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 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.

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.

scholarly journals Carbon and nutrient physiology in shrubs at the upper limits: a multi-species study

2020 ◽  
Author(s):  
Xue Wang ◽  
Fei-Hai Yu ◽  
Yong Jiang ◽  
Mai-He Li
Keyword(s):  
Fine Roots ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Growing Season ◽  
Interactive Effects ◽  
Tree Line ◽  
Shrub Species ◽  
Nutrient Physiology ◽  
Upper Limits ◽  
Species Study

Abstract Aims Carbon and nutrient physiology of trees at their upper limits have been extensively studied, but those of shrubs at their upper limits have received much less attention. The aim of this study is to examine the general patterns of non-structural carbohydrates (NSCs), nitrogen (N) and phosphorous (P) in shrubs at the upper limits, and to assess whether such patterns are similar to those in trees at the upper limits. Methods Across Eurasia, we measured the concentrations of soluble sugars, starch, total NSCs, N and P in leaves, branches and fine roots (< 0.5 cm in diameter) of five shrub species growing at both the upper limits and lower elevations in both summer (peak growing season) and winter (dormancy season). Important Findings Neither elevation nor season had significant effects on tissue N and P concentrations, except for lower P concentrations in fine roots in winter than in summer. Total NSCs and soluble sugars in branches were significantly higher in winter than in summer. There were significant interactive effects between elevation and season for total NSCs, starch, soluble sugars and the ratio of soluble sugar to starch in fine roots, showing lower soluble sugars and starch in fine roots at the upper limits than at the lower elevations in winter but not in summer. These results suggest that the carbon physiology of roots in winter may play an important role in determining the upward distribution of shrubs, like that in the alpine tree-line trees.

Sign in / Sign up

Export Citation Format

Share Document