Image Archegonium.jpg right thumb 240px Diagram of archegonium anatomy An archegonium pl archegonia , from the ancient Greek beginning and offspring , is a multicellular structure or organ of the gametophyte phase of certain plant s, producing and containing the ovum or female gamete . The archegonium has a long neck and a swollen base. Archegonia are typically located on the surface of the plant thallus , although in the hornwort s they are embedded. In the moss Physcomitrella patens , archegonia are not embedded but are located on top of the leafy gametophore s. Figure . The Polycomb protein FIE is expressed in the unfertilised egg cell right as the blue colour after GUS reporter system GUS staining reveals. Soon after fertilisation the FIE gene is inactivated the blue colour is no longer visible, left in the young embryo. ref Assaf Mosquna, Aviva Katz, Eva L. Decker, Stefan A. Rensing, Ralf Reski , Nir Ohad 2009 Regulation of stem cell maintenance by the Polycomb protein FIE has been conserved during land plant evolution. Development 136, 2433 2444. http dev.biologists.org cgi content short 136 14 2433 ref ref The Polycomb gene FIE is expressed blue in unfertilised egg cells of the moss Physcomitrella patens right and expression ceases after fertilisation in the developing diploid sporophyte left . In situ GUS staining of two female sex organs archegonia of a transgenic plant expressing a translational fusion of FIE uidA under control of the native FIE promoter. http dev.biologists.org content vol136 issue14 cover.shtml ref File DEV035048A.jpg thumb Gene expression pattern determined by histochemical GUS assays in Physcomitrella patens They are also much reduced ... part by diploid cells of the megasporangium nucellus inside the ovule . Gymnosperms have their archegonium ... da Arkegonium de Archegonium es Arquegonio fr Arch gone io Arkegonio he lv Arhegonijs nl Archegonium pl Rodnia pt Arqueg nio ru uk ... more details
This article is about a feature in plant morphology. For other uses Calyptra disambiguation Image Tortula muralis kalyptra.jpeg thumb 300px Calyptra of tortula moss Tortula muralis In bryophytes , the calyptra plural calyptrae is an enlarged Archegonium archegonial venter that protects the Capsule anatomy capsule containing the embryonic sporophyte . The calyptra is usually lost before the spores are released from the capsule. The shape of the calyptra can be used for identification purposes. ref Citation last Malcolm Malcolm first Bill Nancy title Mosses and other Bryophytes, an Illustrated Glossary year 2006 publisher Micro Optics Press page 65 isbn 0958222479 ref In flowering plant s, the calyptra is a covering tissue for stamen s and carpel s. The name is also used for the capping tissue of root s. References reflist Category plant morphology botany stub de Kalyptra es Caliptra nl Calyptra pl Czepek botanika ru ... more details
Unreferenced stub auto yes date December 2009 A gametangium plural gametangia is an Organ anatomy organ or cell biology cell in which gamete s are produced that is found in many multicellular protist s, algae , Fungus fungi , and the gametophyte s of plant s. In contrast to gametogenesis in animal s, a gametangium is a haploid structure and formation of gametes does not involve meiosis . Types of gametangia Depending on the type of gamete produced in a gametangium, several types can be distinguished. Female Main Archegonium Oogonium Female gametangia are most commonly called Archegonium archegonia . They produce egg cell s and are the sites for fertilization . Archegonia are common in algae and primitive plants as well as gymnosperm s. In flowering plant s, they are replaced by the embryo sac inside the ovule . Male Main Antheridium The male gametangia are most commonly called Antheridium antheridia . They produce Sperm sperm cells that they release for fertilization. Antheridia producing non motile sperm spermatia are called spermatangia . Some antheridia do not release their sperm. For example, the oomycete antheridium is a syncytium with many sperm Cell nucleus nuclei and fertilization occurs via fertilization tubes growing from the antheridium and making contact with the egg cells. Antheridia are common in the gametophytes in lower plants such as bryophyte s, fern s, cycad s and ginkgo . In higher plants such as conifer s and flowering plants, they are replaced by pollen grain s. Isogamous In isogamy , the gametes look alike and cannot be classified into male or female. For example, in zygomycete s, two gametangia single cells at the end of hypha e form upon contact with each other and fuse into a zygospore . Category Reproduction Category Reproductive system Category Germ cells Botany stub cs Gametangium da Gametangium de Gametangium lv Gametangiji nl Gametangium pl Gametangium pt Gamet ngio ru uk ... more details
