The studies of DNA metabolic dynamics in embryonic cell line and non-embryonic cell line of Onobrychis viciaefolia scop

The hypocotyls of aseptic seedlings of Onobrychis viciaefolia Scop. were used as explants for inducing callus. The embryonic cell line (E-line) and non-embryonic cell line (NE line) were established. The DNA synthesis dynamics in both cell lines were studied by autoradiography. The results showed that: DNA synthesis in E-line was active and confined to embryonic cell or cell masses and then the cells divided quickly and formed somatic embryos at different stages. The changes of DNA metabolism took place in a certain pattern and the maximum rate of DNA synthesis occured during the formation of globular embryo. There was a clear relationship between the difference of DNA synthesis rate and the polarity of the embryo. In NE-line, the beginning of cell division and the forming of callus were also based on DNA replication but were much deoxythymidine. There was a significant difference in DNA synthesis dynamics between the two cell lines