•We detected two pathways through which glyphosate can affect grassland mycorrhiza.•Application on the soil, even at low doses, reduced directly spore viability.•Arbuscules were more affected ...indirectly, when glyphosate was applied to plant tissue.•Mycorrhizal root colonization was similarly reduced by both pathways.•Glyphosate application affects AMF functionality regardless of the pathway involved.
Glyphosate is a systemic non-selective herbicide, the most widely used in the world. Alongside with its use in agricultural and forestry systems, this herbicide is used in grasslands in late summer with the aim of promoting winter species with the consequent increase in stocking rate. However, its effects on non-target organisms, such as arbuscular mycorrhizal fungi (AMF), are unclear. Arbuscular mycorrhizal fungi (AMF) colonize the root of more than 80% of terrestrial plants, improving their growth and survival, and therefore playing a key role in ecosystem structure and function. The aim of this work was to investigate the possible pathways through which glyphosate application affects AMF spores viability and root colonization in grassland communities. Our hypothesis is that glyphosate application can damage AMF directly (through contact with spores and external hyphae) or indirectly through the changes it generates on host plants. The experiment had a factorial array with three factors: (1) plant species, at two levels (Paspalum dilatatum and Lotus tenuis), (2) doses of glyphosate, at three levels (0lha−1, 0.8lha−1 and 3lha −1), and (3) application site, at two levels: soil (direct pathway) and plant foliage (indirect pathway). Spore viability was reduced even under the lowest glyphosate rate, but only when it was applied on the soil. Total root colonization for both species was similarly decreased when glyphosate was applied to plant foliage or on soil, with no difference between 0.8 and 3lha−1. The number of arbuscules was 20% lower when glyphosate was applied on plant foliage, than when it was applied on the soil. Our findings illustrate that glyphosate application negatively affects AMF functionality in grasslands, due to different causes depending on the herbicide application site. While, under field conditions, the occurrence of direct and/or indirect pathways will depend on the plant cover at the time of glyphosate application, the consequences of this practice on the plant community structure will vary with the mycorrhizal dependence of the species composition regardless of the pathway involved.
Silicon-based anodes are extensively studied as an alternative to graphite for lithium ion batteries. However, silicon particles suffer larges changes in their volume (about 280%) during cycling, ...which lead to particles cracking and breakage of the solid electrolyte interphase. This process induces continuous irreversible electrolyte decomposition that strongly reduces the battery life. In this research work, different silicon@graphite anodes have been prepared through a facile and scalable ball milling synthesis and have been tested in lithium batteries. The morphology and structure of the different samples have been studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and scanning and transmission electron microscopy. We show how the incorporation of an organic solvent in the synthesis procedure prevents particles agglomeration and leads to a suitable distribution of particles and intimate contact between them. Moreover, the importance of the microstructure of the obtained silicon@graphite electrodes is pointed out. The silicon@graphite anode resulted from the wet ball milling route, which presents capacity values of 850 mA h/g and excellent capacity retention at high current density (≈800 mA h/g at 5 A/g).
•Soil AMF communities differed according to local conditions and the legacy of past land uses.•Soybean influenced the structure of root-colonising AMF communities.•Soils exhibited a high abundance of ...Gigasporaceae, but roots were predominantly colonized by Glomeraceae.
Arbuscular mycorrhizal fungi (AMF) are a key component of soil microbiota in natural and anthropogenic ecosystems. Even though soil type and climate conditioned land uses in the past, soybean cultivation has overrode such limitations and replaced the earlier diverse agro- and natural ecosystems in many countries of South America. We investigated whether actual diversity patterns of local AMF communities were determined by previous land uses and their intrinsic environmental conditions. We sequenced AMF DNA from root and soil samples collected from current soybean fields with three historical land use situations (HLU): agricultural fields, livestock farming and forest sites. We detected overall high AMF richness: 87 virtual taxa (VT) in soil and 69 VT in soybean roots. Mean number of VT per sample ranged from 8.1 to 19.2; it was not affected by HLU nor type of sample, but correlated with soil texture, pH, and plant density. Conversely, AMF community composition did significantly diverge among HLU and type of sample. A distinctive community composition was observed in roots of historical agricultural fields which differed from any other soil and root sample evaluated in this study. We attribute this finding to variations in the abundance pattern of predominant AMF taxa (Glomeraceae and Gigasporaceae). Our results indicate that soybean cultivation supports relatively high AMF diversity, with apparent legacies from earlier management and natural habitats in the composition of resident AMF communities.
