The correlations between differentiation, the amino acid composition of total protein and of soluble protein, and the disc electrophoretic distribution of soluble protein of carrot tissue cultures and of carrot plants (leaves) were studied. In spite of pronounced and characteristic changes in the electrophoretic distribution of the components of soluble protein in various developmental stages of both bioassays, no significant differences in the amino acid composition of protein were observed. With progressive development of whole carrot plants and of carrot tissue cultures, the number of protein bands on disc electropherogramms increased.