LONG-TERM STORAGE OF SOMATIC EMBRYOGENIC WHITE SPRUCE TISSUE AT AMBIENT-TEMPERATURE

The effect of long-term storage on the viability and regeneration capacity of somatic embryogenic white spruce tissue (Picea glauca) was investigated. It was found that by keeping white spruce embryogenic tissue in serum-capped flasks at ambient temperatures, a viability of 80% could be maintained without subculturing for a period of over one year. Growth characteristics of the embryogenic tissue on solid medium and suspension cultures derived therefrom were essentially identical to the culture from which they originated. Ethylene and carbon dioxide accumulation peaked around days 8 to 10 in serum-capped cultures and declined thereafter during the short-term (20 days). When ethylene and carbon dioxide levels were measured over a period of five months, in flasks varying in their degree of gas tightness, it was found that those cultures that maintained higher carbon dioxide concentrations after five months remained viable and could be recultured under normal conditions. Development to cotyledon stage embryos from immature embryos could be obtained by exposure of the long-term storage material to 10-mu-M ABA, and the number of maturing embryos was found to be similar to that of the original culture.