Effect of sewage sludge or compost on the sorption and distribution of cooper and cadmium in soil

The application of biosolids such as sewage sludge is a concern, because of the potential release of toxic metals after decomposition of the organic matter. The effect of application of sewage sludge (Sw) and compost (C) to the soil (S) on the Cu and Cd sorption, distribution and the quality of the dissolved organic matter (DOM) in the soil, was investigated under controlled conditions. Visible spectrophotometry, infrared spectroscopy, sorption isotherms (simple and competitive sorption systems), and sequential extraction methods were used. The E4/E6 (k at 465 and 665 nm) ratio and the infrared spectra (IR) of DOM showed an aromatic behaviour in compost–soil (C–S); in contrast sewage sludge–soil (Sw–S) showed an aliphatic behaviour. Application of either Sw or C increased the Cu sorption capacity of soil. The Cd sorption decreased only in soil with a competitive metal system. The availability of Cu was low due to its occurrence in the acid soluble fraction (F3). The Cu concentration varied in accordance with the amounts of Cu added. The highest Cd concentration was found in the exchangeable fraction (F2). The Sw and C applications did not increase the Cd availability in the soil

Effects of sewage sludge and sewage sludge compost amendment on soil properties and zea mays l. plants (heavy metals, quality and productivity)

The use of organic wastes in agriculture can improve the soil's productive capacity, and physical and chemical characteristics. This study evaluated the effects of sewage sludge, sewage sludge compost and inorganic fertilizer applications on nickel, copper and zinc contents in soil and corn grains (Zea mays L); maize productivity, and grain nutritional quality. Sewage sludge and sewage sludge compost at 18 Mg ha¿1 and a mineral fertilizer (N-P-K) with a formulation of 150-75-30 were applied. Significant differences were observed in organic matter, phosphorus and zinc content between sewage sludge-soil and compost-soil, and inorganic fertilizer-soil (P < 0.05). Copper concentration was significantly high in compost-soil (P < 0.05). Productivity in compost-soil and sewage sludge-soil mixtures was higher than in inorganic fertilizer-soil. Grain quality, measured by relative percentage of starch, total nitrogen, protein, acid detergent fiber and neutral detergent fiber were adequate for human consumption. Application of sewage sludge or compost did not increase heavy metal concentrations in grain with respect to inorganic fertilizer-soil

Extrafloral nectaries in Opuntia robusta

Descubrimos la existencia de nectáreos extraflorales en Opuntia robustaTo our knowledge, there are no studies about the structure and ecological function of extra- floral nectaries (EFNs) in Opuntia robusta. This is the first description of EFNs in O. robusta, where young spines have an interesting structure and a secreting function, which are differ- ent from EFNs described in other Cactaceae species. We used light, scanning-electron, and transmission-electron microscopy to examine morphology, anatomy, and ultrastructure of the secretory spines in areoles in female and hermaphrodite individuals of O. robusta. Young cladodes develop areoles with modified and secretory spines as EFNs only active during the early growth phase. EFNs are non-vascularized structures, with no stomata, that consist of a basal meristematic tissue, a middle elongation region, and an apical secretory cone formed by large globular epidermal cells, containing nectar and medullar elongated cells. We observed the presence of Golgi apparatus, vesicles and plastids in the medullar and sup-epidermal cells of the spine. We propose that the nectar is stored in the globular cells at the apex of the spine and secreted by breaking through the globular cells or by pores. We recorded a more frequent presence of ants on younger cladode sprouts producing young secreting spines: this result is parallel with the predictions of Optimal Defense Hypothesis, which states that younger plant organs should be better defended than older ones because their loss produces a higher fitness impairment. Although Diaz-Castelazo’s hypothesis states that a more complex structure of EFNs correlates with their lower among-organs dispersion, comparing to less complex EFNs, non-vascularized structure of EFNs in O. robusta is not associated with their higher among-organs dispersion likened to O. stricta, which produces vascularized EFNs. We provide evidence that this characteristic is not a good taxonomic fea- ture of Opuntia genus. Moreover, the comparison of EFNs of O. robusta and O. stricta sug- gests that the hypothesis of Diaz-Castelazo should be revised: it is rather a rule but not a law.CONACyT 180694/201

Biosynthesis of silver nanoparticles using chenopodium ambrosioides

ARTICULO INDEXADOBiosynthesis of silver nanoparticles (AgNPs) was achieved using extract of Chenopodium ambrosioides as a reducer and coating agent at room temperature (25∘C). Two molar solutions of AgNO3 (1 mM and 10 mM) and fie extract volumes (0.5, 1, 2, 3, and 5 mL) were used to assess quantity, shape, and size of the particles. Th UV-Vis spectra gave surface plasmon resonance at 434– 436 nm of the NPs synthesized with AgNO3 10 mM and all extract volumes tested, showing a direct relationship between extract volumes and quantity of particles formed. In contrast, the concentration of silver ions was related negatively to particle size. Th smallest (4.9 ± 3.4 nm) particles were obtained with 1 mL of extract in AgNO3 10 mM and the larger amount of particles were obtained with 2 mL and 5 mL of extract. TEM study indicated that the particles were polycrystalline and randomly oriented with a silver structure face centered cubic (fcc) and fourier transform infrared spectroscopy (FTIR) indicated that disappearance of the –OH group band aftr bioreduction evidences its role in reducing silver ions.CCIQS; “Fideicomiso Revocable y de Administracion no. 157304´ COLPOS” and the L´ınea de Investigacion Prioritaria LPI-16´ “Innovacion Tecnol´ ogica” at the “Colegio de Postgraduados´ COLPOS

