Nodulation and nitrogen fixation by red alder and Sitka alder on coal mine spoils

1982 ◽  
Vol 12 (4) ◽  
pp. 992-997 ◽  
Author(s):  
Paul Heilman ◽  
Gorden Ekuan
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Douglas Fir ◽  
Tree Age ◽  
Fixed Nitrogen ◽  
Red Alder ◽  
Mine Spoils ◽  
Nodule Number ◽  
Western Washington ◽  
The Difference

Nodule number, nodule weight, and nitrogen fixation (nitrogenase activity by acetylene reduction) were determined for 3 years for red alder (Alnusrubra Bong.) and Sitka alder (Alnussinuata Reg. Rydb.) on three types of coal spoils in western Washington. Generally, the two species were similar in number and weight of nodules and in nitrogen-fixation rates when measured in June (these rates varied from 23 to 27 µmol•g−1•h−1). The type of coal spoil material influenced nodule number but not nodule weight. Topsoil covered subsoil had the highest number of nodules. Trees on unweathered subsoil had the lowest number, particularly for Sitka alder. Nodule weight (dry, ash free) varied from 68 kg•ha−1 for 5-year-old Sitka alder interplanted in a 1:1 mix with Douglas-fir (1790 alders•ha−1) to 188–200 kg•ha−1 for pure stands of both alder species at age 5 (5380 trees•ha−1). The difference in nodule weight between species was not significant. Both species fixed nitrogen at similar rates although in the last year of measurement red alder trees fixed 37% more nitrogen than Sitka alder. This difference was not significant, however. Nitrogen fixation per unit area depended on tree age and spacing, varying from 17 kg•ha−1•year−1 at age 3 with 1830 alders•ha−1 to 150 kg•ha−1•year−1 by both species at age 5 and a density of 5380 trees•ha−1. Fixation rates increased from age 3 to 5 years primarily because of increased nodule weight. Nitrogen fixation by the Sitka alder in mixture with Douglas-fir was relatively high and was encouraging for the concept of mixed plantings of these two species. However, response of Douglas-fir to mixed planting with Sitka alder has not been demonstrated.

scholarly journals Anabaena sp. Strain PCC 7120 Gene devH Is Required for Synthesis of the Heterocyst Glycolipid Layer

2005 ◽  
Vol 187 (7) ◽  
pp. 2326-2331 ◽  
Author(s):  
Martha E. Ramírez ◽  
Pratibha B. Hebbar ◽  
Ruanbao Zhou ◽  
C. Peter Wolk ◽  
Stephanie E. Curtis
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Regulatory Protein ◽  
Protein A ◽  
Filamentous Cyanobacterium ◽  
Fixed Nitrogen ◽  
Ultrastructural Studies ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Mutant Forms

ABSTRACT In response to deprivation for fixed nitrogen, the filamentous cyanobacterium Anabaena sp. strain PCC 7120 provides a microoxic intracellular environment for nitrogen fixation through the differentiation of semiregularly spaced vegetative cells into specialized cells called heterocysts. The devH gene is induced during heterocyst development and encodes a product with characteristics of a trans-acting regulatory protein. A devH mutant forms morphologically distinguishable heterocysts but is Fox−, incapable of nitrogen fixation in the presence of oxygen. We demonstrate that rearrangements of nitrogen fixation genes take place normally in the devH mutant and that it is Fix+, i.e., has nitrogenase activity under anoxic conditions. The Fox− phenotype was shown by ultrastructural studies to be associated with the absence of the glycolipid layer of the heterocyst envelope. The expression of glycolipid biosynthetic genes in the mutant is greatly reduced, and heterocyst glycolipids are undetectable.

