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Dilatation of thylakoids in mesophyll chloroplasts was found in needles from diseased Norway spruce. Additionally, the shape of the chloroplasts with extreme swellings of thylakoids had become spherical. These cytopathological symptoms are clearly distinct from structural changes observed in senescent needles from healthy trees.

SUMMARY A single dictyosome from an actively secreting ovary gland cell of Aptenia cordifolia has been reconstructed in 3‐D from a series of twenty‐nine electron micrographs by computer image processing. The reconstruction is presented under different viewing angles in the form of shaded perspective displays. From these displays the entire dictyosome, surrounded by numerous vesicles, appears to be more a spherical than a flat body. The plate‐like region of the dictyósome is demonstrated when only a portion of the electron micrographs is used for the image processing, leading to ‘cut‐off’ displays. Since some upper planes were removed, such ‘cut‐off’ displays revealed both tubular connections between cisternae of the dictyosome and the neighbouring endoplasmic reticulum as well as tubular continuities between adjacent Golgi cisternae within the same stack. Possible consequences of both types of interconnections on transport and processing of proteins and glycoproteins are discussed.

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