Study Of Factors Affecting On Somatic Embryogenesis In Walnut

The cotyledon, embryo, and embryonal axis of J. regia L.were used in the experiment and it was studied a series of factors affecting somatic embryogenesis. The optimal culture medium and conditions for walnut somatic embryogenesis had been selected under the variant hormones combinations and culture conditions. The results of experiment were as follows:The result of sifting basal medium showed that DKW medium accorded nutrient elements in walnut somatic embryogenesis .The explants of different stages in different hormones combinations somatic embryogenesis showed that the high percentage of cotyledon somatic embryogenesis was 58.89%, which was after pollened from the eighth to the eleventh week, they came into being embryogenic callus in DKW medium adding BA1.3mg/L +KT2.2mg/L +IBA0.02 mg/L, and produced embryoid in DKW added no hormones; the high percent of embry somatic embryogenesis was 64.96%,which was after pollened the sixth and eighth week, they came into being embryogenic callus and produced embryoid in DKW medium adding BA1.0mg/L; embryonal axis came into being embryogenic callus in DKW medium adding BA1.0mg/L+KT1.0mg/L +2,4-D2.0mg/L, and produced embryoid in DKW added no hormones.In the experiment, antioxidants and adsorbents, which can prevent explants of walnut trees from browning, were investigated. The result showed that the explants treatment in advance can prevent explants from browning efficiently, which soaked in 2% Na2S2O 3 before explants sterilizing, and soaked in 0.2% Na2S2O 3 after explants sterilizing.In the experiment, some conditions were investigated ,such as the time of transferring , darkness treatment , solidification of agar, source of nitrogen, sugar species and concentrations, affect the somatic embryogenesis. The results showed that DKW added with 500mg/L CH and 250mg/L glu, PH5.8 , and the concentration of saccharose was 4%, which was beneficial of somatic embryogenesis. Transferring after 30-35 days, and darkness of 30 days before transferring the induction medium, which was the necessary conditions for embryoid happening and development.