Seasonal Distribution Pattern Analysis of Cyanobacteria Isolated from Saline/Alkaline Soils.

?Usar? soils that occur widely in certain parts of U.P. and Bihar exhibit extreme ecological conditions in characteristically having a high pH, high degree of salinity and low moisture content during dry weather. Soil salinity is one of the most serious factors limiting the productivity of crops including staple diet in many countries. Cyanobacteria, the cosmopolitan, photosynthetic prokaryotes have been reported to grow extensively on ?Usar? soils. These are capable of thriving in condition which is considered to inhabitable tolerating desiccation, high temperature, extreme pH and high salinity illustrating their capacity to acclimatize to extreme environments. Therefore a study was conducted from July 2012-June 2013 to find out the influence of soil properties on cyanobacterial population of saline-alkaline soils. We selected six experimental sites for our study. On the basis of our results we could reach to the conclusion that the growth of cyanobacteria was slow in highly saline soil during summer due to high pH, only a few genera like Nostoc and Calothrix could survive during highly saline condition. High amount of soluble cations and anions adversely affects inhibit the growth of cyanobacteria especially high Na+ content during summer reduces the population of cyanobacteria. The heterocystous strains were found to be more resistant to salinity like Nostoc calcicola, N. commune, Calothrix bressvissima while non-heterocystous strains like Microcoleus and Lyngbya favored less saline condition and began to appear after few rain showers when slight decrease in pH was observed. Although some of the non- heterocystous strains like Phormidium and Oscillatoria persisted at high salinity during summer but in very low quantity.