Morphological traits in nitrogen fixing heterocytous cyanobacteria: possible links between morphology and eco-physiology

DE TEZANOS PINTO, PAULA; KUST, ANDREJA; DEVERCELLI, MELINA; ZAPOMELOVÁ, ELISKA

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2016 vol. 764 p. 271 - 281

0018-8158

Heterocytouscyanobacteria are able to fix nitrogen (in heterocytes) and to produce dormantcells (akinetes). Heterocyte and akinete shape, size, and  relative position have taxonomical relevanceand possibly ecological value too. We collected?from literature andnature?and compared morphological data on vegetative cells, heterocytes, andakinetes across four genera taxonomically separated from Anabaena. In average,heterocyte size doubled that of vegetative cells?probably because of extra cell wall deposition. Heterocyte morphologywas remarkably similar across genera, both in size and shape (spherical). Thelatter may decrease oxygen diffusion from adjoining vegetative cells. Akineteswere huge (one order of magnitude bigger) compared to vegetative cells,probably because of its massive genome replication, extra deposition of walllayers, allocation of storage and number of vegetative cells fused during akinetedifferentiation. Akinete shape was mostly cylindrical, or oval, but rarely spherical.In line with molecular data, we found morphological differences betweenAnabaena (non-aerotopated, soil or benthic) and Dolichospermum (aerotopated,planktonic), including vegetative cell size, and akinete size, shape, andrelative position to the heterocyte. Differences may relate to adaptations totheir contrasting environments (benthic versus planktic). Further research is needed to generalize ourresults to other heterocytous genera.