PRINGSHEIM’S MEDIUM

Description

Blue green algae are very important organisms for the health and growth of many plants. They are one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia. Blue green algae include a large number of widely distributed species. Inspite of their vigorous growth under natural conditions, only a few of these organisms have been cultured in artificial media. Pringsheims Medium is recommended for the cultivation of Blue Green Algae. The blue-green algae contain a pigment known as phycocyacin in addition to chlorophyll which imparts a special blue green colour to these organisms. Some of the blue-green algae possess specialized cells known as heterocysts which are implicated in nitrogen fixation. The water logged rice soil provides an ideal environment for the growth of certain blue-green algae. It is not easy to isolate pure cultures of algae since several species of algae are covered by mucilaginous matrix which harbours many contaminants. Serial dilutions of soil are made and 1 ml aliquots of each dilution transferred into suitable sterilized liquid medium either in flasks plugged with cotton wool or in bottles filled with sterilized white sand moistened with the algal medium. The flasks or bottles are kept for a few weeks near a source of light. Individual colonies are then transferred to agar slants for identification.