| Abstract: | Using the Iight mieroseope, scanning and transmission eleetron microscopes, it is found that each individuaI Nostoe flagelliforme is composed of hundreds and thousands torulose cells. The filaments are uni-triehome with branches in some cases. The thallus is surrounded by a mueoid sheath with different thicknesses, rough surface, and numerous cracky appearance. The Nostoc flagelliforme cells are typieal prokaryote eells ill which there is no discrete nuclear body. However nueleoplasm exists. occupying the center of the ceils. The cell wall of this prokaryote ceil is three-layered. Bet, when the nueleoplasm and the wall, a great quantity of thylakoids disperse. Moreover, structured granules, polyhedral and polyphosphate bodies intersperse. All of vegetative eells seem to be able to divide. The reproductive manner is of horizontal split, i.e. the regenerated new cell walls expand from periphery towards the center, then the mother cells eonstriet and finally split into two daughter cells. In our opinion, the function of this structural characteristic of heteroeysts is to endure extreme envi-ronment, so that they are able to maintain their species progeny. |
