| Quercus variabilis is one of the primary sources of industrial cork in China. Presently its growth was established mostly by natural regeneration as a result of difficult to store seeds and conventional reproduce such as cutting. It is benefit for propagation excellent clones, genetic improvement and gene resource preservation through somatic embryogenesis plant regeneration for this specie. In this thesis, immature zygotic embryos were used as explants to induce somatic embryos. The physiological and biochemistry characteristics between embryogenic callus (EC) and non- embryogenic callus (NEC) in somatic induction were studied. Meanwhile we also investigated the physiological and biochemistry characteristics changes of somatic embryos by adding different carbon sources,nitrogen sources and ABA on the maturation medium during somatic embryos maturation.. This will provide a sound theoretical basis for establishment of plantlet regeneration system from somatic embryogenesis of Q. variabili. The main results were described as follows:1. The contents of soluble protein, soluble sugar and antioxidant enzyme activities of EC were higher than these of NEC in the same genotype of Q. variabilis. There was no significant difference between different genotypes.2. The effects of different carbon sources,nitrogen sources and ABA on the maturation of somatic embryos were compared. The results showed that 5% sucrose and 1.0g/L CH were beneficial to somatic embryo maturation and germination.The mature rate somatic embryos was the highest on medium with 5% sucrose, which reached 82%;To add 0.5g/L arginine and 0.5g/L glutamine in the medium was help to somatic embryo maturation, but had no effect on germination.To add glucose, mannitol and ABA in the medium was disadvantageous to somatic embryo maturation and germination.With 5% mannitol the mature and germination rate were only 9% and 1.9% ,respectively.3. Adding 5% sucrose in maturation medium, the contents of soluble sugar and protein were higher than that of other carbon sources in mature embryos of Q. variabilis. Medium with 8% sucrose also contributed to the sugar and protein accumulation, but the more serious browning was disadvantageous to somatic embryo maturation and germination.The higher it is of sucrose concentration in the medium, the stronger CAT activity was. The browning was very serious in the medium with mannitol, in which POD and SOD activities of somatic embryos were also higher than that of other carbon sources.4. Adding 1.0g/L CH, 0.5g/L glutamine and 0.5g/L arginine respectively in maturation medium, the contents of soluble sugar and protein were higher than that of other nitrogen sources in mature embryos of Q. variabilis. Adding arginine in maturation medium, the contents of soluble sugar and protein decrease as the concentration increases, this change was in accordance with that of mature rate. The antioxidant enzyme activities were strengthened with the increase of CH concentration in maturation medium.5. Adding different concentration ABA in maturation medium, the contents of soluble protein in the somatic embryos all increased, and there were no significant difference between different concentration treatments. With the somatic embryos maturation, the content of soluble sugar in the somatic embryos also increased gradually in the medium free ABA or with 0.5mg/L ABA.Comparing with free ABA in medium ,the CAT activity of somatic embryos increased with low concentration ABA,and CAT activity decreased with the increase of ABA concentration. To add any concentration of ABA,.POD and SOD activities decreased.6. In the process of maturation, the somatic embryos soluble protein content increase and having a higher peak value resulted in high mature and germination rate. The better mature somatic embryos could be obtaind in those treatments in which the somatic embryos soluble sugar content increased with its matureation. The CAT activity was opposite with the POD activity for most treatments. Exorbitant high or low SOD activity was disadvantageous to somatic embryo maturation and germination in the process of maturati... |
PDF Full Text Request