Nitrogen fixation and acetylene reduction in decaying conifer boles: effects of incubation time, aeration, and moisture content

1982 ◽  
Vol 12 (3) ◽  
pp. 646-652 ◽  
Author(s):  
Warwick B. Silvester ◽  
Phillip Sollins ◽  
Thomas Verhoeven ◽  
Steven P. Cline
Keyword(s):  
Nitrogen Fixation ◽  
Moisture Content ◽  
Forest Ecosystem ◽  
Acetylene Reduction ◽  
Preliminary Survey ◽  
Anaerobic Conditions ◽  
Free Living ◽  
Living Organisms ◽  
Low Activity

Free-living microaerophiles fixed 15N2 and reduced acetylene in fallen tree boles at two old-growth Pseudotsugamenziesii stands in western Oregon. Acetylene reduction was most rapid under an atmosphere of 2–10% O2, whereas under prolonged anaerobic conditions it was at or below detection limits. Acetylene reduction rates increased up to fourfold during long-term incubations in acetylene (> 12 h). Ratios of acetylene reduction to N2 fixation frequently exceeded 6.0 during such long-term incubations but averaged 3.5 when samples were incubated < 7 h; consequently, long-term incubation of low-activity material in acetylene should be avoided. A preliminary survey indicated that N2 fixation by free-living organisms in fallen boles was less than other potential N inputs to fallen boles and to the forest ecosystem.

scholarly journals Nitrogen Fixation in Pozol, a Traditional Fermented Beverage

2020 ◽  
Vol 86 (16) ◽  
Author(s):  
Jocelin Rizo ◽  
Marco A. Rogel ◽  
Daniel Guillén ◽  
Carmen Wacher ◽  
Esperanza Martinez-Romero ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Growth Promotion ◽  
Point Of View ◽  
Intestinal Microbiome ◽  
Acetylene Reduction Activity ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Free Living ◽  
Functional Perspective

ABSTRACT Traditional fermentations have been widely studied from the microbiological point of view, but little is known from the functional perspective. In this work, nitrogen fixation by free-living nitrogen-fixing bacteria was conclusively demonstrated in pozol, a traditional Mayan beverage prepared with nixtamalized and fermented maize dough. Three aspects of nitrogen fixation were investigated to ensure that fixation actually happens in the dough: (i) the detection of acetylene reduction activity directly in the substrate, (ii) the presence of potential diazotrophs, and (iii) an in situ increase in acetylene reduction by inoculation with one of the microorganisms isolated from the dough. Three genera were identified by sequencing the 16S rRNA and nifH genes as Kosakonia, Klebsiella, and Enterobacter, and their ability to fix nitrogen was confirmed. IMPORTANCE Nitrogen-fixing bacteria are found in different niches, as symbionts in plants, in the intestinal microbiome of several insects, and as free-living microorganisms. Their use in agriculture for plant growth promotion via biological nitrogen fixation has been extensively reported. This work demonstrates the ecological and functional importance that these bacteria can have in food fermentations, reevaluating the presence of these genera as an element that enriches the nutritional value of the dough.

Nitrogen fixation in the rhizosphere of freshwater angiosperms

1974 ◽  
Vol 52 (1) ◽  
pp. 217-221 ◽  
Author(s):  
J. Michael Bristow
Keyword(s):  
Nitrogen Fixation ◽  
High Activity ◽  
Acetylene Reduction ◽  
Anaerobic Conditions ◽  
Aerobic Conditions

Acetylene reduction by bacteria in the rhizosphere of Glyceria borealis and Typha sp. was studied under anaerobic and aerobic conditions. Under anaerobic conditions, when roots and rhizomes were incubated with rhizosphere sediments at 25 °C without glucose, acetylene reduction to ethylene was calculated to be 37 μmol g−1 day−1 and 3.6 μmol g−1 day−1 for Glyceria and Typha respectively. The rates were generally lower under aerobic conditions. Washed roots (without sediment) also showed high activity. The reduction of acetylene to ethylene had a Q10 of 4.5 in the Glyceria system. It is estimated that N2 fixation in the rhizosphere of this species may reach 60 kg ha−1 year−1.

Nitrogen fixation in the high arctic tundra at Sarcpa Lake, Northwest Territories

1985 ◽  
Vol 63 (5) ◽  
pp. 974-979 ◽  
Author(s):  
Jim D. Karagatzides ◽  
Martin C. Lewis ◽  
Herbert M. Schulman
Keyword(s):  
Nitrogen Fixation ◽  
Northwest Territories ◽  
Acetylene Reduction ◽  
Biological Nitrogen Fixation ◽  
Arctic Tundra ◽  
High Arctic ◽  
Fixed Nitrogen ◽  
Free Living ◽  
Blue Green Algae ◽  
Biological Nitrogen

The acetylene reduction assay was used to examine biological nitrogen fixation in the high arctic tundra at Sarcpa Lake, Northwest Territories (68°32′ N, 83°19′ W). The highest rates of acetylene reduction (9.37 ± 3.19 μmol C2H4 m−2 h−1) were in habitats that had a high density of the legumes Oxytropis maydelliana, O. arctobia, and Astragalus alpinus. Nitrogen fixation in the wet soils along the shore of a small lake was similar (8.87 ± 4.35 μmol C2H4 m−2 h−1) because of the blue-green alga Nostoc, which associates with mosses. Free-living blue-green algae and lichens made insignificant contributions to the total nitrogen fixation budget because they were uncommon and fixed nitrogen at a slower rate. Nitrogen-fixing lichens in the area included Stereocaulon arenarium and S. rivulorum. It is concluded that legumes have a significant input to the biological nitrogen fixation budget at Sarcpa Lake.

