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Essay on Tobacco

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Tobacco

Tobacco is the common name of the plant Nicotiana tabacum and to a limited extent Nicotiana rustica and the cured leaf that is used, usually after aging and processing in various ways for smoking, chewing, snuffing and the extraction of nicotine, the principal alkaloid of tobacco.(4) The species N. tabacum has never been found to grow in the wild.(1) The use of the word tobacco is generally accepted as referring to the products of the tabacum species and so it will be in what follows. Tobacco holds an unparalleled position among crop plants in the world such as:

1) It is one of the very few crops entering world trade entirely on a leaf basis.

2) It is the most widely grown commercial non-food plant in the world.

3) It …show more content…

N. tabacum has a uniquely high proportion of alkaloids occurring as nicotine and is considered to have survived as a species by man's protection. Creation of new species through hybridization is a natural botanical occurrence. It is an accepted assumption that N. tabacum arose as a natural hybrid. N. sylvestris contributes one genome, but agreement on the other contributor is not agreed upon. Artificial creation of hybrids which results in 'synthetic tobacco' bear very close genetic similarity to N. tabacum. Cultivated tobaccos have changed immensely over time and it is unlikely that the forms of other species now available bear to close a resemblance to what existed in the distant past.(1)

Botany

Tobacco is normally grown as an annual and is potentially a woody, shrub like perennial. The tobacco plant has a very shallow root system which provides poor anchorage for the more extensive above ground development. The N. tabacum types are one of the smaller species of tobacco varieties. The leaves supply the most important economic value of the plant and are given the most attention by botanists. Although there is variation in leaf size and shape there is general uniformity of distribution, size and shape within cultivated types. Between types, size and shape may vary considerably but not in distribution. The characters which may include leaf shape

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