ELECTRON-MICROSCOPIC OBSERVATIONS OF THE ENVELOPES OF ISOLATED ALGAL PACKETS OF AZOLLA

The envelopes of isolated algal packets from cyanobiont-containing and cyanobiont-free Azolla were examined with the electron microscope. Both types of envelope were 10-20 nm thick and composed of three layers. The three-layers structure was also observed when algal packets were treated with cellulase, pectinase, lipase, protease, sodium lhydroxide, nitric acid, or sodium dodecylsulfate. Thus, the envelopes do not appear to be membrane-like in nature and the presence and ultrastructure of the envelopes are not affected by cyanobiont filaments.