Studies On Somatic Embryogenesis Of Quercus Mongolica

In this study,we used decotyledoned immature zygotic embryos,mature zygotic embryos and leaves of Quercus mongolica as explants,and discussed the effects of different disinfectant combinations and disinfection time,types of culture media,hormone concentrations,different sampling periods,different positions and other culture conditions on callus induction,and then screened out the optimum conditions for callus induction.On this basis,the best induction methods of somatic embryo were selected by selecting different hormone combinations,concentration ratios and culture time.The main results of this study are as follows:1.With the decotyledoned zygotic embryos of Quercus mongolica as explants,the best disinfection method for seeds was alcohol for 30s+0.1% mercury for 12 min.At this time,the contamination rate was 29.7%,the mortality rate was 18.7%,and the survival rate was 50.0%.2.MS medium was the best medium for callus induction of decotyledoned immature zygotic embryos.The induction of callus was significantly affected by the time of harvesting.Early July was the best harvesting time.The highest induction rate of zygotic embryo callus could reach 85.7% under the ratio of 1mg/L2,4-D+0.5mg/L6-BA hormone.The size of decotyledoned immature zygotic embryos and light conditions had no significant effect on the induction rate of callus.Different provenances could significantly affect the induction rate of callus.The best medium for somatic embryo induction was MS+0.5mg/L2,4-D+0.5mg/L6-BA.At this time,the highest rate of somatic embryo induction was 72.3%,and the best culture time was four weeks.3.With the leaves of Quercus mongolica as explants,the best disinfection method for leaves was alcohol for 30s+0.1% mercury for 4 minutes.At this time,the contamination rate was 25.7%,the mortality rate was 9.0%,and the survival rate was 65.3%.4.MS medium was the best medium for callus induction of leaves.The induction rate of callus was significantly affected by the time of leaf harvesting,and late March was the best time for callus induction,the highest callus induction rate was 96.7% under the combination of 0.5mg/L2,4-D+0.5mg/L6-BA.The induciton rate of callus was significantly affected by leaf placement and different verticillate points of leaves.There was no significant difference in callus induction rate among different parts of leaves.The best medium for somatic embryo induction was MS+0.1mg/L2,4-D+0.5mg/L6-BA and the induction rate of somatic embryo would reach 58.0%,the best culture time was 4 weeks.The induction rate of somatic embryo would reach 50.0% at the hormone level of 0.5mg/LNAA+0.5mg/L6-BA,at this time,the best culture time was 6 weeks.5.There were obvious differences in appearance and structure between embryogenic callus and non-embryogenic callus.Embryogenic cell clusters can originate either from the outside of the callus or from the inside of the callus.