Reply to ?Measurement of nitrogenase activity in legume root nodules: In defense of the acetylene reduction assay? by J.K. Vessey

1994 ◽  
Vol 158 (2) ◽  
pp. 163-167 ◽  
Author(s):  
Frank R. Minchin ◽  
John F. Witty ◽  
Lance R. Mytton
Keyword(s):  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Acetylene Reduction Assay ◽  
Reduction Assay

scholarly journals Factors Influencing Nitrogenase Activity (Acetylene Reduction) by Root Nodules of Groundnut, Arachis hypogaea L.

1983 ◽  
Vol 10 (1) ◽  
pp. 26-29 ◽  
Author(s):  
P. T. C. Nambiar ◽  
P. J. Dart
Keyword(s):  
Soil Moisture ◽  
Environmental Factors ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Activity Period ◽  
Diurnal Fluctuation ◽  
Factors Influencing ◽  
Arachis Hypogaea L ◽  
Reduction Assay

Abstract Acetylene reduction assay, used to measure nitrogenase activity of legume root nodules, is influenced by environmental factors, which limit its application. The effects of some of the environmental factors on acetylene reduction by groundnut root nodules are described. The activity was nonlinear during the first hour of incubation. Assay temperature above 25 C decreased the activity. Washing the nodulated roots prior to the assay also decreased the activity. The activity was influenced by light intensity, soil moisture, and moisture content in the incubation bottle. Diurnal fluctuation with one maximum and one minimum activity period during a 24 hour cycle was observed. Nitrogenase activity was higher during the postrainy season compared to that of the rainy season. A virginia cultivar Kadiri-71 had higher nitrogenase activity than a dwarf valencia cultivar, MH 2.

Interactions between Lugol's fixative and ethylene in the acetylene-reduction assay for nitrogenase activity in lake water

1980 ◽  
Vol 26 (5) ◽  
pp. 599-605 ◽  
Author(s):  
Lars Leonardson
Keyword(s):  
Liquid Phase ◽  
Vapor Phase ◽  
Lake Water ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Volume Ratio ◽  
Aquatic Organisms ◽  
Acetylene Reduction Assay ◽  
Reduction Assay ◽  
Phase Loss

Lugol's solution is a practical and efficient fixative for the acetylene-reduction assay of nitrogenase activity in aquatic organisms. Correction must be made, however, for the solubility of ethylene in the liquid phase and reactions between Lugol's solution and ethylene. With a vapor phase – liquid phase volume ratio of 1.9:1, the mean solubility of ethylene in mixtures of lake water and Lugol's solution was 7.2%. No correlation was found between ethylene solubility and the concentration of Lugol's solution. Storage of fixed samples for more than 1 day before gas chromatographic analysis resulted in increased loss of ethylene from the vapor phase; the loss amounted to ca. 18% after 3 days. Higher losses were noted at higher concentrations of Lugol's solution. Most probably these effects were caused by iodine addition to ethylene, as indicated by the consumption of ethylene by iodine – potassium iodide solutions. The reaction was catalyzed by the rubber septa of the incubation vessels when the septa were in contact with the liquid phase. Loss of ethylene decreased with increased concentration of phytoplankton because the organisms absorbed iodine. By using a standardized technique and determining ethylene solubility and reaction patterns between ethylene and the mixture of water and Lugol's solution, it is possible to correct for the loss of ethylene.

Bacterial dinitrogen fixation in the leaf of the northern pitcher plant (Sarracenia purpurea)

1991 ◽  
Vol 69 (10) ◽  
pp. 2296-2298 ◽  
Author(s):  
Andrew B. Prankevicius ◽  
Duncan M. Cameron
Keyword(s):  
Key Words ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Dinitrogen Fixation ◽  
Acetylene Reduction Assay ◽  
Sarracenia Purpurea ◽  
Pitcher Plant ◽  
Physiological Conditions ◽  
Reduction Assay ◽  
Unidentified Source

Bacterial (Azotobacteriaceae) nitrogenase activity in the leaf cavity of the insectivorous northern pitcher plant (Sarracenia purpurea L.) was assessed by acetylene reduction assay. Results indicated that bacterial dinitrogen fixation occurs in the leaf cavity under normal physiological conditions. This may represent a previously unidentified source of nitrogen for the pitcher plant, as the level of nitrogenase activity measured was sufficient to provide the plant with nitrogen well in excess of that required. Key words: pitcher plant, Sarracenia purpurea, dinitrogen fixation, Azotobacteriaceae, nitrogenase.

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