Narcissus and Daffodil

Agronomic factors and galanthamine production 277
Table 10.1 Distribution of Narcissus alkaloids in different bulb parts
Part of bulb Weights (g) % total Narcissus alkaloids (mg/100 g dry weight)
Fresh Dry
dry wt.
Total 1a 2 3 4 5 6 7
Basal plates 166.7 47.3 8.3 461.2 168.5 40.9 37.1 10.8 113.7 75.6 14.6
Outer scales 484.3 186.8 32.9 148.5 59.8 16.0 22.0 6.3 25.0 18.7 trace
Inner scales 738.1 268.6 47.4 196.7 78.8 9.9 9.9 2.4 63.2 32.5 trace
Leaves 85.7 16.2 3.0 455.3 132.7 7.7 1.3 20.1 226.5 67.0 trace
Flowers 87.9 28.3 4.9 223.6 68.3 2.7 trace 30.5 73.0 49.1 trace
Bulbil 77.3 19.8 3.5 258.7 105.5 6.2 4.6 13.2 85.6 43.6 trace
Note
a 1 = galanthamine, 2 = lycoramine, 3 = N-demethyl-lycoramine, 4 = caranine, 5 = haemanthamine,
6=lycorine, and 7=hippeastrine.
as storage organs. The scales are held together concentrically by the base plate,
a solid, stem-like tissue at the base of the bulb. The shoot apices initiate scales,
leaves, stems, flowers and new bulb units.
The study of Moraes-Cerdeira et al. (1997a) revealed that the basal plate has
the highest content of galanthamine and of the other dibenzofuran alkaloids,
lycoramine and N-demethyl-lycoramine (Table 10.1). Galanthamine concentrations
were higher in the inner bulb parts. Lycorine, a highly toxic, norpluvine-derived
alkaloid, is similar in its distribution to galanthamine, with a higher concentration
in the inner parts. Galanthamine, lycoramine and N-demethyl-lycoramine have the
same biogenetic precursor, but lycoramine and N-demethyl-lycoramine are found
primarily in the scales. Therefore, no pattern of alkaloid distribution was found
relating to organ specificity and biogenetic origin.
Meristematic tissues contributed one-third (33.5%) of the total alkaloids of the
bulbs. Scales had 66.5% of the total content in 80% of the total dry weight of the
bulb (Table 10.1). The active growth of narcissus bulbs leads to an increased ratio
of meristematic tissue to scale (storage tissue) through growth that depletes the
starch-containing tissues. Therefore, treatments stimulating growth enrich galanthamine
and alkaloids like lycorine (6), haemanthamine (7) and the caranine (5)
content of the biomass, but it may also decrease the content of lycoramine (3) and
N-demethyl-lycoramine (4).
Data from our laboratory on different growth stages of Narcissus ‘Inglescombe’
(Figure 10.1) suggested that plants produced more galanthamine during the
growing period, between emergence and anthesis, reaching as high as 287 mg per
100 g dry weight (C.L. Burandt, Jr. et al., unpublished data). Galanthamine content
decreased after anthesis to 173 mg per 100 g dry weight, a stage marked by scale
growth and leaf senescence. As starch content increased, galanthamine appeared
to become diluted by a metabolic shift towards starch production. Both studies
described above indicated that agronomic factors which stimulate cell growth may
enhance galanthamine content by 50% or more on a dry weight basis. Therefore,
narcissus biomass for galanthamine production should be harvested in April and
May at full foliage in an 18-month growing cycle. Alternatively, it may be even
more economical to lift bulbs after a 24-month crop cycle, then force bulb emergence
and growth by storing the bulbs in a controlled environment at high humidity
and low temperature.