Influence of carbonization temperature on the anatomical characteristics of Ocotea porosa (Nees & Mart. Ex Nees) L. Barroso

The carbonization process causes different physical and chemical transformations to wood, affecting the final properties of the charcoal produced. In Brazil, the cutting and use of Ocotea porosa (Nees & Mart. Ex Nees) L. Barroso is legally prohibited. But the difficulty of identifying the species used to produce charcoal hinders enforcement efforts to protect this and other endangered tree species. The aim of this work was to characterize the anatomy of charcoal made from O. porosa at different temperatures to provide information to facilitate differentiation of the species by the authorities in charge of suppressing illegal commerce. Samples were carbonized by direct heating and final temperatures of 350, 450 and 650 °C, besides a group under a ramp heating regime also with a final temperature of 450 °C. The qualitative characteristics of the O. porosa wood were preserved at the carbonization temperatures studied permitting the use of its anatomical structures for identification of carbonized wood to support control of the illegal trade in charcoal of this species.     

Properties and Microstructure of Plasticized Zein Films

A new method for preparation of zein films involving plasticization of zein with oleic acid to form an intermediate moldable resin was presented. The resin was stretched over rigid frames to form thin membranes that were set in flexible films. The objective of the study was to investigate the effect of film preparation method on film properties. Tensile properties, microstructure, and thermal behavior of zein films plasticized with oleic acid were investigated for films prepared by conventional casting from ethanol solutions and by stretching of plasticized resins. Cast films were stiff and brittle, whereas resin films showed more flexibility and toughness. Differential scanning calorimetry thermograms of cast films indicated phase separations were generated when heated that were not observed for resin films. Microstructure images showed a higher degree of structure development and orientation in resin than in cast films. Glass-transition temperatures of resin films were measured at -94 and 104.4° C, indicating the film remained flexible through a wide temperature range. Resin film flexibility and toughness were attributed to effective plasticization that led to fiber formation and orientation.     

Isotopic compositions of cometary matter returned by Stardust

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single (17)O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is (16)O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.     

A simple and rapid spectrophotometric method to quantify the herbicide glyphosate in aqueous media. Application to adsorption isotherms on soils and goethite

This article presents a simple, fast and low cost UV–vis spectrophotometric method to quantify glyphosate. This method can be used to perform adsorption isotherms on soils and metal oxides. It comprises a derivatization step and further measurement of the absorbance at 265 nm. The trueness of the results is validated using Ultra Performance Liquid Chromatography with tandem mass spectrometry detection (UPLC-MS/MS) as a reference method. The proposed spectrophotometric method is able to quantify glyphosate in the concentration range from 0.084 to 21.8 mg L^? 1. This range is suitable to construct reliable adsorption isotherms. Examples of adsorption isotherms on goethite at pH 4.5 and a soil sample at pH 4.5, 6.0 and 8.0 are given. Interferences caused by dissolved organic matter can be corrected at least up to an organic matter concentration of 12 mg L^? 1.     

Effects of soil flooding on P transformations in soils of the Mesopotamia region,Argentina

In the Mesopotamia region (Argentina), rice is cropped on a wide range of soil types, and the response of rice to fertilizer application has been inconsistent even in soils with very low levels of available phosphorus. Phosphorus transformations in flooded soils depend on soil characteristics that may affect phosphorus availability. This study was conducted to determine which soil characteristics were related to the changes in P fractions during soil flooding. Soils were chosen from ten sites within the Mesopotamia region that are included in five different soil orders: Oxisols, Ultisols, Alfisols, Mollisols, and Vertisols. Soil phosphorus (P) was fractionated by a modified Hedley method before and after a 45 d anaerobic‐incubation period. Changes in the inorganic P extracted with resin depended on soil pH and were related to the exchangeable‐Fe concentration of soils (extracted with EDTA). Inorganic P extracted with alkaline extractants (NaHCO₃ and NaOH) increased due to soil flooding. This increase was related to the organic‐C (OC) percentage of soils (r² = 0.62, p < 0.01), and ranged from 13 to 55 mg kg^–1. Even though previous studies showed that P associated with poorly crystalline Fe played an important role in the P nutrition of flooded rice, in this study, there was no relationship between ammonium oxalate–extractable Fe and P changes in soils due to flooding. Our results suggest that in the Mesopotamia region, changes in P fractions due to soil flooding are related to soil OC, soil pH, and soluble and weakly adsorbed Fe.     

Fruit and seed characterization of wild populations of a traditional Andean crop: Solanum betaceum Cav. (Solanaceae) in the Argentinian Yungas

Genetic Resources and Crop Evolution - Chilto (Solanum betaceum Cav.) is a traditional Andean crop, appreciated for its high nutritional and commercial value. Despite it is cultivated in many...     

