Effect of wheat roots on denitrification at varying soil air-filled porosity and organic-carbon content

Prade, K.; Trolldenier, G.

doi:10.1007/bf00260723

Cited by 40 publications

(26 citation statements)

References 20 publications

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“…Thus, denitrification rate increased ten-fold at a low moisture tension, while at medium, or high moisture tension, plants had no, or even a negative, effect on denitrification (Bakken 1988). Accordingly, Prade and Trolldenier (1988) showed that the rhizosphere effect on denitrification was confined to air-filled porosity below 10-12% (v/v). The primary driver of rhizosphere microbial community development is the release of plantderived low molecular weight organic compounds into the soil, and thus denitrification rates are often positively correlated with total C or soluble organic C (Baggs and Blum 2004;Bijay-Singh et al 1988;Paul and Beauchamp 1989).…”

Section: Nitrate Reduction and Denitrification In The Rhizosphere Of mentioning

confidence: 84%

Biochemical cycling in the rhizosphere having an impact on global change

et al. 2008

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Changes in chemical properties in soil around plant roots influence many microbial processes, including those having an impact on greenhouse gas emissions. To potentially mitigate these emissions according to the Kyoto protocol, knowledge about how and where these gases are produced and consumed in soils is required. In this review, we focus on the greenhouse gases nitrous oxide and methane, which are produced by nitrifying and denitrifying prokaryotes and methanogenic archaea, respectively. After describing the microbial processes involved in production and consumption of nitrous oxide and methane and how they can be affected in the rhizosphere, we give an overview of nitrous oxide and methane emissions from the rhizosphere and soils and sediments with plants. We also discuss strategies to mitigate emissions from the rhizosphere and consider possibilities for carbon sequestration.

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Section: Nitrate Reduction and Denitrification In The Rhizosphere Of mentioning

confidence: 84%

Biochemical cycling in the rhizosphere having an impact on global change

et al. 2008

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“…Klemedtsson et al 1987;Prade et al 1988). Different plant species that exhibit contrasting growth rates and/or root functioning can thus have different influences on the microbially mediated processes such as nitrification and denitrification.…”

Section: Discussionmentioning

confidence: 99%

Stimulation of soil nitrification and denitrification by grazing in grasslands: do changes in plant species composition matter?

Roux

Bardy

Loiseau³

et al. 2003

Oecologia

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Stimulation of nitrification and denitrification by long term (from years to decades) grazing has commonly been reported in different grassland ecosystems. However, grazing generally induces important changes in plant species composition, and whether changes in nitrification and denitrification are primarily due to changes in vegetation composition has never been tested. We compared soil nitrification- and denitrification-enzyme activities (NEA and DEA, respectively) between semi-natural grassland sites experiencing intensive (IG) and light (LG) grazing/mowing regimes for 13 years. Mean NEA and DEA (i.e. observed from random soil sampling) were higher in IG than LG sites. The NEA/DEA ratio was higher in IG than LG sites, indicating a higher stimulation of nitrification. Marked changes in plant species composition were observed in response to the grazing/mowing regime. In particular, the specific phytomass volume of Elymus repens was lower in IG than LG sites, whereas the specific volume of Lolium perenne was higher in IG than LG sites. In contrast, the specific volume of Holcus lanatus, Poa trivialis and Arrhenatherum elatius were not significantly different between treatments. Soils sampled beneath grass tussocks of the last three species exhibited higher DEA, NEA and NEA/DEA ratio in IG than LG sites. For a given grazing regime, plant species did not affect significantly soil DEA, NEA and NEA/DEA ratio. The modification of plant species composition is thus not the primary factor driving changes in nitrification and denitrification in semi-natural grassland ecosystems experiencing long term intensive grazing. Factors such as trampling, N returned in animal excreta, and/or modification of N uptake and C exudation by frequently defoliated plants could be responsible for the enhanced microbial activities.

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“…The impact of the rhizosphere on microbial activities such as denitrification has been previously reported (14,23,28,31). However, little is known about the influence of the rhizosphere on the structure of the nitrate-reducing community and previous studies on this community were performed mainly in the rhizosphere of aerenchymatous plant by using cultivation-based approaches (4, 17).…”

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confidence: 99%

Molecular Analysis of the Nitrate-Reducing Community from Unplanted and Maize-Planted Soils

Philippot

Piutti

Martin-Laurent

et al. 2002

Appl Environ Microbiol

184

137

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Microorganisms that use nitrate as an alternative terminal electron acceptor play an important role in the global nitrogen cycle. The diversity of the nitrate-reducing community in soil and the influence of the maize roots on the structure of this community were studied. The narG gene encoding the membrane bound nitrate reductase was selected as a functional marker for the nitrate-reducing community. The use of narG is of special interest because the phylogeny of the narG gene closely reflects the 16S ribosomal DNA phylogeny. Therefore, targeting the narG gene provided for the first time a unique insight into the taxonomic composition of the nitrate-reducing community in planted and unplanted soils. The PCR-amplified narG fragments were cloned and analyzed by restriction fragment length polymorphism (RFLP). In all, 60 RFLP types represented by two or more clones were identified in addition to the 58 RFLP types represented by only one clone. At least one clone belonging to each RFLP type was then sequenced. Several of the obtained sequences were not related to the narG genes from cultivated bacteria, suggesting the existence of unidentified nitrate-reducing bacteria in the studied soil. However, environmental sequences were also related to NarG from many bacterial divisions, i.e., Actinobacteria and ␣, ␤, and ␥ Proteobacteria. The presence of the plant roots resulted in a shift in the structure of the nitrate-reducing community between the unplanted and planted soils. Sequencing of RFLP types dominant in the rhizosphere or present only in the rhizosphere revealed that they are related to NarG from the Actinobacteria in an astonishingly high proportion.Nitrate-reducing prokaryotes constitute a wide group with members among the ␣, ␤, and ␥ Proteobacteria, gram-positive Bacteria, and even Archea, sharing the ability to obtain energy from dissimilatory reduction of nitrate into nitrite. The nitrite can then be reduced into gaseous nitrogen compounds by denitrification or into NH 4 by dissimilatory nitrate reduction into ammonia. Denitrification is the dominant process in soils and lake sediment, whereas dissimilatory nitrate reduction into ammonia occurs mainly in the rumen and in digested sludge (30). Due to nitrogen losses in agricultural soils and production of the greenhouse gases NO and N 2 O, denitrification has received a lot of attention over the last 20 years (7). There are two distinct forms of dissimilatory nitrate reductase; a periplasmic nitrate reductase and a membrane-bound nitrate reductase (reviewed in references 16 and 22). Only the nitrate reductase is found universally in prokaryotes and can therefore be used as a functional marker for these microorganisms. In addition, many microorganisms can contain both nitrate reductases (22). The membrane-bound nitrate reductase is composed of a soluble ␤ subunit containing four [Fe-S] clusters and the ␥ subunit containing two b-type hemes. The last subunit, encoded by the narG gene, contains a [4Fe-4S] cluster and a molybdopterin guanine dinucleotide cofact...

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Effect of wheat roots on denitrification at varying soil air-filled porosity and organic-carbon content

Cited by 40 publications

References 20 publications

Biochemical cycling in the rhizosphere having an impact on global change

Biochemical cycling in the rhizosphere having an impact on global change

Stimulation of soil nitrification and denitrification by grazing in grasslands: do changes in plant species composition matter?

Molecular Analysis of the Nitrate-Reducing Community from Unplanted and Maize-Planted Soils

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