The Electron Microscopic Investigation of Changes in Cytoplasmic Structures in Leaves ofCucumis sativa L. Infected with Cucumber Virus 4

Leaf cells of healthy cucumber and cucumber infected with Cucumber virus 4 were studied living and fixed, using optical and electron microscopy. Under the electron microscope the infected leaves displayed changes in the structure of the ergastoplasm, Golgi apparatus, mitochondria, bodies with an osmiophil matrix and chloroplasts. The chloroplasts exhibit symptoms of fatty degeneration which affects above all the lamellar systems of grana and intergrana. Weakly osmiophil globules, abundant in damaged chloroplasts, are probably formed through degeneration of grana. Chloroplasts of infected plants resemble some transitional stages of plastids observed during chromoplast formation. The problems of localization of viruses in the cell and degeneration are discussed.