MORPHOGENETIC EFFECTS OF BREFELDIN-A ON EMBRYOGENIC-CELL CULTURES OF DAUCUS-CAROTA L

Brefeldin A, an inhibitor of protein secretion, caused typical alterat ions to the endomembrane system with limited effects on viability when given to unorganized carrot cells growing in suspension. When given t o the same cells during particular stages of embryogenesis, it caused similar endomembrane lesions and an almost complete arrest of the embr yogenic process. Addition of conditioned medium containing extracellul ar secreted proteins to the embryos during treatment with Brefeldin A allowed acquisition of polarity and the continuation of a quasi-normal embryogenic process.