DSpace Colección :

Germinación de semillas de festuca alta de diferentes cultivares con y sin endófito no tóxico (AR854) bajo estrés salino

2026-01-01T00:00:00Z

Título: Germinación de semillas de festuca alta de diferentes cultivares con y sin endófito no tóxico (AR854) bajo estrés salino; Germination of tall fescue seeds from different cultivars with and without the non-toxic endophyte (AR584) under saline stress Autor: Petigrosso LR; Morad J; Defferrari A; Echeverría MM; Crovo V; Miri S; Gundel P Resumen: La salinidad del suelo constituye una de las principales limitantes para la implantación de pasturas, particularmente en especies forrajeras ampliamente utilizadas como la festuca alta. El objetivo de este trabajo fue evaluar la tolerancia a la salinidad por cloruro de sodio (NaCl) durante la germinación de semillas de dos cultivares comerciales de festuca alta, Malma y Taita, libres e inoculados con el endófito no tóxico AR584. El experimento se realizó en una cámara de germinación mediante un diseño en bloques completos aleatorizados con tres repeticiones en el tiempo y un arreglo factorial que combinó cultivar, nivel de endófito y seis concentraciones de NaCl (0–200 mM). Se evaluaron variables asociadas a la germinación y al crecimiento inicial de las plántulas. La salinidad redujo significativamente la germinación en ambos cultivares, registrándose los menores valores de energía y poder germinativo en los tratamientos de 160 y 200 mM de NaCl. Asimismo, el índice de germinación indicó inhibición de la germinación a partir de 120 mM, mientras que el índice de crecimiento relativo evidenció inhibición de la elongación radicular únicamente a 200 mM de NaCl, independientemente del nivel de endófito. El efecto del endófito AR584 fue dependiente del cultivar: en el cv. Taita, la infección redujo la germinación y el crecimiento inicial, mientras que en el cv. Malma se observó un aumento de la longitud del coleóptilo a 40 mM de NaCl, lo que podría favorecer la emergencia bajo salinidad moderada. Estos resultados evidencian una marcada variabilidad genotípica en la tolerancia a la salinidad y destacan que la utilidad agronómica de los endófitos no tóxicos en festuca alta depende del genotipo y de las condiciones ambientales.; Soil salinity is one of the main constraints to pasture establishment, particularly in widely used forage species such as tall fescue. The aim of this study was to evaluate sodium chloride (NaCl) salinity tolerance during seed germination of two commercial tall fescue cultivars, Malma and Taita, either endophyte-free or inoculated with the non-toxic endophyte AR584. The experiment was conducted in a germination chamber using a randomized complete block design with three temporal replicates and a factorial arrangement combining cultivar, endophyte status, and six NaCl concentrations (0–200 mM). Germination and early seedling growth variables were assessed. Salinity significantly reduced germination in both cultivars, with the lowest germination energy and germination capacity values recorded at 160 and 200 mM NaCl. Furthermore, the germination index indicated inhibition of germination from 120 mM NaCl onwards, whereas the relative growth index revealed inhibition of radicle elongation only at 200 mM NaCl, regardless of endophyte status. The effect of the AR584 endophyte on salinity tolerance was cultivar-dependent. In cv. Taita, endophyte infection reduced germination and early seedling growth, whereas in cv. Malma, endophyte presence increased coleoptile length at 40 mM NaCl, which could favor seedling emergence under moderate salinity. These results highlight marked genotypic variation in salinity tolerance during germination and indicate that the agronomic value of non-toxic endophytes in tall fescue depends on host genotype and environmental conditions.

Is mineral nutrient concentration of soybean, maize, and wheat grain affected by cropping sequence and agronomic management?

