Stimulation of somatic embryo formation by mutagens and darkness in culture of immature zygotic embryos of Arabidopsis thaliana (L.) Heynh.

The aim of the study was to evaluate the influence of light conditions,physical state of the induction medium and the mutagenic treatment on theembryogenic ability of Arabidopsis thaliana (L.) immaturezygotic embryos differing in developmental stage. The efficiency of directsomatic embryogenesis (DSE) was analysed in a culture of immature zygoticembryos at an early (ES) and a late (LS) developmental stage. The efficiency ofDSE was scored as a percentage of the explants producing somatic embryos. Theexperiments indicated that the physical state of the induction medium (solid orliquid) did not influence the embryogenic ability of the cultured explants. Inthe cultures on both solid and liquid induction medium, the ES explantsproducedsomatic embryos with a frequency of 25.8–37.3% i.e. 2.5–3-timeslower than LS explants. However, an increase in the embryogenic ability of ESexplants (up to 69.8%) was observed when DSE was induced in darkness. Moreover,the stimulation of DSE efficiency in culture of ES explants was also observedafter mutagenic treatment. The chemical mutagens, MNH and EMS, applied forexplant treatment, both stimulated efficiency of somatic embryo formation inculture of ES explants. The most effective DSE induction was observed when MNHand EMS were applied in doses of 0.125–1.0 mM × 3h and0.05–0.2% × 18h, respectively. In these treatment combinations thefrequency of ES explants forming somatic embryos was found to be about 2 timeshigher than in the control culture.