Name: Haematococcus pluvaialis
Family: Haematoccoceae
Collection Date: October 10, 2011
Location: South Russel, Ohio
Collector: Willa Schrlau
Key Used:
Prescott, G. W. (1978). How to Know the Freshwater Algae . Boston : WCB McGraw-Hill .
Pictured Key to the Common Genera of Freshwater Algae
1b. Plants microscopic, or if macroscopic with cellular structures and branches not clearly visible to the unaided eye; without whorls of branches clearly visible … 4
4a. Cells containing chloroplast with green predominating; or with other pigments predominating: yellow-green, golden-yellow, brownish, reddish or bluish-green … 5
5b. Plants not grass-green or gray-green, but yellowish-green, apple-green, or golden-yellow; or reddish either because of a chloroplast pigment, or haematochrome (carotenoid pigments); or rarely chloroplast with a bluish tinge … 6
6a. Plants reddish with phycoerythrin, or orange-red with carotenoid pigments which partly or completely mask the green of the chloroplast …. 7
7b. Plants solitary cells, or forming colonies invested by a common mucilage … 11
11b. Plants uniceller or incidentally clustered and gregarious, not enclosed in a gelatinous matrix … 16
16b. Cells predominantly non-motile, often encysted and stationary. Sometimes individuals emerge from the encysted condition and become motile in the same habitat … 21
21b. Cells otherwise … 22
22b. Cells otherwise … 23
23b. Cells otherwise … 24
24b. Plants inhabiting rock pools and cemented basins; cells relatively large (up to 50µm diam.), smooth-walled … Haematococcus
"The fresh-water unicellular alga H. pluvialis Flotow (Volvocales) occurs primarily in temporary, small fresh water pools (Droop 1954;Czygan 1970). In its growth stages, it has both motile and non-motile forms. In the former, a pear-shaped cell ranges from 8 to 50 μm in diameter. The cellular structure of this stage is similar to most of its family members: a cup-shaped chloroplast with numerous and scattered pyrenoids, contractile vacuoles which are often numerous and apparently quite irregularly distributed near the surface of the protoplast, a nucleus and 2 flagella of equal length emerging from the anterior papilla which perforate the cellulose wall at a wide angle. The structure's uniqueness is marked by its cell wall which is strongly thickened, gelatinous, and is usually connected to its protoplast by simple or branched strands.
In its non-motile form, the so-called ‘palmella’ stage, the spherical protoplast is enveloped within a closely adherent palmella membrane, and, with the exception of the flagella, the cellular structure remains the same as its motile form. Once growing conditions become unfavorable, cells increase their volume drastically and enter a resting stage in which the cell is surrounded by a heavy resistant cellulose wall, comprised in part by sporopolinine-like substances (S. Boussiba, unpublished). This overall process is termed ‘encystment’. The protoplast is then a markedly red color, determined to be a secondary carotenoid, astaxanthin (Goodwin and Jamikorn 1954)."
References:
, (1954) Studies in Carotenogenesis 11. Carotenoid synthesis in the alga Haematococcus pluvialis.Biochem J 57: 376–381.
Prescott, G. W. (1978). How to Know the Freshwater Algae . Boston : WCB McGraw-Hill .
Figure 1: A) Haematoccus pluvailis grouped together B) H. pluvalis close up, one cell
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