Litter decomposition and nutrient release in Douglas-fir, red alder, western hemlock, and Pacific silver fir ecosystems in western Washington

1980 ◽  
Vol 10 (3) ◽  
pp. 327-337 ◽  
Author(s):  
Robert L. Edmonds
Keyword(s):  
Weight Loss ◽  
Nutrient Release ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Silver Fir ◽  
Rapid Weight Loss ◽  
Red Alder ◽  
Cellulose Decomposition ◽  
The Pacific ◽  
Western Washington

Decomposition rates and changes in the nutrient content of needle and leaf litter were examined in Douglas-fir (Pseudotsugamenziesii Mirb. Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), Pacific silver fir (Abiesamabilis (Dougl.) Forbes), and red alder (Alnusrubra Bong.) ecosystems in western Washington, U.S.A. Nylon litterbags (1-mm mesh) were placed in the stands in November and December 1974. Bags were collected after 3, 6, 12, and 24 months and weighed, except in the Pacific silver fir stand when bags were collected after 6, 9, 14, and 24 months. Litter was analyzed for C, N, P, K, Ca, Mg, Mn, lignin, and cellulose. Decomposition constants (k values) were determined. Fastest decomposition after 2 years occurred in red alder leaves, followed by Douglas-fir, western hemlock, and Pacific silver fir needles. There were significant differences in weight loss among species after 1 year, but no significant differences were evident after 2 years. Red alder leaves showed rapid weight loss in the 1st year but decomposed little in the 2nd year. Decomposition constants were highly positively correlated with minimum air temperatures and negatively correlated with C:N ratios. Low litter moisture tended to reduce decomposition in summer, particularly in the Pacific silver fir stand. Decomposition proceeded under snow in this ecosystem. The pattern of loss of elements from litterbags after 2 years varied from ecosystem to ecosystem, particularly for N. The following element mobility series resulted for the four ecosystems: red alder (K > Mg > Ca > P > N > Mn), Douglas-fir (K > P > Ca > Mg > Mn > N), western hemlock (K > Ca > Mg > N > Mn > P), and Pacific silver fir (K > Mg > Ca > Mn > P > N).

Evaluation of nonspatial approaches and equation forms used to predict tree crown recession

2004 ◽  
Vol 34 (10) ◽  
pp. 1993-2003 ◽  
Author(s):  
David W Hann ◽  
Mark L Hanus
Keyword(s):  
Growth Period ◽  
Allometric Equation ◽  
Douglas Fir ◽  
Tree Age ◽  
Permanent Plots ◽  
Stand Age ◽  
Tree Crown ◽  
Effective Age ◽  
The Difference ◽  
Modeling Data

Two nonspatial approaches for modeling tree crown recession (ΔHCB) were evaluated by using 5341 observations from Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). The first approach applies a static height-to-crown-base (HCB) equation at the start and end of the growth period and uses the difference in these predictions as an estimate of ΔHCB. This allometric method can be applied to species lacking ΔHCB data from permanent plots. The incremental method directly predicts ΔHCB from an equation developed from adequate permanent plot data. Two allometric and six incremental equation forms were examined. Also examined were three approaches for determining the end-of-growth-period tree and plot attributes used by the allometric method. Although the allometric method can produce unbiased estimates of ΔHCB, the best allometric equation forms explained about one-half of the variation explained by the best incremental equation form. The two best incremental equation forms were modifications of a nonlinear logistic equation form previously developed for Douglas-fir. The modifications included using measured stand age (BHA) or predicted tree growth effective age (GEA) instead of measured tree age. The best equation form used BHA, which limits its application to modeling data collected from just even-aged stands. The equation form using GEA could be applied to modeling data sets from both even- and uneven-aged stands.

scholarly journals Importance of cis Determinants and Nitrogenase Activity in Regulated Stability of the Klebsiella pneumoniae Nitrogenase Structural Gene mRNA

1999 ◽  
Vol 181 (12) ◽  
pp. 3751-3760 ◽  
Author(s):  
Holly M. Simon ◽  
Mark M. Gosink ◽  
Gary P. Roberts
Keyword(s):  
Nitrogen Fixation ◽  
Simple Model ◽  
Klebsiella Pneumoniae ◽  
Mrna Stability ◽  
Nitrogenase Activity ◽  
Expression System ◽  
Fixed Nitrogen ◽  
Complicated Model ◽  
A Site ◽  
Gene Mrna

