ALGAE & FUNGI

CLASSIFICATION OF ALGAE BASED ON PIGMENTS ALGAE ARE SIMPLE PLANTS. AS THEY PREPARE THEIR OWN FOOD THEY ARE CALLED AUTOTROPHS. THEY LIVE IN FRESH WATER, OCEANS, MOIST SOIL, MOIST WALLS, RIVERS AND ON PLANTS LIKE GREEN GRASSES. THE ALGAE OCCUR IN GREEN, BROWN AND RED COLOURS. ALGAE ARE MICROSCOPIC, ATTAINING A SIZE OF 0.5MM IN DIAMETER. BUT A FEW ALGAE WHICH GROW IN OCEAN ARE MACROSCOPIC, ATTAINING LENTH OF ABOUT 30METRES. THE BODY OF THE ALGA, KNOWN AS THALLUS, IS VERY SIMPLE IN STRUCTURE. THE BODIES OF THE ALGAE DO NOT HAVE STEM, ROOTS AND LEAVES.

ALGAE ARE CAPABLE OF SYNTHESIZING THEIR OWN FOOD BY PHOTOSYNTHESIS WITH THE HELP OF VARIOUS TYPES OF PHOTOSYNTHETIC PIGMENTS. BASED ON THE TYPES OF PIGMENTS PRESENT, THE ALAGE ARE CLASSIFIED AS; CYANOPHYTA ( BLUE GREEN ALGAE), CHLORROPHYTA ( GREEN ALGAE), RHODOPHYTA ( RED ALGAE), PHAEOPHYTA ( BROWN ALGAE).

(1) CYANOPHYTA NOSTOC THE CELLS OF BLUE- GREEN ALGAE CONTAIN GREENISH CHOROPHYLL PIGMENTS AND BLUISH PHYCOCYANIN PIGMENTS. BECAUSE OF THIS, THEY APPEAR BLUE - GREEN IN COLOUR. HENCE THEY ARE CALLED BLUE - GREEN ALGAE. IN ADDITION TO THESE PIGMENTS PHYCOERYTHRIN AND OTHER PIGMENTS ARE ALSO PRESENT IN THE CELLS OF BLUE -GREEN ALGAE. (E.G.) NOSTOC.

CHLOROPHYTA THE MEMBERS OF THIS GROUP GROW IN WATER BODIES (PONDS,POOLS,ETC.) MOIST, SOIL AND ON THE MOIST SURFACES OF FLOWER POTS AND BARKS. THE PIGMENTS OF GREEN ALGAE ARE CHLOROPHYLL-A, CHLOROPHYLL-B, CAROTENE AND ZANTHOPHYLL. AS THE PIGMENTS CHLOROPHYLL-A AND B ARE ABUNDANTLY FOUND IN THE CELLS OF THESE ALGAE, THEY APPEAR GREEN IN COLOUR. (E.G)SPIROGYRA.

RHODOPHYTA MAJORITY OF RED ALGAE ARE MARTINE FORMS. THEY GROW ON THE SURACES OF ROCKS IN THE TIDAL ZONES AND SOME OF THEM GROW IN WATER AT THE DEPTH OF ABOUT 300FT AND MORE. ONE OR TWO KINDS OF RED ALGAE LIVE IN FRESH WATER. THE CELLS OF RED ALGAE CONTAIN CHYOROPHYLL-A, PHYCOCYANIN, PHYCOERYTHRIN PIGMENTS ETC. THE REDDISH PHYCOERYTHRIN PIGMENTS GIVES RED COLOUR TO THESE ALGAE.(E.G) GRACILLARIA.

PHAEOPHYTA MAJORITY OF THE ALGAE BELONGING TO PHAEOPHYTA OCCUR IN MARINE WATERS. THEY GROW ATTACHED ON THE ROCKS FOUND IN THE TIDAL ZONES. SOME OF THESE ALAGE GROW ON ROCKS SUBMERGED IN SEA WATER AT DEPTH OF ABOUT 75 FT. AND MORE. EXCEPT FEW BROWN ALAGE OTHERS LIVE IN COLD SEAS. BROWN ALAGE HAVE CHLOROPHYLL-A, CAROTENE AND YELLOWISH BROWN FUCOXANTHIN PIGMENTS. AS THE FUCOXANTHIN PIGMENTS OCCUR IN LARGE AMOUNT, THESE ALAGE ARE BROWN IN COLOUR.

CLASSIFICATION OF FUNGI ON THE BASIS OF THE STRUCTURE OF THE THALLUS AND REPRODUCTION, FUNGI ARE CLASSIFIED INTO FIVE MAJOR GROUPS. THEY ARE, MYXOMYCETES PHYCOMYCETES ASCOMYCETES BASIDIOMYCETES DUETEROMYCETES.

MYXOMYCETES MYXOMYCETES HAVE PLASMODIUM TYPE OF THALLUS. IT IS LIKE AMOEBA IN STRUCTURE. THE THALLUS HAS NO CELL WALL. IN THIS RESPECT MYXOMYCETES IS NO RESEMBLE AMIMAL CELL. (E.G) PHYSARUM.

PHYCOMYCETES IN THE OLDER CLASSIFICATION, PHYCOMYCETES IS ONE OF THE FOUR MAJOR GROUPS. AS PHYCOMYCETES HAS BEEN DIVIDED INTO SIX GROUPS, NOW THE TERM PHYCOMYCETES IS INTO USED. THE FUNGI BELONGING TO THIS GROUP HAVE LONG TUBULAR HYPAE. GENERALLY THE HYPAE ARE NOT HAVING CROSS WALL(SEPTA). IN EACH HYPHA SEVERAL NUCLEI ARE PRESENT. THIS CONDITION IS KNOWN AS COENOCYTIC.

ASCOMYCETES THE HYPHAE OF ASOMYCETES ARE SEPTATE. THAT IS, EACH HYPHA IS MADE UP OF SEVERAL CELLS. IN EACH CELL ONE OR TWO NUCLEI ARE PRESENT. THE SEPTEM (CROSS-WALL) HAS A SMALL PORE AT THE CENTRE (E.G) PENICILLIUM. BUT THE YEAST WHICH IS AN ASCOMYCETOUS FUNGUS IS AN UNICELLULAR ORANISM.

BASIDIOMYCETES The cross wall of basidiomycetes fungi is specialied. It is barrel-shaped and it is called dolipore septum. In each cell one or two nuclei are found. Except few basidiocarps, in which basidiospores are produced. Each basidiospore grows in to a new fungus. (e.g) agaricus

DEUTEROMYCETES The Hypae of majority of Deuteromycetes resemble the Hypae of ascomycetes. In these fungi asexual reproduction only takes place. The spores produced by these fungi resemble those of ascomycetes. Only those fungi in which sexual reproduction is absent are included in deuteromycetes. (e.g) colletotrichum.

BY M. JANCY, VII STANDARD FROM T.V. NAGAR HIGH SCHOOL CHENNAI