Intensive agricultural practices are responsible for soil biological degradation. By stimulating indigenous arbuscular mycorrhizal fungi (AMF), cover cropping enhances soil health and promotes ...agroecosystem sustainability. Still, the legacy effects of cover crops (CCs) and the major factors driving the AM fungal community are not well known; neither is the influence of the specific CC. This work describes a field experiment established in Central Spain to test the effect of replacing winter fallow by barley (Hordeum vulgare L.) or vetch (Vicia sativa L.) during the intercropping of maize (Zea mays L.). We examined the community composition of the AMF in the roots and rhizosphere soil associated with the subsequent cash crop after 10 years of cover cropping, using Illumina technology. The multivariate analysis showed that the AMF communities under the barley treatment differed significantly from those under fallow, whereas no legacy effect of the vetch CC was detected. Soil organic carbon, electrical conductivity, pH, Ca and microbial biomass carbon were identified as major factors shaping soil AMF communities. Specific AMF taxa were found to play a role in plant uptake of P, Fe, Zn, Mn, and Cd, which may shed light on the functionality of these taxa. In our conditions, the use of barley as a winter CC appears to be an appropriate choice with respect to promotion of AMF populations and biological activity in agricultural soils with intercropping systems. However, more research on CC species and their legacy effect on the microbial community composition and functionality are needed to guide decisions in knowledge-based agriculture.
Display omitted
•AMF communities under barley differed from those under fallow but not under vetch.•Cover crop and soil properties drive AMF community composition.•Barley was the most-suitable to promote the AMF populations and biological activity.
The main goal of this study was to assess the effect of the inoculation of four autochthonous shrub species with the arbuscular mycorrhizal (AM) fungus Rhizophagus intraradices on the rhizosphere ...bacterial community and to ascertain whether such an effect is dependent on the host plant species. Additionally, analysis of rhizosphere soil chemical and biochemical properties was performed to find relationships between them and the rhizosphere bacterial communities. Non-metric multidimensional scaling analysis and subsequent permutational multivariate analysis of variance revealed differences in bacterial community composition and structure between non-inoculated and inoculated rhizospheres. Moreover, an influence of the plant species was observed. Different bacterial groups were found to be indicator taxonomic groups of non-inoculated and inoculated rhizospheres, Gemmatimonadetes and Anaerolineaceae, respectively, being the most notable indicators. As shown by distance based redundancy analysis, the shifts in bacterial community composition and structure mediated by the inoculation with the AM fungus were mainly related to changes in plant nutrients and growth parameters, such as the shoot phosphorus content. Our findings suggest that the AM fungal inoculum was able to modify the rhizosphere bacterial community assemblage while improving the host plant performance.
Display omitted
•An AMF improved plant performance in the revegetation of a semiarid ecosystem.•AMF and plant species altered the rhizosphere bacterial community structure.•AMF-mediated bacterial community shifts were related to plant performance.•Anaerolineaceae family was an indicator of AMF-inoculated rhizospheres.
A field experiment was performed in a semi-arid Mediterranean agroecosystem to assess the influence of different management practices on the composition and diversity of the arbuscular mycorrhizal ...fungi (AMF) present in the soil. The management practices included residual herbicide use (RH), plowing (P), plowing + oats (OP), addition of oats straw mulch (OS), and a control (land abandonment) (C). An adjacent, non-cultivated area under natural vegetation was used as a standard for local, high-quality soil, and as a reference for natural plant cover (NC). After eight years of management, soil was sampled, DNA was extracted, and the AM fungal small-subunit (SSU) rRNA genes were subjected to PCR, cloning, sequencing, and phylogenetic analyses. Thirty-five different phylotypes were identified, which were grouped in five families: the Glomeraceae, Paraglomeraceae, Diversisporaceae, Ambisporaceae, and Claroideoglomeraceae. The different agricultural management practices assayed affected both the community composition and the phylotypes richness of the AMF recovered from the soil, there being four clearly-different AMF communities (C together with OS, P together with OP, RH, and NC). The diversity of the AMF was positively correlated with soil parameters related with biological activity. The treatments involving plowing greatly altered the composition of the AMF communities but did not affect significantly the diversity and richness of the AMF with respect to treatment NC; however, the addition of herbicide gave the lowest AMF diversity found in this study. The treatment based on the addition of oats straw appears to be the most-suitable management strategy with respect to promotion of the AMF diversity and biological activity in this soil.
•Different management practices influence the composition and diversity of AMF.•Oats straw addition was the most-suitable to promote the highest AMF diversity.•AMF diversity was correlated with soil parameters related with biological activity.
