Effect of a nitrogenous nanocomposite on leaching and N content in lettuce in soil columns.

Nanofertilizers could promote nutrient efficiency with slow release compared to conventional fertilizers (CF). Most of the applied nitrogen is lost on the soil by leaching, due to the rapid release behavior of CF. Clays can function as a nanosized porous structure to retain and slowly release nutrients. The objective of this study was to evaluate a nitrogenous nanocomposite (NCN) and its effect on leaching and N content of lettuce (Lactuca sativa). The treatments applied were: 100% conventional fertilizer, 100% nitrogenous nanocomposite and the mixture in percentage of CF/NCN 25/75, 50/50, 75/25 and 25/0, 50/0 75/0% on columns of soil with lettuce for 45 days. Leachates at the end of the cycle increased in treatments with NCN. Treatments with NCN have higher N content in the leaf. In regard to biomass growth, leaf area, leaf N, drained variables, electrical conductivity and NO3- content, it was possible to show that the doses of 50 and 75% of NCN match the characteristics of the crop compared to the control, which allows us to use lower doses than those recommended with CFs.

Maize Intercropping in the Traditional "Milpa" System. Physiological, Morphological, and Agronomical Parameters under Induced Warming: Evidence of related Effect of Climate Change in San Luis Potosí (Mexico).

Warmer temperatures predicted as a result of climate change will have an impact on milpa. An experiment was carried out with induced passive heat with the objective of simulating the increase in temperature on the physiological, morphological, and yield parameters of milpa from different climates of San Luis Potosí, Mexico. Two different environments, Open-top chambers (OTC) and control, and three milpas, from warm-dry, temperate, and hot and humid climates, were studied. A total of 12 experimental units of 13.13 m2 were used in the random design, with a factorial arrangement of 2 × 3 and two replications. Abiotic variables (minimum, maximum, and mean daily temperatures and accumulated heat units) were determined and compared between the two environments and confirmed that the OTC increased the abiotic variables. The growth and development parameters increased under the warming effect. Furthermore, the milpa from hot and humid climate was the least affected. In contrast, the warming considerably delayed yield parameters. The squash suffered the most, while the bean benefited the most. The warming affected the chlorophyll fluorescence and gas exchange differently for each crop. However, at an early stage, the maximum photochemical efficiency (Fv/Fm) and non-photochemical quenching (qN) for bean and maize were reduced, while at a late stage, they were Fv/Fm, photochemical quenching (qP), and qN for maize; stomatal conductance and transpiration rate of the squash were improved under the warming treatments. In conclusion, the warming delayed the yield and photosynthetic parameters, while growth and development benefited. The milpa systems were differently affected by warming.

Biomass, chlorophyll fluorescence, and osmoregulation traits let differentiation of wild and cultivated Amaranthus under water stress.

Amaranths are recognized by their high nutritive value and their natural tolerance to environmental stresses. In this study, physiological differences in response to water stress were compared between A. hybridus, a wild species considered as weed, and A. hypochondriacus, the most cultivated species for grain production, under the hypothesis that wild species have better adaptation to stress. In both species, photosynthetic parameters, pigments, and gene expression of selected genes were assessed. Biomass, effective quantum efficiency (ΦPSII), photochemical quenching (qP), and electron transport rate (ETR) values were reduced only in A. hybridus due to water deficit. Drought stress promoted proline accumulation by twice in A. hybridus but until three times in A. hypochondriacus. In both species, drought stress reduced net assimilation rate (A), transpiration rate (E), stomatal conductance (gs), and the expression of phosphoenol pyruvate carboxylase (PEPC). While, maximum quantum efficiency (Fv/Fm), chlorophyll, betacyanins, and the expression of ribulose1-5, bisphosphate carboxylase/oxygenase large subunit (LSU) did not change when plants were subjected to water stress. Likewise, both species accumulated total phenolic compounds and Oxalyl-CoA gene was up-regulated in response to drought. Our results have shown that A. hypochondriacus, the cultivated species, exhibited better tolerance to drought than A. hybridus, the wild species, probably due to an unconsciously selected trait during the domestication process.

