Temperature Impact on the Forage Quality of Two Wheat Cultivars with Contrasting Capacity to Accumulate Sugars

Wheat is increasingly used as a dual-purpose crop (for forage and grain production) worldwide. Plants encounter low temperatures in winter, which commonly results in sugar accumulation. High sugar levels might have a positive impact on forage digestibility, but may also lead to an increased risk of bloat. We hypothesized that cultivars with a lower capacity to accumulate sugars when grown under cold conditions may have a lower bloat risk than higher sugar-accumulating genotypes, without showing significantly lower forage digestibility. This possibility was studied using two wheat cultivars with contrasting sugar accumulation at low temperature. A series of experiments with contrasting temperatures were performed in controlled-temperature field enclosures (three experiments) and growth chambers (two experiments). Plants were grown at either cool (8.1 °C–9.3 °C) or warm (15.7 °C–16.5 °C) conditions in field enclosures, and at either 5 °C or 25 °C in growth chambers. An additional treatment consisted of transferring plants from cool to warm conditions in the field enclosures and from 5 °C to 25 °C in the growth chambers. The plants in the field enclosure experiments were exposed to higher irradiances (i.e., 30%–100%) than those in the growth chambers. Our results show that (i) low temperatures led to an increased hemicellulose content, in parallel with sugar accumulation; (ii) low temperatures produced negligible changes in in vitro dry matter digestibility while leading to a higher in vitro rumen gas production, especially in the higher sugar-accumulating cultivar; (iii) transferring plants from cool to warm conditions led to a sharp decrease in in vitro rumen gas production in both cultivars; and (iv) light intensity (in contrast to temperature) appeared to have a lower impact on forage quality

Timing of nitrogen fertilization influences color and anthocyanin content of apple (Malus domestica Borkh. cv ‘Royal Gala’) fruits

Different timings and methods of N application modify N dynamics in the plant and could have differential effects on fruit color. To evaluate this possibility, an experiment was conducted during three seasons in a ‘Royal Gala’/EM9 apple orchard. The treatments were: (a) soil N after harvest; (b) foliar N after harvest; and (c) soil N in spring. No nitrogen was applied to the control. HUE angle, lightness, percentage of coverage color, and anthocyanin concentration were determined in the fruit skin. Among the treatments that received fertilization, the postharvest treatments resulted in fruits with darker colorations, higher percentages of coverage color, and higher concentration of anthocyanins. These could be related, at least partly, to lower values of light interception by the canopy, in comparison to the spring treatment. Our results suggest that the negative effects of N on fruit coloration can be mitigated by differing N application to the postharvest period.EEA Alto ValleFil: De Angelis, Verónica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Sanchez, Enrique Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Tognetti, Jorge Alberto. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Laboratorio de Fisiología Vegetal; Argentin

Diferentes respostas de crescimento de Ficus benjamina verde e variegado à citocinina exógena e sombreamento

