Litvay’s medium is composed for the in vitro culture of cell suspension of Daucus carotus and finally for Pinus taeda L. An increase of Increasing the magnesium concentration from 0.75 mM to 7.5 mM and decreasing the calcium concentration from 1.5 mM to 0.15 mM was also of positive -influence. However, these alterations are not as drastical as the improvement by the enrichement of the medium by additio-nal -phosphate.the phosphate concentration from 0.5 mM to 2.5 mM was essential for improved cell growth and embryo-genesis.