Liquid Culture Systems for in vitro Plant Propagation

Adaptions of the mineral composition of culture media 499
Table 3: Mean dry weight content of adult, healthy Gerbera leaves, and concentrations of
macrominerals in calculated ’ideal’ medium, in media used in experiments and used in
hydroponics
Plant
content
Calculated
medium
GAM DKW MS
mmol g -1 DW mmol l -1
N total 2.1 40
NH4 +
NO3 -
Hydroponics
n.a. n.a. 7 17 20 0.75
n.a. n.a. 33 33 40 7.25
K 1.1 20.7 11.7 18 20 4.5
Ca 0.35 7.7 8 9.3 3 1.6
Mg 0.12 2.4 2.5 3 1.5 0.4
SO4 -2
PO4 -3
n.a. n.a. 2.5 12 1.5 0.7
0.10 1.9 1.7 1.95 1.25 0.6
µmol g -1 DW µmol l -1
Fe n.a. n.a. 100 120 100 25
Mn 1.2 23 100 200 100 5
Zn 0.8 15 30 72 30 3
B 3.2 61 100 78 100 20
Cu 0.13 2.5 0.1 1 0.1 0.5
Mo 0.004 0.075 1 1.6 1 0.5
n.a. = not available
3.3 Gerbera
Table 3 shows the elemental composition of Gerbera leaves according to
Bergmann (1992). The adapted medium was a compromise to approximate
to this formulation using the salts available in the lab, but minimizing the
content of Na and Cl. Adapted media for Gerbera always showed some
white precipitate. The pH of the adapted media was reduced by 0.4 pH units
after autoclaving with BBL agar, whereas for MS this was 0.2 pH units, and
for DKW 0.3 pH units. For Daishin agar this pH reduction was greater, and