Nippon Paper Industries (NPI) has successfully developed a long-term, low-temperature Eucalyptus plant tissue storage method together with Kagawa University represented by Professor Michio Tanaka, and have made it possible to carry out mass clonal Eucalyptus production in a way that is cheaper than current methods for commercial tree plantation.

 

Plant tissue culture is an excellent clonal propagation method because it is available for species that do not propagate by standard cultivating methods. However, the plant tissue needs to be transferred to a sterile, fresh medium every four months due to its continued growth and propagation. In addition, millions of uniform, high quality plantlets should be nurtured and provided for a three-month-planting season for actual plantation. When we apply conventional tissue culture methods to plantation it requires that a considerable number of operators and a lot of equipment be prepared in order to handle the large number of plant tissues which, as a result, significantly increases the production cost of the clone plantlets.

 

On the other hand, using the new method, the plant materials obtained by tissue culture are stored under low temperature conditions, and when the tissue is required for plantation it can be recultured in a short period. Since the tissue can be stored for more than six months, frequent sterile tissue transfers can be decreased and propagation work can be implemented steadily throughout the year. As a result, the number of operators can be reduced to one fifth of those required for conventional tissue culture methods.

 

A detailed procedure is as follows.

Approximately fifty fresh shoots without leaves, roughly 5 cm in length, are stored in a plastic bag, 10 to 15 cm in height made of a gas released fluorine contained resin with the culture medium, being stored under 4 to 10 degree centigrade conditions. Stored shoots are then transferred to a culture medium when they are needed for propagation. One stored shoot can form more than ten additional shoots, and these new shoots are cut for rooting in order to be used as plantlets for the plantation field.

 

NPI has developed a profitable clonal tree plantlet production system based on the three core technologies which are: mass tree production using tissue cultures, a rooting technique using photoautrophic cultures in a high CO2 concentrated environment, and low temperature storage. NPI plans to test plantlets produced by these technologies at its Australian laboratory (scheduled to open in June 2000) expecting commercial utilization within 4 to 5 years.