ABSTRACT The Klebsiella pneumoniae nitrogen fixation (nif) mRNAs are unusually stable, with half-lives of 20 to 30 min under conditions favorable to nitrogen fixation (limiting nitrogen, anaerobiosis, temperatures of 30°C). Addition of O2 or fixed nitrogen or temperature increases to 37°C or more result in the dramatic destabilization of the nifmRNAs, decreasing the half-lives by a factor of 3 to 5. A plasmid expression system, independent of nif transcriptional regulation, was used to define cis determinants required for the regulated stability of the 5.2-kb nifHDKTY mRNA and to test the model suggested by earlier work that NifA is required in trans to stabilize nif mRNA undernif-derepressing conditions. O2 regulation ofnifHDKTY mRNA stability is impaired in a plasmid containing a deletion of a 499-bp region of nifH, indicating that a site(s) required for the O2-regulated stability of the mRNA is located within this region. The simple model suggested from earlier work that NifA is required for stabilizingnif mRNA under conditions favorable for nitrogen fixation was disproved, and in its place, a more complicated model involving the sensing of nitrogenase activity as a component of the system regulating mRNA stability is proposed. Analysis ofnifY mutants and overexpression suggests a possible involvement of the protein in this sensing process.

The fixed nitrogen sensitivity of biological nitrogen fixation in salt marshes sediments from the northeastern United States

2020 ◽  
Author(s):  
Romain Darnajoux ◽  
Rei Zhang ◽  
Katja Luxem ◽  
Xinning Zhang
Keyword(s):  
Nitrogen Fixation ◽  
Salt Marshes ◽  
Biological Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Inorganic Nitrogen ◽  
Ammonium Concentration ◽  
Desulfovibrio Vulgaris ◽  
Fixed Nitrogen ◽  
Sulfate Reducing ◽  
Biological Nitrogen

<p>Biological nitrogen fixation, the main input of fixed N into ecosystems, converts inert N<sub>2</sub> gas into bioavailable ammonium in an energetically costly reaction catalyzed by the prokaryotic metalloenzyme nitrogenase.  The high ATP and reductant requirements of N<sub>2</sub> fixation explain why this process is highly regulated in diazotrophs, with the presence of ammonium inhibiting nitrogenase expression and activity. Yet, several reports of N<sub>2</sub> fixation in ammonium- and nitrate-rich (10 to 300 µM) benthic environments challenge our understanding of a key environmental sensitivity of N<sub>2</sub> fixation. Field studies point to heterotrophic sulfate reducers as the likely diazotrophs in these benthic settings, but the fixed N sensitivity of sulfate-reducing diazotrophs is not well understood due to a dearth of culture studies. Additionally, assays of N<sub>2</sub> fixation in incubations rarely involve parallel measurements of dissolved inorganic nitrogen, possibly leading to experimental bias in favor of detecting activity under ammonium-replete initial conditions.</p><p>To help reconcile the environmental results, we investigate the ammonium sensitivity of N<sub>2</sub> fixation using the acetylene reduction assay and <sup>15</sup>N<sub>2</sub> tracer methods in i) the model sulfate-reducing diazotroph, <em>Desulfovibrio vulgaris</em> str. Hildenborough (DvH), ii) four enrichment cultures from salt marsh sediments of New Jersey, and iii) slurry incubations of sediments collected from three northeastern salt marshes. In all instances, we found that ammonium strongly inhibits biological nitrogen fixation, with nitrogenase activity only detectable when ammonium concentration is below a threshold of 10 µM (slurry incubation) or 2 µM (pure cultures, enrichments). Amendment of ammonium quickly inhibits nitrogen fixation and nitrogenase activity only resumes  once ammonium is depleted to the threshold level. Ammonium additions to actively fixing samples show complete inhibition of N<sub>2</sub> fixation within several hours post-addition. </p><p>Our measurements of the ammonium sensitivity of benthic N<sub>2</sub> fixation are consistent with the traditional understanding of nitrogen fixer metabolism and with early findings of Postgate et al. (1984) demonstrating that N<sub>2</sub> fixation by the sulfate reducer <em>Desulfovibrio gigas</em> is inhibited by ammonium levels that exceed 10 µM. These results help clarify a long-standing paradox in benthic nitrogen cycling. We suggest that prior observations of N<sub>2</sub> fixation at elevated ammonium levels could reflect methodological artifacts due to very fast depletion of ammonium during activity assays, legacy N<sub>2</sub> fixation activity associated with incomplete inhibition by ammonium, or spatial heterogeneity. Further work to standardize fixed N sensitivity assays could help with cross-study comparisons and with clarifying inconsistencies in our understanding of how environmental fixed nitrogen levels control nitrogen fixation.</p>

