In vitro REGENERATION OF TOBACCO (Nicotiana tabacum L. cv. VIRGINIA) AND ASSESSMENT OF VARIATION IN THE PLANTLETS

Somaclonal variation is defined as the variation exhibited among plantlets or clonal plants. Tissue culture technique can be used for conservation of endangered plant species. However, for conservation, it is necessary to avoid somaclonal variation and produce true-to-type plantlets. One of the factors that determine the existence of somaclonal variation in the plantlets is the types of explants used for tissue culture. In this study, shoot apical meristem (SAM) obtained from 5-days-old germinating tobacco (Nicotiana tabacum L. cv. Virginia) seedlings was used as an explant to regenerate entire tobacco plant in vitro and to minimize the variation of the plantlets. SAM was inoculated on semi-solid MS basal media (as a control) and semi-solid MS media supplemented with different concentrations of Indole-3-Acetic Acid (IAA), Kinetin (KIN) and combination of IAA and KIN. For primary establishment, shoot development and root formation were shown in all treatments but the most effective treatment is control with 73% of explant survival, followed by 0.5 mg/l IAA with 60% of explant survival. However, after acclimatization, plantlets from medium supplemented with 0.5 mg/l KIN showed the highest number of leaves and plantlet height with an average of 6.0 leaves and 0.7 cm height, followed by 1.0 mg/l KIN with an average of 5.4 leaves and 0.6 cm height. To detect the variation of the plantlets, the morphology, anatomy and primary metabolism between tobacco plants and plantlets of tobacco were compared. Both morphology and anatomy of tobacco plantlets were similar to tobacco plants. Leaf morphology of the plantlets was also similar to tobacco plants which are the same type of obovate leaf shape, obtuse leaf tip, cuneate leaf base, entire leaf margin and pinnately veined leaf. Both plants also have the same anatomical structure of the midrib of leaf, stem and root. Besides that, there is also no significant difference in the total chlorophyll, carbohydrate and protein content of both tobacco plants and plantlets. In conclusion, no variation was expressed in tobacco plantlets regenerated from SAM. Therefore, SAM is suitable as explants for tissue culture of tobacco plant and to minimize the variation.