STEREOLOGICAL ANALYSIS OF ULTRASTRUCTURAL CHANGES DURING INDUCED EPIDERMAL CELL REDIFFERENTIATION IN DEVELOPING FLOWERS OF CATHARANTHUS ROSEUS (APOCYNACEAE)

Stereological principles were used to study epidermal cell redifferentiation during the post-genital tissue union in the developing flowers of Catharanthus roseus. Volume densities of ultrastructural components at three separate stages of cell differentiation were analyzed and compared. Nuclear volume density decreased and vacuolar volume density increased throughout the period studied. The only other components whose volume densities changed significantly were plastids, mitochondria, and dictyosomes. For each of these organelles, the mean relative volume was greatest at the time of fusion. By 12 hr after fusion, however, the mean relative volume of each fell to a level significantly lower than its volume in the prefusion cells.