Plantas medicinales de los mercados de Izúcar de Matamoros y Acatlán de Osorio, Puebla / Medicinal plants of the markets of Izúcar de Matamoros and Acatlán de Osorio, Puebla

En México los mercados tradicionales son sitios que reflejan interacciones entre los hombres y las plantas, de tal forma que llegan a definir la identidad en la zona donde éstos se encuentran. El objetivo del presente estudio fue registrar la comercialización, uso, y procedencia de las plantas medicinales, así como la comparación entre los mercados de Izúcar de Matamoros y Acatlán de Osorio, en el estado de Puebla. Para cumplir con el objetivo planteado se realizaron seis visitas al mercado "Revolución" de Izúcar de Matamoros y 24 vistas al mercado "General Rafael Sánchez Taboada" de Acatlán de Osorio. Se realizaron entrevistas estructuradas donde se registraron: nombre común, uso de la planta, preparación, vía de administración, tipo de enfermedad que cura, costo por muestra, procedencia de las especies, tiempo en colectarlas; si se adquiere indirectamente, cuánto paga por cada una y como aprendió el uso de las plantas medicinales. La colecta del material botánico se llevó a cabo mediante la adquisición de muestras en estado fresco y seco, para su posterior identificación. Los resultados mostraron que en el mercado de Izúcar de Matamoros se registraron 1 133 puestos de los cuales el 0.71% lo representan los puestos de plantas medicinales; el número de especies registradas fue de 49, pertenecientes a 49 géneros y 35 familias, siendo la más sobresaliente la familia Asteraceae con 12 géneros; de las cuales 43 especies son recolectadas y 11 son cultivadas. En el mercado de Acatlán de Osorio se registraron 641 puestos, de donde el 1.71% lo conforman vendedores de plantas medicinales; el número de especies medicinales fue de 144, repartidas en 122 géneros y 71 familias. Las familias más sobresalientes fueron Asteraceae, Lamiaceae y Fabaceae, de las cuales todas las especies de plantas medicinales registradas se encontró que 61 especies son introducidas, 73 nativas y de 10 se desconoce su origen. También se registró, según las encuestas aplicadas a vendedores que 110 especies son silvestres y 33 cultivadas, todas ellas comercializadas tanto en fresco como en seco de ambos mercados. Las encuestas aplicadas demostraron que en total, en los mencionados mercados se venden plantas para curar 31 enfermedades, 25 fueron del mercado de Izúcar de Matamoros y 27 en el de Acatlán de Osorio. La parte más utilizada para curar los padecimientos son las hojas, los tallos y flores, y la forma de aplicación es oral y local. El empleo de las plantas medicinales es para curar enfermedades del aparato digestivo, circulatorio, excretor, nervioso respiratorio y de síndrome cultural. La forma de comercialización fue el manojo y el compuesto. Se concluye que ambos mercados son tradicionales y las familias de plantas comercializadas que tienen mayor importancia son Asteraceae, Lamiaceae, Fabaceae y Rutaceae.

Seed germination of Agave species as influenced by substrate water potential.

BACKGROUND: Plants of Agave spp. perform Crassulacean acid metabolism (CAM) and are highly drought-tolerant, but little is known concerning seed germination under low water availability. The aim of this study was to assess the effect of substrate water potential (ΨW) on seed germination and contrast hydrotime parameters of seven valuable and commercially-important Agave species from different geographical distributions and climatic regions of Mexico. Our hypothesis was that seed germination of Agave species is not affected by low water availability independently of seed biomass and the climate of their distribution area. RESULTS: Seed germination (at 25°C and in the dark) between 85 and 100% for all species occurred within 80-180 h at -0.03 MPa and 250-430 h at -1.0 MPa. Seed germination at -1.5 MPa declined to less than 50% (p < 0.05) for A. asperrima and A. cupreata but did not change significantly for A. americana var. marginata, A. lechuguilla and A. striata, although they showed the lowest mean base water potential (-2.01 to -2.64 MPa). Seed germination of 40% Agave species, from arid and semi-arid climates in this study, was not affected by the lower ΨW. CONCLUSION: Germination of seeds of Agave species is moderately affected by low water availability, is partially dependent of their ecological distribution, and is independent of seed mass.

