Riboflavin Excretion from the Excised Roots of Hyoscyamus niger

Abstract

Excised roots of Hyoscyamus niger growing in darkness excrete yellow pigment into the liquid culture medium. The pigment has been identified as riboflavin by paper chromatography, thin-layer chromatography, photolysis, and spectrophotometry. The increase of biomass of H. niger roots in the flasks is uniform during the growth period (ca. 30 days), having no exponential phase. A significant decrease in pH was observed in Murashige-Skoog (MS) and Knop-M media during the first 4 days following inoculation. The pH of media then increased slowly until the cultures reached their stationary phase (ca. 35 days) and then increased rapidly. The excretion of riboflavin into the media (expressed per volume of media) was low during the first 4 days of incubation and increased rapidly thereafter during the 6th to 14th days of growth. The maximum content of riboflavin in the medium, expressed per dry weight of the roots, was observed during the 14th to 15th days after inoculation. A decrease in the iron content of the MS medium caused an increase in the excretion of riboflavin; the additional iron in the MS medium resulted in a decrease in the excretion of riboflavin.

Keywords: :

• Excised Roots
• Hyoscyamus Niger
• Iron
• Ph
• Riboflain