A sporeling is a young plant or fungus produced by a germinated spore , similar to a seedling derived from a germinated seed . They occur in alga e, fungus fungi , lichen s, bryophyte s and Pteridophyte seedless vascular plant s. Sporeling development Most spores germinate by first producing a germ rhizoid or holdfast followed by a germ tube emerging from the opposite end. The germ tube develops into the hypha , protonema or thallus tissue thallus of the gametophyte . In seedless vascular plants such as fern s and lycopodiophyta , the term sporeling refers to the young sporophyte growing on the gametophyte. These sporelings develop via an embryo stage from a fertilized egg inside an archegonium and depend on the gametophyte for their early stages of growth before becoming independent sporophytes. Young fern sporelings can often be found with the prothallus gametophyte still attached at the base of their frond s. External links British Pteridological Society http www.nhm.ac.uk hosted sites bps wof wof.htm An introduction to ferns contains a picture of a sporeling fern attached to the prothallus botany stub Category Plant morphology Category Plant reproduction Category Fungal morphology and anatomy ... more details
only antheridium antheridia male organs or archegonium archegonia female organ on a single gametophyte body. Monoicous pteridophytes produce both antheridium antheridia and archegonium archegonia on the same ... more details
inside Archegonium archegonia . Since the archegonium is a haploid structure, egg cells are produced via mitosis . The typical bryophyte archegonium consists of a long neck with a wider base containing the egg cell. Upon maturation, the neck opens to allow sperm cells to swim into the archegonium and fertilize the egg. The resulting zygote then gives rise to an embryo, which will grow out of the archegonium ... gives rise to the archegonium, has been reduced to just eight cells referred to as the embryo ... more details
Image Antheridia.jpg right thumb 240px Diagram of antheridium anatomy An antheridium or antherida plural antheridia is a haploid structure or organ producing and containing male gamete s called antherozoids or sperm . It is present in the gametophyte phase of lower plant s like moss es and fern s, and also in the primitive vascular Psilotophyta psilotophytes . Many alga e and some Fungus fungi , for example ascomycete s and water mould s, also have antheridia during their reproductive stages. An antheridium typically consists of sterile cell biology cell s and spermatogenous tissue biology 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 spermatid s via mitotic cell division . In bryophyte s, the antheridium is borne on an antheridiophore , a stalk like structure that carries the antheridium at its apex. In many gymnosperm s and all angiosperm s, the male gametophytes have been reduced to Pollen pollen grains and their antheridia have been reduced to a single generative cell within the pollen grain. During pollination , this generative cell divides and gives rise to two sperm nuclei. The female counterpart to the antheridium is the archegonium . References C.Michael Hogan. 2010. http www.eoearth.org article Fern Fern . Encyclopedia of Earth. National council for Science and the Environment . Washington, DC Gallery gallery Image Hypnum cupressiforme perichaetialblaetter.jpeg center Magnified view of developing antheridia in Hypnum cupressiforme center gallery Category Plant anatomy Category Plant reproduction Botany stub bg ca Anteridi cs Pelatka de Antheridium es Anteridio fr Anth ridie io Anteridio he lv Anter dijs nl Antheridium pl Plemnia pt Anter deo ru uk zh ... more details
