Effects Of Epibrassinolide On Embryogenic Tissue Induction Of Picea Asperata Mast

Somatic embryogensis of the Picea asperata Mast.could provide a new way to solve the problem of asexual reproduction and breeding.However,there are still some problems,such as low induction rate of embryonal tissues,the difficulty of maintaining high embryos,and low rate of differentiation.In this study,immature zygotic embryos of three genotypes of Picea asperata Mast.in 2015 were used as explant materials.On the basis of the existing somatic embryogenesis system,in the induction of embryogenic tissue,different concentrations of EBR were added to the culture medium to improve the induction rate and optimize the induction system.In the same proliferation cycle at 0th and 10 th day,the changes of physiological and biochemical,as well as the effect of somatic embryogenesis were examined.The results showed that:The low concentration of EBR was added to the induction medium,which effectively increased the induction rate and growth rate of embryogenic tissue P.asperata.After EBR induction of genotype A,B and C immature embryos,the changes of induction rate of embryogenic tissue were 15%~47.5%,12.5%~23.3% and 50%~77.5%,respectively.With regard to endogenous hormone content,different genotypes immature embryos in the different concentrations of EBR induced embryogenic tissue,the most content is IAA and ABA.Analysis the ratio of endogenous hormones,the result showed that: the values of CTK/IAA was lower than that of the control group at the 0th day and the 10 th day of the same proliferative cycle.The values of CTK/GA in embryonic tissues,genotype A and C were higher than that in the control group,while the embryonic tissue of genotype B was lower than that of the control group.Therefore,the changes in the ratio of endogenous hormones in the embryogenic tissues are different,and the hormones maintain a balance by joint or antagonistic co-regulation.After induction,in the embryogenic tissues the contents of 16 kinds of free amino acids and three kinds of free sugars were detected at the 0th day and the 10 th day of the sameproliferative cycle.In the embryogenic tissues formed by the EBR-containing induction medium the total content of free amino acids was lower than that of embryogenic tissues without EBR-induction.At 0th day,the total content of free sugars in genotype A and genotype B was higher than that in the control group.But at 10 th day,the total amount of free sugar in the embryonal tissue genotype A was lower than that in the control group,and the genotype B had no significant difference between the experimental and the control group.And about embryonic tissues of Genotype C,at 0th day and 10 th day,free of total sugar content in the experimental group and the content of polysaccharides,glucose and fructose were lower than the control group.The activity of antioxidant enzymes,MDA and soluble protein in embryogenic tissues were detected.Compared with the control group,the activity of CAT and the soluble protein content were increased at 0th and 10 th,while the changes of SOD and POD activity were opposite,and there was no significant in MDA,which together maintained the balance of active oxygen metabolism in embryogenic tissues.The embryogenic tissues of genotype A immature embryos after the induction medium addition of 0.5 ?M EBR was favorable for the differentiation of somatic embryogenesis,and the embryogenic tissues of genotype B and C immature embryos after the induction medium addition of 1.0 ?M EBR were conducive to the differentiation of somatic embryogenesis.After6 weeks of differentiation,the number of cotyledon embryos respectively were 54.01,52.36 and 74.85,which were 209.87%,238.90% and 105.57% higher than those of embryogenic tissues without adding EBR in induction medium.This is the first by adding the EBR in induction medium to improve the induction rate of embryonic tissues of P.asperata,and optimize the embryogenic tissue induction system.The embryogenic tissues at the 0th and 10 th day of the same proliferative cycle were explored at the physiological and biochemical level for the first time,and the differences in somatic embryogenesis differentiation of embryogenic tissues after the induction medium addition EBR were explored.