| 词条 | Daucus |
| 释义 |
|image = Daucus carota0.jpg |image_caption = Daucus carota |display_parents = 2 |taxon = Daucus |authority = L., 1753 |subdivision_ranks = Species |subdivision = See text }} Daucus is a worldwide genus of herbaceous plants of the family Apiaceae of which the best-known species is the cultivated carrot. Daucus has about 25 species. FeaturesThey differ in the family Apiaceae by their leaves 2–3 pinnatisect. The end sections are always narrow. The Daucus genus are annual plants or mostly biennial plants or also perennial herbs, with a bristly stem. The inflorescences are umbels. The umbel flowers are mostly white, with bracts and bracteoles. The tiny flowers are a compounded. The petals are pure white, reddish, pinkish or yellowish. They are emarginate above and have a pointed, wrapped lobules. The petals are often unequal in size, and the outermost edge of the flower is often brilliant. The fruit is ovoid to ellipsoidal, and cylindrical or compressed. The fruits have ciliated primary ribs and secondary ribs have a row of spines. Some species have a small pale or white edible root, similar to a radish, which may or may not be bitter in taste. EcologyThe pollination is carried by insects: Lepidoptera, Coleoptera, Diptera, and Hymenoptera. It is a worldwide genus with endemic species on islands and isolated areas. The genus centre is in North Africa, and Southwest Asia in the Temperate Zone. Prolonged dry or cold weather retard growth but result in adaptative strategy in the genus evolution. Stages of development not suffers due to the accumulation of resources by underground in the root in some species. Genus Daucus is represented in the Macaronesian Islands by endemic species of wide distribution. Native to Europe is the Carrot, with two subspecies: Wild Carrot and (subsp carota Daucus carota), a cultivated form of carrot, also called garden carrot. Four members of the Daucus genus were examined to determine differences in isoenzyme patterns, and plastid DNA. The four were: Daucus carota subspecies sativus cultivar Danvers, D. carota subsp. gummifer, D. capillifolius, and D. pusillus. Although only one form of HSDH (homoserine dehydrogenase) was present in each Daucus line, the rate of migration of HSDH from cv. Danvers was different from that of the others. Multiple isoenzymic forms of ADH were present in each Daucus cultivar. Comparison of endonuclease restriction fragment patterns from plastid DNAs digested by BamHI revealed only small differences between plastid DNAs of cv. Danvers and subsp. gummifer, whereas large differences were observed between cv. Danvers and D. pusillus plastid DNA patterns. No differences were found between cv. Danvers and D. capillifolius plastid DNA patterns when examined using eight different restriction enzymes. The data indicate that specific isoenzyme and organeile DNA restriction fragment patterns will be useful markers for precise identification of genomes of different Daucus species.[1] SystematicsThe genus comprises about 20 species divided into three sections.[2] The species include:
References1. ^{{cite journal |author1=Benjamin F. Matthews |author2=Kenneth G. Wilson |author3=Lorin R. DeBonte |title=Variation in Culture, Isoenzyme Patterns and Plastid DNA in the Genus Daucus |date=January 1984 |journal=In Vitro |volume=20 |issue=1 |pages=38–44 |jstor=4292775}} 2. ^Sáenz Lain C. 1981. "Research on Daucus L (Apiaceae)". Anales Jardin Botanico De Madrid. 37: 481–533. 3. ^Secretaria Regional do Ambiente e do Mar (2008), Plantas Endémicas dos Açores: Guia da Ilha do Faial, p.10; Flowering between April and July, the azoricus is common in pastures from sea level to about 800 meters altitudes. The article is based on the following sources:
External links
2 : Apiaceae genera|Apioideae |
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