italictitle Taxobox name Jensenia image image width 240px image caption regnum Plant ae divisio Marchantiophyta classis Jungermanniopsida ordo Metzgeriales familia Pallaviciniaceae genus Jensenia genus authority Lindb. 1868 subdivision ranks Species subdivision Jensenia angulata br Jensenia canicruria br Jensenia decipiens br Jensenia difformis br Jensenia erythropus br Jensenia lewisi br Jensenia pisicolor br Jensenia spinosa synonyms Makednothallus Mittenia Jensenia is a bryophyte plant genus in the Marchantiophyta liverwort family biology family Pallaviciniaceae . It has been treated as a subgenus of Pallavicinia by several authors, though a set of features seems to set it apart as a genus. ref name P Cite journal authorlink S.M. Perold title The hepatic, Jensenia spinosa Pallavicinia stephanii Pallaviciniaceae , in southern Africa journal Bothalia volume 23,2 pages 223 229 year 1993 ref The six ref Grolle, 1964 ref or seven ref Engel, 1990 ref species of the genus belong to a southern, possibly Gondwana Gondwanaland element. ref name P General characteristics Jensenia liverworts are Monoicous dioicous . Compared to Pallavicinia liverworts, ref name P ref Grolle & Piippo, 1986 ref their thallus grows erect, and branches tree like, rather than trailing the ground. The thallus is perched on an ascending Stipe botany stipe which grows from a creeping rhizome . Slime Plant cuticle papilla e are absent from the thallus margin, though locally present elsewhere. The midrib of the thallus is broad but ill defined. Reproductive morphology Male reproductive organs are scattered over the thallus s dorsal surface, while female organs are specifically placed near a bifurcation of the frond . The pseudoperianth, a tube of thallus tissue protecting the Archegonium archegonia , is basally Connation fused with the calyptra . Following fertilization, the sporophyte is enveloped by three structures the cup shaped involucre , cylindrical pseudoperianth and the calyptra. The spore su ... more details
Image Liverwort prothallus.jpg thumb right Liverwort Prothallus A prothallium , or prothallus from Latin pro forwards and Greek language Greek thallos twig is usually the gametophyte stage in the life of a fern or other pteridophyte , i.e. a spore bearing plant with vascular tissue . Occasionally the term is also used to describe the young gametophyte of a Marchantiophyta liverwort or Sphagnum peat moss as well. The prothallium develops from a Germination germinating spore . It is a short lived and inconspicuous heart shaped structure typically 2 5 millimeters wide, with a number of rhizoid s root like hairs growing underneath, and the sex organs archegonium female and antheridium male . Appearance varies quite a lot between species. Some are green and conduct photosynthesis while others are colorless and nourish themselves underground as saprotrophs . Image Dixonia prothallus.jpg thumb right 250px Prothallus of the tree fern Dicksonia antarctica note new moss plants for scale Alternation of generations Pteridophyte Spore bearing plants , like all plants, go through a life cycle of alternation of generations . The fully grown sporophyte , what the layman refers to as the fern , produces genetically unique spore s in the sori by meiosis . The haploid spores fall from the sporophyte and germinate by mitosis , given the right conditions, into the gametophyte stage, the prothallus. The prothallus then develops independently for several weeks it grows sex organs and produces ovum ova and sperm flagellated sperm . After rainfall, the sperm are able to swim to the ova for fertilization to form a diploid sporophyte cell. This cell divides by mitosis and grows out of the gametophyte into a new fern, which will produce new spores that will grow into new prothallia etc., thus completing the life cycle of the organism . Advantages of alternation of generations There are two important evolutionary advantages to the alternation of generations plant life cycle. Firstly, by ... more details
Taxobox image Sphaerocarpos texanus.jpg image width 240px image caption Female plants of Sphaerocarpos texanus bearing mature sporophytes. regnum Plant ae divisio Marchantiophyta classis Marchantiopsida ordo Sphaerocarpales familia Sphaerocarpaceae genus Sphaerocarpos species S. texanus binomial Sphaerocarpos texanus binomial authority Aust. ref cite journal last Austin first C. F. year 1877 title New Hepaticae journal Bulletin of the Torrey Botanical Club volume 8 pages 157 158 ref synonyms Sphaerocarpus berterii small Aust., 1873 small br Sphaerocarpus californicus small Aust., 1879 small br Sphaerocarpus europaeus small Lorbeer, 1934 small br Sphaerocarpus