What is special about red algae?

Aug 09, 2022, 16:45 IST

Special about red algae

RHODOPHYCEAE: RED ALGAE

• Red algae are an ancient group of algae with over 5,000 living species.

• They are marine except for a few fresh water species (e.g. Batrachospermum, Compsopogon, Lemnaea).

• Red algae are autotrophic with the exception of a few like Harveyella and Riccardia that are colourless and parasitic on other red algae Harveyella is parasitic over Polysiphonia.

• A motile or flagellate stage is completely absent.

• The plant body varies from unicellular to multicellular forms.

• Cell wall possesses cellulose, pectic compounds and certain mucopolysaccharides called phycocolloids.

• The latter are usually sulphated. The important phycocolloids of red algae are agar, carrageenin and funori.

• The photosynthetic organelles are called chromatophor They have single thylakoid. Photosynthetic pigments include chlorophyll a, carotenoids and phycobilins. Chlorophyll d has been reported in some cases. Phycobilins are water soluble pigments of two types, red coloured phycoerythrin and blue coloured phycocyanin.

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• The red colour of red algae is due to abundant formation of phycoerythrin.

• Reserve food is floridian starch. In constitution, it is very much similar to glycogen.

• Vegetative reproduction takes place by fragmentation, gemmae, and regeneration of holdfast.

• Sexual reproduction takes place through a variety of spores.