Adventitious shoot formation from carnation stem segments: a comparison of different culture procedures

Adventitious shoot regeneration from stem expiants of carnation (Dianthus caryophyllus L., cultivar ‘White Sim’) was studied using three different culture procedures: agar-gelled medium, liquid shaken medium, and an interfacial membrane raft floating on liquid medium. In all culture procedures, expiants derived from the first upper internode exhibited higher adventitious shoot formation than those from the second internode. On agar-gelled medium, the number of regenerated shoots per expiant from the first internode increased with increasing thidiazuron (TDZ) concentration (up to 4 mg l−1) in the presence of 1 mg l−1 naphthaleneacetic acid. In the liquid shaken culture, the number of regenerated shoots peaked at 1 mg TDZ l−1. Maximum shoot regeneration on an interfacial membrane raft was obtained in the presence of 0.25 mg TDZ l−1. A comparison of the overall efficiencies of shoot regeneration for each culture procedure showed that maximum shoot regeneration on the raft was twice and three times that obtained with agar-gelled and liquid shaken media, respectively.