Abstract:Embryonic axes excsied from fresh lychee and longan seeds could be cultured and developed into plantlets in non-hormonal WPW medium with pH4. 8-8. 0. The addition of NAA and KT to the medium caused the inhibition on the normal growth of embryonic axes. The critical moisture contents of the embryonic axes of lychee and longan were about 30% and 23% respectively. Desiccation beyond these thresholds, the viability fell rapidly, and the embryonic axes could not produce normal plantlets after incubation for 25 days. The viability of embryonic axes desiccated by silica gel decreased more quickly than that of non desiccated ones after short-time storage , and the embryonic axes were easily infected by bacteria during incubating. The survival percentages of lychee and longan embryonic axes desiccated to about the critical moisture contents were 0 and 25-50%, respectivity, when they had been storaged in liquid nitrogen for 24 hours.