Figure 1. Schematic diagram of the process used to generate four lines (DEC, DSEI, ECS and ECB) of somatic embryos.

A Mature seed, B somatic embryos were induced from mature seed directly through heat-stressed culture on hormone-free 1/3 MS medium, C secondary embryos were developed directly after transfer somatic embryos to the original culture environment cultured on hormone-free medium for 3–4 weeks, D somatic embryos were developed when secondary embryos were subcultured on hormone-free medium, E somatic embryos, F embryogenic cell clusters were induced from somatic embryos through culture on 1/3 MS medium with 1 mg·L⁻¹ 2,4-D, G mature embryos were developed when embryogenic cell clusters were cultured on hormone-free medium, H embryogenic cell clusters were generated when embryos were cultured on 1/3 MS medium with 1 mg·L⁻¹ 2,4-D, I embryogenic cell clusters, J secondary embryos were developed directly when mature embryos (DEC line) were transferred into 1/3 MS liquid medium without PGR for suspension culture, K secondary embryos in suspension culture, L secondary embryos were developed directly when mature embryos (DEC line) were transferred into 1/3 MS liquid medium without PGR for bioreactor culture, M secondary embryos in bioreactor. 1. DSEI process. 2. DEC process 3. ECS process 4. ECB process.