Interactive Effects of the Potassium and Nitrogen Relationship on Yield and Quality of Strawberry Grown Under Soilless Conditions.

K and N are the nutrients with the highest influence on yield and fruit quality. From this perspective, the aim of this study was to determine the effect of N as NO3-, K+ and their interactions on the yield and quality of strawberries grown under soilless conditions. A solution comprised of micronutrients based on an amended Steiner's Universal Nutrient Solution was mixed with 4 levels of K+ (5, 7, 9 and 11 mol m-3) and 3 levels of NO3- (9, 12, and 15 mol m-3) to obtain 12 treatments. The results suggest that 15 mol m-3 of NO3- in the nutrient solution produced the highest yield, but fruit with low nutraceutical quality. On the other hand, 11 mol m-3 of K+ in the nutrient solution produced the highest yield and fruit with the best nutraceutical quality. The ionic concentration of the Universal Steiner's Nutrient Solution proved to be the best nutritional option to maximize the yield and nutraceutical quality of strawberry fruit. The increase in NO3- concentration in the nutrient solution produced a higher yield of strawberries, while a higher concentration of K+ improved fruit quality, thus reaffirming the significance of nutrients within the plant functioning of this crop.

Carbon Sequestration of Caesalpinia platyloba S. Watt (Leguminosae) (Lott 1985) in the Tropical Deciduous Forest.

Caesalpinia platyloba was evaluated as an alternative for the retention of atmospheric carbon and as a feasible and viable economic activity in terms of income for tropical deciduous forest (TDF) peasants in the carbon markets. A total of 110 trees of C. platyloba from plantations and a TDF in the Northwest of Mexico were sampled. Growth (increase in height, diameter, and volume curves) was adjusted to assess their growth. Growth of individuals (height, diameter at breast height [DBH], age, and tree crown cover) was recorded. The Schumacher model (H = ß(0)e(ß1 • E-1)), by means of the guided curve method, was used to adjust growth models. Information analysis was made through the non-linear procedure with the multivariate secant or false position (DUD) method using the SAS software. Growth and increase models revealed acceptable adjustments (pseudo R(2)>0.8). C. platyloba reaches >8m of height with 12 cm in diameter and 550 cm(3) of volume, presenting the highest increase at 11 years considered as basal age. Highest significant density of wood was in good quality sites (0.80 g • cm(-3)), with a carbon content (average of 99.15tC • ha(-1)) at the highest density of 2500 trees • ha(-1) (without thinning). Average incomes of US$483.33tC • ha(-1) are expected. The profitability values (NPW = US$81,646.65, IRR = 472%, and B/C = 0.82) for C. platyloba make its cultivation a viable and profitable activity, considering a management scheme of the income derived from wood selling and from carbon credits.

Mineral content and biochemical variables of Aloe vera L. under salt stress.

Despite the proven economic importance of Aloe vera, studies of saline stress and its effects on the biochemistry and mineral content in tissues of this plant are scarce. The objective of this study was to grow Aloe under NaCl stress of 0, 30, 60, 90 and 120 mM and compare: (1) proline, total protein, and enzyme phosphoenolpyruvate carboxylase (PEP-case) in chlorenchyma and parenchyma tissues, and (2) ion content (Na, K, Ca, Mg, Cl, Fe, P. N, Zn, B, Mn, and Cu) in roots, stems, leaves and sprouts. Proline and PEP-case increased as salinity increased in both parenchyma and chlorenchyma, while total protein increased in parenchyma and decreased in chlorenchyma, although at similar salt concentrations total protein was always higher in chlorenchyma. As salinity increased Na and Cl ions increased in roots, stems, leaves, while K decreased only significantly in sprouts. Salinity increases typically caused mineral content in tissue to decrease, or not change significantly. In roots, as salinity increased Mg decreased, while all other minerals failed to show a specific trend. In stems, the mineral concentrations that changed were Fe and P which increased with salinity while Cu decreased. In leaves, Mg, Mn, N, and B decreased with salinity, while Cu increased. In sprouts, the minerals that decreased with increasing salinity were Mg, Mn, and Cu. Zinc did not exhibit a trend in any of the tissues. The increase in protein, proline and PEP-case activity, as well as the absorption and accumulation of cations under moderate NaCl stress caused osmotic adjustment which kept the plant healthy. These results suggest that Aloe may be a viable crop for soil irrigated with hard water or affected by salinity at least at concentrations used in the present study.