Benjamin fig (Ficus benjamina) is an important foliage and landscape crop species comprising green and variegated genotypes. The latter develop leaves with yellow and white leaf areas which may impose lower photosynthetic activity, thus resulting in slower growth than green genotypes. In many species, the exogenous supply of cytokinin to pot-grown plants promotes growth, mainly due to enhanced carbon fixation. In this work, we analyze the effect of spraying the cytokinin 6-benzylaminopurine (BAP) on growth and development of green and variegated Ficus benjamina genotypes. Two experiments were carried out in a greenhouse, in which either different number of BAP applications (Experiment 1) or different BAP concentrations (Experiment 2) were tested. In Experiment 2, plants were grown under three different light intensities. BAP sprays promoted rate of leaf appearance, leaf expansion and whole-plant growth, and the effect was stronger in variegated than in green plants. The relative growth rate promotion by BAP was associated with increased net assimilation rate rather than with variation in the leaf area ratio. On the other hand, shading had a more negative impact on growth and development of variegated plants than in green ones. Variegated plants, unlike green ones, developed leaves with high specific leaf area under the lowest light intensity. This led to high leaf area ratio values, which helped to maintain relative growth rates close to those of plants under moderate shading.O Ficus (Ficus benjamina) é uma importante espécie de folhagem usada no paisagismo que compreende genótipos verdes e variegados. Estes últimos desenvolvem folhas com áreas foliares amarelas e brancas que podem impor menor atividade fotossintética, resultando em crescimento mais lento que os genótipos verdes. Em muitas espécies, o suprimento exógeno de citocinina em plantas cultivadas em vaso promove o crescimento, principalmente devido à maior fixação de carbono. Neste trabalho, analisamos o efeito da pulverização da citocinina 6-benzilaminopurina (BAP) no crescimento e desenvolvimento de genótipos verdes e variegados de Ficus benjamina. Foram realizadas dois experimentos em casa de vegetação, nos quais foram testados diferentes números de aplicações de BAP (Experimento 1) ou diferentes concentrações de BAP (Experimento 2). No experimento 2, as plantas foram cultivadas sob três intensidades de luz diferentes. A pulverização com BAP promoveram taxa de aparência foliar, expansão foliar e crescimento de plantas inteiras, e o efeito foi mais forte em variegadas do que em plantas verdes. A promoção da taxa de crescimento relativo pelo BAP foi associada ao aumento da taxa líquida de assimilação, e não à variação na proporção da área foliar. Por outro lado, o sombreamento teve impacto mais negativo no crescimento e desenvolvimento de plantas variegadas do que nas verdes. Plantas variegadas, diferentemente das verdes, desenvolveram folhas com alta área foliar específica sob a menor intensidade de luz. Isso levou a altos valores da razão de área foliar, o que ajudou a manter taxas de crescimento relativas próximas às das plantas sob sombreamento moderado.Fil: Di Benedetto, Adalberto Hugo. Universidad de Buenos Aires; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Galmarini, Claudio Romulo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; Argentina. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Tognetti, Jorge Alberto. Universidad Nacional de Mar del Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Técnicas de análisis de crecimiento de plantas: su aplicación a cultivos intensivos

La descripción del crecimiento de una planta, o de un cultivo, a lo largo de su ciclo de vida o de producción, así como la evaluación de tratamientos capaces de modificar la acumulación de biomasa de un vegetal requieren indicadores objetivos que puedan ser validados estadísticamente. Las técnicas de análisis del crecimiento son herramientas útiles para estos fines. Pueden aplicarse en múltiples situaciones, pero su empleo en cultivos intensivos presenta aspectos particulares y precauciones a ser tenidos en cuenta, acerca de los cuales la información disponible es relativamente escasa y dispersa. En este trabajo de revisión se describen los estimadores del crecimiento más apropiados para ser empleados en especies hortícolas, frutales y ornamentales. Asimismo, se discuten e ilustran distintas alternativas para la utilización de estos indicadores tanto a nivel de planta aislada como de cultivo.The description of plant or crop growth, throughout their life or production cycles, as well as the evaluation of treatments that may modify vegetable biomass accumulation, require the estimation of parameters, which can be statistically tested. Growth analysis methods provide useful tools for these purposes. They can be applied to multiple situations, but their use in intensive cropping systems show particularities and cautions that need to be taken into account, about which information is relatively scarce and scattered. This review describes the most appropriate parameters to be used in vegetable, fruit and ornamental species, and both discusses and illustrates the use of different alternatives that can be chosen for growth description at either the isolated plant or crop levels

Fenología, producción y conservación post cosecha de diferentes cultivares de cebolla en el sudeste de Buenos Aires

p.73-80Los cultivos de cebolla en el S.E. de la Provincia de Buenos Aires se realizan casi exclusivamente con el cultivar Valcatorce INTA. Aunque se ha propuesto el cultivo de cebollas de ciclo más corto, prácticamente no existe información acerca del comportamiento de estos cultivares en la región. En este trabajo se evalúa la fenología, producción y comportamiento postcosecha de seis cultivares de diferente longitud de ciclo, en comparación con Valcatorce. De acuerdo a nuestros ensayos, el empleo de los genotipos de ciclo corto evaluados sólo sería factible para consumo inmediato, debido a su mala conservación. Por otra parte, Valcatorce presentó la mejor conservación y una producción aceptable, mientras que Armada se destacó como una interesante alternativa. Se evalúan, asimismo, diferentes parámetros como indicadores de la longevidad post-cosecha

Técnicas de análisis de crecimiento de plantas : su aplicación a cultivos intensivos

