Abstract
Ultrastructural observations were undertaken to study the viability of fusion products by electrofusing the protoplasts from the mesophyll cells of pansy leaves and the cultured callus cells of wild viola petioles. The result showed that the fusion product was formed between the two different protoplasts and two distinct regions were observed in its cytoplasm ; one region contained chloroplasts from pansy mesophyll and the other, plastids from wild viola callus. In other cases, however, the fusion product was seen which might be derived from merely the wild viola protoplasts because of the lack of well-developed chloroplasts. Also, other cellular components, such as nuclei, endoplasmic reticula, small vesicles and osmiophilic granules, were clearly found in the fusion products. Further, the fate of fused protoplasts is discussed on the basis of the ultrastructural features.
