Description des cultures et des souches  
Isolement/axenisation Culture Description Mesures de biomasse Mesures d'ARA
 
Introduction
Plan du site
Morphologie
Taxonomie
Physiologie

Ecologie, facteurs du milieu

Ecologie dans l'environnement
Aspects appliqués
Méthodes d'étude
Glossaire
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1. Criteria for solid cultures

1.1. Growth type

1.1.1. Spreading growth : Growth that indicates movements of trichomes or hormogonia away from the streaks.

Type:

Generalized:   Growth covers entire plate.
Localized:       Spreading in the vicinity of the streaks.

Aggregation :

Diffuse: Absence of discernable structures in the mat.   Growth spreads out as a delicate cottony patch on and/or under agar surface;   e.g., some homocystous filamentous strains with thin trichomes.
Fibrous: Felt-like mat;   e.g., Calothrix and some homocystous filamentous strains with thick trichomes.
Ropey:   Having clearly discernable wavy structures resulting from the formation of bundles;   e.g., many Anabaena .
Coiled:   Having circular bundles;   e.g., some Anabaena .

Location :

Surface: Growth limited to the agar surface.
Burrowing:    Growing into the agar.

1.1.2. Cohesive growth : Continuous, thick, flat growth, nonspreading, with occasional discrete patches having no definite shape.

1.1.3. Colonial growth :

Type :

Filamentous:

Top view

Radial

Trichomes generally diverging from the center.

Skewed

Trichomes generally growing in one direction.

Irregular

Trichomes growing randomly.

Side view

Flat

Planar growth along the agar surface.

Penicillate

Brush-like growth away from the agar.

Burrowing

Growth into the agar.

Other types:

Top view

Round

Circular.

Elongated

Colonies with unequal axes.

Irregular

Having no definable shape.

Angular

Colonies with relatively straight margins and corners.

Side view

Flat

Planar growth along the agar surface.

Nippled

Planar growth with a central protuberance.

Low convex

Section of a sphere with height smaller than 1/4 diameter.

High convex

Section of a sphere with height between   1/4 and 1/2 diameter.

Globular

Section of a sphere with height larger than1/2 diameter.

Warty

Having irregular protuberances resembling warts.

 

Margin

Smooth

Continuously even, without roughness.

Rough

Uneven margin without marked projections.

Fingerlike

Uneven margin with long projections.

Aura-like

Having a roundish diffuse growth zone spreading around a denser central zone. Frequently results from akinete migration and growth into filaments.

1.2. Luster
Luster is observed by holding the plate between two fingers, placing it about 20 cm over a piece of white paper, and turning it forward and backward around a horizontal axis.

Dull :   Lacking brilliance or luster.   Usually observed with nonmucilaginous, mat-forming strains (i.e., Calothrix ) or strains forming filamentous colonies (i.e., Fischerella ).

Intermediate luster : Usually observed with mucilaginous strains of the spreading and aggregative types.

Glossy :   Glistening, shiny. Usually observed with mucilaginous strains that form colonies.

1.3. Opacity
Opacity is observed by holding the plate between two fingers, placing it about 20 cm over a piece of white paper, and looking through it.

Opaque : Not permitting the passage of light.
Translucent : Permitting the passage of light.
Transparent : Can be seen through, e.g., mucilaginous colonies of some unicellular strains.

1.4. Color of the cyanobacterial material:
The color is defined by the combination of three descriptors:

Intensity:   light, medium, or dark.
Modifier:   greenish, yellowish, bluish, or reddish.
Base color: green or brown.

1.5. Color of the medium:
The color results from the diffusion of water-soluble pigments (e.g., phycocyanins, phycoerythrins) or other substances.  
Four cases are distinguished: none, red/pink, yellow, and brown.

 

1. Criteria specific to solid cultures

2. Criteria specific to liquid cultures

3. Microscopic description

           
           
           
 
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Copyright P. A. Roger 2006