Photosynthesis, Food Products and Nitrogen Fixation in Cyanobacteria !
Photosynthesis, food products:
The process of photosynthesis goes on in cyanobacteria in the same manner as in plants.
The storage food products in cyanobacteria are somewhat different from those of green plants.
The storage product is usually a starch like substance similar to glycogen and is different from the starch produced in plants.
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This is known as Cyanophycean starch. In many of the cyanobacteria the reserve foods are stored in the form of oils. An amino acid known as diaminopimelic acid is found in the proteins of cyanobacteria and bacteria but never found in higher plants or animals. This characteristic feature supports the view that both bacteria and cyanobacteria have common ancestry.
Nitrogen fixation by cyanobacteria:
Many members of cyanobacteria have the ability to fix the atmospheric nitrogen in the soil. Soil is a living mass and apart from soil particles there are in it a number of bacteria, fungi, algae and protozoa. According to Russel, cyanobacteria occupy a volume three times that of the bacteria.
For a long time it was felt that these are the bacteria in the/ sheath which fix nitrogen. P.K. De (1939) conclusively proved that cyanobacteria are the main agents for nitrogen fixation in rice fields, and the part played by bacteria is relatively unimportant. Watanabe (1951) made a far reaching research and proved that Tolypothrix tenuis is a strong nitrogen fixer, and it was also reported that it could fix as much as 780 lbs. of nitrogen per acre per year. Allen (1955) found that Anabaena cylindrica fixes 2,900 lbs. of nitrogen per acre per year.