Protoplasts were cultured in KMP8 or L1D2 medium [3] and trapped in a matrix of 1.2 % (m/v) sea-plaque agarose. Double strength medium and agarose were prepared and then mixed together in equal volumes. This mixture was cooled to 45 °C in a water bath and then cultured. Dishes were kept at 28 ± 2 °C in the dark or in continuous light (40 µmol/m2/s) supplied
by fluorescent tubes. After two weeks, each agarose layer was cut into four segments and 0.5 ml KM8 liquid medium of low osmoticum (Osmolarity = 440 ± 20 mOsm/kg) was added to enhance cell growth. This medium was replaced after 3 weeks.