A mesocosm experiment was conducted to investigate whether communities of arbuscular mycorrhizal (AM) fungi associated with roots of native (Piptatherum miliaceum, Retama sphaerocarpa, Psoralea ...bituminosa, Coronilla juncea, and Anthyllis cytisoides) and for comparison (Lolium perenne) seedlings in a heavy-metal-contaminated, semiarid soil were affected by the application of composted sugar beet waste. We also investigated whether there were relation between AMF diversity and metal concentration (Al, Cd, Cu, Fe, Mn, Pb and Zn) and total P in shoot as well as some soil parameters (total organic carbon and total N) when the SB waste was added to the soil. We analyzed a portion of approximately 795 base pairs of the small-subunit (SSU) rRNA gene by nested PCR, cloning, sequencing, and phylogenetic analyses. Twelve different AMF sequence types were distinguished: seven of these belonged to Glomus group A, one to Glomus group B, one to Diversispora, one to Archaeospora, and two to Paraglomus. The AM fungal populations colonizing roots in a heavy-metal-polluted soil were quite dependent on the host plant, the highest diversity values being obtained in authochtonous plants recognized as metallophytes, such as P. bituminosa, and in an allochtonous, invasive species (L. perenne). No significant correlation was found between AMF diversity and plant metal concentration and soil parameters. Excepting P. bituminosa, when sugar beet waste was added to soil, the populations of AM fungi in roots increased and the shoot metal concentrations decreased in all host plant species studied. Therefore, the addition of sugar beet waste can be considered a good strategy for the remediation and/or phytostabilization of mine tailing sites.
► AMF populations colonizing roots in polluted soil depended on the host plant. ► Application of organic amendment decreases the shoot metal concentrations. ► Sugar beet waste influenced the diversity and composition of the community of AMF. ► Addition of sugar beet waste considered strategy for remediation of mine tailing sites.
The effect of the type of fluid flow velocity profile on the motion of a Brownian particle in a circular tube has been studied using a Monte Carlo technique to simulate particle trajectories. Three ...types of fluid flow were studied: uniform (UF), parabolic (PF), and an initial uniform flow which evolves and may eventually attain the parabolic velocity profile, i.e. transient flow (TF). For UF and PF, radial and axial particle diffusion were simultaneously considered in some cases; for TF, where fluid dynamics equations had to be solved in addition to the Monte Carlo simulations, axial diffusion was neglected for fluid and particles, so that calculations had to be restricted to tube aspect ratios (radius/length) smaller than 0.1, a common scenario in most practical aerosol applications. A first series of simulations were performed to determine the overall particle penetration through the tube. For fixed tube geometry and particle diffusion coefficient, penetration in TF lied between those in PF (highest) and UF (lowest), in such a manner that, for a given value of the diffusion coefficient, the larger the degree of flow development (i.e., the smaller the values of the tube aspect ratio and the Reynolds number), the larger the penetration. These findings are coherent with those found in a former investigation dealing with the particle residence time in the tube. In a second series of simulation runs, calculations were done for selected initial locations of the particle within the tube entrance cross section, to examine the effect that the proximity of the particle starting position to the tube wall or to the tube axis has on variables such as penetration, mean first hitting time and length, mean first exit time, and mean axial velocity of lost and survived particles. When the fluid flow is not uniform but varies from place to place, the mean particle axial velocity is larger than that of the fluid. This counterintuitive fundamental result allows interpretation of the trends observed in penetration and residence time.
•Brownian particle mean axial velocity in a tube is greater than that of the fluid in non-uniform flow.•Aerosol residence time and penetration in transient flow lie between those for uniform and parabolic flow.•Dependence of first passage times on the starting point of the particle trajectory governs the overall aerosol behavior.
In this 9-year manipulative field experiment, we examined the impacts of experimental warming (2 °C, W), rainfall reduction (30 % decrease in annual rainfall, RR), and their combination (W + RR) on ...soil microbial communities and native vegetation in a semi-arid shrubland in south-eastern Spain. Warming had strong negative effects on plant performance across five coexisting native shrub species, consistently reducing their aboveground biomass growth and long-term survival. The impacts of rainfall reduction on plant growth and survival were species-specific and more variable. Warming strongly altered the soil microbial community alpha-diversity and changed the co-occurrence network structure. The relative abundance of symbiotic arbuscular mycorrhizal fungi (AMF) increased under W and W + RR, which could help buffer the direct negative impacts of climate change on their host plants nutrition and enhance their resistance to heat and drought stress. Indicator microbial taxa analyses evidenced that the marked sequence abundance of many plant pathogenic fungi, such as Phaeoacremonium, Cyberlindnera, Acremonium, Occultifur, Neodevriesia and Stagonosporopsis, increased significantly in the W and W + RR treatments. Moreover, the relative abundance of fungal animal pathogens and mycoparasites in soil also increased significantly under climate warming. Our findings indicate that warmer and drier conditions sustained over several years can alter the soil microbial community structure, composition, and network topology. The projected warmer and drier climate favours pathogenic fungi, which could offset the benefits of increased AMF abundance under warming and further aggravate the severe detrimental impacts of increased abiotic stress on native vegetation performance and ecosystem services in drylands.
Display omitted
•Warming reduced shrub biomass growth and long-term survival.•Warming altered the microbial communities, increasing their diversity and richness.•Both warming and rainfall reduction increased arbuscular mycorrhizal abundance.•Pathogenic indicators were identified in the rhizosphere under warming conditions.•The topology of co-occurrence networks was strongly affected by warming.