258-282La descripción del crecimiento de una planta, o de un cultivo, a lo largo de su ciclo de vida o de producción, así como la evaluación de tratamientos capaces de modificar la acumulación de biomasa de un vegetal requieren indicadores objetivos que puedan ser validados estadísticamente.. Las técnicas de análisis del crecimiento son herramientas útiles para estos fines. Pueden aplicarse en múltiples situaciones, pero su empleo en cultivos intensivos presenta aspectos particulares y precauciones a ser tenidos en cuenta, acerca de los cuales la información disponible es relativamente escasa y dispersa.. En este trabajo de revisión se describen los estimadores del crecimiento más apropiados para ser empleados en especies hortícolas, frutales y ornamentales. Asimismo, se discuten e ilustran distintas alternativas para la utilización de estos indicadores tanto a nivel de planta aislada como de cultivo

Técnicas de análisis de crecimiento de plantas : su aplicación a cultivos intensivos

258-282La descripción del crecimiento de una planta, o de un cultivo, a lo largo de su ciclo de vida o de producción, así como la evaluación de tratamientos capaces de modificar la acumulación de biomasa de un vegetal requieren indicadores objetivos que puedan ser validados estadísticamente. Las técnicas de análisis del crecimiento son herramientas útiles para estos fines. Pueden aplicarse en múltiples situaciones, pero su empleo en cultivos intensivos presenta aspectos particulares y precauciones a ser tenidos en cuenta, acerca de los cuales la información disponible es relativamente escasa y dispersa. En este trabajo de revisión se describen los estimadores del crecimiento más apropiados para ser empleados en especies hortícolas, frutales y ornamentales. Asimismo, se discuten e ilustran distintas alternativas para la utilización de estos indicadores tanto a nivel de planta aislada como de cultivo

Climate change in the temperature and precipitation at two contrasting sites of the Argentinean wheat region

Global climate change is shifting temperature and precipitation regimes, which is modifying the environments that define wheat yield and quality. The current work characterises the changes that have occurred in the thermal and hydric environment in two contrasting sites of the wheat-growing region of Argentina, allowing comparison between sites for these changes and for how the changes are accelerating. Temperature and precipitation variables were analysed by regression and trend testing (Mann Kendall), and future projections were made based upon significant relationships. The two sites compared were in the zones around the cities of Azul in the Province of Buenos Aires and Marcos Juárez in the Province of Córdoba, located approximately 500 km apart. The climate data analysed covered the period 1931–2014 for Azul and 1952–2014 for Marcos Juárez. At both sites, temperatures increased significantly in mean and extreme values over these periods, where the rate of change accelerated during the first years of the twenty-first century. The changes observed were in general more pronounced in Marcos Juárez than in Azul. Furthermore, in Marcos Juárez, mean precipitation increased from September to December and there was a higher frequency of extremes of precipitation greater than 100 mm in September and October during the early twenty-first century. Evidence was found for temperature rise and the occurrence of extreme temperature and precipitation events occurring differently between sites, as well as for its acceleration rate in the early twenty-first century. The projected future changes made implied that wheat yield is expected to suffer losses over the coming century.Fil: Basile, Silvana Marisol Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; ArgentinaFil: Tognetti, Jorge Alberto. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Laboratorio de Fisiología Vegetal; ArgentinaFil: Gandini, Marcelo Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina. Laboratorio de Investigación y Servicios En Teledetecci; ArgentinaFil: Rogers, William John. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Observaciones sobre la producción y conservación de cebolla en el sudeste de Buenos Aires en relación con la disponibilidad hídrica

En experimentos con siete cultivares de cebolla de diferente longitud de ciclo, realizados en el sudeste de la provincia de Buenos Aires (Argentina) bajo restricción hídrica, se observó además del esperable tamaño reducido de los bulbos, una llamativa desmejora en su conservación, en relación con ensayos sin limitaciones de agua. La marcada aceleración de la brotación y el incremento en la tasa de pérdida de peso de los bulbos en almacenamiento como consecuencia de las restricciones hídricas durante el llenado fueron confirmadas en un ensayo independiente con el cv. Valcatorce INTA. Estos resultados sugieren la necesidad de replantear el manejo del agua en cebolla al menos cuando se pretende su conservación a largo plazo, como es el caso de los cultivos para exportación.In experiments with seven onion cultivars of different cycle length in the S.E. of Buenos Aires province (Argentina) under restricted water supply, an expected reduction in bulb size but also an unexpected decline in bulb postharvest life were observed, relative to essays with non-limiting irrigation. The remarkable acceleration of sprouting together with an increased weight loss rate, as a consequence of water deficit during bulb filling, was confirmed in an independent experiment with cv. Valcatorce INTA. These results suggest the need of reevaluating water management of the onion crop, especially when destined to long-term storage as required for expor

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation