Potential for nitrogen fixation in the rhizosphere and habitat of natural stands of the wild rice Zizania aquatica

1979 ◽  
Vol 57 (11) ◽  
pp. 1285-1291 ◽  
Author(s):  
M. T. Ogan
Keyword(s):  
Nitrogen Fixation ◽  
Water Column ◽  
Acetylene Reduction ◽  
Wild Rice ◽  
Heterotrophic Bacteria ◽  
Nitrogenase Activity ◽  
Early Summer ◽  
Zizania Aquatica ◽  
Natural Stands ◽  
Root Surfaces

The potential for nitrogen fixation in the rhizosphere and habitat of natural stands of Zizania aquatica (L) was studied by the acetylene reduction method. The data obtained suggested that this potential exists in the water column, the rhizosphere soil of the wild rice habitat, and on the root surfaces of the plants.In situ determination of rates of nitrogen fixation in the water column showed low but significant levels only in late spring – early summer and the rate was thought to be dependent on the presence of the blue-green algae Aphanizomenon. Laboratory experimental evidence showed that acetylene reduction by rhizosphere surface soil was attributable to Oscillatoria species while bacteria were more active in the subsurface soil and on the root surfaces. The bacteria-mediated nitrogenase activity was often preceded by a long lag period. The heterotrophic bacteria involved were enumerated, isolated, and characterised and they belong to the genera Azotobacter and Clostridium. Algal components of blooms occurring within the stands of Zizania at various times were identified.

Ecological aspects of nitrogen fixation (acetylene reduction) associated with plants of a Minnesota wetland community

1988 ◽  
Vol 66 (7) ◽  
pp. 1359-1363 ◽  
Author(s):  
Nancy A. Eckardt ◽  
David D. Biesboer
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Lemna Minor ◽  
Nitrogenase Activity ◽  
Typha Latifolia ◽  
Early Summer ◽  
Acetylene Reduction Activity ◽  
Redox Potentials ◽  
Carex Stricta ◽  
Calamagrostis Canadensis

Nitrogen fixation in association with four plant species of a Minnesota wetland, Typha latifolia L., Carex stricta Lam., Calamagrostis canadensis (Michx.) Beauv., and Lemna minor L., was estimated using the acetylene-reduction technique on soil – root cores. The estimated rates of nitrogen fixation (acetylene reduction) for plants growing in submerged soils, in kilograms per hectare per year, are T. latifolia, 0.91; Carex stricta, 0.47; Calamagrostis canadensis, 0.24; and L. minor, 1.90. Significantly higher fixation rates were found with plants growing in submerged areas than with those on the well-drained shore. These differences could not be correlated with differences in levels of extractable ammonium and nitrate in the substrate and were attributed to low redox potentials favoring nitrogenase activity in submerged areas. The seasonal trend in acetylene reduction activity appeared to be correlated with the reproductive stages of Typha, Carex, and Calamagrostis. Maximum acetylene reduction for these species was observed just after flower maturation, in early summer for Carex and Calamagrostis and late summer for Typha, suggesting that nitrogen fixation may be an important source of nitrogen in developing seeds. Overall, nitrogen fixation was estimated to supply as much as 11 kg N∙ha−1∙year−1 to this wetland community.

Nitrogen fixation (acetylene reduction) by Klebsiella pneumoniae in association with 'Park' Kentucky bluegrass (Poa pratensis L.)

1981 ◽  
Vol 27 (1) ◽  
pp. 52-56 ◽  
Author(s):  
L. V. Wood ◽  
R. V. Klucas ◽  
R. C. Shearman
Keyword(s):  
Nitrogen Fixation ◽  
Klebsiella Pneumoniae ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Surface Sterilization ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

Turfs of 'Park' Kentucky bluegrass reestablished in the greenhouse and inoculated with Klebsiella pneumoniae (W6) showed significantly increased nitrogen fixation (acetylene reduction) compared with control turfs. Mean ethylene production rates per pot were 368 nmol h−1 for K. pneumoniae treated turfs, 55 nmol h−1 for heat-killed K. pneumoniae treated turfs, and 44 nmol h−1 for untreated turfs. Calculated lag periods before activity was observed were generally very short (less than 1 h).When 'Park' Kentucky bluegrass was grown from seed on soil-less medium of Turface, a fired aggregate clay, inoculation with K. pneumoniae (W6) resulted in 9 of 11 turfs showing nitrogenase activity (mean ethylene producion rate per pot was 195 nmol h−1). Only 3 of 11 turfs treated with heat-killed K. pneumoniae showed any activity and their mean rate of ethylene production (40 nmol h−1 per pot) was significantly lower than that for turfs treated with K. pneumoniae.Using the 'Park'–Turface soil-less model system it was shown that acetylene reducing activity was (i) root associated, (ii) generally highest at a depth of 1–4 cm below the surface, (iii) enhanced by washing excised roots, and (iv) inhibited by surface sterilization of excised roots. Klebsiella pneumoniae was recovered from Turface and roots showing acetylene reducing activity.