scholarly journals Optimization of the 15N2 incorporation and acetylene reduction methods for free-living nitrogen fixation

2019 ◽  
Vol 445 (1-2) ◽  
pp. 595-611 ◽  
Author(s):  
Darian N. Smercina ◽  
Sarah E. Evans ◽  
Maren L. Friesen ◽  
Lisa K. Tiemann
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Free Living ◽  
Reduction Methods ◽  
15N2 Incorporation

scholarly journals Influence of environmental factors and exogenous nitrogen on nitrogen fixation by intact thallus and excised cephalodia of Peltigera aphthosa

2020 ◽  
Vol 13 (1) ◽  
pp. 019-024
Author(s):  
Ngerebara NN ◽  
Amadi LO ◽  
Ekiyor HT
Keyword(s):  
Nitrogen Fixation ◽  
Environmental Factors ◽  
Moisture Content ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Nitrogen Addition ◽  
Air Humidity ◽  
Prolonged Incubation ◽  
Combined Nitrogen ◽  
Exogenous Nitrogen

The present study investigates the effects of various abiotic environmental factors: air humidity, moisture content, oxygen and exogenously supplied nitrogen on acetylene reduction by intact thallus and excised cephalodia of Peltgera aphthosa. Intact thallus and excised cephalodia of Peltigera aphthosa were incubated at various conditions of air humidity, moisture contents, oxygen tensions, and addition of exogenous nitrogen, and comparative nitrogen fixation by the intact thallus and excised cephalodia was used as a method for assessment. Acetylene reduction (nitrogen fixation) was enhanced at conditions of lowered oxygen tension and at initial addition of nitrogen to the medium. However, prolonged incubation of Peltigera aphthosa in the medium with combined nitrogen addition resulted in fluctuation of nitrogenase synthesis. Acetylene reduction rates were stimulated in an atmosphere of 100% relative humidity (RH) and moisture content range of 570-620% of dry weight of Peltigera aphthosa. The decrease of nitrogenase activity measurable by acetylene reduction of thallus after prolonged incubation in the medium with combined nitrogen addition shows susceptibility of the symbiosis (lichen) since the thallus showed signs of disintegration at this time. Furthermore, air humidity and moisture content of the thallus influenced nitrogenase synthesis of Peltigera aphthosa considerably on separation of cephalodia such approach decreased nitrogenase activity and also elicited differences in their response to the various treatments. Applicability of this technology would enhance plant sustainability and yield in agricultural farms.

scholarly journals Regulation of nitrogen fixation from free-living organisms in soil and leaf litter of two tropical forests of the Guiana shield

2019 ◽  
Vol 450 (1-2) ◽  
pp. 93-110 ◽  
Author(s):  
Leandro Van Langenhove ◽  
Thomas Depaepe ◽  
Sara Vicca ◽  
Joke van den Berge ◽  
Clement Stahl ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Leaf Litter ◽  
Tropical Forests ◽  
Guiana Shield ◽  
Free Living ◽  
Living Organisms

Conversion factor between acetylene reduction and nitrogen fixation in free-living cyanobacteria from high arctic habitats

1999 ◽  
Vol 45 (3) ◽  
pp. 223-229 ◽  
Author(s):  
Turid Liengen
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Conversion Factor ◽  
Soil Surface ◽  
High Arctic ◽  
Acetylene Reduction Activity ◽  
Nostoc Commune ◽  
Free Living ◽  
Conversion Factors ◽  
N Incorporation

The conversion factor between acetylene reduction and15N incorporation in free-living cyanobacteria was determined in different high arctic habitats in the area of Ny-Ålesund (78.5°N, 11.6°E), Spitsbergen, in the summer of 1994. The experiments were carried out under constant conditions, 19°C and 200 µE·m-2·s-1. The nitrogen-fixation activities, measured as15N-incorporation, were in the range 4.01-6.54 mg N2fixed·gdw-1·day-1(dw, dry weight) in sheets of Nostoc commune and 778-1206 mg N2fixed·m-2·day-1in the cyanobacterial crusts. The acetylene reduction activities were in the range 0.72-1.91 mg ethylene produced·gdw-1·day-1of N. commune and 12.8-63.7 mg ethylene produced·m-2·day-1in the cyanobacterial crusts. The conversion factor of N. commune ranged from 0.11 to 0.48 for ethylene produced to nitrogen fixed, whereas the cyanobacterial crusts covering the soil surface gave conversion factors in the range 0.022-0.073 for ethylene produced to nitrogen fixed. An Anabaena sp., isolated from one of the habitats investigated, gave conversion factors near the theoretical factor of 4, when determined at 14.0 and 17.3°C. It was concluded that the acetylene reduction activity of free-living cyanobacteria in high arctic habitats results in underestimates of the real nitrogen-fixation activity in these environments.Key words: nitrogen fixation, acetylene reduction, conversion factor, cyanobacteria, Nostoc commune, high arctic.

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