Delaying senescence of 'Ruby red' grapefruit and 'Valencia' oranges by gibberellic acid applications

The demonstrate the effectiveness of gibberellic acid (GA3) in delaying fruit senescence in 'Ruby Red' grapefruit and 'Valencia' oranges under sub-optimal orchard management conditions in tropical Veracruz, Mexico. For grapefruit, one or two applications of three different GA3 doses (15, 20 and 40 mg L-1) with or without surfactant (Silwet® L77) at 0.035, 0.05 or 0.1%, were tested. For oranges, one or two applications of three different GA3 doses (10, 15 and 20 mg L-1) with or without surfactant at 0.05%, were tested. Pre-color break application of GA3, at 10 mg L-1 and 15 mg L-1 with surfactant (0.05%),was sufficient to sustain peel firmness and delay colour development in oranges and grapefruit, respectively. GA3 treatments with surfactant caused increased leaf drop in both citrus cultivars, although this was only noticed in trees treated with the highest surfactant dosages and mainly involved photosynthetically inactive leaves. One application of GA3 at 15 mg L-1 with surfactant (0.05%) significantly increased orange and grapefruit weights, resulting in yield increases of ca. 1.7 t ha-1 for oranges and 1.87 t ha-1 for grapefruit. A significant decrease in orange drop during the late harvest season in GA3 treated trees, resulted in a harvest period that could be extended by up to six weeks. The market value of fruit harvested late in the season is up to eight times the value of fruit harvested when the market is saturated.Los datos demuestran la efectividad del ácido giberélico (AG3) para retrasar la senescencia del fruto en toronja 'Ruby Red' y naranja 'Valencia', aún bajo condiciones sub-óptimas de manejo en la región tropical de Veracruz, México. En toronja, experimentamos con una o dos aplicaciones de tres dosis de AG3 (15, 20 y 40 mg L-1) con o sin surfactante (Silwet® L77) a 0.035, 0.05 ó 0.1%. En el caso de la naranja, experimentamos con una o dos aplicaciones de tres dosis de AG3 (10, 15 and 20 mg L-1) con y sin surfactante a 0.05%. La aplicación de AG3 en etapa de pre-coloración, a 10 mg L-1 y 15 mg L-1 con surfactante (0.05%), fue suficiente para mantener la firmeza del epicarpio (cáscara) y retrasar el desarrollo del color en naranjas y toronjas, respectivamente. El tratamiento de AG3 con surfactante provocó un incremento en la caída de las hojas en ambos cí­tricos, aún cuando esto fue especialmente observado en árboles tratados con dosis elevadas de AG3 y surfactante, principalmente en el caso de hojas con inactividad fotosintética. Una aplicación de AG3 a 15 mg L-1 con surfactante (0.05%), incrementó significativamente el peso de la naranja y la toronja, resultando a su vez en un incremento en la cosecha alrededor de 1.7 t ha-1 de naranja y 1.9 t ha-1 de toronja. Debido a la reducción significativa en la caída de la fruta de la naranja durante la íºltima temporada de cosecha en los árboles tratados con AG3, la cosecha podría extenderse por seis semanas adicionales. Los frutos cosechados tardíamente podrían alcanzar un valor de ocho veces mayor que aquellos cosechados cuando el mercado está saturado de producto

Cinética de crecimiento in vitro de Brevibacillus brevis en diferentes medios de cultivo

Abstract The development of techniques for the reproduction of soil beneficial rhizobacteria opens up a range of alternatives for your research. The ignorance of chemical and physical conditions of an optimal means for development Brevibacillus brevis generates this research by evaluating five liquid culture media (SM 1%, SM 0.5%, SM 0.1%, LB and NFb), three pHs (6, 7 and 8) and two incubation times (48 and 96 h). The objective of this work was to evaluate an optimal medium for the reproduction of the bacteria at the laboratory level. The methodology included processing, standardizing of culture media, reactivation of the strain, Gram staining, inoculation, incubation for reproduction and bacterial count. The triple interaction showed that the medium SM 1% (Sábila and Melaza), with pH 7 and 48 h had the best results, compared to the other media and conditions with 15.38 x 1011 CFU mL-1.Resumen El desarrollo de técnicas para la reproducción de rizobacterias benéficas del suelo abre una gama de alternativas para su investigación. El desconocimiento de condiciones químicas y físicas de un medio óptimo para el desarrollo Brevibacillus brevis generó la presente investigación al evaluar cinco medios de cultivo líquidos (SM 1%, SM 0.5%, SM 0.1%, LB y NFb), tres pHs (6, 7 y 8) y dos tiempos de incubación (48 y 96 h). El objetivo fue determinar un medio óptimo para la reproducción de la bacteria en laboratorio. Se estandarizaron los medios de cultivo, reactivo la cepa, tinción de Gram, inoculación, incubación para reproducción y recuento de bacterias. La interacción demostró que el medio SM 1% (Sábila y Melaza), con pH 7 y 48 h tuvo los mejores resultados, comparado con los otros medios y condiciones con 15.38 x 1011 UFC mL-1

