Somatic embryogenesis was induced in embryos of Picea abies by adding 2,4-D and BAP to the culture medium. The content of IAA, ABA, zeatin-ribosid and 2ip was determined
at various stages of callus tissue formation using ELISA. The process of embryogenic callus formation depended on the content of IAA and ABA in cultured tissues. The embryos capable of forming embryogenic callus contained 5–6 times more IAA than those incapable of somatic embryogenesis. The ABA content in embryos capable of forming embryogenic callus was two times higher than in embryos incapable of embryogenesis. A sufficiently high level of ABA was observed in embryogenic callus. One of the conditions for the formation of embryogenic callus was a high content of cytokinins in cultured embryos. The data showed that embryogenic callus contained a significantly smaller amount of cytokinins than the cultured tissue of embryos. The level of phytohormones observed in embryogenic callus was low compared to the callus it was formed on. The concentration gradient of phytohormones or a major difference between embryogenic and nonembryogenic callus showed special embryo tissue sensitivity to the growth regulators that determined its competence and readiness to accept exogenous hormonal signal and respond to it in a certain way.