AUTORADIOGRAPHY OF PENETRATION OF [MANNITOL-C-14 INTO COSMARIUM-BOTRYTIS CELLS AND PROTOPLASTS

Mannitol, a commonly used osmoticum labeled with 14C, penetrated within 24 h into vegetative cells of the desmid C. botrytis and into cells plasmolyzed with 0.4 M mannitol, and within 6 h into protoplasts prepared by incubation in 0.4 M mannitol and 2.5% cellulysin. As determined by autoradiography of 2 .mu.m thick sections, the labeled mannitol was in all areas of the cytoplasm except the nucleus and the pyrenoids.