In the present study, both carbenicillin and cefotaxime rather promoted both growth and
development of the embryogenic calli at all concentrations tested, indicating that these two
antibiotics may be appropriate for eliminating bacteria in an Agrobacterium-mediated
transformation system. Although the mechanism of the stimulatory effect of these two
betalactam antibiotics has yet to be identified, similar observations have been reported for
several plant species including Antirrhinum majus (Holford and Newbury, 1992), Dianthus
spp. (Nakano and Mii, 1993) and Lilium formosanum (Suzuki et al., 1989).