Distinctive autoantibody profile in Mexican Mestizo systemic sclerosis patients.

Systemic sclerosis (SSc) shows variable clinical expression among different ethnic groups. Herein, we describe the clinical features, prevalence of organ involvement, and autoantibody profile in Mexican Mestizo SSc patients and we compare them with patients from other ethnic groups.We included 139 SSc patients. They underwent clinical evaluation and were tested for antinuclear antibodies (ANA), anticentromere antibodies (ACA), anti-topoisomerase I, anti-RNA polymerase III, anti-U1 RNP, anti-U3 RNP, anti-U11/U12 RNP, anti-Th/To, anti-PM-Scl, anti-Ku, antinucleosome, anti-double-stranded DNA (dsDNA), anti-Sm, anti-SSA, and anti-SSB antibodies. Female predominance (93.5%) was noted; 56.8% of patients had limited cutaneous SSc; 91% had peripheral vascular involvement; 70% had joint involvement; 27% had musculoskeletal damage; 66% had gastrointestinal involvement; 41% had interstitial lung disease; 32% had pulmonary arterial hypertension (PAH); 11% had cardiac involvement; and in 1.4% renal involvement was observed. Our patients showed lower frequency of renal crisis and higher frequency of PAH than patients from other ethnic groups; also they showed higher frequency of ACA than Japanese and African American patients, higher frequency of anti-topoisomerase I than Caucasian and African American patients, higher frequency of anti-PM-Scl and anti-Ku and lower frequency of anti-RNA Pol III than the other ethnic groups. High frequencies of antinucleosome (41%) and anti-dsDNA (63%) were identified. SSc-specific autoantibody frequencies are different in our patients and in those from other ethnic groups; associations of autoantibodies with clinical manifestations are confirmed in our patients. Ethnicity and the interaction of gene and environmental factors may influence the clinical picture and autoantibody profile in SSc patients.

Effects of plant growth promoting bacteria and mycorrhizal on Capsicum annuum L. var. aviculare ([Dierbach] D'Arcy and Eshbaugh) germination under stressing abiotic conditions.

Capsicum annuum var. aviculare to Tarahumara and Papago Indians and farmers of Sonora desert is a promising biological and commercial value as a natural resource from arid and semiarid coastal zones. Traditionally, apply synthetic fertilizers to compensate for soil nitrogen deficiency. However, indiscriminate use of these fertilizers might increase salinity. The inoculation by plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) represents an alternative as potential bio fertilizer resources for salty areas. Seeds ecotypes from four areas of Sonora desert (Mazocahui, Baviacora, Arizpe, La Tortuga), in order to inoculate them with one species of PGPB and AMF. Two germination tests were carried out to study the effect of salinity, temperature regime (night/day) and inoculation with PGPB and AMF growth factors measured on germination (percentage and rate), plant height, root length, and produced biomass (fresh and dry matter). The results indicated that from four studied ecotypes, Mazocahui was the most outstanding of all, showing the highest germination under saline and non-saline conditions. However, the PGPB and AMF influenced the others variables evaluated. This study is the first step to obtain an ideal ecotype of C. a. var. aviculare, which grows in the northwest of México and promoting this type of microorganisms as an efficient and reliable biological product. Studies of the association of PGPB and AMF with the C. a. var. aviculare-Mazocahui ecotype are recommended to determine the extent to which these observations can be reproduced under field conditions.

Efecto de sistemas de labranza e incorporación de abono verde (lablab purpureus L) sobre la respiración edáfica en un yermososol háplico / Effect of tillage systems and green manure (lalab purpureus L) incorporación on edafic respiration in a haplic yermosol

