New Researches in Biotechnology - Facultatea de Biotehnologii ...

Proceeding of the 4 rd International Symposium“NEW RESEARCH IN BIOTECHNOLOGY” USAMV Bucharest, Romania, 2011Centaurea davidoviiOnly one seed of C. davidovii germinated two months after being placed in the MSmedium. Interestingly, after two more months the plant had two stems with large leaves andsome long roots growing from a common base of enlarged, callus-like tissue (Fig. 5). Thishappened in the absence of PGRs or any other treatment. The two stems were separated andtransferred to fresh MS medium, where they continued growing and forming new leaves.One of the plants grew one more stem. The callus-like tissue had numerous small leavesand was easy to divide into small clusters - 66 altogether, which were transferred to freshMS medium. Eleven of them (16%) grew large leaves (Fig. 6).Fig. 5. C. davidovii on the MS mediumFig. 6. Tissue clusters of C. davidoivii growingleaves and roots on the MS medium.Leaf and root explants from the 3 stems were placed on C4, C5, C6, C7, C8, CC1, CC2and CG media. Those on the C4, C5 and C6 media formed calluses, but they turned brownin 6 weeks and no organogenesis was observed.After two months on the C7 and C8 media, the leaf explants became very enlarged andformed callus, and on C7, small leaflets formed at the margins of the explants, possibly bysomatic embryogenesis. Kumar & al. (2008) reported somatic embryogenesis in Carthamustinctorius L in media containing 3,5 mg/l TDZ and 1,4 mg/l 6-[γ,γ dimethylallyl amino]-purine (2iP) or 6 mg/l TDZ, 1,5 mg/l 2iP and 2,5 mg/l indole-3-butyric acid (IBA). Ourmedia C7 and C8 had the same concentration of PGRs, however we used BAP and NAAinstead of 2iP and IBA respectively. Fifty-six excised leaflet clusters were transferred toМS medium, where 27 of them (48%) grew further and formed new leaves (Fig. 7).Callus was also formed on the CC1 and CC2 media. As with C. caliacrae, the explantson the CG medium formed callus, but it turned brown and died.In the five months since germination, 5 new single stems and the above-mentioned 11clumps with large leaves were obtained from one seedling. This clone of well-propagatingplants will be used for further experiments with varying media composition.Centaurea finazzeriOf 45 seeds, 9 (20%) germinated in the first month. None of them were treated with GA 3 .After these seedlings grow, their subcultivation is intended to the media in which the othertwo species had the best response.137