| Larix gmelinii is one of the important forest trees in northeastern China. Recently, it is short of good seeds due to increasing demand and documental character of its seeds, whereas we can obtain plenteous seedlings with good qualities by somatic embryogenesis (SE). Therefore, in this study, mature and immature zygotic embryos (ZC) of L. grnelinii were used as explants to induction embryogenic callus (EC), then the factors which might influence the induction were assayed. This study is hoping for establish efficient and stable somatic cell line and provide some basic experimental data for somatic embryogenesis system. The results as follows:(1) The induction rate (IR) of embryogenic callus (EC) from zygotic embryo (ZE) explant with its endosperms was higher than that from ZE explant without its endosperms. The IR of EC from mature ZE explant from Inner Mongolia seed source was significantly higher than that which from Daxing'an Mountains seed source (p＜0.05). The IR of EC from mature ZE explant derived from seeds stored at 4℃for two months could be improved evidently. 2,4-D had greater effects on EC induction than BA and KT, and these three hormones had certain coefficient effects. S medium was more effective than MS and DCR media.(2) The IR of EC from immature ZE explants derived from seeds collected in different developmental stages was significant different. None of the explants was induced when the explants was collected in the early of June, while highest IR (40.19%) of EC could be obtained from immature ZE explant collected on July 5.The IR was decreasing with time flying after later part of July.(3) The combination of different kind hormone have a significant effect on IR of EC, and ZE from different stage was influenced different by hormone. Regardless of concentrations of hormone, IR was zero at the period of embryo selection. The highest IR (53.71%) was obtained at the period of pre-cotyledon embryos with 1 mg·L-1 2,4-D, 0.1 mg.L-1 BA, 0.5 mg·L-1 KT. Furthermore 2,4-D play an important role in induction of EC, but adding BA and KT can improve IR. In addition, higher IR was obtained on medium with 4 g·L-1 agar.(4) It is best to subculture when EC were culture between 17 days and 24 days. If wait too long time for subculture, the EC would lost their activities and won't develop further. A little of hormone also necessary need in proliferation stage, adding 0.5 mg·L-1,2,4-D,0.05 mg·L-1 BA and 0.25 mg·L-1 KT in the first time which can made the increasing weight of EC achieving 1.5 g. After the first time, the concentration of hormone reduce to 10%. The explants would die, if transformed them to the medium with no hormone.(5) Adding ABA (2 mg·L-1 to mature medium, cotyledon embryos turned up after .30 days. PEG and inositol also have some effects on polarization, but growth of somatic embryos were not good as ABA and didn't found cotyledon embryos. Combination of ABA with PEG have no effect on polarization. Light-yellow cotyledons turned to green, opened slowly, lower hypocotyl elongate, but rooting was bad, after transformation of cotyledon embryos on generation medium for 5-7 days.
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