Determination of reducing sugars is carried out routinely in the food industry, in biological research, or pharmaceutical and biomedical quality control to estimate metabolically assimilable sugars. Widespread detection methods are complex, expensive, or highly polluting. Here, we propose the use of spectrophotometric quantification for reducing sugars (Benedict q ) based on the qualitative method of Benedict. The protocol was validated, to verify its reproducibility and precision. With the proposed method (Benedict q ), the reducing sugar glucose can be determined in a range of 0.167–10 mg mL –1 , with an R 2 of 0.997 and accuracy (expressed as % of recovery) greater than 97%. Other reducing sugars, such as maltose, fructose, and lactose, showed similar values. The method robustness was verified for pH values greater than or equal to 4. In the case of protein presence, a correction is proposed in the range of 0–1.67 mg mL –1 . Modifications implemented in the protocol reduce cost, working time, and reaction volumes with respect to the original assay without detriments in accuracy and precision. In addition, waste reduction represents an important contribution of the method.

During seed germination, metabolism is reactivated, DNA is repaired and cell division is restarted in the meristems. The mechanisms that co-ordinate cell growth and division in maize embryonic axes during germination are not well understood. However, the presence of a factor similar to IGF (insulin-like growth factor) that accelerates germination has been reported. In the present work, the regulation of the cell-cycle restart by bovine insulin [which has been demonstrated to produce similar effects as insulin-like growth factor of maize (ZmIGF) in maize seeds] was studied in germinating embryonic axes. Our results showed that bovine insulin differentially stimulates growth, S6K phosphorylation, S6rp transcript accumulation on the polysomal fraction, as well as de novo DNA synthesis in the radicles and the coleoptiles of the embryonic axis. A stronger and earlier effect was observed in radicles compared to coleoptiles; therefore, the effect of insulin on the cell cycle of the root meristem was studied by flow cytometry. The G1–S transition was stimulated and cell proliferation was induced. Furthermore, it was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) that bovine insulin increased E2F and PCNA (proliferating cell nuclear antigen) transcription after 15 h of germination and PCNA de novo synthesis at 15 h of germination. These results show that bovine insulin preferentially stimulates growth in the radicles of germinating embryonic axes and suggest that its effect on the G1–S transition and the activation of cell proliferation is mediated by the induction of E2F and PCNA transcription.

The objective of this work was to determine the effect of water pre-conditioning on the percentage of germination and emergence of Capsicum chinense. The seeds were cultivated during the productive cycle from December 2015 to February 2016. For the pre-conditioning, the seeds were imbibed with 2.5, 3.5, 5, 7.5 and 10 ml of water. The volume of 7.5 ml was used as a reference. Germination results indicate that the three best imbibition volumes were 2.5, 3.5 and 5 mL, with a Pearson correlation of -0.905 (p= 0.000) between the volume of water and the percentage of accumulated germination, as well as the decrease of the germination time 50. Subsequently, the same seeds were transplanted to evaluate the emergence. The best imbibition volumes for the emergency were, in that order, 3.5, 5 and 2.5 ml. In the emergency, the volume with the best percentage of germination (2.5 ml) occupied the third place, which modified the Pearson coefficient to -0.641 (p= 0.01). The results suggest that a certain degree of stress, generated by the decrease in water supply, favors germination and establishment, which could be related to the synthesis and accumulation of ethylene within the germination system. On the other hand, the increase in the diameter of the water film generates a decrease in the availability of oxygen. The contribution of the present work was to demonstrate that the correct hydration of the seeds influences later stages of germination, without adding growth regulators.

Los germinadores automatizados, son una herramienta indispensable para optimizar los procesos agrícolas. Sin embargo, tienen altos costos, por lo que se requiere el diseño, construcción y operación de aparatos con precios accesibles para pequeños productores. El objetivo del presente trabajo fue, diseñar, construir y verificar un prototipo de germinador de bajo costo, bajo las directrices de diseño de un prototipo. Dicho germinador, se construyó usando materiales disponibles en la región y es capaz de controlar automáticamente la temperatura y fotoperiodo mediante los circuitos W1401 y Tem-8 48386 respectivamente. Además, mediante conmutadores simples se puede controlar la intensidad lumínica. Adicionalmente, se construyó un verificador de temperatura con una tarjeta Arduino Uno. El sistema de verificación permitió el monitoreo de los cambios de temperatura en tiempo real (cada minuto). El prototipo se probó germinando semillas de Capsicum chinense, usando distintos volúmenes de agua de imbibición. De acuerdo con los resultados obtenidos, el prototipo construido se ajusta a los requerimientos recomendados tanto por la International seed testing association (ISTA), como por la Food and Agriculture Organitation (FAO) para la evaluación de semillas, pero, además mostró un rendimiento mayor, en comparación con una incubadora comercial y aun costo de construcción y operación muy menor.

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