Effect of 2,4-Dichlorophenoxyacetic Acid on the Expression of Embryogenic Program in Carrot

Embryogenesis in a wild carrot cell line, W001C, can start and progress up to the first morphogenetic stage (the globular-stage embryo) in 2,4-dichloropenoxyacetic acid (2,4-D). To clarify the quantitative effect of 2,4-D on this cell line, morphological and biochemical criteria have been used to monitor embryogenesis in the presence of increasing concentrations of 2,4-D. The biochemical criteria are the ability to inactivate cycloheximide and the expression of an embryogenic polypeptide E(1). The results show that 2,4-D can affect embryogenesis in a quantitative manner but never fully suppresses embryogenesis unless it is coupled with high cell density.