Blue-green algae (also called cyanobacteria) are ubiquitous, pristine and pioneer photosynthetic microorganisms. Many species of cyanobacteria are capable of fixing atmospheric nitrogen and such species in wet soils are simultaneously augmenting the fertility of the soil, acting as natural bio-fertilizers. Nostoc and Anabaena are the two important genera of heterocystous cyanobacteria capable of contributing nitrogen to soil, especially in paddy fields. The major objectives of the investigation included survey, collection, isolation and pure culture of nitrogen-fixing species of Cyanobacteria in the soils of Kerala state, India. Altogether, pure cultures of 12 species of Nostoc and 5 species of Anabaena are prepared.
Aiyer, R. S. (1965): Comparative algological studies in the rice fields in Kerala state. – Agr. Res. J. Kerala. 3: 100-104. http://krishikosh.egranth.ac.in/handle/1/5810061033
Anand, N. and Hooper, S. R. S. (1995): Distribution of blue-green algae in rice fields of Kerala state, India. – Phycos. 34(1-2): 55–64.
Choudhury, A. T. M. A. and Kennedy, I. R. (2005): Nitrogen fertilizer losses from rice soils and control of environmental pollution problems. – Comm. Soil Sci. Plant Anal. 36: 1625-1639. https://doi.org/10.1081/CSS-200059104
De, P. K. (1939): The role of blue green algae in nitrogen fixation in rice fields. – Proc. Roy. Soc. London., Ser. B. 127: 121-139. https://doi.org/10.1098/rspb.1939.0014
Desikachary, T. V. (1959): Cyanophyta. – Indian Council of Agricultural Research, New Delhi, 686 pp.
Dominic, T. K. and Madhusoodanan, P. V. (1999): Cyanobacteria from extreme acidic environments. – Curr Sci. 77 (8): 1021–1023. https://www.jstor.org/stable/24103571
Frank, B. (1889): Über den experimentellen Nachweis der Assimilation freien Stickstoffs durch erdbodenbewohnenden Algen. – Ber. Deutsch. bot. Ges. 7: 34–42.
Gupta, A. B. (1966): Algal flora and its importance in the economy of rice fields. – Hydrobiologia 28 (2): 213–222. https://doi.org/10.1007/BF00037323
Hrouzek, P., Alena, L., Jan, M. and Stefano, V. (2013): Description of the cyanobacterial genus Desmonostoc gen. nov. including D. muscorum comb. nov. as a distinct, phylogenetically coherent taxon related to the genus Nostoc. – Fottea Olomouc 13 (2): 201–213. https://doi.org/10.5507/fot.2013.016
Hunt, M. E., Floyd, G. L. and Stout, B. B. (1979): Soil algae in field and forest environments. – Ecology 60 (2): 362–375. https://doi.org/10.2307/1937665
John, K. C. (1963): Species of algae found in acidic sulphur springs of Kerala. – Agr. Res. J. Kerala. 2: 20–21.
Kaushik, B. D. (1994): Blue-green algae and sustainable agriculture. – In: Deb, L. (ed.): Natural resource management for sustainable agriculture and development. Angkor Publs. Pvt. Ltd., New Delhi, pp. 403–416.
Rippka, R., Waterbury, B. J. and Stanier, R. Y. (1981): Isolation and purification of cyanobacteria: some general principles. – The prokaryotes: a hand book on habitats, isolation and identification of Bacteria. pp. 212–220.
Sahu, D., Priyadarshani, I. and Rath, B. (2012): Cyanobacteria as potential bio-fertilizers. – CIB Tech J. Microbiol. 1(2-3): 20–26. https://doi.org/10.1007/BF02839213
Schopf, J. W. (1970): Precambrian microorganisms and evolutionary events prior to the origin of vascular plants. – Biol. Rev. 45: 319-352. https://doi.org/10.1111/j.1469-185X.1970.tb01644.x
Tiffany, L. M. (1951): Ecology of fresh water algae. – In: Smith, G. M. (ed.): Manual of phycology: chronocia botanica. Waltham, Massachusetts, pp. 293–311.
Umamaheswari, N. A. (2005): Isolation and characterisation of Nostocales (Cyanobacteria) of paddy fields of Kerala. – Ph. D. Thesis, Calicut University.
Venkataraman, G. S. (1972): Algal bio-fertilizers and rice cultivation. – Today and tomorrow Printers and Publishers, New Delhi.
Vijayan, D. and Ray, J. G. (2015): Ecology and diversity of cyanobacteria in Kuttanadu paddy wetlands, Kerala, India. – Amer. J. Plant Sci. 6: 2924-2938. https://doi.org/10.4236/ajps.2015.618288
Zapomelova, E., Jezberova, J., Hrouzek, P., Hisem, D., Rehakova, K. and Komarekova, J. (2010): Polyphasic characterization of three strains of Anabaena reniformis and Aphanizomenon aphanizomenoides (cyanobacteria) and their reclassification to Sphaerospermum gen. nov. (incl. Anabaena kisseleviana). – J. Phycol. 45: 1363-1373. https://doi.org/10.1111/j.1529-8817.2009.00758.x