Studies on the Requirements of Conservation of Eucalyptus Germplasm Encapsulated in Alginate Beads at Room Temperature

Eucalyptus grandis×E.urophylla microcuttings in vitro were encapsulated with alginate as the gel bead style and maintained in agar medium without nutrition.It was found that this style was a suitable method for the conservation of Eucalyptus germplasm.Regenerative rates of shoot were 52% after ten months' conservation.High vigor of germplasm was observed in low concentration(1.5%～2.0%)of encapsulated sodium alginate.The tests of basic components supplemented in the alginate by single factor or multiple factors orthogonal design showed that sucrose concentration was the key factor limiting the vigor and regenerative rate of germplasm.Low concentration of sucrose(0.5%)and minerals showed the benefited effect,but 5.5% sucrose induced blackening of microcuttings,decreasedthe vigor,and decreased the regenerative rate of germplasm.During the conservation period,changes of alginate bead colour from green to white or to black were the two main apparent indicators of losing vigor and regeneration capacity.The results suggest that apparent colour of gel bead might be used to estimate the vigor status of conserved germplasm.Light was a necessary factor for conservation of the encapsulated culture germplasm.