[An ultrastructural study of acid phosphatase activity localized in bud primordia of an organogenic culture of Nicotiana tabacum L. var. P. 19].

Acid phosphatase activity in particularly organogenic strain of tobacco has been localized in two kinds of tissue: the internal bud primordia and the adjacent tissues. Generally the reactions are weaker in the undifferentiated cells. In differentiating cells, the localization of precipitates from the reaction shows up the continuity of membrane systems such as the endoplasmic reticulum, the nuclear membrane and the vacuoles. The relative weakness of the reactions observed in the vacuoles is in agreement with the rareness of hydrolysis. Parenchymatous cells between the meristems and the surface of the tissue culture undergo autolysis, which seems to help the growth of buds produced by neoformation. Specific and often intense reactions occur in the cell walls.