Cyclamen seed germination and tuber regeneration In vitro

Cyclamen seeds which were sterilized for 2 minutes with a solution containing 10% Clorox and 90% Alconox and placed on Knudson's medium (- sucrose) were compared with seeds sown in a darkened bed in the greenhouse. Germination was 5 weeks earlier in vitro than in the greenhouse. Germination was 90% in vitro and 60% in the greenhouse. In vitro germination was similar at 20 and 22°C. Similar rates of germination were achieved in vitro with unsterilized seeds but contamination ensued. Even sterilized seeds were contaminated when the nutrient agar medium contained the recommended quantity of sucrose.

Cyclamen endosperm was shown to consist of small condensed protoplasts widely separated by massive cell walls in both dry and imbibed but nongerminating seeds. The histological results revealed that germination was accompanied by decomposition of endosperm cell walls.

Tubers were separated from seedlings germinated in vitro, sterilized in Clorox-Alconox solution for 30 minutes, divided in pieces, and placed on either Knudson's medium or Murashige shoot-tip rooting medium. Explanted tuber pieces regenerated roots and shoots when auxin and kinetin were included in the media. No regeneration occurred without the hormones. Tubers retained high regenerative capacity when divided in halves or thirds but not in fourths.