Influence of ammonium and nitrate nutrition on levels of ammonium-nitrate and total nitrogen in the callus of Atropa belladonna (Solanaceae)
Annales Botanici Fennici 21(4): 367-382
The growth and the tissue levels of ammonium, nitrate and total N were studied with 2 A. belladonna L. callus strains of different ages when NO-3 and combinations of NH+4 and NO-3 in the ratios of 1:2 and 1:1 were used as N sources at 4 concentrations (5, 15, 25, 35 mM N) in the dark and in light. The callus cultures used all the N sources well: the highest dry wt were obtained on a combination of NH+4 and NO-3 in the ratio of 1:2 in light. The optimum concentration was 15-25 mM. The age of the callus strain and culture in the dark vs. periodic light had no distinct effect on the growth. On nutrient media containing both NH+4 and NO-3, higher total and organic N levels (about 3% of dry wt) were achieved than on media containing only NO-3 (about 2% of dry wt). In tissues grown on nitrate, the increase in the total N content between 25 and 35 mM nutrient nitrate was largely caused by accumulated NO-3-N. The combination of NH+4 and NO-3 in the ratio of 1:1 did not cause any great accumulation of NO-3 in the tissues. Nitrate accumulation was in general greater in the dark than in light. The NH+4-N contents were almost the same for the 3 treatments. The N sources containing both NH+4 and NO-3 were more suitable than NO-3 alone for the cultures of Atropa in media with a N concentration over 25 mM.