terrestris small Bisch., 1827 small Sphaerocarpos texanus is a species of Marchantiophyta liverwort in the Sphaerocarpaceae family, found in the Americas, northern Africa and Europe. Description S. texanus are small, thallus thalloid , dioecy dioecious liverworts. ref name H Cite journal authorlin C. C. Hayes title Sphaerocarpos hians sp. nov., with a revision of the genus and illustrations of the species journal Bull. Torr. Bot. Club volume 37,5 pages 215 230 year 1910 ref The species is sexual dimorphism sexually dimorphic , with male plants usually 3 5 mm in diameter, females up to 12 mm in diameter ref name M Cite journal authorlin D. N. McLetchie title Sex specific germination response in the liverwort Sphaerocarpos texanus Sphaerocarpaceae journal Bryologist volume 104,1 pages 69 71 year 2001 ref . Both male bearing antheridium antheridia and female bearing archegonium archegonia plants are bright green, with the thallus branching up to several times ref name H . The plant is a winter annual, appearing in autumn and dying in spring ref name M . Notably, the spore spores occur in sets of four, called tetrads. Unlike most other species of liverwort, the spores stay in these tetrads until they germinate ref name H ref name M . Habitat The plant is found on flat, lightly shaded soil. Usually by roadsides ref ... more details
Italic title Taxobox name Chara image CharaFragilis.jpg image caption Chara globularis regnum Plant ae divisio Charophyta classis Charophyceae ordo Charales familia Characeae genus Chara genus authority Carolus Linnaeus L. , 1753 subdivision ranks Species subdivision See text Chara is a genus of green algae in the family Characeae . Structure Chara species are multicellular and superficially resemble land plants because of Plant stem stem like and leaf like structures. The branching system is complex with branches derived from apical cells which cut off segments at the base to form nodal and internodal cells alternately. They are typically anchored to the littoral Substrate biology substrate by means of branching underground rhizoid s. Chara plants are rough to the touch because of deposited calcium salts on the cell wall. The metabolic processes associated with this deposition often give Chara plants a distinctive and unpleasant smell of hydrogen sulfide . ref F.E.Round, The Biology of the algae, Ernest Arnold, 1966 ref Morphology The plant body is a gametophyte. It consists of a main axis differentiated into nodes and internodes , dimorphic branches long brach of unlimited growth and short branches of limited growth , rhizoids multicellular with oblique septa and stipulodes needle shaped structures at the base of secondary laterals. Occurrence Species are found in fresh water, particularly in limestone areas throughout the northern temperate zone. They prefer less oxygenated and hard water and are not found in the waters where mosquito larvae are present. Chara grow submerged attached to the muddy bottom of the pools and ponds of clear water. They are covered with calcium carbonate deposits. Reproduction Chara reproduces vegetatively and sexually. Vegetative reproduction takes place by tubers, amylum stars and secondary protonema. The fructifications for sexual reproduction are globule or antheridium male and nucule or archegonium female . Species Chara braunii IT ... more details
Taxobox status image Moos 5772.jpg image width 250px regnum Plant ae divisio Marchantiophyta classis Marchantiopsida ordo Marchantiales familia Marchantiaceae genus Marchantia species M. polymorpha binomial Marchantia polymorpha binomial authority Carolus Linnaeus L. synonyms Marchantia alpestris br Marchantia aquatica Marchantia polymorpha , sometimes known as the common liverwort or umbrella liverwort , is a large Marchantiophyta liverwort with a wide distribution around the world. It is variable in appearance and has several subspecies . It is dioecious , having separate male and female plants. Description It is a thallus thallose liverwort which forms a rosette of flattened thalli with forked branches. The thalli grow up to 10 cm long with a width of up to 2 cm. It is usually green in colour but older plants can become brown or purplish. The upper surface has a pattern of hexagonal markings. The underside is covered by many root like rhizoid s which attach the plant to the soil. The plants produce umbrella like reproductive structures