Figures 5 and 6 show the results of reducing
mannitol concentration in medium and
treatment with activated charcoal on formation
of macrocolonies (>0.5 mm in diameter)
and embryos. Treatments I and III, in which
protoplast-plated regions were surrounded by
agar-solidified medium without mannitol, promoted
macrocolony and embryo formation.
This promotion may have been caused by a
gradual decrease in osmolality. Adding 1%
activated charcoal to the surrounding medium
did not significantly promote the formation of
colonies and embryos.