The behaviour of the virus in the plant

Abstract

The actual route along which a virus spreads in an affected plant has been investigated by numerous workers and the accumulated evidence suggests that there are two paths of movement by which systemic infection is achieved. There is firstly a slow spread of virus from cell to cell, followed by a more rapid invasion of the whole plant via the phloem. That the initial movement of virus in an affected plant must be from cell to cell, at all events in some cases, is suggested by the fact that a mere wiping of the leaves of a susceptible plant with a virus suspension is sufficient to produce infection, provided a few trichomes are broken. Although the existence of this initial cell-to-cell movement seems certain, the exact mechanism of the movement is not so clear. The virus may pass through the cell walls by diffusion but a more likely explanation is that it passes via the plasmodesmata, the protoplasmic Connections between the cells.