The Ultrastructure of the Vegetative Cell of Blue-Green Algae

Abstract

An electron-microscopic study has been made of the vegetative cells of eight genera of the blue-green algae. A basic structure has been defined for the vegetative cell. There is a cyto-plasmic matrix which extends throughout the cell. No membrane-bound organelles of the categories chloroplast, mitochondrion, nucleus, golgi body, and endoplasmic reticulum can be recognized therein. There are two regions within the cell. The peripheral region is distinguished by the presence of "photosynthetic" lamellae and various granular inclusions. The central region is distinguished by the presence of crystalline granules, and areas of low electron density which resemble the nucleoid regions of bacteria. Ribosome-like granules are seen scattered throughout the cytoplasmic matrix. Intercellular connections, involving the plasma membranes of adjacent cells, have been seen.