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Las interacciones de los nutrimentos en las plantas pueden ser cuantificadas mediante las concentraciones nutrimentales en los órganos vegetales, sin embargo, hay pocos estudios que evalúen la interacción de más de un nutrimento en el mismo experimento, y escasos reportes de la interacción N/K en la solución nutritiva en el rendimiento y la composición mineral de papa (Solanum tuberosum L.). El objetivo de esta investigación fue evaluar en invernadero e hidroponía la interacción de tres relaciones porcentuales NO3-/aniones (40/100, 60/100 y 80/100) y tres de K+/cationes (15/100, 35/100 y 55/100) sobre la composición mineral de hojas, tallos, tubérculos y el rendimiento de papa cv Agatha. El diseño experimental utilizado fue completamente al azar con arreglo factorial de tratamientos 32. La interacción NO3-/aniones x K+/cationes fue significativa para las concentraciones de P, K, Ca y Mg en hojas; K, Ca y Mg en tallos; y Ca y Mg en tubérculos. Las relaciones NO3-/aniones y K+/cationes, y la interacción NO3-/aniones x K+/cationes no afectaron estadísticamente el diámetro de tubérculo, la materia seca del tubérculo, el número de tubérculos y el rendimiento. Estos resultados indican que la producción de papa en un sistema hidropónico cerrado y sustrato de fibra de coco las relaciones NO3-/aniones y K+/cationes no deben ser mayores a 60/100 y 15/100, respectivamente, ya que relaciones altas de NO3-/aniones (80/100) y K+/cationes (55/100) reducen el rendimiento de tubérculos 16.7% y 12.8%, cada una

A la relación NO3-/K+ en la solución nutritiva (SN) se le considera un factor clave para obtener altos rendimientos; sin embargo, por la falta de investigaciones al respecto, su importancia está sujeta a discusión. El objetivo de este trabajo fue evaluar en invernadero el efecto de tres relaciones NO3-/aniones (40, 60 y 80/100) y tres de K+/cationes (15, 35 y 55/100) sobre el crecimiento, composición mineral y el rendimiento de pepino (Cucumis sativus L. cultivar Luxell). El experimento constó de dos etapas: la 1, desde la siembra al trasplante, y la 2, desde trasplante hasta cosecha; en ambas etapas el diseño experimental utilizado fue completamente al azar con arreglo factorial 32. En la etapa1, los efectos de las relaciones NO3-/K+ sobre las variables de crecimiento no fueron significativos, aunque para las concentraciones de P, K y Mg en hojas hubo significancia. En la etapa 2, hubo diferencias (p≤ 0.05) en el rendimiento para la relación NO3-/ aniones y para K+/cationes, pero no para su interacción. El mayor rendimiento (90.56 t ha-1) se obtuvo con la relación intermedia (60/100 NO3-/aniones), mientras que para la relación K+/cationes el mayor rendimiento (83.40 t ha-1) fue obtenido también con la relación intermedia (35/100). Con relaciones altas de NO3-/aniones y de K+/cationes, los rendimientos disminuyen 9.98 y 31.84%, respectivamente, por lo que es indispensable hacer un manejo equilibrado de las relaciones NO3-/aniones y de K+/cationes en la SN para no alterar las concentraciones nutrimentales en las hojas y reducir el rendimiento de pepino cultivado en hidroponía.

Dietary fiber extracted from soybean and chickpea husks was used in the formulation of white bread. Treatments at different concentrations of dietary fiber (DF): bread + 0.15%, 0.3%, 1.5%, 2% soybean dietary fiber (SDF); bread + 0.15%, 0.3%, 1.5%, 2% chickpea dietary fiber (CDF), and a control treatment (Bread 0% DF) were used initially. However, the treatments that showed the greatest improvement effects were: bread + 2% SDF and bread + 2% CDF. The functionality and the nutritional contribution in the treatments were evaluated during four days of storage. The weight loss on the third day of storage was 30% higher in the control treatment than the products with 2% SDF and 2% CDF, while for the evaluation of firmness, the control obtained a hardness of 86 N, and treatments with 2% SDF and 2% CDF 60 N and 45 N, respectively. The presence of phenolic compounds and their antioxidant activity was evident, mainly in the 2% SDF treatment, which had a total phenolic content of 1036, while in the Bread 0% DF it was 232 mgEAC/kg. The antioxidant activity for 2% SDF by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (3-ethyl-benzothiazoline-6-sulfonic acid), and FRAP (ferric reducing antioxidant power) was 1096, 2567, and 1800 µmolTE/kg, respectively. Dietary fiber addition favored the reduction of weight loss and firmness of white bread during storage. In addition, color was not affected and the content calcium, phenolics, as well as antioxidant capacity were slightly improved.

