1978 Volume 44 Issue 4 Pages 420-425
The surface structure of local lesions on cowpea leaves infected by cucumber mosaic virus was observed with a scanning electron microscope. When the leaf surface was rubbed with inoculum virus and Carborundum, a variety of injuries were produced on the surface. The local lesion was composed of a few injured cells and 20-30 surrounding uninjured cells. The injured cell had a wound hole of 30-150nm diameter on the cell surface having a lump-like structure. All of the cells within the local lesion showed shrinkage, and the lesion area was concave and sharply distinguishable from the surrounding areas. On the other hand, no lesion was developed from seriously wounded cells. These observations suggested that virus might enter through the micro-holes at the lump-like structure of the injured cells, and that the surrounding cells might become infected by infectious materials synthesized in the initially infected cells, followed by the cell shrinkage and the lesion formation.