In this study a morphological and anatomical variation analysis was carried out with leaves and fruits of Sechium edule, collected in the central region of Veracruz, Mexico. The collected fruits were classified in eight groups according to their typical characteristics. The results showed that the phenotypical distinction of the studied infraspecific S. edule complex is related to morphological and anatomical changes in order to improve the adaptive specialization of the different chayote types with respect to the environment, and suggests that cultivated chayotes have followed different routes in the process of coevolution with man, showing stable variation patterns in the so-called ''green'' and ''yellow'' groups. Considering the phenotypic variability existing in the analyzed characters, a certain prediction may be proposed about the direction the variation patterns may follow facing the transference of chayotes to environments of lower altitudes than mountain cloud forest.

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The Sechium edule Perla Negra cultivar is a recently-obtained biological material whose progenitors are S. edule var. nigrum minor and S. edule var. amarus silvestrys, the latter of which has been reported to have antiproliferative activity against the HeLa P-388 and L-929 cancer cell lines. The present study aimed to determine if the methanolic extract of the fruit of the Perla Negra cultivar had the same biological activity. The methanolic extract was phytochemically characterized by thin layer chromatography (TLC) and column chromatography (CC), identifying the terpenes and flavonoids. The compounds identified via high performance liquid chromatography (HPLC) were Cucurbitacins B, D, E, and I for the terpene fractions, and Rutin, Phlorizidin, Myricetin, Quercetin, Naringenin, Phloretin, Apigenin, and Galangin for the flavonoid fractions). Biological activity was evaluated with different concentrations of the methanolic extract in the HeLa cell line and normal lymphocytes. The methanolic extract inhibited the proliferation of HeLa cells (IC50 1.85 µg·mL−1), but the lymphocytes were affected by the extract (IC50 30.04 µg·mL−1). Some fractions, and the pool of all of them, showed inhibition higher than 80% at a concentration of 2.11 µg·mL−1. Therefore, the biological effect shown by the methanolic extract of the Perla Negra has some specificity in inhibiting tumor cells and not normal cells; an unusual feature among molecules investigated as potential biomedical agents.

Los cultivos absorben en promedio de 20 a 40% del fertilizante aplicado, el porcentaje restante se pierde del sistema agrícola por diversos mecanismos, ocasionando cuantiosas pérdidas económicas y contaminación ambiental. Entre los beneficios del uso de microorganismos en la agricultura está su capacidad para mejorar la asimilación de nutrimentos. Se realizó un experimento en campo cuyo objetivo fue evaluar el efecto de la inoculación de biofertilizantes bacterianos y fúngicos sobre la eficiencia de asimilación del fertilizante nitrogenado en el cultivo de trigo. El diseño experimental fue de bloques completos al azar con cuatro repeticiones y nueve tratamientos de biofertilización empleando la técnica de dilución isotópica de 15N para determinar el N en la planta derivado del fertilizante y el porcentaje de utilización del fertilizante N. La fertilización química produjo los mayores rendimientos de grano y asegura su calidad. La inoculación del trigo con HVA incrementó significativamente el rendimiento de grano hasta en 1 291 kg ha-1, la cantidad de N en la planta proveniente del fertilizante hasta en 15 kg y la eficiencia de utilización del fertilizante nitrogenado hasta en 11% en comparación con el testigo sin inocular. Hubo diferencias significativas en la interacción planta-microorganismo en la producción de biomasa y asimilación de N.