A veritable calcium-ion battery using CaCo2O4 (s.g. P2/m) as a positive electrode, V2O5 (s.g. Pmmn) as a negative electrode and calcium perchlorate in acetonitrile as electrolyte solution has been ...evaluated for the first time. The electrochemical tests, XRD results and X-ray photoelectron spectra confirm that the calcium ion can be firstly removed from CaCo2O4 and then reintercalated, and this material can be an interesting candidate for developing non-aqueous calcium-ion batteries.
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•Calcium ions were firstly removed from CaCo2O4 and then re-intercalated.•The prepared electrode opens the possibility to develop a calcium-ion battery based on two intercalation compounds.•A new phase is formed for calcium extraction beyond Ca0.6Co2O4.
Fall armyworm (FAW),
Spodoptera frugiperda
, is a migratory polyphagous pest that causes major damage to economically important cultivated grasses, such as corn. Native to the neotropics in America ...but recently reported as an invasive pest in Africa and Asia, FAW imposes a serious threat to food security and sustainable crop productivity due to lack of effective management. In this study, the introduction of entomopathogenic fungi as endophytes was explored as an alternative more sustainable management strategy against FAW in corn. The study determined (1) the effect of isolates and inoculation methods on the ability of entomopathogenic fungi to colonize corn plants, and (2) the effect of colonized plants on
S. frugiperda
survival, development, reproduction, and food preference
.
Although all tested isolates (twelve of
Beauveria bassiana
and one each of
Metarhizium anisopliae
and
Metarhizium robertsii
) colonized inoculated plants, there was a highly significant interaction between isolates and inoculation methods. Highest plant colonization was obtained by
Beauveria bassiana
isolate (LPSc 1098) using foliar spray. Endophytic
B. bassiana
caused significant reductions in larval and pupal survival, length of different developmental stages, total
S. frugiperda
lifespan, and leaf area consumed by third instar larvae. Plant colonization also significantly reduced female longevity, fecundity, and fertility. This is the first report for the negative effects of endophytic
B. bassiana
on
S. frugiperda
growth, reproduction, and food preference. Our results highlight the promising potential of incorporating entomopathogenic fungi as endophytes in integrated pest management practices to protect corn against FAW if their efficacy is also confirmed under field conditions.
► Glyphosate impact on AMF spore viability and root-colonization ability were examined. ► Spore viability was significantly reduced, even at the lowest dose assessed. ► Total root colonization and ...arbuscules were also negatively affected by glyphosate. ► These effects may lead to changes in plant community.
Glyphosate is the most widely used herbicide in the world, but its effects on non-target organisms, such as arbuscular mycorrhizal fungi (AMF), are unclear. No studies have been found that made reference to effects of glyphosate on AMF spore viability despite its importance as a source of propagules for the perpetuation and spread of AMF in the system. The objective of this study was to evaluate the effect of glyphosate application on AMF spore viability, and their ability to colonize roots. Soil samples were collected from a grassland area located in the Flooding Pampa region (Argentina). We evaluated three herbicide rates: 0, 0.26 and 1× recommended field rate, 10 and 30 days after application. Part of the soil from each tray was used to estimate the spore viability, and the remainder was used as substrate for growing Lolium multiflorum Lam. One month after sowing, total root colonization and percentage of arbuscules and vesicles were determined. The spore viability in herbicide untreated soils was between 5.8- and 7.7-fold higher than in treated soils. This reduction was detected even when the lower rate was applied. Root colonization was significantly lower in plants grown in glyphosate treated soil than in untreated ones. A decrease in arbuscular colonization (but not in vesicles) was found in plants grown in soils treated with the highest herbicide rate. That would indicate that symbiosis functionality was affected, given that arbuscules are the main site for host–fungus nutrient exchange. The results indicate that soil residence time of glyphosate and/or its degradation products was enough to reduce AMF spore viability and their ability to colonize roots. This decrease in propagules viability may affect plant diversity, taking into account the different degrees of mycorrhizal dependency between plant species that may coexist in grassland communities.
Climate change, the shortage of fertilizers and reduced land for cultivation have drawn attention to the potential aid provided by soil-borne organisms. Arbuscular mycorrhizal fungi (AMF) offer a ...wide range of ecosystem benefits and hence, understanding the mechanisms that control AMF occurrence and maintenance is essential for resilient crop production. We conducted a survey of 123 soybean fields located across a 75,000-km
2
area of Argentina to explore AMF community composition and to quantify the impact of soil, climate, and geographical distance on these key soil organisms. First, based upon morphological identification of spores, we compiled a list of the AMF species found in the studied area and identified
Acaulospora scrobiculata
and
Glomus fuegianum
as the most frequent species.
