Effects of cytokinin-auxin combinations on cell arrangement in the basal stems and tropane alkaloid production in cultured non-rooted shoots of Duboisia myoporoides

Abstract

In non-rooted shoots regenerated from calluses induced with nine different cyokinin–auxin combinations, basal stem elongation and the cell arrangement in the basal stem sections depended on the cytokinin–auxin combinations used at the callus-induction stage. Elongated basal stems like seedling and large cells in the secondary xylem were found in the non-rooted shoots regenerated from calluses induced with benzyladenine (BA) 10 µM + naphthaleneacetic acid (NAA) 1 µM and BA 10 µM + indole-3-butyric acid (IBA) 0.1 µM. Tropane alkaloids were detected in these shoots. The peak hyoscyamine and scopolamine contents were 38.5 × 10 –4 and 6.5 × 10 –4 % dry weight, respectively. Various patterns of vascular regions without large cells in the secondary xylem were found in the basal stem sections of the non-rooted shoots regenerated from calluses induced with the other cytokinin–auxin combinations. No tropane alkaloids were detected in these shoots.