Study on Somatic Embryogenesis and Histological Observation of Camellia yuhsienensis Hu

[Objective] The research aimed to investigate the somatic embryogenesis from Camellia yuhsienensis Hu using cotyledons as explants. [Method] Embryogenic calluses were obtained from cotyledons which had been cultured in MS+2.0 mg/L 2, 4-D+1.0 mg/L KT. Then, embryogenic calluses were incubated for somatic embryogenesis in MS basic medium with different concentrations of 6-BA and NAA. Somatic embryos at different developmental stages were sectioned and observed under light microscope. [Result] The results showed that the embryogenic calluses were initiated within 15 d. The optimal medium for somatic embryo differentiation was MS + 2.0 mg/L 6-BA + 0.6 mg/L NAA and the induction frequency was 87.78%. The somatic embryos were also formed in the MS medium without phytohormones, but the induction frequency was less than 6.67%. The histological observations indicated that somatic embryos originated from epidermal cells or some cells near epidermis. The mature somatic embryos were finally formed via globular embryo, heart-shaped embryo and cotyledon-shaped embryo stages. [Conclusion] The optimal medium for somatic embryos differentiation from embryogenic callues was MS +2.0 mg/L 6-BA + 0.6 mg/L NAA.