Seed germination of Agave species as influenced by substrate water potential

BACKGROUND: Plants of Agave spp. perform Crassulacean acid metabolism (CAM) and are highly drought-tolerant, but little is known concerning seed germination under low water availability. The aim of this study was to assess the effect of substrate water potential (ΨW) on seed germination and contrast hydrotime parameters of seven valuable and commercially-important Agave species from different geographical distributions and climatic regions of Mexico. Our hypothesis was that seed germination of Agave species is not affected by low water availability independently of seed biomass and the climate of their distribution area. RESULTS: Seed germination (at 25°C and in the dark) between 85 and 100% for all species occurred within 80 - 180 h at -0.03 MPa and 250 - 430 h at -1.0 MPa. Seed germination at -1.5 MPa declined to less than 50% (p < 0.05) for A. asperrima and A. cupreata but did not change significantly for A. americana var. marginata, A. lechuguilla and A. striata, although they showed the lowest mean base water potential (-2.01 to -2.64 MPa). Seed germination of 40% Agave species, from arid and semi-arid climates in this study, was not affected by the lower ΨW. CONCLUSION: Germination of seeds of Agave species is moderately affected by low water availability, is partially dependent of their ecological distribution, and is independent of seed mass.

Double blind, randomized, placebo-controlled study of dexamethasone therapy for hematogenous septic arthritis in children.

BACKGROUND: Septic arthritis is associated with residual dysfunction in 10 to 25% of affected children. Concentrations of cytokines detected in synovial fluid of children with bacterial arthritis correlate with the severity of inflammation. Treatment with dexamethasone decreased cartilage degradation in experimental Haemophilus influenzae b and Staphylococcus aureus arthritis. ENDPOINTS: To decrease the number of patients with residual dysfunction of the affected joint at the end of therapy and at 6 and 12 months and to speed clinical recovery by the administration of dexamethasone. METHODS: In a double blind manner we randomly selected 123 children with suspected hematogenous bacterial arthritis to receive dexamethasone or saline for 4 days. Antibiotic therapy was tailored according to age and the recovered pathogen. RESULTS: Of the 123 children enrolled, 61 were assigned to the dexamethasone group and 62 to the placebo group. Only 50 and 50 patients in each group were evaluable. The 2 groups of patients were comparable with respect to age, sex, duration of symptoms, pathogen, affected joint and therapeutic and diagnostic procedures. Staphylococcus aureus accounted for 67% of the isolates, Haemophilus influenzae type b for 13% and Streptococcus pneumoniae for 9%. Dexamethasone therapy reduced residual dysfunction at the end of therapy, P = 0.000068; at 6 months, P = 0.00007; and at 12 months, P = 0.00053 of follow-up and shortened the duration of symptoms (P = 0.001) during the acute phase. The 26% incidence of residual dysfunction in the control patients was similar to the 25% found in other series. CONCLUSIONS: A short course of dexamethasone reduced residual joint dysfunction and shortened significantly the duration of symptoms in children with documented hematogenous septic arthritis. These results suggest that a 4-day course of low dose dexamethasone given early benefits children with hematogenous septic arthritis.

Fibrosis del cuádriceps en niños post-inyección: reporte preliminar / Fibrosis of the cuadriceps in children post-injection: preliminary report

Diez pacientes con contractura del cuádriceps unilateral fueron estudiados. Todos tenían el antecedente de inyección intramuscular en el muslo en el período postnatal. Todos fueron tratados con resección de la fibrosis, liberación o elongación. Los resultados a corto plazo (más de tres meses y menos de un año en 9 pacientes) fueron: 5 buenos (extensión de rodilla 0º y flexión más de 100º) y 4 malos (extensión 0º y flexión menos de 100º) uno tenía menos de tres meses de evolución.