Estimating N2fixation in two species ofAlnusin interior Alaska using acetylene reduction and15N2uptake

Anderson, Michael D.; Ruess, Roger W.; Uliassi, Daniel D.; Mitchell, Jennifer S.

doi:10.1080/11956860.2004.11682814

Cited by 37 publications

(48 citation statements)

References 33 publications

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“…While ARA measures are often scaled up to infer rates of N 2 fixation at the landscape scale, such calculations can be subject to methodological bias (Bergersen 1970;Minchin et al 1983;Anderson et al 2004). We recognize that our dataset offers a unique opportunity to provide crude estimates of fixation directly below the crown of individual fixing trees.…”

Section: Nitrogenase Activity and N 2 Fixationmentioning

confidence: 98%

“…For trees with low nodule density, collection for ARA measurements was deemed too destructive and not performed, and neighboring tree data were used for estimates. We calculated C 2 H 4 :N 2 conversion ratios by subdividing nodules into two replicate ARA incubations and a third in a 20-at% 15 N 2 atmosphere (Anderson et al 2004). …”

Section: Acetylene Reduction Assaysmentioning

confidence: 99%

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Facultative nitrogen fixation by canopy legumes in a lowland tropical forest

2010

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Symbiotic dinitrogen (N(2)) fixation is often invoked to explain the N richness of tropical forests as ostensibly N(2)-fixing trees can be a major component of the community. Such arguments assume N(2) fixers are fixing N when present. However, in laboratory experiments, legumes consistently reduce N(2) fixation in response to increased soil N availability. These contrasting views of N(2) fixation as either obligate or facultative have drastically different implications for the N cycle of tropical forests. We tested these models by directly measuring N(2)-fixing root nodules and nitrogenase activity of individual canopy-dominant legume trees (Inga sp.) across several lowland forest types. Fixation was substantial in disturbed forests and some gaps but near zero in the high N soils of mature forest. Our findings suggest that canopy legumes closely regulate N(2) fixation, leading to large variations in N inputs across the landscape, and low symbiotic fixation in mature forests despite abundant legumes.

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Section: Nitrogenase Activity and N 2 Fixationmentioning

confidence: 98%

Section: Acetylene Reduction Assaysmentioning

confidence: 99%

Facultative nitrogen fixation by canopy legumes in a lowland tropical forest

2010

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“…The reductions in alder growth and nitrogen fixation associated with alder canker are ecologically important, as a result of alder's role in nitrogen accumulation during floodplain succession (Van Cleve et al 1971, Ruess et al 2006. Green alder (Alnus crispa) in uplands also interacts with drought-mediated diseases , which has important implications for post-fire nitrogen dynamics (Anderson et al 2004, Mitchell and. Table 2 summarizes the damage and ecological implications of climate changes on insects and diseases significantly impacting Interior-boreal forests.…”

Section: Types Of Change In Alaskan Forestsmentioning

confidence: 99%

Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

et al. 2011

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Abstract. The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer-to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral-and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important v www.esajournals.org 1 November 2011 v Volume 2(11) v Article 124 consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates assessment of current and future consequences of a changing climate, emphasizes regional differences in biophysical factors, and points to linkages that may exist but that currently lack supporting research. The framework also serves as a visual tool for resource managers and policy makers to develop regional and global management strategies and to inform policies related to climate mitigation and adaptation.

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“…The growth curve was drawn by counting the colony forming units (CFU) using the drop method described by Barbosa et al (1995). The nitrogenase activity was measured by acetylene reduction assay (Anderson et al, 2004). Analyses of amino acids and IAA were performed in the filtered supernatants by reverse phase highperformance liquid chromatography (HPLC) with a C18 column, (Shimadzu Shim-pack CLC ODS) and a fluorescence detector according to Ferrara et al (2012).…”

Section: Bacterial Growth Curve Nitrogenase Activity and Detection Omentioning

confidence: 99%

Sugarcane growth promotion by Kosakonia sp. ICB117 an endophytic and diazotrophic bacterium

Kleingesinds¹,

Ferrara²,

Floh³

et al. 2018

Afr. J. Microbiol. Res.

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The present study investigates the strain Kosakonia sp. ICB117, an endophytic, N 2 -fixing bacterium that belongs to a genus recently described. The bacteria were isolated from sugarcane stalks (Saccharum sp. variety SP791011) and inoculated into other sugarcane plants of the same variety. The effect of inoculation on sugarcane growth was then studied in the presence or absence of nitrate supplementation (10 mM). The following plant growth parameters were analyzed: biomass, plant height and number of leaves. Furthermore, CO 2 assimilation and the C and N content of plants were also determined, as was the size of the endophytic bacteria population resulting from the inoculation. The findings showed that inoculation with bacteria (both with or without additional nitrate) led to an increase of plant biomass, CO 2 assimilation, total C and N in the roots, and the number of leaves. In addition, the polyamine putrescine and indole-3-acetic acid were actively released by the bacterium in in vitro assays and might be released in internal plant tissues as well, resulting in plant growth promotion. In conclusion, inoculation of sugarcane with Kosakonia sp. ICB117 increased the efficiency of the plant's metabolism.

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Estimating N₂fixation in two species ofAlnusin interior Alaska using acetylene reduction and¹⁵N₂uptake

Cited by 37 publications

References 33 publications

Facultative nitrogen fixation by canopy legumes in a lowland tropical forest

Facultative nitrogen fixation by canopy legumes in a lowland tropical forest

Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

Sugarcane growth promotion by Kosakonia sp. ICB117 an endophytic and diazotrophic bacterium

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