Can ammonium stress be positive for plant performance?

In this article, we propose a change of paradigm where ammonium nutrition may be considered not exclusively as an undesirable situation for plant performance, but as a way to provoke changes in plant metabolism that can be beneficial for crop quality and plant physiology. While some of the positive effects of ammonium referred here still require further evaluation, the cross-tolerance induction of NH+4 to certain subsequent stresses, notably salinity, is clear. However, the molecular actors governing these interactions are almost completely unknown, and future works will be essential in order to fully exploit the benefits of ammonium-based fertilizers.This work was funded by the Basque Government (IT-932-16) and the Spanish Ministry of Economy and Competitiveness (Grants BIO2017-84035-R and AGL2017-86293-P, both co-funded by FEDER)

Physiological traits involved in grazing tolerance of alfalfa genotypes

Alfalfa [1] is one of the most largely distributed forage legume species in the world and it is used on more hectares than any other forage legume. Even so, alfalfa production in Brazil is still limited by the low persistence of this species, especially when used for grazing. Therefore, the objective of this study was to evaluate and select grazing-tolerant germplasm by evaluating genotypes based on their physiological traits. Eight alfalfa genotypes were grown in two different and simultaneous experiments. The experiment ‘A’ evaluated physiological traits: a) chlorophyll content b) sum of lateral roots and shoot and c) length of the first internode The experiment ‘B’ consisted of a jasmonate treatment, which induced remarkable effects on alfalfa roots performance. The CRAltR genotype showed the most promising results for length of the first internode 0.429 cm at the last day of evaluation (day 15). Furthermore, this genotype obtained higher rates in the evaluation of chlorophyll. E1C4AltR in addition to being selected in previous studies for grazing tolerance showed variability for decumbent habit and intermediate values for chlorophyll. The genotypes E1C4 AltR and CRAltR presented more promising results and they will be used for further field evaluations in Brazil

Assessing the effects of soil liming with dolomitic limestone and sugar foam on soil acidity, leaf nutrient contents, grape yield and must quality in a Mediterranean vineyard

[EN] Aluminium toxicity has been recognized as one of the most common causes of reduced grape yields in vineyard acid soils. The main aim of this study was to evaluate the effect of two liming materials, i.e. dolomitic lime and sugar foam, on a vineyard cultivated in an acid soil. The effects were studied in two soil layers (0-30 and 30-60 cm), as well as on leaf nutrient contents, must quality properties and grape yield, in an agricultural soil dedicated to Vitis vinifera L. cv. ‘Mencía’ cultivation. Data management and analysis were performed using analysis of variance (ANOVA). As liming material, sugar foam was more efficient than dolomitic limestone because sugar foam promoted the highest decrease in soil acidity properties at the same calcium carbonate equivalent dose. However, potassium contents in vines organs, including leaves and berries, seemed to decrease as a consequence of liming, with a concomitant increase in must total acidity. Soil available phosphorus also decreased as a consequence of liming, especially with sugar foam, though no effects were observed in plants. For these reasons fertilization of this soil with K and P is recommended along with liming. Grape yields in limed soils increased, although non-significantly, by 30%. This research has therefore provided an important opportunity to advance in our understanding of the effects of liming on grape quality and production in acid soils.SIWe are especiallly grateful to “Losada Vinos de Finca, S.A.”, for its assistance in the research project. The authors would also like to thank the editor and the two anonymous reviewers for their comments and remarks that were of much help to improve the article

Auxins seem promising as a tuning method for balancing sugars with acidity in grape musts from cv. Tempranillo, but not defoliation or application of magnesium to leaves

[EN] Global warming boosted by climate change affects grape quality, with increasing total soluble solids (TSS) content and decreasing total acidity (TA). However, current wine preferences increasingly include moderate alcohol content, higher acidity and the preservation of primary aromas reminiscent of grapes. Therefore, we hypothesised that applying phytohormones or mineral nutrients to leaves or carrying out defoliation can improve grape must properties in the face of climate warming and in accordance with current oenological trends. The effects of these three viticultural strategies were assessed independently from one another during three growing seasons in a Vitis vinifera L. cv. Tempranillo vineyard in northern Spain. Specifically, three 1-naphtaleneacetic acid (NAA) treatments, two early defoliations (ED; moderate and severe) and two foliar fertilisations with magnesium (Mg) were applied. Treatment with NAA was the most encouraging strategy for decreasing must TSS while increasing TA: it had slight effects on TSS in general and also slight effects on TA when applied close to veraison. The effects of the Mg treatments and moderate ED had null to slightly adverse effects. Finally, severe ED was clearly counter-productive. This study contributes to understanding the effects of both auxin and early defoliation treatments on grape must TSS, acidity and even yeast assimilable nitrogen (YAN) at harvest time. The favourable effects of NAA application are shown to be consistent though slight. Therefore, according to these results, the application of auxins may be an adequate choice for balancing sugars with acidity in grape musts. However, the results also suggest that more research needs to be undertaken to better characterise the effects of auxin treatments on grape must properties at harvest. In particular, different types of auxins, rates, concentrations and number of applications should be tested in the quest for more marked effects.SIThe authors are most grateful to both Consejo Regulador de la Denominación de Origen Ribera del Duero and Bodega and Viñedos Martín Berdugo, S.L., for assisting with this research project

