scholarly journals Quantification and nitrogen fixation of cyanobacteria in rice field soils of Bangladesh

1970 ◽  
Vol 37 (2) ◽  
pp. 183-188 ◽  
Author(s):  
ZN Tahmida Begum ◽  
R Mandal ◽  
Farzana Binta Amin
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Rice Field ◽  
Correlation Study ◽  
Rice Fields ◽  
Soil Reaction ◽  
Key Words Cyanobacteria ◽  
Total N ◽  
Rice Field Soil ◽  
Nostoc Linckia

Quantification of cyanobacterial population and nitrogen fixation of 18 heterocystous cyanobacteria isolated from rice fields soils of 11 districts of Bangladesh have been studied. The taxa recorded were, namely Nostoc linckia, N. carneum, N. ellipsosporum, N. piscinale, Anabaena oryzae, Scytonema mirabile, Calothrix marchica and Hapalosiphon welwetschii. The number of cyanobacterial population varied significantly ranging from 14.6 × 104 to 141.0 × 104/g soil. N2-fixation of Nostoc linckia isolated from rice fields of Dhaka and Brahmanbaria ranged from 1.84 to 8.13 mg N 50/ml. However, the potentiality of other species was more or less similar. Single correlation study suggests that quantitative variation in cyanobacterial population was significantly related positively to soil reaction, available P and available S and negatively to total N content of soil. However, multiple correlations reflects that variation of cyanobacterial population was due to cumulative contribution of all the variables.  Key words: Cyanobacteria, Quantification, N2-fixation, Rice field soil doi:10.3329/bjb.v37i2.1728 Bangladesh J. Bot. 37(2): 183-188, 2008 (December)

Differential responses of the sunn4 and rdn1-1 super-nodulation mutants of Medicago truncatula to elevated atmospheric CO2

2021 ◽  
Author(s):  
Yunfa Qiao ◽  
Shujie Miao ◽  
Jian Jin ◽  
Ulrike Mathesius ◽  
Caixian Tang
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
Medicago Truncatula ◽  
N2 Fixation ◽  
Sink Strength ◽  
Wild Type ◽  
Total N ◽  
Autoregulation Of Nodulation ◽  
Nodulation Mutants ◽  
Fixation Capacity

Abstract Background and Aims Nitrogen fixation in legumes requires tight control of carbon and nitrogen balance. Thus, legumes control nodule numbers via an autoregulation mechanism. ‘Autoregulation of nodulation’ mutants super-nodulate and are thought to be carbon-limited due to the high carbon-sink strength of excessive nodules. This study aimed to examine the effect of increasing carbon supply on the performance of super-nodulation mutants. Methods We compared the responses of Medicago truncatula super-nodulation mutants (sunn-4 and rdn1-1) and wild type to five CO2 levels (300-850 μmol mol -1). Nodule formation and N2 fixation were assessed in soil-grown plants at 18 and 42 days after sowing. Key results Shoot and root biomass, nodule number and biomass, nitrogenase activity and fixed-N per plant of all genotypes increased with increasing CO2 concentration and reached the maximum around 700 μmol mol -1. While the sunn-4 mutant showed strong growth-retardation compared to wild-type plants, elevated CO2 increased shoot biomass and total N content of rdn1-1 mutant up to two-fold. This was accompanied by a four-fold increase in nitrogen fixation capacity in the rdn1-1 mutant. Conclusions These results suggest that the super-nodulation phenotype per se did not limit growth. The additional nitrogen fixation capacity of the rdn1-1 mutant may enhance the benefit of elevated CO2 on plant growth and N2 fixation.

scholarly journals Profile of microbial community of organic and conventional rice field using metagenomic analysis

2021 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Arum Asri Trisnastuti ◽  
Edi Purwanto ◽  
Ari Susilowati
Keyword(s):  
Microbial Community ◽  
Relative Abundance ◽  
Rice Field ◽  
Fertilizer Application ◽  
Rice Fields ◽  
Community Diversity ◽  
Total N ◽  
Organic C ◽  
Organic Rice ◽  
Significant Difference

Organic farming can increase the diversity of soil bacterial. This research aimed to compare the profile of microbial community of organic and conventional rice fields in early (0 Day After Planting/DAP), mid (15 DAP), and late (45 DAP) fertilizer application period. The total DNA genome from the soil sample was extracted then analyzed metagenomically using Next Generation Sequencing (NGS). There was nine genus of bacteria found in high relative abundance, 95.28%, while 4.72% included in Domain of Archaea (genus Methanosaeta). Phylum of Firmicutes (genus Clostridium has 24.50% relative abundance, Bacillus 11.90%, Lactobacillus 9.69%); Proteobacteria (genus Defluviicoccus 12.10%, Buchnera 18.46%, Rosenbergiella 2.46%); and Actinobacteria (genus Nocardioides 12.21%, and Streptomyces 3.96%). Meanwhile, the average plant height of organic rice fields was shorter than conventional rice fields got directly measured coincided with soil sampled. Based on alpha and beta diversity analysis, the highest community diversity and abundance were found in organic rice field soil samples taken at 45 DAP, i.e., at the end of the fertilizer application period. However, in both organic and conventional rice field soils, there was almost no significant difference in the bacterial community, so it impacts that organic and conventional systems do not make a real difference in the total N, P available, CEC, and pH values. It makes a significant difference in organic C and organic matters.

