PATHOLOGICAL CYTOLOGY OF TOBACCO LEAF INFECTED WITH TOBACCO MOSAIC VIRUS BY MEANS OF ULTRA-MICROTOMY. I

Abstract

The fine structure of intracellular localization of virus particles and some pathological changes within host cells were investigated by electron microscopic observations of ultrathin sections of tobacco young leaf showing slight symptoms of systemic infection with tobacco mosaic virus common strain fixed in buffered osmium tetroxide solution.
The intracellular virus rod particles occurred usually in fibrous masses, and in these fibrous masses, the individual virus particles evidently associated with each other by end-to-end as well as side-to-side association.
Two types of mass of virus particles were found in the diseased leaf. The masses associated with chloroplasts or cell walls were surrounded by membraneous organelles built up fine granules, while the masses immersed in cytoplasmic region were found without these organelles.
The intracellular inclusion bodies, believed to be X-bodies, appeared as dense granular structures and contained vacuoles. Although, in the present observations, many virus rod particles were easily found within cytoplasm or on the surface of intracellular inclusion bodies, it was rather difficult to find them within the inclusion bodies. However, virus rod particles were sometimes observed within the intracellular inclusion body.