La adopción de sistemas de labranza reducida y utilización de abonos verdes en áreas de riego en México ha sido muy limitada, a pesar de múltiples reportes sobre los beneficios de tales prácticas. La preparación convencional de suelos, con un paso de arado, uno o dos rastreos y escasa incorporación de residuos orgánicos, ha propiciado una severa degradación del suelo, sobre todo en zonas áridas de baja fertilidad natural y principalmente en el contenido de materia orgánica (MO). Se evaluó el efecto de labranza convencional, reducida y mínima, y del uso de abono verde, en la recuperación de fertilidad en un suelo árido con pobres características nutrimentales y contenido de MO del 0,54 por ciento. Como abono verde se utilizó el frijol dolichos Lablab purpureus en dos condiciones (con o sin incorporación) y se consideraron dos fechas de muestreo. Las muestras de suelo a 0-30cm mostraron incrementos (promedio) de MO (0,12 por ciento), K (12,64mgúkg-¹) y actividad microbiana (36,6 por ciento) en el segundo muestreo con respecto al primero, previo a la incorporación del abono verde. Las parcelas con incorporación de abono tuvieron incrementos de MO (0,17 por ciento), K (12,46mgúkg-¹) y tasa de respiración (48,3 por ciento) en los primeros 10cm de suelo, respecto a las parcelas sin incorporación. Las variables estudiadas fueron analizadas en conjunto por correlación canónica (ACC) utilizando el programa CANOCO, cuyos resultados muestran un incremento significativo tras la incorporación del abono verde con respecto al contenido de carbón mineralizado, macronutrientes (N, P y K) y MO

Impacto de la asociación de cultivos en la densidad de insectos hemípteros entomófagos / The impact of interplanting crops on the density predation of hemiptera predators

Se evaluó el impacto de cultivos intercalados con algodonero (Gossypium hirsutum) en la densidad de insectos hemípteros depredadores. Además se pretendió encontrar evidencias de interdepredación. Los cultivos intercaladados con algodonero fueron canola (Brassica napus), alfalfa (medicago sativa), veza (Vicia villosa) y esparceta (Onobrychis viciifolia). La densidad fue presentada como promedio de individuos en 30m lineales (i/30m). Se establecieron también parcelas de algodonero, sin cultivos intercalados, bajo tratamientos con productos para control de gusano rosado (Pectinophora gossypiella) y un testigo sin ningún tipo de control. Los cultivos intercalados al algodonero promovieron densidades altas de depredadores, existiendo migración significativa de éstos al algodonero intercalado al final de la temporada. Geocoris spp. mostró sumayor densidad en veza, con un aumento gradual hasta el muestreo final en sus estados de ninfa y adulto. Nabis spp. también fue más abundante en veza, como ninfa al principio y como adulto a la mitad de la temporada, y disminuyó posteriormente su densidad en todos los cultivos, siendo en la segunda mitad del ciclo superior en alfalfa y esparceta. Orius spp. mantuvo su mayor densidad en alfalfa, excepto en el último muestreo, cuando fue mayor en el algodonero intercalado. Una significativa reducción de Orius spp. en proporción al incremento de Geocoris spp., así como otros resultados, proporcionaron indicios de interdepredación de Geocoris spp. hacia Orius spp. e incluso hacia Nabis spp. El tratamiento insecticida químico presentó los valores más bajos para todas las especies evaluadas.

El uso de compostas como alternativa ecológica para la producción sostenible del Chile (capsicum annuum L): en zonas áridas / The use of compost as an ecological alternative for sustainable production of hot pepper (Capsicum annuum L) in arid zones

El Chile (Capsicum annuum L.) es una de las especies cultivadas más importantes en México y muchos otros países. Uno de los problemas más importantes que actualmente enfrenta no sólo este cultivo, sino la agricultura en general, es la pérdida de la fertilidad del suelo. Conociendo la importancia de la materia orgánica en el suelo, se realizó un experimento con la variedad de chile Anaheim TMR 23 en un suelo yermosol háplico. Como tratamiento, se aplicaron tres dosis de composta (25, 50 y 100t-ha-1). Estos tratamientos se compararon con una parcela testigo sin la aplicación de composta, con el fin de determinar la dosis para obtener una mejor producción. Se evaluó en el suelo la humedad del suelo, capacidad de campo, humedad aprovechable, porosidad total, densidad aparente, densidad real y punto de marchitamiento permanente. Los resultados mostraron que las dosis mayores mejoraron todas estas variables físicas del suelo. No se encontraron diferencias significativas (P=0,05) en lo que respecta al rendimiento, sin embargo, se muestra una tendencia de mayor rendimiento en la dosis de 25t-ha-1. La mayor producción de frutos sí presentó diferencias significativas (P=0,05) y correspondió a la dosis de 25t-ha-1. Con base en estos resultados se recomienda la aplicación de dicha dosis para este tipo de suelos yermosol háplico para el cultivo del chile, mientras que las dosis mayores (50 y 100t-ha-1) se recomiendan para mejorar las características físicas del suelo en condiciones áridas en plazos cortos de tiempo