EN
Flower buds and immature embryos of P. nil Chois., which were grown in vivo , were material for the study. Flower bud (2-3 mm size) were treated with osmotic/trophic shock (12% sucrose) for 24h. After this time these explants were exposed on regeneration medium (MS supplemented with BAP in concentration 5 mg.dm-3 and NAA in concentration 0,1 mg.dm-3). After 4-6 weeks organogenesis of shoots was observed. Plantlets were isolated and transferred on MS medium with addition of GA3 [0,5 mg.dm-3] and NAA [0,1 mg.dm-3]. The plantlets developed into whole plants. Those plants were able to produce flower without photoperiodic induction, because these shoots regenerated from inducted tissue and ?remembered? this information. Immature embryos were isolated from previously sterilised fruit and afterwards transferred to MS without plant hormones. The embryos were cut across their axis. After 4-6 weeks of cultivation somatic embryos were formed in the injury place (hypocotyl region). These embryos were isolated and transferred on the same medium, which was used in shoots regenerated from flower buds. Embryos were converted into complete plants, but they weren?t able to flower without photoperiodic induction. However even the smallest embryos, which were used to our study (1 mm long) were able to flower, after a single induction cycle (16 hour of darkness), when the induction was given directly after isolation of embryos.