The influences of temperature and soil water on growth, photosynthesis, and nitrogen fixation of red alder (Alnusrubra) seedlings

1994 ◽  
Vol 24 (5) ◽  
pp. 1029-1032 ◽  
Author(s):  
B.J. Hawkins ◽  
S. McDonald
Keyword(s):  
Nitrogen Fixation ◽  
Water Potential ◽  
Soil Water ◽  
Water Status ◽  
Net Photosynthesis ◽  
Field Capacity ◽  
Plant Water ◽  
Red Alder ◽  
Plant Water Potential ◽  
The Difference

A 3 × 2 factorial experiment was conducted to investigate the interaction of temperature and soil water status on the growth, photosynthetic, transpiration, and nitrogen fixation rates of 2-month-old red alder (Alnusrubra Bong.) seedlings. Three day: night temperature treatments, 15:10 °C, 20:10 °C, and 25:10 °C were used. Two soil-water treatments kept pots between 85 and 100% of field capacity (wet) and 70–85% of field capacity (dry). Treatment effects on growth, net photosynthetic, transpiration and nitrogen fixation rates, plant water potential, and foliar nutrient concentration were measured over a 9-week period. The greatest seedling growth occurred at 25 °C day temperatures, while 20 and 25 °C days produced the greatest nodule growth. The allocation of biomass to roots increased with decreasing temperature. The highest rates of net photosynthesis occurred at 15 and 20 °C whereas transpiration was greatest at 25 °C. Plant water stress was greatest at 25 °C. The difference in plant water potential between the wet and dry treatments was only 0.04 MPa, which was not great enough to produce significant effects on growth or photosynthesis. Nitrogen fixation rates were highest in the wet treatment seedlings at 20 and 25 °C.

Nitrogen fixation by Klebsiella grown in the presence of oxygen

1972 ◽  
Vol 18 (12) ◽  
pp. 1845-1850 ◽  
Author(s):  
Robert Klucas
Keyword(s):  
Nitrogen Fixation ◽  
Dissolved Oxygen ◽  
Nitrogenase Activity ◽  
Fixed Nitrogen ◽  
Submerged Cultures ◽  
Continuous Cultures ◽  
Dissolved Oxygen Tension ◽  
Whole Cells ◽  
Oxygen Effects ◽  
Oxygen Tensions

Several facultative asymbiotic N2-fixing bacteria exhibited nitrogenase activity when grown in the presence of air and a limiting amount of fixed nitrogen. One isolate (S-4) identified as Klebsiella was examined in more detail for oxygen effects. Nitrogenase was not detectable in highly aerated submerged cultures but was detectable in shaken and continuous cultures at dissolved oxygen tensions of 3 and 10 mm of Hg respectively. No nitrogenase activity was found in cells from continuous cultures maintained at a dissolved oxygen tension of 15 mm of Hg or above. The nitrogenase activity in whole cells was not oxygen dependent but was oxygen tolerant.

Phytomass production in young mixed plantations of Alnus rubra (Bong.) and cottonwood in western Washington

1983 ◽  
Vol 29 (8) ◽  
pp. 1007-1013 ◽  
Author(s):  
Paul Heilman ◽  
R. F. Stettler
Keyword(s):  
Nitrogenase Activity ◽  
Populus Trichocarpa ◽  
Dry Weight ◽  
Alnus Rubra ◽  
Mixed Stands ◽  
Red Alder ◽  
Short Rotation ◽  
Mixed Plantations ◽  
Rotation Culture ◽  
Western Washington

Use of red alder in mixture with 28 clones of cottonwood in close spaced, short-rotation culture for fiber and energy was investigated. Early growth was rapid with red alder averaging 7.2 m and cottonwood mixed with alder averaging 8.2 m in height after 3 years. Alder significantly increased nitrogen content of cottonwood foliage in the 1st and 2nd years but not in the 3rd. Mean height of cottonwood at 3 years was increased in mixture with red alder. However, heights of the shortest cottonwood clones were reduced. Dry weight production on mixed plots (both species combined) was generally less than for pure cottonwood. Only with the slowest growing cottonwood clones did mixed stands show increased dry weight production. The best cottonwood clone, a hybrid (Populus trichocarpa × P. deltoides), produced 20.3 t∙ha−1∙year−1 dry weight for 3 years in pure stands compared with 2.8 t∙ha−1∙year−1 for the poorest. Production by alder was inversely related to cottonwood production in mixed plantings. Nodulation and C2H3 reduction was evaluated during the third growing season. Results indicated severe decline in nitrogenase activity where overtopping and shading of red alder by adjacent cottonwood occurred. At this site, the success of this mixture appears to depend upon use of cottonwood clones that do not outgrow the alder. Since the highest yielding cottonwood clones are much more productive at this site than the alder that we used, there would seem to be little incentive for mixed plantings of these species under the conditions of this experiment.

scholarly journals Effect of Sowing Depth on Nodulation, Nitrogen Fixation, Root and Hypocotyl Growth, and Yield in Groundnut (Arachis hypogaea)

1987 ◽  
Vol 23 (3) ◽  
pp. 283-291 ◽  
Author(s):  
P. T. C. Nambiar ◽  
B. Srinivasa Rao
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Field Experiments ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Growth And Yield ◽  
Fixed Nitrogen ◽  
Hypocotyl Growth ◽  
Hypocotyl Length ◽  
Sowing Depth

SUMMARYHypocotyl length in groundnut is a function of sowing depth. In field experiments deep sowing increased the mass of hypocotyl but decreased that of roots, pods and haulm. Few nodules were formed on the hypocotyls of plants from shallow sown seeds (4–5 cm deep). More hypocotyl nodules occurred on Virginia types when deep sown but the number and activity of nodules on the roots decreased. Nodules on the hypocotyl appeared later and fixed less nitrogen than root nodules. Although hypocotyl nodules fixed nitrogen during the later stages of plant growth, this activity could not compensate for the loss in nitrogenase activity due to deeper sowing. Deeper sowing also resulted in decreased pod yields.

Inheritance of Symbiotic Nitrogen Fixation in Two Peanut Crosses1

1989 ◽  
Vol 16 (2) ◽  
pp. 66-70 ◽  
Author(s):  
T. D. Phillips ◽  
J. C. Wynne ◽  
G. H. Elkan ◽  
T. J. Schneeweis
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Specific Activity ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Dominance Model ◽  
Nodule Number ◽  
Shoot Dry Weight ◽  
Arachis Hypogaea L ◽  
Reciprocal Differences

Abstract Symbiotic nitrogen fixation in peanut (Arachis hypogaea L.) may be improved by genetically manipulating the host plant. This requires an understanding of the inheritance of the traits involved in nitrogen fixation. The objectives of this study were to determine the inheritance of several N2 fixation-related traits for two peanut crosses based on Mather and Jink's fixation-related traits for two peanut crosses based on Mather and Jink's additive-dominance model, and to determine if epistasis was important in the inheritance of these traits. A generation means analysis usingparents, reciprocal F1s and F2s, and two back-cross generations was conducted for both crosses. Plants of different generations were grown in modified Leonard jars in the greenhouse for about 60 days at which time nodule number and dry weight, shoot dry weight, nitrogenase activity, and specific activity were measured. Means of the traits for the generations from both crosses (Robut 33-1 x NC 4 and Robut 33-1 x Argentine) showed significant differences. Reciprocal differences were found for most traits measured in the cross of Robut 33-1 x Argentine, a cross of Virginia x Spanish botanical types. Lack of fit of the additive-dominance model indicated significant epistasis for inheritance of nodule number, nodule weight, top dry weight, and nitrogenase activity in both crosses. Three types of digenic interactions (additive x additive, additive x dominance and dominance x dominance) were found. The presence of nonadditive genetic effects suggests that early generation selection would be ineffective.

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