Ecology of deepwater rice-fields in Bangladesh 4. Nitrogen fixation by blue-green algal communities

Hydrobiologia ◽  
1988 ◽  
Vol 169 (1) ◽  
pp. 43-56 ◽  
Author(s):  
J. A. Rother ◽  
Abdul Aziz ◽  
N. Hye Karim ◽  
B. A. Whitton
2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Isamu Maeda

Biological nitrogen fixation catalyzed by Mo-nitrogenase of symbiotic diazotrophs has attracted interest because its potential to supply plant-available nitrogen offers an alternative way of using chemical fertilizers for sustainable agriculture. Phototrophic purple nonsulfur bacteria (PNSB) diazotrophically grow under light anaerobic conditions and can be isolated from photic and microaerobic zones of rice fields. Therefore, PNSB as asymbiotic diazotrophs contribute to nitrogen fixation in rice fields. An attempt to measure nitrogen in the oxidized surface layer of paddy soil estimates that approximately 6–8 kg N/ha/year might be accumulated by phototrophic microorganisms. Species of PNSB possess one of or both alternative nitrogenases, V-nitrogenase and Fe-nitrogenase, which are found in asymbiotic diazotrophs, in addition to Mo-nitrogenase. The regulatory networks control nitrogenase activity in response to ammonium, molecular oxygen, and light irradiation. Laboratory and field studies have revealed effectiveness of PNSB inoculation to rice cultures on increases of nitrogen gain, plant growth, and/or grain yield. In this review, properties of the nitrogenase isozymes and regulation of nitrogenase activities in PNSB are described, and research challenges and potential of PNSB inoculation to rice cultures are discussed from a viewpoint of their applications as nitrogen biofertilizer.


Hydrobiologia ◽  
1988 ◽  
Vol 169 (1) ◽  
pp. 23-30 ◽  
Author(s):  
B. A. Whitton ◽  
J. A. Rother ◽  
Ashit R. Paul
Keyword(s):  

2015 ◽  
Vol 6 (1) ◽  
pp. 253-259
Author(s):  
MA Hasan

The experiment was conducted to carry out the nitrogen fixing cyanobacterial (BGA) resources and their distribution pattern in rice fields of North-West region of Bangladesh during the period of 2011. Considering the vast importance of Blue-green algae (BGA) in agricultural land especially in rice fields, their twelve months long systematic was undertaken. A total of 10 genera with 37 species of filamentous-heterocystous blue-green algal forms were identified and recorded from this region. Out of 37 species, 9 species belonging to the genus Anabaena, 8 to Nostoc, 5 to Cylindrospermum, 4 to Calothrix, 3 to Rivularia, 3 to Gloeotrichia and 2 to Aulosira; while 1 species belonging to each genus of Anabaenopsis, Microcheate and Aphanizomenon. The distribution pattern of filamentous-heterocystous BGA in rice fields over the study area has also been observed in this study. With few exceptions, the filamentous-heterocystous BGA are more or less uniformly distributed all over the study areas. All of the BGA members have a tremendous ability to contribute on enhancing agricultural production by fixing atmospheric nitrogen and adding organic matter, vitamins, growth promoting substances etc to the soil and crops.DOI: http://dx.doi.org/10.3329/jesnr.v6i1.22075 J. Environ. Sci. & Natusral Resources, 6(1): 253-259 2013


1999 ◽  
Vol 35 (2) ◽  
pp. 141-152 ◽  
Author(s):  
P. C. RAM ◽  
A. K. SINGH ◽  
B. B. SINGH ◽  
V. K. SINGH ◽  
H. P. SINGH ◽  
...  

Floodwater was characterized through field surveys over three years in rainfed lowland and deepwater rice areas of Eastern India. Measurements focused on dissolved O2 and CO2, pH and irradiance during flash floods in rice fields. Over locations and time, dissolved O2 concentrations ranged from zero to 0.28 mol m−3 (0–1.1 times air-saturated water at 30 °C) while dissolved CO2 ranged from 0.28 to 1.96 mol m−3 (31–217 times air-saturated water). Floodwater pH varied from 6.6 to 9.7. Irradiance decreased with depth in the water profile to an extent depending on turbidity. Turbidity varied greatly over locations and time. The significance of these measurements in assessing rice submergence tolerance is discussed.


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