Browsing by Author "San Martin, Ricardo"

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    Adventitious root initiation in adult and juvenile cuttings of Guindilia trinervis, an endemic plant of Chile suitable for biodiesel production
    (2010) Jordan, Miguel; Prehn, Doris; Gebauer, Marlene; Neumann, Jorge; Margot Parada, Gloria; Velozo, Juan; San Martin, Ricardo
    Guindilia trinervis is a native Chilean shrub that bears seeds with a high content of oil suitable for biodiesel production. It was tested for its capacity to form roots in cuttings of juvenile and adult plants in ex vitro as well as in vitro conditions. Variables such as type of cutting, exogenous application of IBA(1) and time of collection were studied. For adult plants, the best ex vitro rooting (79 %) was obtained with distal polynodal cuttings collected in late summer and treated with 100 mg L-1 IBA, but rooting was also achieved in the presence of water alone (up to 69 %). Juvenile plants displayed the best rooting (84 %) with single node cuttings and 50 mg L-1 IBA, as well as in the presence of Seradix (72 %). This treatment also showed the highest number of roots per explant. In vitro rooting of shoot tips took place on modified MS media supplemented with 1.0 mg L-1 IBA yielding roots up to 82 %, compared to nodal sections that rooted scantily. Rooted material could be acclimated and adapted well to greenhouse and nursery conditions. Controls of adult and juvenile cuttings treated with water exhibited spontaneous rooting in most of the treatments. Cuttings from adult plants harvested in late summer rooted better than those harvested in winter. Spring cuttings collected during flowering and fructification did not root. Results indicate that by means of adventitious root initiation G. trinervis can be effectively propagated by distal cuttings, collected in summer or winter. This may allow large-scale production of plant material with desired traits.
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    CHARACTERISTICS AND MATHEMATICAL MODELING OF CONVECTIVE DRYING OF QUINOA (CHENOPODIUM QUINOA WILLD.): INFLUENCE OF TEMPERATURE ON THE KINETIC PARAMETERS
    (WILEY, 2010) Vega Galvez, Antonio; San Martin, Ricardo; Sanders, Mariela; Miranda, Margarita; Lara, Elena
    The aim of this research was to model the drying kinetics of quinoa and to evaluate the temperature influence on the kinetic parameters of the models used. Prior to drying process, quinoa grains were washed at 60C and the removal of saponins was studied. Hot air drying temperatures were 40, 50, 60, 70 and 80C. Initial saponin content was 6.34%, reaching a final saponin content of 0.25% after 120 min of washing. Sorption isotherm was determined at 60C giving a monolayer moisture content of 0.051 g water/g dry matter. Drying kinetics was modeled with different equations. Diffusional coefficient increased with temperature from 3.78 to 7.67 x 10-11 m2/s, for a range of temperatures between 40 and 80C, with an estimated of E-a 15.95 kJ/mol. According to the statistical tests used, the logarithmic and Weibull models gave the best fit for experimental data (determination coefficient > 0.98, sum squared error < 0.001 and Chi-square < 0.001).
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    Evaluation of guindilla oil (Guindilia trinervis Gillies ex Hook. et Arn.) for biodiesel production
    (2010) San Martin, Ricardo; de la Cerda, Teofilo; Uribe, Adolfo; Basilio, Paola; Jordan, Miguel; Prehn, Doris; Gebauer, Marlene
    Guindilla plants (Guindilia trinervis Gillies ex Hook. et Arn.) are small shrubs that grow wildly in the mountains of Central Chile in soils and climates not suitable for agriculture. Whole guindilla seeds contain 28-29% w/w oil. Cotyledons represent 45% w/w of the seed and contain 63-64% w/w oil. Main unsaturated fatty acids are oleic (63% w/w), linoleic (8% w/w) and gadoleinic (9.5% w/w), while main saturated fatty acids are palmitic (9.1% w/w) and stearic (3.1% w/w). The content of free fatty acids was 0.06%. Transesterification reactions yielded a biodiesel with ester content > 99%; cetane number 59; oxidative stability at 110 degrees C, 18.9 h; kinematic viscosity at 40 degrees C, 4.867 mm(2)/s; cold filter plugging point, CFPP + 4 degrees C; sulfur content 1.0 mg/kg; sulfated ash < 0.01% p/p; acid value 0.024 mg KOH/g and phosphorous content (< 0.5 mg/kg). All values were within European and US specifications. The relatively high CFPP value limits the use of unblended guindilla biodiesel to high temperature weather locations. The high oxidative stability is probably due to the low content (8.8% w/w) of polyunsaturated acids (e. g. C18:2 + C18:3 + C20:2 + C20:3). Guindilla plants grow wildly with estimated yields of 1000 L oil/ha. Plant improvement programs could make these plants a viable alternative for biodiesel production. (C) 2010 Elsevier Ltd. All rights reserved.
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    Molluscicidal effects of saponin-rich plant extracts on the grey field slug
    (2013) Gonzalez-Cruz, Diego; San Martin, Ricardo
    Slug control is a major concern in crop fields because these mollusks consume and damage plants that are destined for human consumption and ornamentation. The grey field slug Deroceras reticulatum (Muller, 1774) is one of the most commonly occurring mollusks with agronomic importance, consuming up to 80% of the leaf surface of raps and other crops. The major difficulty in slug control is that the main products used for this purpose can also endanger non-target animals, such as pets and birds. New methods of control that are naturally based and environmental friendly are urgently required, both for the farmer who applies the product and for the final consumer. In this study, we analyzed the anti-molluscal activity of extracts from three plant with a high content of saponins: Camellia oleifera, Gleditsia amorphoides and Quillaja saponaria. Forced oral injection and histological analyses of the digestive system were performed to measure the effects of the plant extracts against slugs. All three extracts showed anti-feeding activity and toxicity against slugs when injected orally at a range of concentrations between 1 and 4% w/w. All three extracts also damaged the gastric epithelium of the crop region of the slugs, suggesting that they show strong membranolytic properties in the digestive system of these mollusks. This study revealed novel natural compounds that can potentially be used in the control of grey field slugs. The data hereby presented could be useful in future comparative studies between other mollusks with agronomic importance.