Effect of Low Temperature Pretreatment on Somatic Embryogenesis of Fraxinus mandshurica Rupr.

The effects of low temperature pretreatment on somatic embryogenesis of Fraxinus mandshurica were investigated by using zygotic embryos from immature seeds that pretreated under 4 ℃ for 0–30 d as explants. The results showed that the total somatic embryos and cotyledonary somatic embryos induced from the pretreated explants were lower than those of control; the fluctuation trends of abnormal somatic embryos and their ratio to total somatic embryos along with the pretreatment time changes were similar to those of total somatic embryos and induction ratio; however,although the absolute normal somatic embryos and its ratio to total somatic embryos were very low in the 20 d treatment,they were much higher than those of control. This indicated that 4 ℃ low temperature pretreatment had no improvement effect on F. mandshurica somatic embryogenesis and abnormal somatic embryo control,but the proper treatment had the potential to improve normal somatic embryogenesis.