Somatic Embryogenesis In Pinus Bungeana

Pinus bungeana is a native tree species in China. It is widely used garden green and ecological afforestation in north China. In this thesis, immature zygotic embryos were used as a source of initial explants. Factors affecting somatic embryogenesis as well as physiological and biochemical characteristics difference between embryogenic callus (EC) and non–embryogenic callus (N–EC) were investigated. The results would lay a good foundation for propagation excellent clones, gene preservation, genetic improvement and large-scale artificial seed production for Pinus bungeana.The results were as follows:1. Embryogenic callus can be induced on DCR1, BM1 and MSG medium with immature zygotic. Compareing with BM1 and MSG medium, the callus produced on DCR1 growed fast, and had a strong differentiation ability. The induction rates reached 56.59%.2. Higher inducing rates of EC were obtained on DCR1 medium with high 2,4-D and 6-BA concentration combination. The different concentration combination of 2,4-D and 6-BA , as well as their interaction had a significant effect on induction rates of EC. The result of Duncan's multiple range test showed that 6 mg·L-12,4-D + 2 mg·L-16-BA was more favorable to induce EC.3. The different development stage of immature zygotic embryos have significant effect on. induction rates. More efficient induction of embryogenic cultures was achieved from the immature zygotic embryos sampled on June 30, Inducing rates reached 97.22%. The average induction rates was 76.23%.4. The mature zygotic embryos sampled on July 30 and August 10 were difficult to induce EC. EC produced from one or two explants growth potential became weak after subculture and could not further differentiated embrionic cell.5. 0.3 mg·L-1 2,4-D + 0.2 mg·L-1 NAA was more favorable hormone combination for EC maintain and proliferation.6. The subculture manners had a remarkable influence on EC multiplication rate. 88.89% multiplication rate achieved with solid/liquid alternate manner.7. The late stage proembryos were induced in EC of multiplication medium with 9,000 mg·L-1myo–inositol and 0.1 mg·L-1 IBA. More EC group could change into embryogenic suspensored cell mass with low concentration IBA.