A SUBMICROSCOPICAL STUDY OF LEAVES OF ALFALFA, BASIL, AND TOBACCO EXPERIMENTALLY INFECTED WITH LUCERNE MOSAIC VIRUS

The leaves of three species of plants (Medicago sativa L., Ocymum basilicum L., and Nicotiana tabacum L., cv. Samsun), previously infected with lucerne mosaic virus (LMV), were studied in the electron microscope. In the leaves of M. sativa and O. basilicum the infection was systemic, while in the leaves of N. tabacum the infection was local. In all the three species LMV particles were always detected only in the cytoplasm. Apart from the presence of virus particles in the cytoplasm, no ultrastructural alterations were found in M. sativa and N. tabacum. In O. basilicum, the green leaf areas did not show any prominent alterations, while the yellow leaf areas showed marked alterations of the chloroplasts. In these, the lamellar system was scarcely developed, and the few thylakoids tended to fragment, curl and disappear. In the chloroplast stroma, there was an abnormal development of filamentous structures, resembling the stromacentre. © 1969 Springer-Verlag.