A full habituated cell line C_ 20hi was screened from 2,4_D dependent line (C_ 20D) of Catharanthus roseus (L.) G. Don. The investigation involved the cell growth, ajmalicine production and enzyme activity related to indole alkaloid biosynthesis in both cell lines. These results indicated that C_ 20hi cells grew faster than C_ 20D cells, and average ajmalicine content in C_ 20hi cells was 18.4 times more than that in C_ 20D when cultured in the production medium. In the growth medium, average ajmalicine content in C_ 20hi cells was 31.9 times more than that in C_ 20D cells, while the cell growth has no obvious difference. The comparison of enzyme activities in C_ 20hi and C_ 20D cells indicated that tryptophan decarboxylase (TDC), strictosidine synthase (SSS) and geraniol_10_dehydrogenase (G10H) activities have no close relation to ajmalicine accumulation, although the activities of these enzymes were higher when cells were cultured in the production medium than in the growth medium. The C_ 20hi cells are relatively stable in five years of culture.
