Nitrogen fixation in forests of central Massachusetts

1979 ◽  
Vol 57 (1) ◽  
pp. 11-16 ◽  
Author(s):  
John Tjepkema
Keyword(s):  
Nitrogen Fixation ◽  
Tree Species ◽  
Acetylene Reduction ◽  
Time Course ◽  
Reduction Method ◽  
Old Fields ◽  
Soil Cores ◽  
Nitrogen Inputs ◽  
Woody Litter

The acetylene reduction method was used to measure nitrogen fixation in soil cores of 16 cm diameter and 16 cm depth that included A and B horizon soil, roots, and decaying litter. Forty-three combinations of location and associated tree species were sampled. The rate of nitrogen fixation for most soil cores was 1 g N ha−1 day−1 or less, which extrapolates to less than 0.2 kg N ha−1 year−1. The highest rates, with values of up to 23 g N ha−1 day−1, were observed in old fields being invaded by trees. The time course of acetylene reduction was usually linear for a 24-h period, most of the activity was in the upper 15 cm of soil, and the maximum rates were observed in midsummer. No significant nitrogen fixation was observed in preliminary measurements of decaying woody litter or of aerial surfaces of trees and rocks. It is suggested that nitrogen fixation is not a significant input of nitrogen for the forests studied. If so, there may be significant unrecognized nitrogen inputs to forests, such as dry absorption of ammonia from the atmosphere.

Estimate of nitrogen fixation on leaf surfaces of forest species in Minnesota and Oregon

1979 ◽  
Vol 9 (4) ◽  
pp. 474-477 ◽  
Author(s):  
Edward Sucoff
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Reduction Method ◽  
Forest Species ◽  
Shrub Species ◽  
Nitrogen Economy ◽  
Upper Limits ◽  
Leaf Surfaces

Leafy branches from 52 tree or shrub species collected from Minnesota forests during July and August, 1976, and (or) May and September, 1977, were tested for their ability to fix nitrogen. Seven species were similarly sampled in western Oregon during November, 1976. Nitrogen fixation was assessed by the acetylene reduction method. Little, if any, acetylene reduction was detected on branches without epiphytes. The upper limits of possible nitrogen fixation on the leaf surfaces were below amounts important in the nitrogen economy of the stands.

Nitrogen fixation by intact grass-soil cores using 15N2 and acetylene reduction

1985 ◽  
Vol 17 (1) ◽  
pp. 87-91 ◽  
Author(s):  
D.R. Morris ◽  
D.A. Zuberer ◽  
R.W. Weaver
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Soil Cores

Nitrogen fixation by naturally occurring duckweed–cyanobacterial associations

1985 ◽  
Vol 31 (4) ◽  
pp. 327-330 ◽  
Author(s):  
Tran Phuoc Duong ◽  
James M. Tiedje
Keyword(s):  
Nitrogen Fixation ◽  
Annual Cycle ◽  
Acetylene Reduction ◽  
Acetylene Reduction Activity ◽  
Lower Epidermis ◽  
Reduction Activity ◽  
Naturally Occurring ◽  
Favorable Environment ◽  
Nitrogen Inputs

Nitrogen fixation as measured by acetylene conversion to ethylene was found to be common for duckweed blooms on ponds, lakes, and streams in Michigan. Twenty-six of 29 sites with duckweed sampled over a 2-year period showed acetylene reduction activity (ARA). These activities corresponded to N inputs of 3.7–7.5 kg N∙ha−1 per annual cycle for typical blooms but dense Lemna trisulca blooms could be 10 times greater. The ARA was stimulated five- to six-fold by light, was not removed when plants were shaken in water, and was usually associated with the leaves and not the roots. Colonies of heterocyst-bearing cyanobacteria of the genera Nostoc, Gloeotrichia, Anabaena, Calothrix, and Cylindrospermum were observed attached to the lower epidermis or in the reproductive pockets of leaves of Spirodela and Lemna plants but not on Wolffia plants. The ARA correlated reasonably well with the density of cyanobacterial colonies observed. The duckweed appeared to provide a more favorable environment for the cyanobacteria which should result in enhanced nitrogen inputs to aquatic and sediment environments harboring duckweed. The N2 fixation was not sufficient, however, to meet all the nitrogen needs of the duckweed bloom.

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.

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.

Nitrogen fixation in cottonwood wetwood

1986 ◽  
Vol 16 (5) ◽  
pp. 1118-1120 ◽  
Author(s):  
B. J. van der Kamp
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Forest Ecosystems ◽  
Reduction Method ◽  
Black Cottonwood ◽  
Significant Phenomenon

Samples of wetwood from four living western black cottonwood (Populustrichocarpa Torr. and Gray) trees growing near Vancouver, B.C., were incubated anaerobically with acetylene to detect nitrogen fixation using the acetylene-reduction method. Significant acetylene reduction was detected in all trees and ranged up to 5.16 nmol acetylene g–1 day−1. It is suggested that nitrogen fixation in wetwood may be a significant phenomenon in forest ecosystems.

Sign in / Sign up

Export Citation Format

Share Document