Effect of inoculum density and gaseous atmosphere renovation in <i>Digitalis purpurea</i> L. shoots culture in Temporary Immersion Systems

Abstract

Digitalis purpurea L. is one of the two unique species of economic interest in the genus Digitalis. It is important because is one of the principal source of cardenolides, irreplaceable drugs in the treatment of heart failure. The present work was done with the objective to determinate the effect of inoculum density and gaseous atmosphere renovation in D. purpurea plants cultivated in Temporal Immersion Systems (TIS). To do this, several parameters like inoculums density (6, 12, 18 explants per TIS) and the use forced ventilation were studied. The highest biomass production was obtained when 12 explants were inoculated (104.03 gFW and 5.74 gDW). On the contrary, the lower inoculum density caused a negative effect in plant development and the biomass did not increase. On the other hand, the renovation of atmosphere mediated by forced ventilation induced a higher oxidative stress associated to an increase of digitoxin synthesis. Both factors are of great importance for biomass and secondary metabolites production in plants with pharmaceutical interest. Keywords: cardenolides, forced ventilation, liquid medium, secondary metabolites