Water Conservation and Green Infrastructure Adaptations to Reduce Water Scarcity for Residential Areas with Semi-Arid Climate: Mineral de la Reforma, Mexico

The increasing population and urban sprawl will continue to add significant pressure to natural resources in arid and semi-arid zones. This study evaluates the theoretical effectiveness of adapting resilient strategies such as water conservation and green infrastructure to mitigate the water scarcity faced by the inhabitants of a residential area with a semi-arid climate. Three scenarios were analyzed at a micro-basin level to determine the mitigation of surface runoff and the volume that can be theoretically intercepted for further use: (a) unaltered natural watershed (scenario 1), (b) currently urbanized watershed (scenario 2), and (c) watershed adapted with resilient strategies (scenario 3). For this last scenario, the annual usable volume of rainwater intercepted on the dwelling rooftops was obtained. The runoff and peak flow in the natural watershed were lower than in the other two scenarios. In contrast, a decrease in the runoff was observed in scenario 3 concerning scenario 2, which indicates that the interception of rainwater on house roofs and the adoption of green infrastructure solutions would significantly reduce the diameter of urban drainage pipes required in new developments, as well as the dependency of inhabitants on potable water services. In sites with semi-arid climates, it is possible to take advantage of the rainwater harvested on rooftops and the runoff intercepted through green infrastructure to mitigate local water scarcity problems, which should be considered and adopted in new residential developments

Preliminary Model-Based Evaluation of Water Conservation Strategies in a Semi-Arid Urban Zone

The U.S. Environmental Protection Agency stormwater management model was applied to a semi-arid urban micro watershed. The sub-catchment’s current features were modeled as scenario A, while the insertion of a set of LID technologies (rain barrels, bioretention cells, permeable pavement, and infiltration trenches) was represented as scenario B. A third scenario (C), considering only the most feasible LID technologies, was also modeled. All the scenarios were evaluated under two representative storm events (30 and 9 mm in two consecutive days, and 39 mm of rainfall in one day) occurred during the sampling performed in this study. Water quality was also simulated for a 30-mm storm event and compared against field assessment results after a real 30-mm storm event. Through the model, the inefficiency of current evacuation methods after 30- and 39-mm storm events was demonstrated. Simulation of scenario B showed that LID technologies could satisfactorily diminish peak flows generated by the selected storm events as well as runoff-conveyed pollution, while the realistic scenario allowed a lower but satisfactory hydrological performance and almost the same runoff quality than scenario B. This preliminary study could contribute to spread awareness about the benefits of LID technologies in semi-arid urban areas of the developing world

Preliminary Model-Based Evaluation of Water Conservation Strategies in a Semi-Arid Urban Zone

The U.S. Environmental Protection Agency stormwater management model was applied to a semi-arid urban micro watershed. The sub-catchment’s current features were modeled as scenario A, while the insertion of a set of LID technologies (rain barrels, bioretention cells, permeable pavement, and infiltration trenches) was represented as scenario B. A third scenario (C), considering only the most feasible LID technologies, was also modeled. All the scenarios were evaluated under two representative storm events (30 and 9 mm in two consecutive days, and 39 mm of rainfall in one day) occurred during the sampling performed in this study. Water quality was also simulated for a 30-mm storm event and compared against field assessment results after a real 30-mm storm event. Through the model, the inefficiency of current evacuation methods after 30- and 39-mm storm events was demonstrated. Simulation of scenario B showed that LID technologies could satisfactorily diminish peak flows generated by the selected storm events as well as runoff-conveyed pollution, while the realistic scenario allowed a lower but satisfactory hydrological performance and almost the same runoff quality than scenario B. This preliminary study could contribute to spread awareness about the benefits of LID technologies in semi-arid urban areas of the developing world