In this work we compared the cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) contents of muscle, liver and placenta of gestating females of the viviparous shark Rhizoprionodon longurio and of muscle, liver and umbilical cord of their respective embryos. The higher values of the essential Cu and Zn were in embryonic or embryo-related tissues (placenta and umbilical cord). Maternal muscle and liver had the highest values of Pb and Cd, respectively. There were significant direct correlations between the Zn and Cd concentrations of placenta and umbilical cord, as well as between maternal muscle and embryonic livers for Pb and Cd, but the relation between these tissues was inverse in the case of Zn. All correlations between the metal content of embryonic tissues and size of the embryos were negative, suggesting an inverse relation between the rate of mother-to-embryo metal transfer and embryonic growth.

The aim of this work was to survey the discharges of dissolved and particulate Cd, Cu, Fe, Mn, Pb and Zn of the eight main rivers of Sinaloa State to the Mexican coastal environment. Zn was the most abundant dissolved metal and Fe was the most abundant particulate (8.02-16.90 and 51.8-1,140.3 μg/L, respectively). Only particulate Mn had significantly (p = 0.028) higher values in summer-fall (rainy season), whereas the significantly (p = 0.036) higher values of dissolved Zn were observed in winter and spring. The highest annual total discharges to Sinaloa coastal waters were those of the rivers San Lorenzo and Piaxtla (2 × 10(3) m.t.) and the lowest those of rivers Baluarte and El Fuerte (349 and 119 m.t., respectively). Pb concentrations may become of concern, because they are higher than the value recommended for the welfare of aquatic communities of natural waters.

The increasing order of the mean concentrations of Cd, Cu, and Zn in the tissues of Mugil cephalus of seven coastal lagoons of Sinaloa State (NW Mexico) was liver > gills > muscle, while for Pb it was gills > muscle ≥ liver. There were no differences between the mean concentrations of Cd and Pb of the three tissues determined in the samples of the seven lagoons and, although there were some significant differences, there was no indication of a latitude-related trend in the distribution of Cu and Zn: the Cu content of the muscle tended to be higher in the northern than in the southern lagoons, although in the case of the gills the highest and lowest mean values indicated an opposite trend, with the highest and lowest values in one southern and one northern lagoon. In the case of the liver, there were no differences and no indication of a regional trend. There were no differences in the mean Zn contents of muscle and gills; in the case of the liver, one of the lagoons of the central part of the state had a significantly higher value than one of the southern lagoons and all the rest had similar values. In addition, there was no clear indication of season-related differences in any of the three tissues. According to our results, the metal contents of the muscle of this species are not of concern for human health, since the allowable ingestion would be in the order of 0.9 kg/day.

This study shows the concentrations of Cd, Cu, Pb, and Zn in the muscle and hepatopancreas of Pacific white shrimps, Litopenaeus vannamei, cultured during 2010 in 26 commercial farms of the three main producer states of the Mexican NW, Sonora, Sinaloa, and Nayarit and compares the results to those obtained in 2000 using samples collected in16 farms of the same states. No significant changes were detected in Cd concentrations, but the 2010 Zn levels were significantly higher in all states in the hepatopancreas and in Sinaloa in the case of the muscle. Cu showed a tendency to higher hepatopancreas values in 2010, but differences were significant only in Sonora and for the global mean value. In contrast, Pb was one order of magnitude lower in both organs in 2010, possibly because of the almost 15 years since leaded gasoline was discontinued in Mexico.

The ranges of concentrations of Cd, Cu, Pb and Zn of the soft tissues of C. corteziensis collected in seven coastal lagoons of NW Mexico were 1.55-7.45, 17.50-166.36, 4.13-9.49 and 245.34-2,304.12 microg/g (dry weight), respectively. Their distributions were not consistent and there were no seasonal trends, indicating different point sources of the metals in each lagoon. The mean Cd and Pb concentrations were 5.34 and 6.30 microg/g (dry weight), which are higher than the values indicative of polluted areas. Our data indicate that only the levels of Cd are a possible health risk in six of these lagoons, and only in the case of regular local consumers. In one, Cu and Zn reach levels of concern.