Abstract
Examination of thin sections of tissues from various plants infected with pepper ringspot virus showed the presence of characteristic aggregates of tubular particles, about 2000 Å long and 200 to 250 Å wide, considered to be pepper ringspot virus in situ. The pepper ringspot virus aggregates were associated with mitochondria in such a way that the virus particles were positioned perpendicularly on the surface of mitochondria. Aggregates of short (550 Å) particles were not found.
Except in xylem vessels, pepper ringspot virus aggregates were present in practically every type of tissue in infected plants, including the meristematic zone of shoot apex and root tip.