Apomixis

In botany, apomixis was defined by Winkler as replacement of the commonplace sexual retort by asexual imitation, without fertilization.[1] This definition notably does not mention meiosis. Thus normal asexual reproduction of plants, such as propagation from cuttings or leaves, has never been considered to be apomixis, but replacement of the seed by a plantlet, or replacement of the flower bybulbils argon types of apomixis. Apomictically produced offspring are genetically analogous to the parent plant. In flowering plants, the term apomixis is normally employ in a restricted sense to prize agamospermy, i.e. asexual reproduction throughseeds. Apogamy is a related term that has had divers(prenominal) meanings over time. In plants with independent gametophytes (notably ferns), the term is still use interchangeably with apomixis, and both refer to the formation of sporophytes by  parthenogeny of gametophyte cells. See also Male apomixis in a coniferous tree below. Apomixis and evolution As apomictic plants are genetically identical from angiotensin converting enzyme generation to the next, each has the characters of a true species, maintaining distinctions from near other  congenator apomicts, while having much smaller differences than is normal among species of virtually genera. They are therefore often called microspecies.

In some genera, it is likely to identify and name hundreds or even thousands of microspecies, which may be grouped together as aggregate species, typically listed in Floras with the convention Genus species agg. (e.g., th e bramble,Rubus fruticosus agg.). In someÂ!  plant families, genera with apomixis are preferably common, e.g. in Asteraceae, Poaceae, and Rosaceae. Examples of apomixis rouse be found in the genera genus Crataegus (hawthorns), Amelanchier (shadbush), Sorbus (rowans and whitebeams), Rubus(brambles or blackberries), Poa (meadow grasses), genus Hieracium (hawkweeds) and genus Taraxacum (dandelions). Although the evolutionary advantages of sexual reproduction are lost, apomixis can pass...If you fate to get a full essay, order it on our website: BestEssayCheap.com

If you want to get a full essay, visit our page: cheap essay