Blue-Green Algae: Fine Structure of the Gas Vacuoles.

The gas vacuoles seen in several species of blue-green algae under the light microscope are shown by electron microscopy to correspond to packed arrays of cylindrical, electron-transparent vesicles. Single vesicles average 75 millimicrons in diameter, range from 0.2 micron to 1.0 micron in length, have conical ends, and are bounded by a single membrane 2 millimicrons wide. The reversible disappearance of gas vacuoles induced by sudden application of pressure is accompanied by a reversible collapse of the individual gas vesicles.