluster of antheridia is called an androecium while a cluster of archegonia is called a gynoecium. (Note these terms have a different meaning when used to refer to flower structures.) Bryophytes have the most elaborate gametophytes of all living land plants, and thus have a wide variety of gametangium positions and developmental patterns.