This research was conducted to identify the effect of BAP and NAA on plant regeneration from flower bud of A. macrocephala. Flower buds the plant were used as target explants for tissue culture. Plant tissues were sterilized with each 45ml of 50% ethanol and 0.8% sodium hypochlorite containing 20ul of Tween20 for each 5 minutes, respectively, and then washed 5 times with sterile distilled water. Four pieces of the sterilized explants were cultured in a petri-dish at 25±2℃ under 16hr/day light condition. LS basal medium and BAP (0.2 and 2 mg·L-1) and NAA (0.2 and 2 mg·L-1) were used for the experiment. When the target explants were cultured on the media containing both BAP and NAA, explants of the flower buds were swelled about 15~25mm long and then calli were induced from receptacles at about 20 days after planting. However, there were no significant differences between the concentrations of the phytohormones. In results, normal shoots were successfully regenerated on the media supplemented with 2 mg·L-1 BAP and 0.2 mg·L-1 NAA prior to root induction. However, under the conditions of 0.2 mg·L-1 BAP and 2 mg·L-1 NAA, only roots were induced from the calli instead of shoot regeneration.

Until now many strategies have been used to produce marker-free transgenic plants such as co-transformation with negative selectable markers, site-specific recombination system, transposable elements mediated transformation, and etc. In this research, embryogenic calli induced from japonica rices, Ilmibyeo and Dongjinbyeo, were tranformed with the vector which simultaneously constructed with cre/loxP and argE genes in T-DNA. Transformation efficiencies were comparably lower than those of our previous studies, since the constructed genome size was relatively big (>10Kb). For eliminate the transformed tissues which contained positive selectable marker gene, tunicamycin was treated at regeneration and selection stages, since cre recombinase gene is expressed under the presence of this antibiotics. The plants were selected first under 50 mg․L-1 hygromycin at 28℃ for 2 weeks after the Agrobacterium-infection at 25℃ for 7 days. And then, the regeneration plants were successfully obtained on MS basal regeneration medium containing 0.1 mg․L-1 tunicamycin. The regenerated plants are now acclimatizing in greenhouse and molecular analysis are currently accomplished with these plants.