1982 Volume 48 Issue 4 Pages 444-451
Multiplication and distribution of the virus in tobacco leaves mechanically inoculated with cucumber mosaic virus were examined by the fluorescent antibody technique. The epidermis which had been peeled off from the inoculated leaves was fixed and the inner side cell wall of epidermis was partially digested by cell wall degrading enzymes. The epidermis was then stained with a flourescent antibody. Primarily infected cells were observed in the epidermis 9 to 10hr after inoculation at 25C; the majority of the primarily infected cells were ordinary epidermal cells but some were subsidiary cells of stomatal guard cells. The virus antigen gradually spread concentrically from the primarily infected cells to surrounding cells. The rate of spreading of the antigen was 8.4μm, 20.3μm and 26.3μm per hour at 20C, 25C and 30C, respectively. In epidermal cells the antigen was first detected in the nucleolus-like bodies and thereafter it became distributed in cytoplasm and increased in its intensity of fluorescence. The virus appeared to move from an infected cell to an adjacent cell was observed to occur after a considerable amount of virus antigen had accumulated in the cytoplasm of the infected one. On the bases of the observation of leaf sections it is assumed that the virus first spread from the primarily infected site to both horizontal and vertical directions simultaneously, passing from cell to cell. After the virus reached the lower epidermis, it spread mainly in the horizontal direction.
