Growth and nitrogen fixation by non-heterocystous filamentous cyanobacteria of rice fields of Uttar Pradesh, India
2000
Tiwari, O.N. (Indian Agricultural Research Inst., New Delhi (India). Dhar, D.W. | Prasanna, R. | Shukla, H.M. | Singh, P.K. | Tiwari, G.L.
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, Lynbya birgei and L. 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, L. martensiana, L. semiplena and Plectonena boryanum grew well only up to 25 ppm of Malathion, but L. aestuarii, L. birgei and P. 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, P. boryanum grew well only up to 1 ppm concentration of Dimecron
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