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Oscillatoria – Life of Simplest Filamentous Blue Green Algae (Case Study)

Oscillatoria – Characteristics, Systematic Position, Morphology, Anatomy, Microscopic View, Reproduction

Oscillatoria (oscillare, to swing) is very common in moist places which are rich in decaying organic matter. Such common places are ponds, streams and other stinking moist places such as roadside ditches, drains or sewers.

Characteristics and Morphology

The oscillatoria is represented by 100 species. It is one of the simplest filamentous blue green algae. It forms thin blue green mucilaginous coating of the surface or edges of objects under flowing water. One specie has been reported from hot spring. Some species e.g., O. princeps and O. formosa are found in association with Nitrogen fixing Bacteria. Some common species are O. formosa, O. splendida, O. lomosa, O. prolifica.

Systematic Position

  • Class: Cyanophyceae
  • Order: Oscillatoriales
  • Family: Oscillatoriaceae
  • Genus: Oscillatoria

Oscillatoria Morphology

It consists of a single row of cells forming trichomes or un-branched filaments with a very thin gelatinous sheath. The cells are broader than longer but cylindrical. All cells of a filament are similar with the exception of apical cell which is convex at the top. ln some species it may end in a subacute point or be more or less dilated, or capitated having a thickening known as a cap or calyptra at the tip. Species with the narrow trichome however have cylindrical cells in which the length may be equal to or, greater than the breadth e.g. O. splendid. If fresh material is observed under the microscope specific oscillating movement is observed.

oscillatoria-structure
Oscillatoria Structure: A, Few filaments; B, Single enlarged filament; C, a single cell

Cell Structure

All cells have well developed cell wall. The cell wall consists of an inner thin cellular layer a medium pectic layer and outer mucilage. Well defined nucleus is absent. Mitochondria, endoplsamic reticulum and Golgi bodies are also absent. The proptoplasm consists of peripheral and central cytoplasm. Pigments are found in the periphery so it is known as chromoplasm. Several small granules are also present. Pseudo-vacuole is additionally found in some cases. Glycogen like substance is the reserve food material. Few oil drops may also be found stored as reserve food.

oscillatoria-sp
Oscillatoria sp. A — B, Vegetative structure. C, Cell structure; D, Filament showing separating disc; E, Hormogones

Oscillatoria Under Microscope

The microscopic view of oscillatoria single strain is described below:

oscillatoria-under-microscope
Oscillatoria Under Microscope: The microscopic view of oscillatoria given above

Reproduction – Life Cycle of Oscillatoria

  1. It is restricted only to the vegetative reproduction, which takes place with the help of hormogones.
  2. Hormogones are the parts or lengths of filaments separated from the filament by the formation of the separating disc.
  3. Heterocyst and resting spores are not produced.
  4. The trichomes which break into pieces accidentally give rise to fragments.
  5. These fragments develop into new plants by cell division. Asexual and sexual reproduction is absent.
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