Richness of earthworms in an Argiudol soil under soybean (Colonia Ensayo, Entre Ríos)

En las últimas décadas la producción agrícola experimentó una creciente demanda de insumos agroquímicos, en especial plaguicidas, con aplicación de siembra directa y reducción de rotaciones con tendencia al monocultivo soja. En este contexto, las prácticas de manejo aplicadas generan efectos en la biodiversidad del suelo. En particular, las lombrices cumplen un rol clave en las funciones ecosistémicas y responden a los cambios producidos por estas prácticas. Por lo cual constituyen un grupo muy apropiado para evaluar la calidad del suelo que habitan. El objetivo del trabajo fue evaluar la densidad y riqueza de la oligoquetofauna en un suelo bajo sistema de producción soja: rastrojo-suelo. El estudio se realizó en el campo experimental ?Dr. Ramón J. Roldan? de la FCA-UNER (Diamante, Entre Ríos) con producción de soja mediante siembra directa y aplicación de plaguicidas (tratamientos: Glifosato/barbecho, Glifosato/barbecho-postemergencia y Glifosato/barbecho-postemergencia-Cipermetrina). Se determinaron características físicas y químicas del suelo y residualidad de plaguicidas en las tres zonas: baja, media y alta, determinadas en base a la topografía del lugar. La oligoquetofauna fue muestreada antes del inicio de los tratamientos (otoño y primavera 2013) y al finalizar los mismos (otoño 2014). En los muestreos de 2013 tanto la densidad como la riqueza mostraron diferencias por estación (p<0,05), registrándose dos especies: Aporrectodea rosea y Micros-colex dubius. En otoño 2014 la densidad no mostró diferencias con la registrada en 2013, pero varió por tratamientos (p<0,05) destacándose Glifosato/barbecho con el mayor valor (140 ind.m-2). Si bien la riqueza coincidió con la de 2013, la abundancia de A. rosea fue notable-mente mayor, dominando las endogeas. Respecto a los residuos de glifosato y su metabolito AMPA hallados en este estudio, estarían afectando la abundancia y dinámica poblacional de oligoquetos.Agricultural production with the incorporation of non-tillage, developed a very important increase of agrochemical application (specially plaguicides). Earthworms play a crucial function in the soil ecosystem and are an appropiate indicator of soils quality. The aim of this work was to evaluate density and diversity of earthworms in soybean production fields. Tests were done in the experimental field “Dr. Ramón J. Roldán” of the FCA-UNER (Diamante-Entre Ríos) and consisted of the following treatments: Glyphosate/fallow; Gliphosate/fallow-postemergence and Glyphosate/fallow-postemergenceCipermetrine. In coincidence with the field topography, the physical and chemical characteristics of the samples were determined at three levels: low, medial and high. Plaguicide residues were also determined. Earthworms were determined before the beginning and end of treatments (autumn and spring 2013, autumn 2014) respectively. Samples obtained during 2013 showed significant differences (p<0.05) in density and diversity between seasons, with two species: Aporrectodea rosea and Microscolex dubius being identified. No differences in density were observed between autumn 2013 and 2014. Significant differences (p<0.05) were obtained between treatments, principally Glyphosate/fallow with the highest value (140 ind.m-2 ). A. rosea was the most abundant specie. Glyphosate residues and AMPA metabolite were found, the results suggest that play an important role in the dynamics and abundance of earthworms.Fil: Masin, Carolina Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); ArgentinaFil: Rodriguez, Alba R.. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); ArgentinaFil: Maitre, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Desarrollo Tecnológico Para la Industria Química (i); Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Cerana, Jorge. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Hernandez, Juan. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Anglada, Marta. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Elizalde, José. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; ArgentinaFil: Lallana, Maria del Carmen. Universidad Nacional de Entre Ríos. Facultad de Ciencias Agropecuarias; Argentin

Captive reptile mortality rates in the home and implications for the wildlife trade

The trade in wildlife and keeping of exotic pets is subject to varying levels of national and international regulation and is a topic often attracting controversy. Reptiles are popular exotic pets and comprise a substantial component of the live animal trade. High mortality of traded animals raises welfare concerns, and also has implications for conservation if collection from the wild is required to meet demand. Mortality of reptiles can occur at any stage of the trade chain from collector to consumer. However, there is limited information on mortality rates of reptiles across trade chains, particularly amongst final consumers in the home. We investigated mortality rates of reptiles amongst consumers using a specialised technique for asking sensitive questions, additive Randomised Response Technique (aRRT), as well as direct questioning (DQ). Overall, 3.6% of snakes, chelonians and lizards died within one year of acquisition. Boas and pythons had the lowest reported mortality rates of 1.9% and chameleons had the highest at 28.2%. More than 97% of snakes, 87% of lizards and 69% of chelonians acquired by respondents over five years were reported to be captive bred and results suggest that mortality rates may be lowest for captive bred individuals. Estimates of mortality from aRRT and DQ did not differ significantly which is in line with our findings that respondents did not find questions about reptile mortality to be sensitive. This research suggests that captive reptile mortality in the home is rather low, and identifies those taxa where further effort could be made to reduce mortality rate

Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors.

Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7-/-) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7-/- mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7-/- mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7-/- mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7-/- mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7-/- mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7-/- mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7-/- mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus

Effect of 20-years crop rotation and different strategies of fertilization on weed seedbank

Crop rotation is thought to reduce weed density and maintain species diversity, preventing the domination of few competitive weeds. In this work rotations of 1, 2, 4 and 6 years length have been compared in a long-term experiment since 1976. In order to detect the effect of rotation length and fertilization on weed community evolution, a specific study was performed on weed seedbank with soil sampling in 1993 and 2012.Results: show that weed density was not affected by rotation length or fertilization type or rate, and that about 98% of weed species were indifferent to the factors applied. The dominance of Portulaca oleracea and increment of a few grass weeds were consequences of an inadequate management of late emergence and post-harvest weeds. Furthermore, no significant changes in the distribution of seeds longevity groups occurred in the seed-bank from 1993 to 2012. In cropping systems where herbicides are used according to best practices or to In-tegrated Weed Management principles, the effect of rotation on weeds is hard to detect even in long-term experiments. For this, the effect of herbicides must be included in a more general theory of rotational effects

Short-term responses to salinity of soybean and chenopodium album grown in single and mixed-species hydroponic systems

Weeds account for losses in crop yields, and this event might be exacerbated by salinity. Therefore, we investigated the responses of Chenopodium album L. and soybean (Glycine max (L.) Merr.) to salt stress, as well as interferences between species. Ten-day old plants were grown for 1 week in a single- or mixed-species set-up, either with or without 100 mM of NaCl. C. album reduced the biomass of soybean similarly to salt stress, while its growth was unaffected under any condition. C. album decreased the crop protein content when salinity was applied. This effect was ascribed to altered protein metabolism and/or N usage to produce other N metabolites, including osmolytes. The two species did not reciprocally affect the capacity to accumulate Na+, but the weed contained two-fold more Na+ in the leaves. Elevated initial K+ concentration and high K+ delivery to the shoot likely explained the better acclimation of C. album to salinity. C. album produced more phenolics and proline and exhibited greater antioxidant activity, but low lipid peroxidation, in the mixed set-up under salinity. Thus, it is possible that the weed could become more resilient to salinity when growing in a soybean field. In the long term, this might cause significant losses in soybean productivity as expected by the dramatic decline in crop protein content

Morphology, geometric morphometrics, and taxonomy in relict deciduous oaks woods in northern Italy

Abstract: The Euganean Hills are a well-known refugee site for thermophilous woody flora in northern Italy. Among the species recorded here, there is Quercus dalechampii. The Euganean Hills are the only northern Italy site where the occurrence of this oak species is considered. The aim of this paper was to verify the presence of Q. dalechampii in the study area and to select possible diagnostic morphological traits that are usable to distinguish it from Q. petraea and Q. pubescens. Forest stands dominated by Q. petraea, Q. pubescens, and the presumed Q. dalechampii were sampled using the phytosociological approach to highlight their ecological features. Leaf and fruit material from 104 oak individuals was analysed from a macro-morphological and micro-morphological point of view. Leaf shape was also analysed using the geometric morphometric approach. All multivariate analysis procedures applied on the matrices of leaf and fruit traits highlighted two main clusters of morphological diversity. One was restricted to Q. pubescens individuals, and the other one was a mix of Q. petraea and presumed Q. dalechampii individuals. According to the twig and leaf trichome traits, all presumed Q. dalechampii individuals were classified as belonging to the Q. petraea collective group. Morphological differences between Q. petraea and presumed Q. dalechampii were considered not significant. In conclusion, the occurrence of a third oak species, in addition to Q. petraea and Q. pubescens, was not confirmed for the study area by the results of this paper. Graphic abstract: [Figure not available: see fulltext.]

Low energy inelastic electron scattering from carbon monoxide: I. Excitation of the a³ Π, a'³ Σ ⁺ and A¹ Π electronic states

Differential scattering cross sections for electron excitation of the three lowest excited electron states of carbon monoxide are obtained experimentally using low-energy electron energy-loss spectroscopy and theoretically using the R-matrix method. The incident electron energies range from near-threshold of 6.3 eV to 20 eV. Experimental scattering angles range from 20° to 120°. The normalization of the experimental cross sections is made to available experimental elastic scattering data (Gibson et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 3197). The R-matrix calculations use three distinct close-coupling models and their results are compared to available experimental and theoretical cross sections. The overall comparison leads to significantly improved description of the excitation cross sections for this target