Liquid Culture Systems for in vitro Plant Propagation

A new approach for automation 421
Table 1: Sowing of dehydrated somatic embryos onto 240-cell trays using a precision
seeding system (percentage of individual cells containing 0, 1 or 2 embryos)
Number of embryos per cell 0 1 2
Carrot 23�6 72�6 5�4
Coffee 11 88 1
Data are the mean percentage of six measures for carrot (i.e. six 240-cell trays). Only one
measure for coffee (i.e. one 240-cell tray).
Table 2: Effect of the seeding precision system on the embryo-to-plantlet conversion rate of
carrot somatic embryos
Embryos (n) Plantlets (n) Conversion (%)
Control 100 62 62
After seeder 50 33 66
After seeder with phytoprotection a 80 50 63
a according Dupuis et al. (1999)
4. Conclusion
Desiccation of somatic embryos may not be effective for all species
and/or must be adapted to their specific requirements. For example, the
desiccation procedure described in this work did not maintain the survival of
coffee embryos: they can be successfully dehydrated under 75 % R.H. but
they regrow through a secondary embryogenesis process under 43 % R.H.
conditions (Florin et al., 1995). Consequently, the possibility to handle
coffee embryos using seed technologies must be assessed after a desiccation
under a 75 % instead of a 43 % R.H. regime. Another key point for the
implementation of this method is the scaling-up of desiccation i.e. to