Asymbiotic N2-fixing bacteria associated with three boreal conifers

1984 ◽  
Vol 14 (4) ◽  
pp. 595-597 ◽  
Author(s):  
L. Z. Florence ◽  
F. D. Cook
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Seedling Root ◽  
Natural Stands

Azotobacter spp., Azospirillum spp., and Desulfovibrio spp., were identified as the predominant nitrogen-fixing bacteria associated with seedling root sections collected from natural stands of Pinusbanksiana Lamb., Piceamariana (Mill.) B.S.P., and Larixlaricina (Du Roi) K. Koch growing in Alberta. Samples from the sandy upland habitat of P. banksiana exhibited lower average rates of nitrogen fixation relative to the wet lowland occupied by P. mariana and L. laricina. Average nitrogen-fixing capacity (by acetylene reduction) was greater among bacteria isolates from L. laricina than those from P. mariana. Azospirillum spp. were strongly associated with P. mariana, while Azotobacter spp. were isolated more frequently from L. laricina.

Nitrogen Fixation (Acetylene Reduction) Associated with Sea Urchins (Strongylocentrotus droebachiensis) Feeding on Seaweeds and Eelgrass

1977 ◽  
Vol 34 (3) ◽  
pp. 416-420 ◽  
Author(s):  
M. L. Guerinot ◽  
W. Fong ◽  
D. G. Patriquin
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Sea Urchins ◽  
Nitrogenase Activity ◽  
Average Rate ◽  
Strongylocentrotus Droebachiensis ◽  
Molar Ratio ◽  
Laminaria Digitata ◽  
Bare Rock ◽  
Nitrogenase Activities

Sea urchins feeding in different macrophyte zones in St. Margaret's Bay, Nova Scotia, in November and December 1975 were examined for nitrogenase activity using the acetylene reduction technique. For sea urchins feeding on Laminaria digitata and L. longicruris, the average rate of acetylene reduction was equivalent to N2 fixation of 55 μg N2 per sea urchin per day assuming a 3:1 molar ratio of C2H2 reduction to N2 fixation. Lower nitrogenase activities were observed for sea urchins feeding on Agarum cribrosum and Zostera marina, and no nitrogenase activity was observed for sea urchins taken from bare rock substrate on which kelp had been absent for 4 yr. Samples of separated digestive tracts but not the degutted bodies of sea urchins exhibited nitrogenase activity, suggesting that the digestive tract is the site of nitrogen fixation in whole sea urchins.

Seasonal and diurnal variation of nitrogenase activity (acetylene reduction) in barrel medic (Medicago truncatula Gaertn.) grown in pots

1978 ◽  
Vol 29 (5) ◽  
pp. 951 ◽  
Author(s):  
JJ Ruegg ◽  
AM Alston
Keyword(s):  
Nitrogen Fixation ◽  
Diurnal Variation ◽  
Medicago Truncatula ◽  
Acetylene Reduction ◽  
Time Course ◽  
Nitrogenase Activity ◽  
Seasonal Pattern ◽  
Molar Ratio ◽  
Multiple Use ◽  
Seasonal And Diurnal Variation

Seasonal and diurnal variation of nitrogenase activity in Medicago truncatula Gaertn. was measured by means of the acetylene reduction assay on plants grown in pots. In a glasshouse set at 20°C, the seasonal pattern of acetylene reduction (AR) activity was closely correlated with dry weight and photosynthetic area. Short-term fluctuations in AR activity were mainly associated with irradiance. Measurements made of the diurnal variation of AR activity showed that rates of AR at noon were 10–60% (average 33%) higher than the mean daily rates. Effects of defoliation and shading gave further evidence for the importance of light and recent photosynthate for nitrogen fixation in root nodules of legumes. Values for acetylene reduction integrated over time were highly correlated with the total amount of nitrogen in the plant. The molar ratio of acetylene reduced to nitrogen accumulated by the plants at the end of the experiment was 1.2 : 1. The significance of this value is discussed. Multiple use of the same plant material to study the time course of nitrogen fixation by the AR assay was found to be feasible under certain conditions.

