B. Sadhana1 and N. Panneerselvam2
1Centre for Research and P.G Department of Botany, Thiagarajar College, Madurai-625009, Tamil Nadu, India..E.mail:sadhanakarthik2004@yahoo.co.in
2Centrefor Research and P.G Department of Botany, The Madura College, Madurai,
Tamil Nadu, India.E.mail:npanneerselvam1958@gmail.com
Abstract: Pesticidal effect was studied on rice field Cyanobacteria – Anabaena cylindrica in Perambalur, Tamil Nadu. In the present study lower concentrations of Dithane M45 and Malathion (5 ppm, 10 ppm and 15 ppm) stimulated the algal growth and their higher concentrations inhibited the algal growth when compared to control. It was clearly observed in chlorophyll a and phycobilin content of pesticides treated cells. But the increase in concentrations of both Pesticide did not affect the nitrogen fixing activity, because there was no significant decrease in nitrogen contents of cells in different treatments. Ammonia excretion by the algae was gradually decreased in 5ppm – 50ppm of Dithane M45 treated cells when compared to control. While maximum ammonia excretion was observed in 5ppm of Malathion treated cells when compared to other concentrations. The application of Cyanobacteria in rice field can increase the soil fertility and reduce the use of chemical pesticides for crop improvement.
Keywords: Ammonia excretion, cyanobacteria, chlorophyll a,nitrogen fixation, rice field, pesticides, phycobilins
REFERENCES
Bharathi, S.G., and Angadi, S. B. (1981). Short and long term effects of fungicides on nitrogen fixing blue-green algae. Phykos., 20(1-2): 58-64.
Bhunia, A. K., Basu, N.K., Roy, D., Chakrabarti, A., Banerjee, S. K. (1992). Chlorophyll-a content, N2 fixing ability and certain metabolic activities of Nostoc muscorum: effect of methyl parathion and benthiocarb. Bull. Environ .Contam. Toxicol., 47 (1): 43-50.
Kalita, M.C. (1997). Effect of Malathion on growth, chlorophyll biosynthesis and total nitrogen accumulation of Azolla – Anabaena symbionts. J. Ecotoxicol. Environ. Monit., 7(1):59-63.
Kaushik, B. D., Venkataraman, G. S. (1983). Response of cyanobacterial nitrogen fixation to insecticides. Curr. Sci., 52 (7): 321-323.
Latorre, C., Lee, J. H., Spiller, H., Shanmugam, K. T. (1986). Ammonium- ion excreting cyanobacterial mutants as a source of nitrogen for growth of rice: a feasibility study. Biotechnol. Lett., 8: 507-512.
Newton, J.W. (1986). Liberation of ammonia by cyanobacteria. Plant Physiol. (Suppl)., 80 : 12.
Subramanian, G. and Shanmugasundaram, S. (1986). Influence of herbicide 2, 4-D on nitrogen fixation and ammonia excretion by the cyanobacteria- Anabaena. Proc. Indian Natl. Sci. Acad., 52: 308-312.
Subramanian, G., Krishnamurthi, M. S., and Lakshmi Prabu, S. (1987). Influence of some insecticides on photosynthetic oxygen evolution in the cyanobacterium Anabaena. Curr. Sci., 59: 549-550.