Taxonomy Of Nicotiana Tabacum Biology
The genus of Nicotiana tabacum is member of the family Solanaceae that contains 75 species. Some of important species are: Nicotiana rustica, Nicotiana clevelandi, Nicotiana otta and Nicotiana tabacum. Nicotiana tabacum is the well-known species which spreads all around the world. Table 2.1 described the detail taxonomy of Nicotiana tabacum and Figure 2.1 shows the Nicotiana tabacum with enlarge flower (Ivan A. Ross, 2008; Vinod kumar, 1988).
Table 2.1: Taxonomy of Nicotiana tabacum
Taxonomy of Nicotiana tabacum
TracheobiontaÂ -- vascular plants
MagnoliophytaÂ -- angiospermes, angiosperms, flowering plants,
MagnoliopsidaÂ -- dicots, dicotylédones, dicotyledons
SolanaceaeÂ -- nightshades, solanacées
NicotianaÂ L. - tobacco
TabacumÂ L. -- cultivated tobacco
Nicotiana tabacum has been used widely as medicinal herb, crop plant and trade commodity in many different cultures and cultivated by human being for thousands of years. In the past, the species of Nicotiana tabacum was utilized, as a model plant in genetic-engineering research and plant-cell cultures. For higher plants, Nicotiana tabacums are applied as a model organism because of high homogeneity and high growth speed, featuring behavior of plant cell. Due to N. Tabacum's economic value and importance as a biological research tool, it has been focused to study its origin, organization and genome structure. (Ivan A. Ross, 2008; Amran, 2000; Watson, 1979)
Figure 2.1: Nicotiana Tabacum plant with 4 times enlarge flower Scalebar=4cm (left) Scalebar=1cm (right)
The flowers of Nicotiana tabacum have terminal or sub terminal position in the form a raceme as a cyme. In addition, the terminal has several flowered inflorescences, the tube 5-6 cm long and 5 mm in diameters, widened in the lower calyx and upper throat, lobes generally triangular, white-pinkish with pale violet or carmine colored tips tube yellowish white (Feyza, 2004).
N. tabacum is one of amphidiploids which is thought to be created from two progenitors. In addition, Kenton et al. (1993), described on cytological evidence, have what a portion of the N. tabacum genome originated from N. sylvestris and an introgressed hybrid between N. tomentosoformis and N. otophora (Nita Sachan, 2004).
Nicotiana tabacum contains many alkaloids and the major alkaloid is nicotine. Nicotine's biosynthesis is managed by many kind of factors such as, phythormones, developmental age and biotic and abiotic stress. Nicotine and related alkaloid play a key function in plant defense against herbivore and insect attack in nature. In plants, the nicotine and related alkaloids initiates with the putrescine and/or polyamine, formed by one of two pathways. In the roots of N. tabacum, the nicotine biosynthesis happens exclusively. After synthesis, nicotine and other N. tabacum' alkaloids are shifted from the roots through the xylem to the leaves, in that they are collected in high density (Nita Sachan, 2004).
The soil and climate conditions influence N. tabacum under growth and alkaloid formation . In addition, it is sensitive for ground humidity, air, type of soil and physical property. The best temperature is from 20 to 30 Â°C for growth; and atmospheric humidity of 80 to 85%. N. tabacum is a local of tropical and subtropical America, and generally, the plant seeds are sown in the spring (either outside or in a greenhouse), the plants blows in summer and the tobacco is ripe for harvesting at the beginning of autumn. But in the last century, N. tabacum is commercially cultivated in all tropical countries (Wikipedia, Watson 1979).2.2
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