Efecto del selenito e inulina en la interacción Capsicum annuum L. - Phytophthora capsici en invernadero

Capsicum annuum L. is a crop of great economic importance in Mexico and is severely affected by the wilt caused by Phytophthora capsici. The objective of this work was to determine the effect of selenite and inulin on the incidence of Phytophthora capsici and the growth of serrano pepper plants (Capsicum annuum L.) in greenhouse. Seedlings 30 days after sowing were treated twice with selenite (100 μM) (Se + PHC) or inulin (200 μM) (I + PHC) per application to the base of the plants: 10 days before and at the time of inoculation with P. capsici (PHC). A PHC control and an absolute control without treatment or inoculation were included. After two weeks of treatment, the control seedlings remained without symptoms, while those inoculated with PHC, and those treated with selenite and inulin and inoculated showed a survival rate of 0, 80 and 40%, respectively. The height was higher in the control seedlings. In plants treated with selenite and inoculated a seedling fresh mass was higher than in the PHC and I + PHC, treatments. The viability of the root was similar in the treatments with selenite and inulin and decreased in the seedlings inoculated with PHC. Selenite was more effective than inulin in reducing the incidence of the disease, increasing the fresh mass and maintaining the viability of the plant tissue. The results suggest the potential use of selenite and inulin in the integral management of P. capsici.Keywords: incidence, fructans, plant protection, selenium, symptoms of wiltCapsicum annuum L. es un cultivo de gran importancia económica en México y es severamente afectado por la marchitez ocasionada por Phytophthora capsici. El objetivo de este trabajo fue determinar el efecto del selenito e inulina sobre la incidencia de Phytophthora capsici y el crecimiento de las plantas de chile serrano (Capsicum annuum L.) en invernadero. Plántulas de 30 días después de la siembra se trataron dos veces con selenito (100 µM) (Se+PHC)  o inulina (200 µM) (I+PHC) por aplicación a la base de las plantas: 10 días antes y al momento de la inoculación con P. capsici (PHC). Se incluyó un control PHC y un control absoluto sin tratar ni inocular. Después de dos semanas de tratamiento, las plántulas control permanecieron sin síntomas, mientras que las inoculadas con PHC, y las tratadas con selenito e inulina e inoculadas mostraron un índice de supervivencia de 0, 80 y 40%, respectivamente. La altura fue superior en las plántulas control. En las plantas tratadas con selenito e inoculadas se registró una masa fresca de plántula superior a los tratamientos PHC e I+PHC. La viabilidad de raíz fue similar en los tratamientos con selenito e inulina y disminuyó en las plántulas inoculadas con PHC. El selenito fue más efectivo que la inulina en reducir la incidencia de la enfermedad, incrementar la masa fresca y mantener la viabilidad del tejido vegetal. Los resultados sugieren el uso potencial del selenito y la inulina en manejo integral de P. capsici. Palabras clave: incidencia, fructanos, protección de plantas, selenio, síntoma de marchite

Effective antimicrobial activity of ZnO and Yb-doped ZnO nanoparticles against Staphylococcus aureus and Escherichia coli

Nanostructured Zn1-xYbxO (0.0 ≤ x ≤ 0.1) powders were prepared by the solution method using polyvinyl alcohol (PVA) and sucrose. The effect of the ytterbium doping content on the structural, morphological, optical and antimicrobial properties was analyzed. X-ray diffraction (XRD) analysis revealed that the hexagonal wurtzite structure was retained, and no secondary phases due to doping were observed. The crystallite size was under 20nm for all the Zn1-xYbxO (0.0 ≤ x ≤ 0.1) powders. The optical band gap was calculated, and the results revealed that this value increased with the ytterbium content, and the Eg values varied from 3.06 to 3.10 eV. The surface chemistry of the powders was analyzed using X-ray photoelectron spectroscopy (XPS), and the results confirmed the oxidation state of ytterbium as 3+ for all the samples. Zn1-xYbxO (0.0 ≤ x ≤ 0.1) nanoparticles were tested as antimicrobial agents against Staphylococcus aureus and Escherichia coli, resulting in a potential antimicrobial effect at most of the tested concentrations. These results were used in an artificial neural network (ANN). The results showed that it is possible to generate a model capable of forecasting the absorbance with good precision (error of 1–2%)