Mechanisms of ammonium toxicity and the quest for tolerance

Ammonium sensitivity of plants is a worldwide problem, constraining crop production. Prolonged application of ammonium as the sole nitrogen source may result in physiological and morphological disorders that lead to decreased plant growth and toxicity. The main causes of ammonium toxicity/tolerance described until now include high ammonium assimilation by plants and/or low sensitivity to external pH acidification. The various ammonium transport-related components, especially the non-electrogenic influx of NH3 (related to the depletion of 15N) and the electrogenic influx of NH4+, may contribute to ammonium accumulation, and therefore to NH3 toxicity. However, this accumulation may be influenced by increasing K+ concentration in the root medium. Recently, new insights have been provided by “omics” studies, leading to a suggested involvement of GDP mannose-pyrophosphorylase in the response pathways of NH4+ stress. In this review, we highlight the cross-talk signaling between nitrate, auxins and NO, and the importance of the connection of the plants’ urea cycle to metabolism of polyamines. Overall, the tolerance and amelioration of ammonium toxicity are outlined to improve the yield of ammonium-grown plants. This review identifies future directions of research, focusing on the putative importance of aquaporins in ammonium influx, and on genes involved in ammonium sensitivity and tolerance.The authors acknowledge the support of research grants AGL2014-52396-P from the Spanish Ministry of Economy and Competitiveness (MINECO) and PTDC/BIA-BEC/099323/2008 and PTDC/BIA-ECS/122214/2010 from the Portuguese Fundação para a Ciência e Tecnologia (FCT). RE received a JAE-Doc-2011-046 fellow from the Spanish CSIC, co-financed by the European Social Fund

Drought tolerance response of high-yielding soybean varieties to mild drought: physiological and photochemical adjustments

Soybean is a crop of agronomic importance that requires adequate watering during its growth to achieve high production. In this study, we determined physiological, photochemical and metabolic differences in five soybean varieties selected from the parental lines of a nested association mapping population during mild drought. These varieties have been described as high yielding (NE3001, HY1; LD01-5907, HY2) or drought tolerant (PI518751; HYD1; PI398881, HYD2). Nevertheless, there has been little research on the physiological traits that sustain their high productivity under water-limited conditions. The results indicate that high-yielding varieties under drought cope with the shortage of water by enhancing their photoprotective defences and invest in growth and productivity, linked to a higher intrinsic water use efficiency. This is the case of the variety N-3001 (HY1), with a tolerance strategy involving a faster transition into the reproductive stage to avoid the drought period. The present study highlights the role of the physiological and biochemical adjustments of various soybean varieties to cope with water-limited conditions. Moreover, the obtained results underscore the fact that the high phenotypic plasticity among soybean phenotypes should be exploited to compensate for the low genetic variability of this species when selecting plant productivity in constrained environments.This work was supported by grants from the Spanish Ministry of Science and Innovation and FEDER funds (AGL2014-52396) and from the Basque Government (UPV/EHU-GV IT-1018-16; IT-932-16). J.B. is a holder of a PhD fellowship from the Public University of Navarre. R.E. received a Juan de la Cierva-incorporacion grant (IJCI-2014-21452)

Adaptación social y su relación con el bienestar psicológico en personas pertenecientes a la red de víctimas del conflicto armado salvadoreño en el período de marzo a octubre de 2018

En el informe final de trabajo de grado se abordan las temáticas de adaptación social y bienestar psicológico. La importancia de este estudio se centra en la necesidad de establecer relaciones, a nivel investigativo, entre las características de un colectivo poco abordado psicológicamente a modo de revelar necesidades adicionales y brindar conocimiento concreto de esto a la población misma y al Departamento de Psicología de la Universidad de El Salvador. Al abordar la variable de bienestar psicológico se retoma el modelo de Ryff, que considera seis dimensiones: autoaceptación, relaciones positivas con otras personas, autonomía, dominio del entorno, propósito en la vida y crecimiento personal. En cuanto a la variable adaptación social, se retoman cuatro áreas fundamentales: relaciones externas a la familia, trabajo y ocio, intereses sociointelectuales, y relaciones familiares y estrategias de conducta

Estudio mercadológico para determinar la factibilidad de la apertura de una nueva sucursal de MC El Brasil en la zona paracentral

La creación de una nueva sucursal es una decisión muy importante la cual requiere la realización de estudios previos que permitan conocer el panorama del comportamiento del mercado, de los clientes y de la competencia, fidelización, esto con la finalidad de tomar decisiones acertadas que nos permitan obtener los resultados deseados. Se pretende que, con la posterior elaboración del trabajo de Grado, la propuesta logre desarrollarse de una manera eficient

Effects of liming on soil properties, leaf tissue cation composition and grape yield in a moderately acid vineyard soil. Influence on must and wine quality

[EN] Aims: Soil acidity decreases soil fertility and grapevine growth. Aluminum toxicity has been recognized as one of the most common causes of reduced grape yields in acid vineyard soils. The main aim of this study was to evaluate the effect of two liming materials, i.e. dolomitic lime and sugar foam, on a vineyard cultivated in an acid soil. Methods and results: The effects were studied in two soil layers (0-30 and 30-60 cm), as well as on leaf nutrient contents, grape yield, and must and wine quality properties, in a vineyard dedicated to Vitis vinifera L. cv. Mencía cultivation. The data management and analysis were carried out using ANOVA. Conclusion: Sugar foam was more efficient than dolomitic limestone as liming material since it induced the highest decrease in soil acidity properties at the same calcium carbonate equivalent dose. Effects of liming on leaf nutrient contents, grape yield, and must and wine quality properties were barely observed. Significance and impact of the study: Until recently, little was known about the effects of liming on both vine nutritional status and must/wine quality properties. Thus, this research fills an important knowledge gap.SIThis work was funded by the “Excelentísima Diputación Provincial de León”. We are specially grateful to “Losada Vinos de Finca, S.A.” for assistance in the research project