scholarly journals Influence of Partial Pressures of Acetylene and Nitrogen upon Nitrogenase Activity of Species of Beijerinckia

1977 ◽  
Vol 30 (6) ◽  
pp. 593 ◽  
Author(s):  
IC MacRae
Keyword(s):  
Nitrogen Fixation ◽  
Spectrophotometric Method ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Optical Emission ◽  
Molar Ratios ◽  
Partial Pressures ◽  
Beijerinckia Indica

Acetylene reduction and nitrogen fixation by strains of Beijerinckia indica and B. lacticogenes increased with increased partial pressures of acetylene and nitrogen up to 80 kPa. The optical emission spectrophotometric method was used for the determination of 14N : 15N ratios. The molar ratios of acetylene to nitrogen varied greatly from the theoretical value.

Nitrogen Fixation by Native Australian Legumes

1981 ◽  
Vol 29 (2) ◽  
pp. 143 ◽  
Author(s):  
AC Lawrie
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Sand Dune ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Sand Dunes ◽  
Late Summer ◽  
Open Forest ◽  
Seasonal And Diurnal Variations ◽  
Major Factors

Nitrogen fixation was studied by the acetylene-reduction technique in root nodules of 10 native Australian legumes in three habitats in Victoria: low open-forest. sandy heathland and coastal sand dunes. Nodular activity reached a maximum in spring (and in autumn in sand-dune species), declined to a minimum in late summer and continued at a low level throughout winter. Mean nitrogenase activity was 1.73 μmol C2H2 reduced g-1 fresh wt nodules h-1, with spring maxima 8-250 times summer minima. It is suggested that variations in rainfall and temperature were the major factors influencing seasonal variations in nodular activity. Estiniates of minimum acetylene reduction per hectare per year were derived from measurements of seasonal and diurnal variations in acetylene reduction and abundance of nodules per hectare, and were used to derive approximate minimum values for nitrogen fixation of 0.004-0.746 kg ha-1 yr-1. The quantities of nitrogen fixed are compared with other reports and the significance of nitrogen fixation by these native legumes is discussed.

The temperature dependence of thallus nitrogenase activity in Peltigera canina

1975 ◽  
Vol 53 (6) ◽  
pp. 527-529 ◽  
Author(s):  
E. Maikawa ◽  
K. A. Kershaw
Keyword(s):  
Nitrogen Fixation ◽  
Temperature Dependence ◽  
Soil Nitrogen ◽  
Acetylene Reduction ◽  
Reduction Method ◽  
Nitrogenase Activity ◽  
Low Levels ◽  
Peltigera Canina

Comparative rates of nitrogen fixation in the lichen Peltigera canina from subarctic and temperate habitats have been examined using the acetylene reduction method. Maximum acetylene reduction at thallus saturation and with 20000 lx illumination takes place at 16 °C in subarctic material and at 21 °C in temperate material. This adaptation of nitrogenase activity to temperature in P. canina is discussed in relation to low levels of soil nitrogen in arctic systems.

Site-to-site variations in nitrogenase activity in a subarctic black spruce forest

1983 ◽  
Vol 13 (5) ◽  
pp. 782-788 ◽  
Author(s):  
Margaret M. Billington ◽  
Vera Alexander
Keyword(s):  
Nitrogen Fixation ◽  
High Latitude ◽  
Acetylene Reduction ◽  
Black Spruce ◽  
Nitrogenase Activity ◽  
Base Line ◽  
Spruce Forest ◽  
Experimental Burn ◽  
Alaskan Arctic ◽  
A Site

An estimate of nitrogen fixation in terms of acetylene reduction was made at two sites in a subarctic black spruce (Piceamariana (Mill.) B.S.P.) forest to determine site-to-site variations. The work was initially done to provide base-line comparative data for the primary intensive site, and for a site preparatory to an experimental burn. The principal conclusions were that, in contrast with the Alaskan arctic coastal tundra, microtopographic variations were not associated with big differences in acetylene reduction. Lichens with nitrogen-fixing phycobionts were an important influence on the activity; however, a high overall proportion of the activity was attributable to the moss cover, at least in part because of associated cyanobacteria. Daily rates for June and July averaged 74, 119 and 109 μg C2H4•m−2•day−1, respectively, for the 3 years. In common with other high-latitude sites, moisture was the major factor controlling nitrogenase activity.

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.

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