Badania cytologiczne mezofilu Phaseolus vulgaris L. odmiany 'Red Kidney' porażonych wirusem S ziemniaka (potato virus S – PVS) [Cytological investigations of mesophyll of Phaseolus vulgaris L. 'Red Kidney' infected with PVS]

Abstract

We have put under cytological observation 2-, 4-, and 8-day fragments of mesophyll of the leaves Phaseolus 'Red Kidney' infected with PVS. In the necrosis caused by PVS can be distinguished a necrotic centre, a seminecrotic zone, and a belt of terminal cells. The necrotic centre is the most changed area whose cells are most often decayed. In the seminecrotic zone, the presence of viruses in the cell causes some pathological changes. The ER canals assume the shape of swollen cisterns. The chloroplasts reacts with the softening of granas, the growth of starch granules and plastoglobules content as well as with the presence of proteinaceous fibrous structures. The karyolymph and mitochondrium matrix become elucidated. The continuity of plasmalemma and tonoplast become interrupted. Virus particles appear in the area of cytoplasm of seminecrotic zone and in the necrotic centre, they are dispersed or rarely arranged in aggregations which often are in contact with tonoplast. We have observed virus packs enclosed with lipoproteid membrane. Viruses were not stated in the terminal zone. We have ascertained the intensive development of cell walls in the cells of terminal and seminecrotic zones. A lobar or punctual way of the development appeared in different areas of the cell wall and was found independently in various cells. The modified areas included as well plasmodesmata. The above observations enable us to presume that the cells of necrotic centre and seminecrotic zone are the place of replication and assembling of viruses and is responsible for the mechanical localization of virus infection.