Abstract: Epicotyls and stem segments from sterile seeding of Poncirus tnfoliata Raf. Were cultured ire vitro. The results indicated that epicotyls were suitable for culture in vitro, BA at a concentration of 1 mg/L gave the highest shoot formation frequency (86.0% ). As BA concentrations increased, the ability of shoot formation de-creased. Epicotyls oriented with their apical ends protruding from the medium produced more shoots than when they were placed with their basal end upright or were placed horizontally. Explants used for transformation were the epicotyls from Pondrus trifoliata Raf. The selection pressure for kanamycin was 50mg/L. Ceftaxime used as antibiotics was better than carbenicillin. After 1.5 months 14.2 resistant shoots were emerged from the ex-plants. Histochemical GUS assay showed that 70.0 of the resistant plants were GUS-positive.

Key words: Poncirus trifoliata