Search results for "soil"

Fluorescent pseudomonads harboring type III secretion genes are enriched in the mycorrhizosphere of Medicago truncatula

2011

Type III secretion systems (T3SSs) of Gram-negative bacteria mediate direct interactions with eukaryotic cells. Pseudomonas spp. harboring T3SS genes (T3SS+) were previously shown to be more abundant in the rhizosphere than in bulk soil. To discriminate the contribution of roots and associated arbuscular mycorrhizal fungi (AMF) on the enrichment of T3SS+ fluorescent pseudomonads in the rhizosphere of Medicago truncatula, their frequency was assessed among pseudomonads isolated from mycorrhizal and nonmycorrhizal roots and from bulk soil. T3SS genes were identified by PCR targeting a conserved hrcRST DNA fragment. Polymorphism of hrcRST in T3SS+ isolates was assessed by PCR-restriction fragm…

Chapter 4 Iron Dynamics in the Rhizosphere

2008

Abstract Iron is an essential micronutrient for most organisms due to its role in fundamental metabolic processes. In cultivated soils, soil solution iron is mostly oxidized [Fe(III) species] unless local anoxic conditions develop. The concentration of these Fe(III) species is small in soil solution due to the low solubility of ferric oxides, oxyhydroxides, and hydroxides, which is minimal at neutral and alkaline pH. In the rhizosphere, iron concentration in the soil solution is even lower because of its uptake by aerobic organisms (plants and microorganisms), leading to a high level of competition for Fe(III). In order to face iron competition, these organisms have evolved active uptake st…

atzgene expressions during atrazine degradation in the soil drilosphere

2010

One of the various ecosystemic services sustained by soil is pollutant degradation mediated by adapted soil bacteria. The pathways of atrazine biodegradation have been elucidated but in situ expression of the genes involved in atrazine degradation has yet to be demonstrated in soil. Expression of the atzA and atzD genes involved in atrazine dechlorination and s-triazine ring cleavage, respectively, was investigated during in situ degradation of atrazine in the soil drilosphere and bulked samples from two agricultural soils that differed in their ability to mineralize atrazine. Interestingly, expression of the atzA gene, although present in both soils, was not detected. Atrazine mineralizati…

SOILS AND PLANTS IN AN ANTHROPOGENIC DUMP OF THE KOKDZHON PHOSPHORITE MINE (KAZAKHSTAN)

2017

Soil development is a crucial aspect in the process of mine spoil restoration and is also critical for the establishment of the vegetation. In this short paper, we present the features of mine proto-soils (i.e. soils at the early stage of development) and the natural vegetation species colonizing mine sites in a dry arid environment of Kazakhstan characterized by surface disturbance due to mine activity to access phosphorite deposit. These disturbed soils showed morphological features very different from each other (particularly horizons depth and sequence), even if the main chemical features were quite homogeneous. This is reasonably linked to the features of the Human Transported Material…

Evaluation of geomorphometric characteristics and soil properties after a wildfire using Sentinel-2 MSI imagery for future fire-safe forest

2021

Abstract Understanding spatiotemporal geomorphological and pedological changes as a consequence of wildfires can allow stakeholders, land planners, and policymakers to design efficient fire safety-based afforestation and restoration programs of forest lands. The use of remote sensing techniques is a key tool to achieve this goal. The suitable combination of Sentinel-2 MSI data for mapping of different spectral indices related to burn severity and their relationship with other morphometric and soil properties can contribute to a better understanding of the impact of fire, and this is relevant in regions where is still scarce fire-related research such as Turkey. In this investigation, the us…

Microstructure and shear strength evolution of a lime-treated clay for use in road construction

2020

The results of a comprehensive experimental programme are presented for assessing the long-term microstructural modifications and evaluating the effects of microstructural rearrangement on the stress–strain behaviour of a lime-treated high-plasticity clay for road embankments. The stress–strain behaviour at different lime content and curing time was investigated by means of direct shear tests; microstructural analyses were carried out combining Scanning Electron Microscope observations and Mercury Intrusion Porosimetry tests. The results show that the stress–strain behaviour of treated clay is strongly dilatant with a high peak of strength, which increases with time and lime content. Furthe…

Multi-sensor spectral synergies for crop stress detection and monitoring in the optical domain: A review

2022

Snowpack concentrations and estimated fluxes of volatile organic compounds in a boreal forest

2012

Abstract. Soil provides an important source of volatile organic compounds (VOCs) to atmosphere, but in boreal forests these fluxes and their seasonal variations have not been characterized in detail. Especially wintertime fluxes are almost completely unstudied. In this study, we measured the VOC concentrations inside the snowpack in a boreal Scots pine (Pinus sylvestris L.) forest in southern Finland, using adsorbent tubes and air samplers installed permanently in the snow profile. Based on the VOC concentrations at three heights inside the snowpack, we estimated the fluxes of these gases. We measured 20 VOCs from the snowpack, monoterpenes being the most abundant group with concentrations …

Effective and environmental half-lives of radiocesium in game from Poland.

2021

For the first time changes in the 137Cs activity in game throughout Poland, including its most contaminated part known as the Opole Anomaly, were analyzed. Due to its long physical half-life, 137Cs continuously demonstrates high activity both in soil and biota. The species of game mammals, along with forest fruit and mushrooms, tend to accumulate this radionuclide, becoming one of the main sources of secondary contamination in people. In this study the 137Cs activity in roe deer, wild boar and red deer muscle tissue samples, within the years of 1986–2019, were studied. The effective and environmental half-lives were determined for each of the mentioned species for four regions including NE …

Old sleeping Sicilian beauty: seed germination in the palaeoendemic Petagnaea gussonei (Spreng.) Rauschert (Saniculoideae, Apiaceae).

2015

Petagnaea gussonei (Apiaceae) is a perennial herbaceous species endemic to northeast Sicily (Nebrodi Mountains). It is considered a remnant of the Sicilian Tertiary flora, and is endangered according to the Red List. There is no information in the literature about the germinability of its seeds, even though seed production is know to occur. The aim of this study was to obtain data to better understand seed germination of this species and its biological implications. Thus, several approaches were employed: vitality analyses, gibberellic acid supply, germination and soil microbial flora analyses via end-point and qPCR. The results suggest that seed germination occurs after ca. 1.5 years at a …