Apomixis

In botany, apomixis was defined by Winkler as replacement of the frequent sexual retort by asexual counterpart, 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  are types of apomixis. Apomictically produced offspring are genetically identical to the parent plant. In flowering plants, the term apomixis is usually employ in a restricted sense to think about agamospermy, i.e. asexual reproduction throughseeds. Apogamy is a related term that has had various(a) meanings over time. In plants with independent gametophytes (notably ferns), the term is still utilize interchangeably with apomixis, and both refer to the formation of sporophytes by  virgin birth of gametophyte cells. See also Male apomixis in a conifer b elow. 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 separate  congenator apomicts, while having much smaller differences than is normal amid species of virtually genera. They are therefore often called microspecies.

In virtually genera, it is likely to identify and name hundreds or even thousands of microspecies, which whitethorn be grouped together as aggregate species, typically listed in Floras with the convention Genus species agg. (e.g., the brambl e,Rubus fruticosus agg.). In some plant fa! milies, genera with apomixis are preferably common, e.g. in Asteraceae, Poaceae, and Rosaceae. Examples of apomixis bath 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: OrderCustomPaper.com

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