Long-termin vitro storage ofColocasia esculenta under minimal growth conditions

The storage of a clone ofColocasia esculenta at 28/24°C over a 12-h photoperiod in the absence of mannitol, was not feasible with transfer intervals of more than eight months. Mannitol had a positive effect on survival at this temperature, but caused abnormalities at high concentrations. At 9°C in total darkness,C. esculenta could be stored for more than eight years with transfer intervals of approximately three years. After this period, more than 90% of the cultures showed living shoots, but not all shoots per culture showed regrowth. Cultures which were transferred three times during the experimental period, had a significantly (=0.05) lower number of regrowing shoots than cultures which were transferred twice. This might be due to the fact that the former cultures were transferred at a less favourable developmental stage. The addition of mannitol to the storage medium did not improve survival and regrowth, nor did a more gradual lowering of the temperature to 9°C.