Abstract: Gloxinia was efficiently plant-regenerated using its leaf, petiole and root segements as explants via two different organ biogenesis pathways. In the first pathway, the three types of explants all first formed callus and adventitious buds on Murashige and Skoog (MS) medium with 6-benzylaminopurine (BA) andα-naphthalene acetic acid (NAA) , and the buds then produced roots after transformed onto the same medium.The optimal hormone combination was 2.0 mg·L - 1 BA + 0.2 mg·L - 1 NAA, at which 99.04% of the explants produced buds, 5.53 buds per explants at average, and 98.81%of the buds formed roots. In the second pathway, all the types of explants first produced callus and roots on MS medium with NAA alone, and the roots later formed buds on the same medium. The optimal NAA level was 1.0 mg·L - 1 , at which 90.38% of the explants produced buds, 2.44 shoots per explant on average, and 100% of the root then formed buds. The leaf explants appearred the best. In addition, some mutants with the changed phyllotaxy was found after generations of subcuture. This mutant may be very useful for studying the molecular genetic mechanism of plant phyllotaxis patterning.

Key words: Sinningia speciosa, regeneration pathway, tissue culture, spontaneous mutantion, phyllotaxis