Studies On Somatic Embryogenesis And Specific Proteins In Picea Likiangensis

Cell totipotency refers to that plant cells have the whole genetic information, either gengrative or somatoplasm, in given conditions, can express and grow into an intact plant. And somatic embryogenesis has given expression to it. As one major technical breakthrough of later 20th century in plant tissue culture, the technique of somatic embryogenesis has shown great significance both in theoretical research and practical application.Conifer species distribute widely in the world and occupy very important position in all tree species. However, the characteristics of this group trees contribute to the difficulties of its somatic embryogenesis. Anyway, somatic embryogenesis for spruce trees is relatively easy. So they are usually taken as mode trees in conifers for researches related.Picea Likiangensis is the only species of Picea distributed in Yunnan. Taking its mature zygotic embryos as explants, the paper explored embryogenic callus induction on different basal media, plant growth regulator combinations and genotypes. And the media for embryogenic callus initiation, proliferation, for somatic embryos maturation and germination were obtained. At last the soluble protein content and composition of somatic embryos in different development stages were determined and analyzed. The research will lay a foundation for further study on somatic embryogenesis of other conifers and molecular mechanism of somatic embryogenesis. The results are as follows:1. 331 embryogenic callus from 7 individual trees were obtained, which can be used for Picea Likiangensis clone rapid propagation, and can also be used for the further study on mechanism of somatic embryogenesis.2. Somatic embryogenesis system for Picea Likiangensis has been established. Media for embryogenic callus initiation is 1/2LM+2,4-D3mg·L-1+BA 1.5mg·L-1, for embryogenic callus proliferation is that the same as the former. And media for somatic embryos maturation is 1/2LM + ABA(60mg/l) + PEG (7.5%), for germination is DCR + AC (0.2%). All cultures were kept in dark and room temperature or 21-23℃.3. The study on embryogenic callus initiation shows that initiation rate varies greatly from different basal media, plant growth regulator combinations and genotypes. In all media tested, the medium of 1/2LM+2,4-D3mg·L-1+BA 1.5mg·L-1 has the highest induction rate, which reaches 15.37%.4. The relative soluble protein contents in non- embryogenic callus, embryogenic callus and somatic embryos in 4 development stages (globular, heart, torpedo and cotyledon stages) were determined by the methods of G-250, by which dynamic characteristics of their changes were analyzed.5. The specific proteins of above materials were analyzed by way of SDS-PAGE gel electrophoresis. The results shows that 94KD,64KD,31KD proteins are expressed in non- embryogenic callus, 96KD,63KD,58KD,35KD proteins in embryogenic callus and 60KD,58KD,45KD specific proteins present during the development of somatic embryos. The results will provide beneficial information for further research on molecular mechanism and other basic theoretical research of somatic embryogenesis of conifer trees.