Diffusible Factors Essential for Epidermal Cell Redifferentiaion in Catharanthus roseus.

During postgenital tissue fusions, some plant epidermal cells redifferentiate into parenchyma, a different cell type. Diffusible factors cause this response in the fusing gynoecium of the Madagascar periwinkle (Catharanthus roseus). Surgical manipulations of the gynoecium showed that epidermal cells from normally nonfusing surfaces could trasmit and respond to the diffusible factors. Furthermore, the diffusible fators could be trapped in agar-impregnated barriers, as shown by the redifferentiation of carpel epidermal cells from nonfusing regions when the factor-loaded barriers were appressed to them.