A hand-held SPAD-502 chlorophyll meter provides rapid and nondestructive measures of chlorophyll content. Integrating this meter into basil production can reduce costs and may improve basil quality. This study determined the relationship between SPAD-502 and the leaf chlorophyll (total, a, b). Over 500 leaf samples were collected from a field study conducted in 2006. Comparisons between chlorophyll contents and meter readings showed that SPAD meter readings were positively correlated to actual chlorophyll content. Regression analysis SPAD readings should be corrected by leaf area. Findings suggest that SPAD meter readings can be used as a tool to improve Basil quality and for assessing the relative chlorophyll content during the growing season.

Salinity stress limited the production in over 30% of irrigated crops and 7% of dryland agriculture worldwide. The objective was to evaluate the effects of NaCl-stress on the enzymatic activity in tomato. Two experiments were carried out in germination and early vegetative growth stages. The activity of proline and peroxidase of eight varieties (Missouri, Yaqui, Vita, Feroz, Rio Grande, Tropic, Ace, and Floradade) submitted to NaCl concentrations (0, 50, 100, 150 and 200 mM de NaCl) and the semi-quantitative activity of 19 enzymes APY ZYM^® were measured under a completely randomized design with four replications. Data were analyzed using univariate-multivariate analysis of variance, Tukey’s HSD (p = 0.05), canonical discriminant and cluster analysis. The results showed significant differences between varieties and NaCl in proline content. Proline increased as the NaCl concentration increased. Peroxidase did no show significant differences. Eight enzymes were included within the model to properly classify the varieties and NaCl. In shoots, varieties and NaCl showed that enzymatic activity was higher in the order of alkaline-phosphatase > leucine arylamidase > acid phosphatase > naphthol-AS-BI-phosphohydrolase > n-acetyl-β-glucosaminidase > β-galactosidase, while in roots was higher in the order of alkaline-phosphatase > naphthol-AS-BI-phosphohydrolase > acid phosphatase > n-acetyl-β-glucosaminidase. Acid and alkali phosphatase, lipase, esterase, β-galactosidase, and trypsin can be a potential biomarker for NaCl-stress tolerance in tomato.

La enseñanza basada en investigación hace referencia al diseño del programa académico donde los estudiantes requieren hacer conexiones intelectuales y prácticas entre el contenido y habilidades declarados en el programa, y los enfoques de investigación y fronteras de las disciplinas que lo componen. Por lo que se puede establecer que la metodología ABI ha logrado el interés del profesorado por fortalecer sus capacidades investigativas, capacitarse en conocimientos teóricos sobre el ABI e incluir al alumnado en las investigaciones, para poder con todo ello hacer frente a la necesidad de formar profesionistas con creatividad; con capacidad de analizar, pensar críticamente, escribir y expresarse con eficacia; resolver problemas complejos, y sintetizar, entre otros retos de la realidad educativa del siglo XXI.

Potassium (K) influences the variables that determine quality of fruit and the concentration of phytonutrients to human health and therefore consumer preferences. The objective of this study was to evaluate the effect of different concentrations of K in the nutrient solution (5, 7, 9 and 11 mM of K) on yield and quality of Cantaloupe fruits under greenhouse conditions. The experiment was conducted in pots using a completely randomized design with 15 replications. Analysis of variance, correlation, regression and multiple comparisons among means (Tukey p<0.05) were performed. Results showed higher values of yield, average fruit weight, equatorial diameter, pulp thickness, fruit firmness, soluble solids content, phenolic content and antioxidant capacity of fruits at the concentrations of 9 and 11 mM of K. All variables, except equatorial diameter, increased their values as K concentrations increased, showing a lineal, positive and significant trend, which evidences that the optimal dose of K in muskmelon is higher than 11 mM, being suggested for future research, to evaluate concentrations above this value.