N2 fixation associated with wood decayed by some common fungi in western Montana

1978 ◽  
Vol 8 (3) ◽  
pp. 341-345 ◽  
Author(s):  
Michael J. Larsen ◽  
Martin F. Jurgensen ◽  
Alan E. Harvey
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Tree Species ◽  
Western Montana ◽  
Decay Fungi ◽  
Woody Substrates

Decay caused by some common wood-destroying fungi in several associated tree hosts of the Intermountain forests of western Montana was evaluated as a potential environment for the fixation of dinitrogen. Differences in the rates of fixation were demonstrated between various decay stages, tree species, decay fungi, and brown and white rots. Advanced brown-rotted wood was a more favorable system for nitrogen fixation than wood partially brown rotted. Also, brown-rotted substrates proved to be more favorable than did white rotted, particularly Pseudotsugamenziesii (Mirb.) Franco wood decayed by Fomitopsispinicola (Swartz ex Fr.) Karst. Data demonstrate that a nitrogenase function coexists naturally with decay fungi in woody substrates and that appreciable and significant amounts of nitrogen are fixed in these substrates.

scholarly journals The Quorum Sensing Auto-Inducer 2 (AI-2) Stimulates Nitrogen Fixation and Favors Ethanol Production over Biomass Accumulation in Zymomonas mobilis

2021 ◽  
Vol 22 (11) ◽  
pp. 5628
Author(s):  
Valquíria Campos Alencar ◽  
Juliana de Fátima dos Santos Silva ◽  
Renata Ozelami Vilas Boas ◽  
Vinícius Manganaro Farnézio ◽  
Yara N. L. F. de Maria ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Quorum Sensing ◽  
Ethanol Production ◽  
N2 Fixation ◽  
Energy Demand ◽  
Zymomonas Mobilis ◽  
Biomass Accumulation ◽  
High Energy ◽  
Gram Negative ◽  
Expression Of Genes

Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production of public goods, or pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria, and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair, and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N2 fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N2 fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production in industrial plants.

Differential responses of the sunn4 and rdn1-1 super-nodulation mutants of Medicago truncatula to elevated atmospheric CO2

2021 ◽  
Author(s):  
Yunfa Qiao ◽  
Shujie Miao ◽  
Jian Jin ◽  
Ulrike Mathesius ◽  
Caixian Tang
Keyword(s):  
Nitrogen Fixation ◽  
Elevated Co2 ◽  
Medicago Truncatula ◽  
N2 Fixation ◽  
Sink Strength ◽  
Wild Type ◽  
Total N ◽  
Autoregulation Of Nodulation ◽  
Nodulation Mutants ◽  
Fixation Capacity

Abstract Background and Aims Nitrogen fixation in legumes requires tight control of carbon and nitrogen balance. Thus, legumes control nodule numbers via an autoregulation mechanism. ‘Autoregulation of nodulation’ mutants super-nodulate and are thought to be carbon-limited due to the high carbon-sink strength of excessive nodules. This study aimed to examine the effect of increasing carbon supply on the performance of super-nodulation mutants. Methods We compared the responses of Medicago truncatula super-nodulation mutants (sunn-4 and rdn1-1) and wild type to five CO2 levels (300-850 μmol mol -1). Nodule formation and N2 fixation were assessed in soil-grown plants at 18 and 42 days after sowing. Key results Shoot and root biomass, nodule number and biomass, nitrogenase activity and fixed-N per plant of all genotypes increased with increasing CO2 concentration and reached the maximum around 700 μmol mol -1. While the sunn-4 mutant showed strong growth-retardation compared to wild-type plants, elevated CO2 increased shoot biomass and total N content of rdn1-1 mutant up to two-fold. This was accompanied by a four-fold increase in nitrogen fixation capacity in the rdn1-1 mutant. Conclusions These results suggest that the super-nodulation phenotype per se did not limit growth. The additional nitrogen fixation capacity of the rdn1-1 mutant may enhance the benefit of elevated CO2 on plant growth and N2 fixation.

scholarly journals Exploratory Sampling of Spalting Fungi in the Southern Peruvian Amazon Forest

Challenges ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 32
Author(s):  
Sarath M. Vega Gutierrez ◽  
Javier F. Illescas Guevara ◽  
Claudia C. Andersen ◽  
Jose Koechlin von Stein ◽  
Seri C. Robinson
Keyword(s):  
Tree Species ◽  
Economic Value ◽  
Economic Importance ◽  
Edible Mushrooms ◽  
Amazon Forest ◽  
Peruvian Amazon ◽  
Fruiting Bodies ◽  
Wood Decomposition ◽  
Decay Fungi ◽  
Madre De Dios

Most of the research related to Peruvian Amazon fungi is focused on edible mushrooms and pathogens. Other important fungi, such as the spalting type (decay fungi that pigment wood internally), are not broadly studied, as most of them do not produce fruiting bodies and can be difficult to locate. Spalting fungi, however, are of broad economic importance due to their ability to produce pigments that enhance wood aesthetics, resulting in an increased economic value. In order to begin understanding the diversity of spalting fungi within certain regions of the Amazon, a sampling of downed trees and branches (through the opening of the xylem to identify potential pigmenting and zone line producing fungi) was done in the district of Las Piedras, Madre de Dios, Peru. Fungi suspected of causing internal pigment and zone lines were collected, cultured, isolated, and sequenced. The species found belonged to the orders Helotiales, Xylariales, Hypocreales, Russulales, Polyporales, Botryosphaeriales and two specimens of the class Leotiomycetes. The fungi collected produced pigments or zone lines in wild conditions and all of them were capable of wood decomposition. Interestingly, these are the same orders and genera as North American spalting fungi, which may indicate a correlation within species that pigment wood. The results obtained start a specific database of spalted fungi in the Amazon and, with it, help support an effort to increase the forest value of ecosystems primarily used for a few high-valued tree species.

Sowing time and tillage practice affect chickpea yield and nitrogen fixation. 2. Nitrogen accumulation, nitrogen fixation and soil nitrogen balance

1996 ◽  
Vol 36 (6) ◽  
pp. 701 ◽  
Author(s):  
CP Horn ◽  
RC Dalal ◽  
CJ Birch ◽  
JA Doughton
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
N Balance ◽  
Grain Legume ◽  
Nitrogen Accumulation ◽  
Soil Nitrate ◽  
Soil N ◽  
Tillage Practice ◽  
Sowing Time ◽  
N Accumulation

Following long-term studies at Warra, on the western Darling Downs, chckpea (Cicer anetinum) was selected as a useful grain legume cash crop with potential for improvement of its nitrogen (N) fixing ability through management. This 2-year study examined the effect of sowing time and tillage practice on dry matter yield, grain yield (Horn et al. 1996), N accumulation, N2 fixation, and the subsequent soil N balance. Generally, greater N accumulation resulted from sowing in late autumn-early winter (89-117 kg N/ha) than sowing in late winter (76-90 kg N/ha). The amount of N2 fixed was low in both years (15-32 kg N/ha), and was not significantly affected by sowing time or tillage. The potential for N2 fixation was reduced in both years due to high initial soil nitrate levels and low total biomass of chickpea because of low rainfall. Nitrogen accumulation by grain was higher under zero tillage (ZT) than conventional tillage (CT) for all sowing times, and this affected the level of grain N export. The consequence of low N2 fixation and high N export in chickpea grain was a net loss of total soil N, (2-48 kg N/ha under CT and 22-59 kg N/ha under ZT). Management practices to ensure larger biomass production and lower soil nitrate-N levels may result in increased N2 fixation by chickpea and thus a positive soil N balance.

Basidiomycete decay fungi within stems of Nothofagus windfalls in a Southern Hemisphere beech forest

2008 ◽  
Vol 38 (7) ◽  
pp. 1897-1910 ◽  
Author(s):  
I. A. Hood ◽  
P. N. Beets ◽  
J. F. Gardner ◽  
M. O. Kimberley ◽  
M. W.P. Power ◽  
...  
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Tree Species ◽  
Coarse Woody Debris ◽  
Woody Debris ◽  
Beech Forest ◽  
Study Data ◽  
Decay Fungi ◽  
Mean Diameter

Fungi were isolated to determine the predominant decomposer species active in the coarse woody debris in a beech forest in the central North Island of New Zealand. Basidiomycetes were obtained in 55% of 4569 isolation attempts from discs cut from six trees each of Nothofagus fusca (Hook. F.) Oerst. and Nothofagus menziesii (Hook. F.) Oerst. uprooted during a storm 24 years earlier. Percentage yields varied significantly among trees but not between tree species. However, for N. fusca, basidiomycetes were obtained less frequently from stems of greater mean diameter. In total, 96% of basidiomycete isolates were composed of 18 species, the most abundant being Armillaria novae-zelandiae (G. Stev.) Herink, mainly present in the outer 12 cm, and Ganoderma cf. applanatum sensu Wakef. and Cyclomyces tabacinus (Mont.) Pat., which penetrated more deeply. These fungi were distributed along the stems as somatically incompatible colonies reaching lengths of 11, 2, and 3 m for each species, respectively; those of G. cf. applanatum were separated by brown pseudosclerotial plates. Fruiting of these species was significantly associated with isolation of cultures and, for G. cf. applanatum and C. tabacinus, provided a reliable guide to stem colonization. Basidiomycete diversity in the Nothofagus stems was greater than in two podocarp species in an earlier study. Data from this investigation are being used to assess how decay fungi, together with other factors, influence rates of decomposition of indigenous coarse woody debris.

Nitrogen fixation in chickpea. II. Comparison of 15N enrichment and 15N natural abundance methods for estimating nitrogen fixation

1995 ◽  
Vol 46 (1) ◽  
pp. 225 ◽  
Author(s):  
JA Doughton ◽  
PG Saffigna ◽  
I Vallis ◽  
RJ Mayer
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Full Range ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Enrichment Method ◽  
Mineral N ◽  
Crop Establishment ◽  
15N Enrichment ◽  
15N Natural Abundance Method

The 15N enrichment and 15N natural abundance methods for estimating N2 fixation in chickpea were compared over a range of soil NO3-N levels at crop establishment varying from 10 to 326 kg N/ha (0-120 cm depth). Barley was used as a non-N2 fixing control crop. Both methods estimated reduced N2 fixation as soil NO3-N levels at crop establishment increased. Similar estimates of % N2 fixation were obtained at high values, but at low values the enrichment method gave lower estimates, some of which were negative. The 15N natural abundance method provided realistic estimates of % N2 fixation across all soil N03-N levels at crop establishment. An asymptotic curve described a close ( R2 = 0.95) relationship between these factors. Standard errors of estimates of means for the 15N natural abundance method remained acceptable and relatively stable over the full range of measurements; however, with the 15N enrichment method they became unacceptably large at low values of % N2 fixation. These large errors may have been partly due to legume and control plants assimilating mineral N of differing 15N enrichment. High mineral N levels associated with low values of % N2 fixation were also shown to reduce reliability of N2 fixation values estimated by the 15N enrichment method. These errors caused potentially greater inaccuracy at low values of % N2 fixation than at high values. To compare N2 fixation means statistically, transformations were necessary to stabilize variance and to impart lower weightings to plots with low values of % N2 fixation.

scholarly journals Role of arbuscular mycorrhiza fungi on tolerance to salinity of the tree legume Albizia lebbeck (L.) inoculated by Rhizobium

2014 ◽  
Vol 2 (01) ◽  
pp. 45-50 ◽  
Author(s):  
Gaurav Bhushan ◽  
Santosh Kr Sharma ◽  
Priyanka Sagar ◽  
Nishtha Seth ◽  
A. P. Singh
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Mycorrhizal Fungi ◽  
Block Design ◽  
Protective Role ◽  
Tree Legume ◽  
Randomized Block Design ◽  
Acaulospora Laevis ◽  
Different Levels ◽  
Injurious Effects

Myrica esculenta (Myricaceae) and Syzygium cumini(Myrtaceae), the Indian traditional fruits The effect of different level of salinity on growth, nodulation and Nitrogen fixation of single and dual inoculated tree legumes which help arbascular mycorrhizal fungi (AMF) Acaulospora laevis Gerd. and Trappe with Rhizobium bacteria in the presence of different levels of salinity (concentration of NaCl) conducted in earthen pots in a completely randomized block design with three replications resulted in effective plant growth, shoot and root biomasses, nodulation and N2 fixation. The effect of different levels of salinity (concentration of NaCl) on growth, nodulation and N2 fixation of single (Rhizobium or AMF alone) and dual inoculated (Rhizobium + AMF ) tree legume has a pot culture experiment using The parameter growth , nodulation, nitrogen fixation and % AMF colonization of roots were considerable influenced with the increase in salt concentration from 0.5 % to 4.0 % NaCl. It was observed that the mycorrhizal tree legume (inoculated with the most preferred AMF Acaulospora laevis) performed better in the increasing levels of salinity in comparison to non-mycorrhozal ones. These investigations suggested a protective role play by AMF in providing resistance to the tree legume against injurious effects of salinity. Inoculation of efficient strain of AMF (Acaulospora laevis) during the course of study, prevented the injurious effects of salinity in the test plants due to enhanced water and sustainable nutrient uptake thereby promoting growth, nodulation and biogeochemical N2 cycle (fixation of nitrogen) of the tree legume under investigation.

scholarly journals Modeling the impact of iron and phosphorus limitations on nitrogen fixation in the Atlantic Ocean

2006 ◽  
Vol 3 (5) ◽  
pp. 1391-1451 ◽  
Author(s):  
V. J. Coles ◽  
R. R. Hood
Keyword(s):  
Nitrogen Fixation ◽  
Atlantic Ocean ◽  
N2 Fixation ◽  
Iron Concentration ◽  
Near Surface ◽  
Dissolved Iron ◽  
Dynamic Representation ◽  
The Impact ◽  
Nitrogen Phosphorus ◽  
Do So

Abstract. The overarching goal of this study is to simulate subsurface N* (sensu, Gruber and Sarmiento, 1997) anomaly patterns in the North Atlantic Ocean and determine the basin wide rates of N2 fixation that are required to do so. We present results from an Atlantic implementation of a coupled physical-biogeochemical model that includes an explicit, dynamic representation of N2 fixation with light, nitrogen, phosphorus and iron limitations, and variable stoichiometric ratios. The model is able to reproduce nitrogen, phosphorus and iron concentration variability to first order. The latter is achieved by incorporating iron deposition directly into the model's detritus compartment which allows the model to reproduce sharp near surface gradients in dissolved iron concentration off the west coast of Africa and deep dissolved iron concentrations that have been observed in recent observational studies. The model can reproduce the large scale N* anomaly patterns but requires relatively high rates of surface nitrogen fixation to do so (1.8×1012 moles N yr−1 from 10° N–30° N, 3.4×1012 moles N yr

scholarly journals The Laccate Ganoderma of the Southeastern United States: A Cosmopolitan and Important Genus of Wood Decay Fungi

EDIS ◽  
2017 ◽  
Vol 2017 (1) ◽  
pp. 6
Author(s):  
Andrew L. Loyd ◽  
Jason A. Smith ◽  
Brantlee S. Richter ◽  
Robert A. Blanchette ◽  
Matthew E. Smith
Keyword(s):  
United States ◽  
Plant Pathology ◽  
Tree Species ◽  
Southeastern United States ◽  
Wood Decay ◽  
Decay Fungi ◽  
Fact Sheet ◽  
Lower Trunk ◽  
Wood Decay Fungi

Ganoderma Karst. is a large and diverse genus of wood decay fungi that can rot the roots and/or lower trunk of many tree species. There are several laccate (varnished or polished) Ganoderma species that are found in the southeastern United States and this six-page fact sheet provides an overview of the different species. Written by Andrew L. Loyd, Jason A. Smith, Brantlee S. Richter, Robert A. Blanchette, and Matthew E. Smith and published by the Plant Pathology Department.­http://edis.ifas.ufl.edu/pp333

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