Morphological and ultrastructural variability of planktonic Cyanophyceae in relation to seasonal periodicity. IV. Aphanizomenon flos-aquae: Vegetative cells, heterocysts, akinetes

Abstract

Morphology, cytology and ultrastructure of vegetative cells, heterocysts and akinetes of Aphanizomenon flos-aquae are described for the first time from wild populations. Previously undescribed features of the vegetative cell include junctional pores in the murein sacculus and globular evaginations of the outer membrane wall layer. Akinete envelopes are compound structures with elaborate localized sculpturing. Fungal infection of a mature akinete is recorded as a complex tubular network pervading the protoplast.