AN ELECTRON MICROSCOPY STUDY OF PENETRATION OF TOBACCO MOSAIC VIRUS INTO LEAVES FOLLOWING EXPERIMENTAL INOCULATION

Leaves of Vigna sinensis were inoculated with tobacco mosaic virus (TMV) by gently rubbing their surface with a suspension of virus particles mixed with Carborundum powder. The modifications induced by this treatment on the leaf surface and in the epidermal cells were studied on replicas of the leaf surface and in ultrathin sections of the leaf. On the leaf surface scratchings and a great number of TMV particles were detected; some of the TMV particles were attached to the surface in vertical position. In the epidermal cells, as seen in sections, the external cell wall showed blebs under the cuticle. It is inferred that the rubbing of the leaf surface favors the implantation of some virus particles on the cuticle, and that the alterations of the cell wall provide an easy way of penetration of the particles into the epidermal cells. © 1969.