To analyze the clinical and psychometric properties of observational gait assessment scales in people with neurological disorders.
The databases used for the literature search were MEDLINE, the ...Cochrane Central Register of Controlled Trial, Web of Science, and the Cumulative Index to Nursing and Allied Health. The search was conducted between September 15 and November 30, 2014.
Studies that investigate and validate observational gait assessment scales in people with central nervous system disorders.
General characteristics of the studies, including number of patients and observational gait assessment scales analyzed and their psychometric properties, were extracted.
After the literature search, 15 articles were included in this review. Seven of the 15 articles studied the Tinetti Gait Scale (TGS), 2 studied the Rivermead Visual Gait Assessment (RVGA), 1 studied the Gait Assessment and Intervention Tool (G.A.I.T.), 3 studied the Wisconsin Gait Scale, and one of them compared the TGS and the G.A.I.T.
The scale that appears to be the most suitable for both clinical practice and research is the G.A.I.T. because it has shown to be valid, reliable, and sensitive to change, homogeneous, and comprehensive, containing a large number of items that assess most components of the gait pattern. The RVGA was studied in those with diverse neurological disorders, including multiple sclerosis. For those with Parkinson disease, the TGS showed sensitivity and the Tinetti Performance-Oriented Mobility Assessment (POMA) showed predictive capability for falls and mortality as well as intra- and interrater reliability. The Tinetti POMA was also studied in those with normal pressure hydrocephalus, showing sensitivity and in those with Huntington disease, showing reliability and validity. More research is needed to more comprehensively analyze the psychometric properties of the RVGA, Wisconsin Gait Scale, TGS, and G.A.I.T. in patients with diverse neurological disorders, other than stroke.
It is suggested that the diversity of arbuscular mycorrhizal fungi (AMF) and their association with distinct plants species are crucial in the early stages of revegetation procedures since the AMF ...roots colonisation plays an important role improving plant establishment and growth. We carried out a study where we analyse the AMF community composition in the roots of
Ephedra fragilis,
Rhamnus lycioides,
Pistacia lentiscus and
Retama sphaerocarpa fourteen months after revegetation in a Mediterranean semiarid degraded area of southeast Spain in order to verify whether different plant species can variably promote the diversity of AM fungi in their rhizospheres after planted. We analysed a portion of approximately 795 bases pairs of the small-subunit ribosomal DNA by means of nested PCR, cloning, sequencing and phylogenetic analyses. Eight fungal sequence types belonging to
Glomus group A and B and to the genus
Paraglomus were identified. The different plant species had different AM fungal community composition. Thus,
R. lycioides harboured the highest number of four fungal sequence types while from
E. fragilis only two types could be characterized that were specific for this plant species.
P. lentiscus and
R. sphaerocarpa harboured each one three sequence types and two of them were shared. All AMF sequence types were found in the natural soil. These results show that one effective way of restoring degraded lands is to increase the number of plant species used, which would increase the AMF diversity in the soil and thus the below-ground, positive interactions.
► AMF diversity is strongly dependent on the host plant. ► AMF plays an essential role in the early stages of the plant. ► One effective tool to restore degraded lands is to increase the plant species.
There is evidence for the influence of socioeconomic status (SES) on healthy behaviours but the effect of social mobility (SM) is not yet well known. This study aims to analyse the influence of ...origin and destination SES (O-SES and D-SES) and SM on healthy behaviours and co-occurrence, from an integrated gender and age perspective. Data were obtained from the controls of MCC-Spain between 2008-2013 (3,606 participants). Healthy behaviours considered: healthy diet, moderate alcohol consumption, non-smoking and physical activity. SM was categorized as stable high, upward, stable medium, downward or stable low. Binary and multinomial logistic regression models were adjusted. Those aged <65, with a low O-SES, D-SES and stable low SM are less likely to have healthy behaviours in the case of both women (physically active: OR = 0.65 CI = 0.45-0.94, OR = 0.71 CI = 0.52-0.98, OR = 0.61 CI = 0.41-0.91) and men (non-smokers: OR = 0.44 CI = 0.26-0.76, OR = 0.54 CI = 0.35-0.83, OR = 0.41 CI 0.24-0.72; physically active: OR = 0.57 CI = 0.35-0.92, OR = 0.64 CI = 0.44-0.95, OR = 0.53 CI = 0.23-0.87). However, for those aged ≥65, this probability is higher in women with a low O-SES and D-SES (non-smoker: OR = 8.09 CI = 4.18-15.67, OR = 4.14 CI = 2.28-7.52; moderate alcohol consumption: OR = 3.00 CI = 1.45-6.24, OR = 2.83 CI = 1.49-5.37) and in men with a stable low SM (physically active: OR = 1.52 CI = 1.02-1.26). In the case of men, the same behaviour pattern is observed in those with a low O-SES as those with upward mobility, with a higher probability of co-occurring behaviours (three-to-four behaviours: OR = 2.00 CI = 1.22-3.29; OR = 3.13 CI = 1.31-7.48). The relationship of O-SES, D-SES and SM with healthy behaviours is complex and differs according to age and gender.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
