Organogenesis, differentiation and histolocalization of alkaloids in cultured tissues and organs of Duboisia myoporoides R. Br.

Duboisia myoporoides R. Br. shoots were regenerated from non-organogenic an d organogenic calli induced with nine different cytokinin/auxin combination s. Alkaloid colour reagents localized tropane alkaloids in the vascular reg ions which had large cells in the secondary xylem of the basal stem section s of the non-rooted shoots. Tropane alkaloids were localized in shoots rege nerated from calli induced with two different cytokinin/auxin combinations. No alkaloids were localized in shoots regenerated from calli induced with other cytokinin/auxin combinations. However, only nicotine was detected by GC-MS in the non-rooted shoots regenerated from calli induced with three di fferent cytokinin/auxin combinations. Tropane alkaloids were also localized in xylem cells of roots regenerated from calli induced with two different cytokinin and auxin combinations independently. The presence or absence of nicotine, hyoscyamine and scopolamine in different cultured plant materials was confirmed by GC-MS, indicating that although the root is the main site for alkaloid biosynthesis, with suitable cell differentiation, alkaloid bi osynthesis may take place in cultured shoots without root initiation. (C) 2 000 Annals of Botany Company.