Tissue culture regeneration of hybrid Liquidambar styraciflua × L. formosana

ObjectiveLiquidambar sp. has strong adaptability, fast growth, high ornamental values, it can be used as commercial tree species and landscaping tree species. Liquidambar styraciflua can be interfertiled with Liquidambar fomorsana, and their offspring can show robust growth. However, the rapid propagation technology and genetic transformation system of hybrid sweetgum need to be improved.

MethodIn this study, using Liquidambar styraciflua as female parent and Liquidambar fomorsana as male parent to obtain hybrid sweetgum, and hybrid sweetgum cotyledon, cotyledon node and hypocotyl explants were used to establish an efficient tissue culture regeneration system, we also compared the differentiation ability of the three explants.

Result(1) The best bud induction medium of cotyledon and cotyledon node explants was 0.2 mg/L TDZ+0.1 mg/L NAA basal WPM, but the best bud induction medium of hypocotyl explants was 0.1 mg/L TDZ+0.1 mg/L NAA basal WPM; (2) Shoot elongation liquid medium contained 0.5 mg/L 6-BA+0.1 mg/L NAA+0.8 mg/L GA without agar WPM performed the highest average adventitious bud induction number for three explant types; (3) Adventitious buds were rooted in 2.0 mg/L IBA+0.1 mg/L NAA WPM medium, and its rooting rate reached 100%;(4) After the adventitious buds being cultured in rooting medium for 2 months, the plantlets were transferred into greenhouse, and the transplant survival rate was more than 90%.

Conclusion(1) The differentiation abilities of the three explants were as follows: cotyledonary node>cotyledon> hypocotyl, in which the differentiation ability of cotyledonary nodes was significantly higher than cotyledon and hypocotyl; (2) TDZ can effectively promote the induction of adventitious buds, and GA has a significant effect on adventitious shoot elongation; (3) The hybrid sweetgum explants obtained the highest adventitious bud induction rate in the solid medium, the highest number of adventitious buds was obtained in the liquid medium, and no vitrification occurred in the liquid culture. The results of this experiment lay a solid foundation for the rapid propagation of new varieties and the establishment of genetic transformation system of hybrid sweetgum.