The effect of nitrate and ammonium concentrations on growth and alkaloid accumulation of Atropa belladonna hairy roots

The growth, the alkaloid production, as well as the scopolamine/hyoscyamine ratio of two clones of belladonna hairy roots were studied. The effects of nitrate and ammonium concentrations on these cultures were investigated. A rise in ammonium concentration caused the decline of the hairy roots, whil e nitrate had a marked effect on the alkaloid content. The alkaloid product ion obtained with 15.8 mM of NO3- and 20.5 mM of NH4+ was 1.2-1.4 times hig her than that obtained when the roots were grown in the standard Murashige and Skoog medium (MS medium, 39.5 mM of NO3- and 20.5 mM of NH4+). The nitr ate and ammonium concentrations in the culture medium also had a strong inf luence on the scopolamine/hyoscyamine ratio. When nitrate or ammonium conce ntrations were raised, that ratio also was increased 2-3-fold. The hairy ro ot clones originating from transformations with two distinct strains of Agr obacterium had similar responses. (C) 2001 Elsevier Science B.V. All rights reserved.