Vesicle formation during electro-fusion of mesophyll protoplasts of Kalanchoë daigremontiana.

Following electro-fusion of plant protoplasts the volume of the fused cell is the sum of the volumes of the parent cells. As shown for mesophyll protoplasts from leaves of Kalanchoë daigremontiana, the excess in membrane material arising from the reduction in membrane area is removed-at least to a larger extent - by the formation of vesicles which are visible in the light microscope. These vesicles, which may have been formed by the fusion of sub-microscopic vesicles, are observed in the contact zone of the fusing cells. The mechanism of the formation of vesicles during electro-fusion is discussed.