Liquid Culture Systems for in vitro Plant Propagation

106 K. Y. Paek et al.
protocol, more than 500,000 somatic embryos of thornless Aralia elata, at
different developmental stages, were harvested from a 10-litre BTBB after 6
weeks of culture.
5.3 Phalaenopsis
Phalaenopsis is an important ornamental orchid, which is difficult to
propagate vegetatively. There is a number of tissue culture reports of its
propagation, but few use bioreactors. We have now reported the mass
multiplication of Phalaenopsis in bioreactors (Figures 4 a and b) (Park et al.,
2000). Continuous immersion culture (air-lift column and air-lift-balloon
bioreactor), and temporary immersion cultures (with or without a charcoal
filter attached) were used for the culture of protocorm-like bodies (PLB)
sections. In all four cases, 2 litres modified Hyponex medium (Kano, 1965;
1 g l -1 of ‘6.5N-4.5P-19K’ + l g l -1 of ‘20N-20P-20K’ + 1% (w/v) potato
homogenate) was used and 20 g of inoculum (~1000 PLB explants) was
inoculated into the medium. For the temporary immersion bioreactors, PLB
sections were placed on a plastic net installed in the vessel. The system was
programmed to immerse the PLB sections in the medium for 5 min in every
125-minute period via a timer and solenoid valve. In continuous-immersion
culture, PLB sections were submerged in liquid medium during the entire
culture period. A temporary immersion culture with charcoal medium-filter
attached was found to be most suitable for PLB culture and about 18,000
PLBs were harvested from 20 g of inoculum. These PLBs were regenerated
into plantlets and transplanted to pots containing peat moss and perlite (1:1)
(Figure 4c).
5.4 Anoectochilus
A simple protocol is described for the in vitro mass propagation of
Anoectochilus formosanus, an endangered orchid, using an automated low
cost bioreactor system. Comparative studies between culture on gelled media
and in a bioreactor (balloon type bubble bioreactor-BTBB), using both nodal
and shoot-tip explants, demonstrated that shoot multiplication was most
efficient in BTBB culture when using nodal explants. Shoots grown on a
TDZ-containing medium grew slowly and had small leaves. To overcome
this problem, shoots were transferred to a medium without TDZ;
comparative studies between cultures on gelled medium and in bioreactors
(continuous immersion with air supply, continuous immersion without air
supply and temporary immersion using ebb and flood) demonstrated that
plantlet growth was greatest in a continuous-immersion bioreactor with an