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Cytology and Histology

Cytological Alterations Associated with Flame Chlorosis, a Novel Viruslike Disease of Barley, Wheat, and Oat. J. Chong, Research scientists, Agriculture Canada, Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada, R3T 2M9; S. Haber, Research scientists, Agriculture Canada, Research Station, 195 Dafoe Road, Winnipeg, Manitoba, Canada, R3T 2M9. Phytopathology 82:815-821. Accepted for publication 28 April 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/Phyto-82-815.

The cytological alterations associated with flame chlorosis were similar for the three known hosts, barley, wheat, and oat. The first detectable changes in affected mesophyll cells were the appearance of double-membrane-bounded vesicles, which contained densely staining fibrils, along the periphery of the chloroplasts and mitochondria. Affected chloroplasts became swollen, rounded, and clumped in groups; they became extensively vesiculated mainly in the periplastidial spaces between the chloroplast membranes. Whorls of membranous structures occurred in a majority of affected chloroplasts. Mitochondria also were altered; the most striking features were hypertrophy and extensive ramification of cytoplasmic channels through the organelles. Vesiculation occurred extensively in the perimitochondrial spaces around these invaginations. Affected mitochondria were closely associated with endoplasmic reticulum. Five different types of inclusion bodies, consisting of electron-dense amorphous material, were observed. No virus particles were observed in any of the affected cells.