scholarly journals The Quorum Sensing Auto-Inducer 2 (AI-2) Stimulates Nitrogen Fixation and Favors Ethanol Production over Biomass Accumulation in Zymomonas mobilis

2021 ◽  
Vol 22 (11) ◽  
pp. 5628
Author(s):  
Valquíria Campos Alencar ◽  
Juliana de Fátima dos Santos Silva ◽  
Renata Ozelami Vilas Boas ◽  
Vinícius Manganaro Farnézio ◽  
Yara N. L. F. de Maria ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Quorum Sensing ◽  
Ethanol Production ◽  
N2 Fixation ◽  
Energy Demand ◽  
Zymomonas Mobilis ◽  
Biomass Accumulation ◽  
High Energy ◽  
Gram Negative ◽  
Expression Of Genes

Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production of public goods, or pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria, and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair, and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N2 fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N2 fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production in industrial plants.

scholarly journals Response of the protistan community of a rice field soil to different oxygen tensions

2017 ◽  
Vol 93 (5) ◽  
Author(s):  
Yuriko Takenouchi ◽  
Kazufumi Iwasaki ◽  
Jun Murase
Keyword(s):  
Rice Field ◽  
Field Soil ◽  
Rice Field Soil ◽  
Oxygen Tensions

Integration of the rice field design software with AutoCAD Сivil 3D

2021 ◽  
pp. 347-351
Author(s):  
E.E. Dmitrieva ◽  
E.V. Kalinova
Keyword(s):  
Rice Field ◽  
Field Model ◽  
Rice Fields ◽  
Engineering System ◽  
Design Software

The article discusses the use of AutoCAD Civil 3D engineering system with the software for rice fields designing. The article contains the examples of graphic materials (rice field model) created in AutoCAD Civil 3D based on the design results in RIS software.

New records of Cyanobacterial morphotypes with Leptolyngbya indica sp. nov. from terrestrial biofilms of the Lower Gangetic Plain, India

Phytotaxa ◽  
2017 ◽  
Vol 316 (2) ◽  
pp. 101 ◽  
Author(s):  
MANOJIT DEBNATH ◽  
TARKESHWAR SINGH ◽  
PUNYASLOKE BHADURY
Keyword(s):  
Rice Field ◽  
New Records ◽  
Indian Subcontinent ◽  
Culture Conditions ◽  
South East Asia ◽  
Gangetic Plain ◽  
Gangetic Plains ◽  
Rice Field Soil ◽  
Green Remediation ◽  
Mangrove Soils

Macroscopic cyanobacterial biofilms were collected from alluvial plain soils and estuarine mangrove soils representing the Lower Gangetic Plains of South East Asia (India). The composition of the biofilms was investigated using light microscopy and field emission scanning electron microscopy of collected samples. In this study four simple trichal non-heterocytous morphotypes were found to be unique. Out of four, three morphotypes clearly showed differences with respect to described taxa as based on most recent taxonomic classification and possibly represent new report from the Indian subcontinent. One morphotype was successfully established under culture conditions and described as Leptolyngbya indica sp. nov. isolated from the alluvial arsenic affected rice field soil. This study provides vital information on morphotypic diversity of Cyanobacteria from specific biotopes which can contribute key information on their biogeography and potential application in green remediation.

scholarly journals Polarisasi etnis dan potensi konflik dalam kebijakan pencetakan sawah baru: Sebuah kajian kepustakaan

2021 ◽  
Vol 16 (1) ◽  
pp. 81
Author(s):  
Dwi Wulan Pujiriyani
Keyword(s):  
Literature Review ◽  
Ethnic Groups ◽  
Ethnic Conflict ◽  
Rice Field ◽  
Aging Population ◽  
Rice Fields ◽  
Ethnic Composition ◽  
Productive Labor ◽  
Potential Problems ◽  
Future Potential

This study aims to analyse the implementation of new rice field plan  policies in Indonesia and their impacts on population and ethnic composition in new rice field locations. This research is conducted by applying a literature review method. It is shown that the implementation of the policies had two major implications. Firstly, it creates assimilation opportunities through collaboration between ethnic migrants and local ethnic groups to work on or cultivate new rice fields. Secondly, the great flows of transmigrants that move to the new rice field locations trigger ethnic polarization, which is prone to cause inter-ethnic conflict. In the future, potential problems associated with the provision of new rice fields are available are the risk of having aging population. The aging population indicates a decrease in productive labor that may also affect on decreasing attractiveness of the rice fields to the younger generation. This situation can lead to the re-involvement of older generation in managing the new rice fields. However, it can raise a new concern on their ability to improve the rice fields’ productivity or, even worse, the new rice fields might be neglected or be sold. 

scholarly journals Potential of Phototrophic Purple Nonsulfur Bacteria to Fix Nitrogen in Rice Fields

2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Isamu Maeda
Keyword(s):  
Nitrogen Fixation ◽  
Regulatory Networks ◽  
Nitrogenase Activity ◽  
Field Studies ◽  
Rice Fields ◽  
Purple Nonsulfur Bacteria ◽  
Available Nitrogen ◽  
Nitrogenase Activities ◽  
Plant Available Nitrogen ◽  
Biological Nitrogen

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.

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