Bulletin of British earthquakes 2015

"To our knowledge, there are no studies about the structure and ecological function of extrafloral nectaries (EFNs) in Opuntia robusta. This is the first description of EFNs in O. robusta, where young spines have an interesting structure and a secreting function, which are different from EFNs described in other Cactaceae species. We used light, scanning-electron, and transmission-electron microscopy to examine morphology, anatomy, and ultrastructure of the secretory spines in areoles in female and hermaphrodite individuals of O. robusta. Young cladodes develop areoles with modified and secretory spines as EFNs only active during the early growth phase. EFNs are non-vascularized structures, with no stomata, that consist of a basal meristematic tissue, a middle elongation region, and an apical secretory cone formed by large globular epidermal cells, containing nectar and medullar elongated cells. We observed the presence of Golgi apparatus, vesicles and plastids in the medullar and sup-epidermal cells of the spine. We propose that the nectar is stored in the globular cells at the apex of the spine and secreted by breaking through the globular cells or by pores. We recorded a more frequent presence of ants on younger cladode sprouts producing young secreting spines: this result is parallel with the predictions of Optimal Defense Hypothesis, which states that younger plant organs should be better defended than older ones because their loss produces a higher fitness impairment. Although Diaz-Castelazo’s hypothesis states that a more complex structure of EFNs correlates with their lower among-organs dispersion, comparing to less complex EFNs, non-vascularized structure of EFNs in O. robusta is not associated with their higher among-organs dispersion likened to O. stricta, which produces vascularized EFNs. We provide evidence that this characteristic is not a good taxonomic feature of Opuntia genus. Moreover, the comparison of EFNs of O. robusta and O. stricta suggests that the hypothesis of Diaz-Castelazo should be revised: it is rather a rule but not a law.

Designing and evaluation of sodium selenite nanoparticles in vitro to improve selenium absorption in ruminants

Sodium selenite is used to prevent selenium deficiency known as nutritional muscular dystrophy or white muscle disease. In ruminants, selenium supplements are transformed partiality in insoluble form by ruminal microorganisms and its process decrease the selenium absorption in digestive gastrointestinal. However, the objective in this research was focused in encapsulated sodium selenite to be release into of a pH less than four, similarity to an intestinal environment. It was encapsulated by nanoprecipitation and emulsion–evaporation methods, within polymeric nanoparticles. The effect of these methods, polymer proportion (Eudragit RL and RS) and solvent (ethanol and acetone) on the physicochemical (drug entrapment, polidispersity index (PDI) and z potential) and morphological characteristics (particle morphology and particle size) were evaluated. Particle size from each nanoparticles, formulation ranged from 36.64 to 213.86 nm. Particle size, z potential and PDI increased (P ≤ 0.01) when nanoprecipitation and ethanol were used. No significant differences (P > 0.05) were observed when different polymeric proportions were used. Selenium entrapment was 26% when emulsion–evaporation method was used and 78% with nanoprecipitation. Nanoparticles produced by nanoprecipitation were spherical and had a great variation in particle size; on the other hand, nanoparticles produced by emulsion–evaporation were spherical as well as amorphous and presented a homogeneous nanopartcicle size distribution. The release of selenium from nanoparticles was higher in acid pH (less than 4), this condition may represent a better availability of the mineral in the small intestine

El CaCl2 en la vida florero de gerbera: pigmentos, fenoles, lignina y anatomía del escapo

"Gerbera jamesonii presenta una vida f lorero corta caracterizada por el doblado del tallo floral (escapo). Con el objetivo de alargar la vida florero de gerbera se probaron tres concentraciones de CaCl2 (0.1, 0.5 y 1.0%) en las variedades Duela y Shirla

Inducción de proembriones somáticos en ave del paraíso (Strelitzia reginae Banks)

El ave del paraíso (Strelitzia reginae Banks) es una planta ornamental que por su belleza es altamente cotizada como flor de corte. Se propaga por semilla y por división de matas, aunque ambos métodos son muy lentos. La multiplicación de plantas in vitro vía embriogénesis somática, ha sido exitosamente establecida en muchas especies ornamentales. Para S. reginae no existen reportes de su propagación mediante dicho proceso ya que presenta serios problemas de oscurecimiento de los explantes cultivados. En este trabajo se estableció un procedimiento para la inducción de proembriones somáticos (PES) a partir de fragmentos (explantes) del nudo cotiledonar de plántulas de 30 d de edad. A los cinco meses de incubación, los explantes cultivados en oscuridad produjeron PES en el medio Murashige y Skoog a 100 % y 50 % de su concentración, suplementado con 2,4-D (0.5 a 2.0 mg L-1), sacarosa (30 g L-1) y carbón activado (0.1 g L-1). Los PES crecieron y formaron estructuras de 5 a 6 mm de longitud, cuyo extremo distal presentó una organización celular comparable a la de un meristemo de raíz pero sin centro quiescente. Los cortes histológicos no evidenciaron la presencia de un meristemo apical de brote, lo cual pudo haber causado que los proembriones in vitro no completaran su desarrollo