[en] The results indicate a contamination of the seed coats with microorganisms which possibly could falsify the results on uptake and incorporation of radioactive precursors into nucleic acids and proteins. On the other hand, contamination of isolated embryos does not falsify the results on uptake and incorporation of the precursors, although the contamination of the embryos was not lower than the contamination of intact seeds. The extent of contamination with bacteria and fungi was detected on dry and imbided Melandrium noctiflorum and Agrostemma githago seeds as well as on isolated Agrostemma embryos. The uptake of radioactive precursors such as amino acids, purine and pyrimidine bases, and nucleosides is much higher in isolated embryos than in intact seeds. The precursors taken up by intact seeds remain mainly in the perisperm. Consequently, experiments with intact seeds give no information concerning the synthetic activity of the embryo. (author)