ABSTRACT
Protoplast isolation and culture is a very efficient, and perhaps absolutely necessary methodology for crop improvement by genetic engineering with cells of higher plants. When dealing with cytodifferentiation in cultures arising from isolated protoplasts, it seems appropriate to confine descriptions to the early stages of development, including microcolonies. Protoplasts of noncycling cells can be induced to divide by employing media with auxins and cytokinins, once a new cell wall has formed. In mesophyll protoplasts, biochemical processes associated with the regeneration of the cell wall will overlap with processes linked to the "change of program" of the regenerating cells. Protoplasts were isolated from leaves from axenic plants which had been regenerated from an androgenic stem embryo system of Brassica napus cv. Tower and cv. Loras. The formation of tracheary elements in Zinnia and in Brassica, of alkaloid cells in Macleaya and of nonzygotic embryos in Brassica is presented with details.
