Acta Univ Latv (2007) 723: 27–35

Somatic embryogenesis and plant regeneration in immature zygotic embryos of Brassica napus

Abstract

The effect of zygotic embryo age and pH of media on somatic embryogenesis induction of spring rapeseed was investigated. Immature zygotic embryos cultured on a growth regulator-free Murashige & Skoog medium produced primary somatic embryos without an intervening callus phase. Secondary somatic embryo induction was also possible on hormone-free medium. Similar to direct embryogenesis, the efficiency of secondary embryogenesis depended on pH of media. Higher pH (5.0) stimulated the proliferation of primary somatic embryos 25 to 26 days after pollination of zygotic embryos, while a lower pH (3.5) significantly increased the number of responding primary somatic embryos developed 20 to 21 days after pollination of zygotic embryos. Our study showed that primary somatic embryogenesis proceeded at a lower rate than secondary, but the highest number of somatic embryos per responding explant was obtained in primary somatic embryogenesis. Upon transfer to B5 medium, cotyledonary embryos developed into plantlets at a frequency of 7.3 – 30 %.