Euglenophyta
enUK| Noun | 1. | Euglenophyta - free-swimming flagellate algae |
| 单词 | euglenophyta | |||
| 释义 | EuglenophytaenUK
EuglenophytaenUKEuglenophyta(yo͞o'glənŏf`ətə), small phylum (division) of the kingdom ProtistaProtistaor Protoctista , in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms. ..... Click the link for more information. , consisting of mostly unicellular aquatic algaealgae [plural of Lat. alga=seaweed], a large and diverse group of primarily aquatic plantlike organisms. These organisms were previously classified as a primitive subkingdom of the plant kingdom, the thallophytes (plants that lack true roots, stems, leaves, and flowers). ..... Click the link for more information. . Most live in freshwater; many have flagella and are motile. The outer part of the cell consists of a firm but flexible layer called a pellicle, or periplast, which cannot properly be considered a cell wall. Some euglenoids contain chloroplastschloroplast , a complex, discrete green structure, or organelle, contained in the cytoplasm of plant cells. Chloroplasts are reponsible for the green color of almost all plants and are lacking only in plants that do not make their own food, such as fungi and nongreen parasitic ..... Click the link for more information. that contain the photosynthetic pigments chlorophyll a and b, as in the phylum ChlorophytaChlorophyta , phylum (division) of the kingdom Protista consisting of the photosynthetic organisms commonly known as green algae. The organisms are largely aquatic or marine. ..... Click the link for more information. ; others are heterotrophic and can ingest or absorb their food. Food is stored as a polysaccharide, paramylon. Reproduction occurs by longitudinal cell division. The most characteristic genus is Euglena, common in ponds and pools, especially when the water has been polluted by runoff from fields or lawns on which fertilizers have been used. There are approximately 1,000 species of euglenoids. Euglenophytaa division of microscopic algae usually consisting of a single free-swimming cell. Colonial forms are rare. The nucleus is clearly pronounced, and the green, rarely colorless, chloroplast may lack pyrenoids. The plastmatic cover, or periplast, of some species bears hard, iron-incrusted capsules. At the anterior end of the cell there is a gullet, through which one, two, or sometimes more flagella extend. The contracting vacuoles and stigma are located on the sides of the gullet. In creeping forms the flagellum is rudimentary. Reproduction is by means of longitudinal splitting. Under unfavorable conditions, some species discard their flagella and form protective spores (cysts). Nutrition is primarily phototrophic in green individuals and saprophytic and holozoic (according to the animal type) in colorless individuals. Parasitic species are few in number. The carbohydrate paramylum and oil serve as a food reserve. There are about 60 genera, embracing more than 900 species, usually found in shallow reservoirs rich in organic matter. The USSR has 33 genera, with 429 species. The algae give water a green, red, or brown coloration when they grow abundantly. Many zoologists classify the Euglenophyta among the Protozoa. REFERENCEPopova, T. G., and T. A. Safonova. Evglenovye vodorosli, Leningrad, 1976.L. A. RUNDINA Euglenophyta[‚yü·glə′näf·əd·ə]EuglenophytaenUKEuglenophytaa division of the algae (sometimes classified by zoologists in the class flagellata). They normally possess chlorophyll a and b, but this may be lost; colourless forms do not regain their chlorophyll and no members of the division are completely AUTOTROPHIC.EuglenophytaenUK
Synonyms for Euglenophyta
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