2026-01-01T00:00:00Z

Título: Is mineral nutrient concentration of soybean, maize, and wheat grain affected by cropping sequence and agronomic management? Autor: Becheran, D. E.; Miguez, F. H.; Miguez, F. E.M; Peper, A.; Benedit, B. Resumen: Producers in the Argentine Pampas often fail to fully replenish the nutrients extracted by crops, leading to unsustainable soil fertility management. The objectives of this study were to (i) evaluate grain yield, mineral nutrient concentration, and extraction for maize (Zea mays L.), wheat (Triticum aestivum L.), and soybean (Glycine max L. Merr.) under contrasting agronomic management systems and (ii) compare mineral nutrient concentration with nutrient removal values commonly used as reference in Argentina when assessing crop nutrient soil uptake. The study was conducted over 8 years in a field experiment located in the central Rolling Pampas, under three crop sequences: continuous soybean (Sy), a 2-year rotation alternating maize and soybean (Mz–Sy), and a 3-year rotation including wheat/soybean double crop, maize, and soybean (Wt/SyDC–Mz–Sy). In addition, these were evaluated with either fallow or winter cover crops (CCs) present under two agronomic systems: conventional management (CM) and intensified management (IM). The IM system included different genotypes, plant densities, fertilizer types, and rates. The IM increased yield for Mz by 1.25 Mg ha−1 (p < 0.01), Wt by 0.82 Mg ha−1 (p < 0.05), Sy1 (soybean full season crop) by 0.28 Mg ha−1 (p < 0.05), and SyDC by 0.39 Mg ha−1 (p < 0.05). The inclusion of a CC decreased yield for Mz by 1.20 Mg ha−1 (p < 0.01) and Sy1 by 0.34 Mg ha−1 (p < 0.05), only within CM and in the drier years. The IM increased nitrogen (N) and sulfur (S) concentrations for Sy but had no consistent effects on nutrient concentrations in other crops. Observed grain nutrient concentration values, despite their variability, could be used to estimate nutrient exports by these crops.

Valorisation of quinoa scarification residues: impact of desaponification methods on functional and emulsifying properties

2026-01-01T00:00:00Z

Título: Valorisation of quinoa scarification residues: impact of desaponification methods on functional and emulsifying properties Autor: Ragonese, Verónica E.; Moscoso Ospina, Yeisson A.; Cabezas, Darío M.; Kakisu, Emiliano J. Resumen: BACKGROUND: Quinoa is widely recognised for the high biological value of its proteins. However, its outer layer contains saponins, an antinutrient that must be removed for consumption. The process of dry desaponification of grains is known as scarification and produces a residual powder that is usually discarded. RESULTS: The quinoa scarification residue (QSR) contained 5 g kg−1 of saponins. Thus, washing with water, homogenisationassisted washing (HQSR) and sonication-assisted washing (SQSR) methods were evaluated. The assisted washing methods used 50% less water, although all of them reduced the residual saponin content (∼0.5 g kg−1 ) and significantly concentrated the protein content of the samples (∼270–290 g kg−1 ), compared to the control sample (∼210 g kg−1 ). The electrophoretic profile in sodium dodecyl sulfate–polyacrylamide gel electrophoresis showed the presence of the structural protein chenopodin, with its acidic (30–40 kDa) and basic (20–25 kDa) subunits, as well as protein macromolecules higher than 100 kDa. Fragmented particles were also observed in the HQSR and SQSR samples using low-vacuum scanning electron microscopy, although the latter also presented porous structures. Both a decrease in oil/water interfacial tension – mainly in HQSR (19.22 mN m−1 ) − and a significant increase in interfacial viscosity in SQSR (1.5 E−5 Pa s) were observed. Emulsions formulated with the sonicated sample showed greater stability against coalescence, creaming and sedimentation processes. CONCLUSION: Ultrasound-assisted desaponification proved to be efficient, improving the functional characteristics of this residue and opening new possibilities for its use in food systems.

Epanechnikov Nonparametric Kernel Density Estimation Based Feature-Learning in Respiratory Disease Chest X-Ray Images

2026-01-01T00:00:00Z

Título: Epanechnikov Nonparametric Kernel Density Estimation Based Feature-Learning in Respiratory Disease Chest X-Ray Images Autor: Marsico, Verónica; Quintero-Rincón, Antonio; Batatia, Hadj Resumen: This study presents a novel method for diagnosing respiratory diseases using image data. It combines Epanechnikov’s nonparametric kernel density estimation (EKDE) with a bimodal logistic regression classifier in a statistical-model-based learning scheme. EKDE’s flexibility in modeling data distributions without assuming specific shapes and its adaptability to pixel intensity variations make it valuable for extracting key features from medical images. The method was tested on 13808 randomly selected chest X-rays from the COVID19 Radiography Dataset, achieved an accuracy of 70.14%, a sensitivity of 59.26%, and a specificity of 74.18%, demonstrating moderate performance in detecting respiratory disease while showing room for improvement in sensitivity. While clinical expertise remains essential for further refining the model, this study highlights the potential of EKDE-based approaches to enhance diagnostic accuracy and reliability in medical imaging.