ಚಿತ್ರದುರ್ಗ ಜಿಲ್ಲಾ ವಿಜ್ಞಾನ ಶಿಕ್ಷಕರ ಸಂಘ: November 2008

Tuesday, November 25, 2008

Spirogyra - Green Algae

Scientific classification
Domain: Eukaryote
(unranked): Archaeplastida
Kingdom: Plantae
(unranked): Streptophyta
Phylum: Chlorophyta
Class: Zygnematophyceae
Order: Zygnematales
Family: Zygnemataceae
Genus: Spirogyra

Spirogyra is a genus of filamentous green algae of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts that is diagnostic of the genus. It is commonly found in freshwater areas, and there are more than 400 species of Spirogyra in the world.[1] Spirogyra measures approximately 10 to 100μm in width and may stretch centimeters long.

General Characteristics

Spirogyra is unbranched with cylindrical cells connected end to end in long green filaments. The cell wall has two layers: the outer wall is composed of cellulose while the inner wall is of pectin. The cytoplasm forms a thin lining between the cell wall and the large vacuole it surrounds. Chloroplasts are embedded in the peripheral cytoplasm; their numbers are variable (as few as one). The chloroplasts are ribbon shaped, serrated or scalloped, and spirally arranged, resulting in the prominent and characteristic green spiral on each filament. Each chloroplast contains several pyrenoids, centers for the production of starches, appearing as small round bodies.
Spirogyra is very common in relatively clean eutrophic water, developing slimy filamentous green masses. In spring Spirogyra grows under water, but when there is enough sunlight and warmth they produce large amounts of oxygen, adhering as bubbles between the tangled filaments. The filamentous masses come to the surface and become visible as slimy green mats. Mougeotia and Zygnema are often found tangled together with Spirogyra.

Courtesy : Wikipedia

http://en.wikipedia.org/wiki/Spirogyra