​Diversity of Non-heterocystous Cyanobacteria in Paddy Field Soil

Abstract

Paddy field soil is a natural habitat for many Cyanobacteria. Generally Heterocystous form dominate the nitrogen deficient soil. Non-heterocystous forms are also known to fix nitrogen. The diversity and the distribution of these forms vary. 20 Soil samples were serial diluted in BG-11 devoid of nitrogen supplement. Later the colonies were streaked to obtain axenic culture. The soil pH was also determined to study the effect on the diversity. The relative abundance of the BGA species was determined .Diversity of non-heterocystous form in the paddy field was found to be dominated by filamentous BGA, Lynbgya by 21%, Oscillatoria and Phormidium by 17% and colonial form Chrococcus sp by 12.5% Followed by Myxosarcina sp., 8%, while Aphanocapsa sp., Chlorogloea sp., Crinaluim sp., Gleocapsa sp, Plectonema sp. and Schizothrix sp., were 4%. A majority of the non-heterocystous BGA were found in the soil which had a pH ranging between 8.2-8.6. Diversity study of non-heterocystous BGA can help in understanding the distribution and further aid in the study of nitrogen fixation in these forms.