This book offers an in-depth analysis of the cell biology of cyanobacteria, a group of phototrophic microorganisms performing an important function in the biosphere. The chapters present the authors and her colleagues pioneering investigations of the ultrastructure of cyanobacteria under high-light and dark conditions, during irradiation by extremely high fluxes of light, in the course of L-transformation and within model associations and natural symbioses with plants. Diverse patterns of ultrastructural change are illustrated in electron micrographs and schematics. The book further introduces a new concept of bacterial ultrastructural plasticity - the reversible rearrangement of ultrastructure in response to environmental changes, as a strategy for finding and investigating cell adaptation mechanisms and intraspecies structural diversity of cyanobacteria and other prokaryotes. It serves as a valuable guide for teaching and research in the field of cell biology of microorganisms and plant-cyanobacteria symbioses.

Introduction.- Ultrastructural Plasticity of Cyanobacteria under Dark and Light Intensity Conditions.- Ultrastructural Plasticity of Cyanobacteria During Enzymatic Induction of L-Transformation.- Ultrastructural Plasticity of Cyanobacteria in Model Associaations with Plant Partners.- Ultrastructural Plasticity of Cyanobacteria in Natural Symbioses with Plants. Conclusion.