Continuous Embryogeny and Plant Regeneration System from Seocondary Embryos in Brassica napus cv. `Topas'

摘要

A method for continuous secondary embryo formation and plant regeneration in Brassica napus cv. `Topas' is described. Secondary embryos that emerged from immature zygotic embryos via heat shock were separated and subcultured onto B5 plant growth regulator-free medium. Most secondary embryos (i.e. 70%) produced secondary embryos in a subsequent generation directly on the surface of elongated hypocotyls. Similarly, about 70% of the secondary embryos formed newly produced secondary embryos in a subsequent generation after subculturing, and the embryogenic potential of these secondary embryos has been maintained by repetitive subculture. The application of 1 0μM abscisic acid (ABA) induced desiccation tolerance in secondary embryos. Consequently, 60% of the desiccated embryos grew, all of which regenerated into normal plants. On the other hand, ABA-treated secondary embryos without desiccation treatment grew abnormally having an elongated hypocotyl, and all secondary embryos not treated with ABA lost their viability after desiccation.