The ultrastructural changes in leaf cells of Chenopodium quinoa caused by Arabis mosaic virus (ArMV) infection have been investigated in electronmicroscopic studies. The techniques of negative staining and embedding sections from leaves in epoxy resin were applied. ArMV virions have been found in the cytoplasm and either singularly scattered or forming different arrangements in the vacuoles as well. Tubules with virions have been observed only rarely. Two types of inclusions have been identified and their structure illustrated. Ultrastructural changes in leaf cells of C. quinoa caused by ArMV infection are partially similar and partially different from those occurring on Phaseolus vulgaris plants infected with ArMV. It might suggest that some ultrastructural changes are typical for the virus and some are characteristic for the host plant.

Two experimental methods were used in the study. The aim of the first one was focused on a detection of Arabis mosaic nepovirus (ArMY) particles and tubules with viruses in extracts obtained from crushed leaves of bean. Second one consisted on investigation of ultrastructural changes occwing in the bean leaf tissues with symptoms caused by ArMY. Characteristic membranous inclusions in the cytoplasm were observed and described. ArMY occured either as irregularly scattered particles in the cytoplasm, crystal-like aggregates or semiconcentric and concentric layers. Not numerous but sometimes very long tubules with viruses were mainly observed near the cell wall. Protrusion of the cell wall into the protoplast very often containing viruses in the plasmodesmata were observed many times. Plasmalemmasomes were frequently situated near the cell wall.

Plant viruses create many changes in the morphology of the plant cell once the infection process has begun. This paper describes and compares the ultrastructural changes induced in maize cells by two isolates of Maize dwarfmosaic virus (MDMV), Spanish (MDMV-Sp) and Polish (MDMV-P), and one isolate of Sugarcane mosaic virus (SCMV) at 10 and 42 days post-inoculation: the concentration and arrangement of virus particles, inclusion bodies associated with infection, and other cytological alterations. The most important difference between maize cells infected with MDMV isolates and with SCMV-P1 was in the form of cytoplasmic cylindrical inclusions. In cells infected with MDMV only typical inclusions such as pinwheels and scrolls were observed, but laminar aggregates were also present in SCMV-infected cells. No virus particles were found in plant cell organelles. Specific virion arrangements occurred in cells infected with MDMV-Sp and SCMV. The most interesting new finding was of specific amorphous inclusions in the cytoplasm of MDMV-Sp-infected cells, which clearly differentiated the two MDMV isolates studied.