G. fuegianum
abundance was negatively correlated with precipitation seasonality and positively correlated with mean annual precipitation as well as mycorrhizal colonisation of soybean roots. Second, we observed that species richness was negatively correlated with soil P availability (Bray I), clay content and mean annual precipitation. Finally, based on partitioning variation analysis, we found that AMF exhibited spatial patterning at a broad scale. Therefore, we infer that geographical distance was positively associated with spore community composition heterogeneity across the region. Nevertheless, we highlight the importance of precipitation sensitivity of frequent species, overall AMF richness and community composition, revealing a crucial challenge to forthcoming agriculture considering an expected change in global climate patterns.
Recent improvements of sodium ion batteries have been achieved by the use of graphitic carbon as an anode and glyme-based electrolytes. In this work, expanded graphites are prepared by thermal ...expansion, Broddie and Hummer's modified methods. Their structural, morphological and electrochemical properties are compared with those of the original natural graphite. XRD patterns, XPS and Raman spectra corroborate the presence of graphite oxide intermediates and reveal different reduced forms of expanded graphite which can affect the sodium insertion properties. The use of sodium triflate in diglyme enhanced the electrochemical performance in terms of delivering a flat plateau at ca. 0.65 and 0.55 V in discharge/charge cycles. The thermally expanded graphite increased the capacity and efficiency from 100 to 115 mA h g−1 and from 93 to 96% over 100 cycles when cycled at C rate as compared to natural graphite. Ex-situ XRD patterns reveal the presence of new set of reflections ascribable to sodium ordering in different stages as evidenced by the calculated Patterson diagrams. The new results described here would account for development of carbon-based material and their prospects and challenges for sodium ion battery anodes.
The use of Mg in rechargeable batteries can be competitive with Li in terms of economy, safety, environment and capacity. In contrast to lithium and sodium, the compounds with NASICON-type structure ...have received little attention as hosts for reversible magnesium insertion. The selection of the electrolyte solution and voltage window seems to be crucial for controlling sodium/magnesium (de)insertion. Here, Na3V2(PO4)3 (NVP) has been tested as a positive electrode vs. Mg metal with 0.5M magnesium bis(trifluoromethanesulfonimide) in 1,2-dimethoxyethane as electrolyte solution, and the mechanism of the charge/discharge process has been studied. In magnesium cell, firstly sodium is partially deinserted from the framework of NVP up to ca. Na1.3V2(PO4)3 through a single voltage-plateau at 1.7V, the cell of the crystal lattice is contracted, and a magnesium-sodium hybrid electrolyte is formed in situ. Secondly, sodium and magnesium are inserted through two consecutive voltage-plateaus at 1.6 and 1.2V, respectively, while the main framework is preserved and the lattice is expanded. With further charge-discharge cycling, only one discharge plateau is observed at 1.2V due to insertion of magnesium. If sodium ions are removed from the electrolyte solution after the first charge, only magnesium is inserted in the NASICON-type framework during the discharge. The electrochemical behavior of this material as electrode in magnesium battery is very promising, providing a reversible capacity of ca. 60mAhg−1 after 100 cycles.
Lithium manganese‐rich layered oxides are promising cathode materials for lithium‐ion batteries due to their high discharge capacity, but they suffer from capacity fading and poor rate performance. ...Herein we report on the physicochemical and electrochemical properties of Li1.15Mn0.7Ni0.2Co0.1O2 synthesized via a sol gel method, and study the effect of copper doping on the resulting materials. Electrochemical testing at 1 C revealed 1 % Cu doping enhanced capacity retention (from 58 % to 78 %) but also decreased capacity, while in contrast 10 % Cu doping increased capacity by 21 %. Thorough characterization (including x‐ray diffraction, scanning electron microscopy, inductively coupled plasma‐optical emission spectroscopy, and electrochemical analyses such as voltage vs. capacity and dQ/dV plots) was employed to understand these results, which may be attributed to the competition of two different phenomena depending on the copper content. Consequently, this work highlights the importance of targeting bespoke stoichiometries depending on the desired electrochemical characteristics – an important point for the future design of materials for fast charging and high power applications.
Tug of War: Copper doping of lithium‐manganese rich materials was found to both decrease Ni2+ (reducing capacity) and increase interlayer distances (improving rate capability). At high rates there is tension between these two phenomena – with the degree of copper doping determining which takes precedence, and thus the resulting electrochemistry.
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