Abstract
Electron microscopic examination of chinese cabbage leaves systemically infected with turnip yellow mosaic virus (TYMV) showed that numerous particles assumed to be virus were present in the cytoplasmic spaces between clumped chloroplasts. In the general ground cytoplasm TYMV particles were undistinguishable from the ribosomes. When whole leaves, detached from intact plants showing mosaic, were heated at 60C for 5min and kept at room temperature (about 20C) for 18hr, particles located in the spaces between chloroplasts and general cytoplasm were apparently crystallized. No such crystalline arrays were seen in healthy cells. The interparticle distance in the crystals formed in wilted tissue was 270-300A. There was no evidence that cytoplasmic ribosomes have a tendency to crystallize under such conditions. It is suggested that TYMV particles are crystallized by the wilting procedure used.