known as gametophore s. The gametophores of female plants consist of a stalk with star like rays at the top. These contain archegonium archegonia , the organs which produce the ovum ova . Male gametophores are topped by a flattened disc containing the antheridium antheridia which produce sperm . Reproduction Marchantia polymorpha can reproduce both sexual reproduction sexually and asexual reproduction asexually . Sexual reproduction involves sperm from the male plant fertilisation fertilizing ova from the female plants. A fertilized ovum develops into a small sporophyte plant which remains attached to the larger gametophyte plant. The sporophyte produces male and female spore s which develop into free living gametophyte plants. Asexual reproduction can occur when older parts of the plant die and newer branches develop into separate plants. It can also occur by means of gemma botany gemma e, balls of cells which are geneti ... more details
, the female organs are known as archegonium archegonia singular archegonium and are protected by the thin surrounding perichaetum plural perichaeta . ref name Schofield 1985 Each archegonium has a slender ... where they are produced to the archegonium where the eggs are held. The sperm of liverworts is biflagellate ... of a diploid sporophyte. After fertilisation, the immature sporophyte within the archegonium develops ... elongates, pushing its way out of the archegonium and rupturing it. While the foot remains anchored ... Archegonium.jpg center The archegonium of Porella . center Image Porella SPT.jpg center A sporophyte emerging from its archegonium. center Image Porella platyphylla.jpg center Porella platyphylla clump ... more details
gametophyte plants. Eventually, plants with archegonium archegonia were found, which resembled ... are very brittle. Unlike in other bryophyte s, the egg producing archegonium archegonia and sperm ... more details
shaped sporophyte grows from an archegonium embedded deep in the gametophyte. The sporophyte ... are known as archegonium archegonia singular archegonium and the male organs are known as antheridium ... more details
italic title Taxobox name Penicillium image Penicillium Pengo.jpg image width 250px image caption Penicillium sp. regnum Fungus Fungi phylum Ascomycota classis Eurotiomycetes ordo Eurotiales familia Trichocomaceae genus Penicillium subdivision ranks Species subdivision See text Penicillium from Latin penicillus paintbrush is a genus of Ascomycota ascomycetous Fungus fungi of major importance in the natural environment as well as food and drug production. It produces penicillin , a molecule that is used as an antibiotic, which kills or stops the growth of certain kinds of bacteria inside the body. Characteristics The thallus mycelium typically consists of a highly branched network of multinucleate, septate, usually colorless hyphae . Many branched conidiophores sprout on the mycelia, bearing individually constricted conidiospores . The conidiospores are the main dispersal route of the fungi, and often green. Sexual reproduction involves the production of ascospore s, commencing with the fusion of an archegonium and an antheridium , with sharing of nuclei. The irregularly distributed ascus asci contain eight unicellular ascospores each. Ecology Species of Penicillium are ubiquitous soil fungi preferring cool and moderate climates, commonly present wherever organic material is available. Saprophytic species of Penicillium and Aspergillus are among the best known representatives of the Eurotiales and live mainly on organic biodegradable substances. They are commonly known as molds and are among the main causes of food spoilage. Many species produce highly toxic mycotoxin s. Some species have a blue color, commonly growing on old bread and giving it a blue fuzzy texture. Economic value Several species of the genus Penicillium play a central role in the production of cheese and of various meat products. To be specific, Penicillium molds are found in Blue cheese . Penicillium camemberti and Penicillium roqueforti are the molds on Camembert , Brie , Roquefort , and many oth ... more details
producing structures or archegonium archegonia egg producing structures on a single plant body. Monoicous bryophytes produce both antheridium antheridia and archegonium archegonia on the same plant ... more details
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