| Philippine Journal of Science | ||
| 129 (2): 101-107, December 2000 | ||
| ISSN 0031-7683 |
Growth and Nitrogen Fixation by Non-Heterocystous Filamentous Cyanobacteria of Rice Fields of Uttar Pradesh, India
O.N. Tiwari1, Dolly Wattal Dhar2, Radha Prasanna2,
H.M. Shukla3, P.K. Singh2 and G.L. Tiwari
1National for Conservation and Utilization of Blue-Green Algae Indian Agricultural Research Institute, New Delhi - 110 012
2National Centre for Conservation and Utilization of Cyanobacteria, Indian Agricultural Research Institute, New Delhi - 110 012, India
3Department of Botany, University of Allahabad, Allahabad - 211001, India
ABSTRACT
Thirty four non-heterocystous filamentous cyanobacterial strains belonging to eight genera of the Order Oscillatoriales namely Pseudanabaena (one), Limnothrix (one), Phormidium (five), Porphyrosiphon (one), Microcoleus (two), Oscillatoria (nine), Lyngbya (ten) and Plectonema (five) were isolated from rice field soils belonging to various localities of Uttar Pradesh, India. Out of these isolates, six were selected based upon their capacity to grow in nitrogen deficient (-N) medium. These were examined for growth attributes and pesticide tolerance. A wide variation was exhibited by these isolates with respect to biomass production, generation time, nitrogen fixation and pesticide tolerance. Porphyrosiphon notarisii, Lyngbya birgei and Lyngbya semiplena were found to exhibit appreciable nitrogen fixation. The different cyanobacterial strains varied in their tolerance to 2,4- Dichlorophenoxy acetic acid, Malathion and Dimecron. While, Lyngbya martensiana, L. semiplena and Plectonena boryanum grew well only up to 25 ppm of Malathion, but Lyngbya aestuarii, L. birgei and Plectonema boryanum were able to tolerate up to 200 ppm of 2,4 D. In Dimecron supplemented cultures, the maximum concentration tolerated was 10 ppm by L. birgei and L. aestuarii. However, Plectonema boryanum grew well only up to 1 ppm concentration of Dimecron.
Cynobacteria (Blue-Green Algae) occupy a unique taxonomic position among microorganisms possessing both an autotrophic mode of growth that is common to eukaryotic plant cells and a metabolic system that is generally regarded as bacteria. These prokaryotic organisms thus, combine the advantages of high growth potential of microbial cells with the efficient light harvesting capabilities of plant cells making themselves ideal candidates for biosolar energy conversions. . . . . read more