Lethal and sublethal effects of withanolides from Salpichroa origanifolia and analogues on Ceratitis capitata

Biological effects on Ceratitis capitata were evaluated for several withanolides isolated from Salpichroa origanifolia (Solanaceae), (20S,22R,24S,25S,26R)-5alpha,6alpha:22,26:24,25-triepoxy-26-hydroxy-17(13-->18)-abeo-ergosta-2,13,15,17-tetraen-1-one (salpichrolide A, 1), (20S,22R,24S,25S,26R)-22,26:24,25-diepoxy-5alpha,6beta,26-trihydroxy-17(13-->18)-abeo-ergosta-2,13,15,17-tetraen-1-one (salpichrolide C, 2), (20S,22R,24S,25S,26R)-5alpha,6alpha;22,26:24,25-triepoxy-15,26-dihydroxy-17(13-->18)abeo-ergosta-2,13,15,17-tetraen-1-one (salpichrolide G, 3), and (20S,22R,24S,25S,26R)-5alpha,6alpha:22,26:24,25-triepoxy-1,26-dihydroxy-17(13-->18)-abeo-ergosta-2,13,15,17-tetraene (salpichrolide B, 5), and for chemically modified analogues. Influence of chemical modifications on development delay was analyzed. The compounds were incorporated into the larval diet and the adults' drinking water. Significant development delays from larvae to puparia were observed in treatments with the natural withanolides salpichrolides A, C, and G (1-3) at a concentration of 500 ppm. Salpichrolide B (5) was the most toxic compound, the highest mortality (95%) being observed at the larval stage. Exposure of adults to drinking water containing natural withanolides 1-3 and 5 produced mortality in all cases.     

Karyotypic studies in wild germplasm of <Emphasis Type="Italic">Arachis</Emphasis> (Leguminosae)

The karyomorphology for eight diploid species of Arachis belonging to three sections has been described for the first time, Sect. Extranervosae: A. macedoi (2n = 20m) and A. retusa (2n = 14m + 6sm); Sect. Heteranthae: A. sylvestris (2n = 16m + 4sm); Sect. Procumbentes: A. chiquitana (2n = 18m + 2sm); Sect. Arachis: A. cruziana (2n = 18m + 2sm), A. herzogii (2n = 18m + 2sm), A. simpsonii (2n = 20m) and A. williamsii (2n = 20m). A pair of satellited chromosomes was observed in all species. A chromosomes were found in A. chiquitana, A. herzogii and A. simpsonii. Karyotypic differences between sections were observed, but not enough to establish a characteristic karyotype pattern for each section. However, the species may be differentiated by the presence of A chromosomes, the type and position of satellites, and the karyotype formulae. These results are discussed with regard to karyotype evolution in Arachis to contribute to understanding the role of chromosome changes in the evolution of the genus.     

Heritability of in vitro plant regeneration capacity in sunflower

Cotyledons from 20 inbred lines of sunflower were evaluated in vitro for their regeneration ability on two culture media supplemented with growth regulators. Plant regeneration by direct organogenesis was observed after 4 weeks. Significant differences among inbred lines were found for the in vitro traits ‘percentage of organogenic explants’,‘percentage of shooting explants’,‘percentage of hypertrophing explants’ and ‘percentage of callusing explants’. The medium effect was significant for all variables. Some in vitro traits displayed significant genotype‐culture medium interaction. Regeneration ability was influenced by culture medium, genotype and their interaction and genetic parameters were estimated taking this interaction into account. Heritability values ranged from 0.74 to 0.45. Strong positive correlations were observed among the organogenesis‐related traits ‘percentage of organogenic explants’, ‘percentage of shooting explants’ and ‘proliferation rate’.     

ISSR markers detect high genetic variation among <Emphasis Type="Italic">Fusarium poae</Emphasis> isolates from Argentina and England

Fusarium poae is one of the Fusarium species isolated from cereal grains infected by Fusarium head blight (FHB), and in recent years it has been identified as a major FHB component. In this study, 97 F. poae isolates from Argentina (n = 62) and England (n = 35) were analysed by inter-simple sequence repeats (ISSR) to examine the genetic diversity and to determine whether intraspecific variation could be correlated with geographic and/or host origin. The molecular analysis showed high intraspecific variability within F. poae isolates, but did not reveal a clear relationship between variability and the host/geographic origin. Fusarium poae isolates from the same geographic region or host appeared in different subclusters. Conversely, isolates with the same haplotype were also collected from different geographic regions. However, we did observe subclusters consisting of isolates from Argentina only or from England only. Furthermore, a single seed sample was found to host different haplotypes. Analysis of molecular variance (AMOVA) indicated a high genetic variability in F. poae, with most of the genetic variability explained by differences within, rather than between Argentinean and English populations. This is the first report on genetic diversity of F. poae using ISSR markers. Moreover, ISSR fingerprinting generates highly polymorphic markers for F. poae and proved to be a useful and reliable assay for genetic variability studies.