OSCILLATORIA

Contents hide
1 OSCILLATORIA
1.1 CLASSIFICATION OF OSCILLATORIA
1.2 STRUCTURE OF A FILAMENT AND SINGLE CELL
1.3 REPRODUCTIVE STRUCTURES
1.4 IDENTIFICATION OF OSCILLAtORIA​

OSCILLATORIA

CLASSIFICATION OF OSCILLATORIA

Sub-division :- Algae

Class :- Myxophyceae

Order :-  Oscillatoriales

Family :- Oscillatoriaceae

Genus :- Oscillatoria

One can hardly miss Oscillatoria when on a collection trip. It is almost cosmopolitan and occurs abundantly on moist rocks, cliffs, damp soil, muddy banks of streams, ponds, surface of the water reservoirs, sewage ponds, etc. A few species are marine and float on the surface.

STRUCTURE OF A FILAMENT AND SINGLE CELL

COMMENTS :-

  • Filaments occur either singly or interwoven to form a flat or spongy, free swimming mat. 
  • Filament consists of an inconspicuous and barely recognizable sheath enclosing unbranched trichome. 
  • Trichome consists of a single row of cells. 
  • The apical cell of the trichome may have calyptra-thick wall on its outer free face.
  • The cells show typical myxophycean cell structure. It has no definite nucleus, no chloroplasts or no membrane bound organelles (prokaryotic cell).
  • The cell shows many shining cyanophycean granules. 
  • Floating species show numerous gas vacuoles.
OSCILLATORIA

REPRODUCTIVE STRUCTURES

COMMENTS :-

  • The only method of reproduction is hormogone formation.
  • The hormogones (small pieces of trichome with one to many uniform cells) are formed as a result of the death of intecalary cell or by the formation of special biconcave separation discs.
  • Hormogones are liberated by the disintegration of discs.
  • Each hormogone develops into a new filament.
Oscillatoria. A trichome showing separation disc.

IDENTIFICATION OF OSCILLAtORIA​

  • Sub-division – Algae
    1. Thallus simple,
    2. Chlorophyll present.
    3. Cell walls of cellulose.  
  • Class – Myxophyceae
    1. Chromatophore not organised, pigments diffused, blue-green.
    2. Photosynthetic reserve cyanophycean starch.
    3. True nucleus absent.
    4. Sexual reproduction absent.
  • Order – Nostocales
    1.  Thallus with trichomes, unbranched, or with false branching.
    2. Hormogones, heterocysts, exospores and endospores generally present.  
  • Family – Oscillatoriaceae
    1. Trichomes uniseriate, sometimes tapering at the ends.
    2. Heterocysts and spores absent
    3. Sheath absent or diffluent.
  • Genus – Oscillatoria
    1. Trichomes not in bundles.
    2. Trichomes without a sheath.
    3. Trichomes straight and cylindrical.

Leave a Reply