Abstract
14C-labelled benzyladenine-7-glucoside (0.57 μM) supplied to cytokinin-requiring Nicotiana tabacum (cv. Wisconsin 38) cells cultivated in liquid medium was slowly absorbed and resulted in rather large intracellular quantities of benzyladenine-7-glucoside (30 pmol/105 cells) but did not show any biological activity, while 0.01 μM benzyladenosine induced cell division. In this case the resulting intracellular quantity of benzyladenine-7-glucoside formed was 3.3 pmol/105 cells. Also, N6-(Δ2-isopentenyl)adenosine induced cell division in these tobacco suspensions without being significantly 7-glucosylated. These data provide strong evidence that the 7-glucosylation of cytokinins is not a prerequisite of the expression of their biological activity.