Narcissus and Daffodil

232 C. Codina
Effect on growth and morphology of the explants
The different origin of the shoot-clumps used in this experiment (bulbs or seeds)
did not seem to influence significantly the growth of the explants, although the
shoot-clumps derived from bulbs were slightly bigger. In both cases, the clusters
formed in the treatment with 90 g/l of sucrose exhibited the best growth index of
weight, showing a well formed bulb and emerging intensely green leaves. The
shoot-clumps treated with concentrations of sucrose higher than 90 g/l showed
pale leaves, with a tendency to vitrification. In addition, the tissue of the base of
the bulb was yellowish, sometimes showing necrotic areas, and the emergence of
leaves was less vigorous. Apparently, high concentrations of sucrose (≥ 150 g/l)
became toxic to the explants derived from both strains of shoot-clumps (coming
from bulbs or seeds), and caused shoot dormancy.
Effect on alkaloid production
Although the two strains showed a similar growth and morphology, they exhibited
different behaviour in relation to the production of alkaloids.
Bulb-derived shoot-clumps
The effect of sucrose concentrations on the production of alkaloids in bulb-derived
shoot-clumps is shown in Figure 7.13. The main alkaloid was haemanthamine,
with a value of 0.87 mg/g DW in the treatment with the lowest sucrose concentration
(3%), whereas the minor alkaloid was tazettine, with a value of 0.15 mg/g
DW in the same treatment. The maximum accumulation of galanthamine took
place in the treatments with the highest and lowest doses of sucrose (3 and 18%),
reaching practically the same value, 50 mg/g DW. The maximum production
of N-formylnorgalanthamine occurred in the explants treated with 30 g/l of
sucrose.
In general, the qualitative profile of the alkaloids in the different treatments
with sucrose was very similar. From the quantitative point of view, however, an
increase in the source of carbon led to a corresponding decrease in the production
of alkaloids, the minimum value thus being obtained in the treatment with 90 g/l of
sucrose. At higher concentrations of sucrose, the production of alkaloids increased,
but without reaching the maximum values observed in the treatment with 30 g/l of
sucrose. In all cases, the alkaloids were mainly accumulated in the tissue, a very
small proportion being released to the culture medium (Figure 7.13).
Seed-derived shoot-clumps
The production of alkaloids in the seed-derived shoot-clumps and treated
with different doses of sucrose are shown in Figure 7.14. In this case, one can
observe that the accumulation of galanthamine type alkaloids was higher in
the medium culture than in the tissue, except in the treatments with 90 and
120 g/l of sucrose. In the case of the haemanthamine type alkaloids, the percentage
accumulated in the tissue was generally higher than that released to
the liquid medium.