High voltage electron microscopy of membrane interactions in wheat.

Structural interactions between intracellular membranes in root cells of Triticum sativum L. have been investigated with the 3 MeV electron microscope in Toulouse after selective labeling of the membranes with either zinc iodide-osmium tetroxide or phosphotungstate at low pH. Direct membrane continuities between endoplasmic reticulum, Golgi apparatus, and biogenetically derived compartments of the exoplasmic space are more extensive than commonly suggested from conventional electron microscopy. The results are discussed with reference to current concepts suggesting a membrane flow from the endoplasmic reticulum to the terminal components, plasmalemma, and vacuoles.