REVERSIBLE INHIBITION OF SOMATIC EMBRYO DIFFERENTIATION BY BROMODEOXYURIDINE IN CULTURED-CELLS OF DAUCUS-CAROTA L

Somatic embryogenesis induced in suspension cultures of carrot (Daucus carota) was inhibited by BUdR at concentrations which do not influence the rate of RNA or protein synthesis, or the growth of the cells. At the time of embryo induction 2 days treatment with 6 μM BUdR was sufficient for the complete supression of differentiation. The degree of inhibition showed a dependence on the applied concentration of BUdR, as well as on the level of BUdR substitution in DNA. The BUdR inhibition proved to be reversible and the embryogenic capacity of the carrot cells was restored after removel of the analogue. Addition of thymidine prevented the inhibitory effect of BUdR by decreasing the incorporation of BUdR into DNA. The experiments reported here indicate that the effect of BUdR on the somatic embryo differentiation was probably associated with BUdR substitution of thymidine in the DNA. © 1979.