Somatic embryogenesis of Picea pungens Engelmann

Somatic embryogenesis is critical for understanding the mechanism of embryo development and clonal propagation. In this study,we investigated the optimal culture medium and growth regulator concentration for the in vitro somatic embryogenesis of Picea pungens,using mature embryos as explants. The mature embryos were first cultured on DCR medium containing 2,4-D 5.0 mg/L+ 6-BA 4.0 mg/L+ KT 2.0 mg/L for fifteen days,then transferred to DCR medium supplemented with 2,4-D 1.0 mg/L+ 6-BA 0.5 mg/L+ KT 0.5 mg/L,on which the highest induction frequency of embryogenic callus was up to 45.3%. Then the embryogenic callus were subcultured and proliferated on 1/2 LM culture medium with 2,4-D 1.0 mg/L+ 6-BA 0.5 mg/L+ KT 0.5 mg/L+ PEG4000 1.0 g/L,with the highest proliferation rate reaching 102.27%. During the induction of somatic embryos,addition of IBA 0.5 mg/L+ ABA 2.0 mg/L to the 1/2 LM culture medium resulted in the highest induction frequency of 38.10%. All the above-mentioned culture media contained glutamine 450 mg/L,casein hydrostat 500 mg/L,sucrose 30 g/L and agar 5.0 g/L with the pH value of 5.8. Regenerated somatic embryos could germinate and grow on 1/2 MS culture medium with AC 1.0 g/L,but fewer roots were produced. Further research is needed to improve the regeneration frequency of somatic embryos and the root generation.