Contribución de Amynthas gracilis (Megascolecidae) y de Octolasion cyaneum (Lumbricidae) a la estabilidad física del suelo : una experiencia en mesocosmos

The contribution of the introduced species Amynthas gracilis (Kinberg, 1867) and Octolasion cyaneum (Savigny, 1826) to the physical stability of the soil was evaluated in a mesocosm experiment. Pore formation and stable aggregates were measured; as well as changes in bulk density, porosity, and soil moisture. Mesocosm pots were organized into three treatments: 1- soil + Amynthas gracilis, 2- soil + Octolasion cyaneum and 3- soil (control containers). The experiment ran for 13 weeks and it was conducted in controlled conditions in a greenhouse. At the end of the experiment both treatments with earthworms had higher number of pores and stable aggregates at the two considered depths (0 - 5 cm and 5 - 10 cm). The presence of both earthworm species favors the formation of a significantly higher proportion of stable aggregates larger than 5 mm (60%), when compared to the control without worms. These structures helped maintaining bulk density and porosity and improved water circulation. The results show that when compared to the control, both treatments had a lower loss of pore space, lower bulk density, and higher soil moisture, all attributable to earthworm presence. It is concluded that, despite both being introduced species, in intensive agricultural systems, A. gracilis and O. cyaneum can contribute to the maintenance of soil physical stability thus helping to preserve the sustainability of agro-ecosystems, even if native species became rare or locally extinct.En un experimento de mesocosmos se evaluó la contribución a la estabilidad física del suelo de las especies introducidas Amynthas gracilis (Kinberg, 1867) y Octolasion cyaneum (Savigni, 1826). Se midió la formación de poros y de agregados estables, así como cambios en la densidad aparente, porosidad y humedad del suelo. Los contenedores de los mesocosmos fueron organizados en tres tratamientos: 1- suelo + A. gracilis, 2. Soil + O. cyaneum, and 3. Soil (contenedores control). El experimento se realizó a lo largo de 13 semanas en condiciones controladas en invernáculo. Al final del experimento los tratamientos con ambas especies generaron poros y mostraron mayor proporción de agregados estables a las dos profundidades consideradas (0 - 5 cm y 5 - 10 cm). Ambas especies de lombrices facilitaron la generación de una proporción significativamente mayor de agregados mayores a 5 mm (60%), en comparación con los controles sin lombrices. Estas estructuras ayudaron a mantener la densidad aparente y la porosidad y mejoraron la circulación de agua. Los resultados muestran que, comparados con el control, ambos tratamientos tuvieron una menor pérdida de espacio de poros, menor densidad aparente y mayor humedad de suelo, todos atribuibles a la presencia de las lombrices. Se concluyó que, a pesar de ser ambas especies introducidas, en sistemas agrícolas intensivos A. gracilis y O. cyaneum pueden contribuir al mantenimiento de la estabilidad del suelo, ayudando así a preservar la sustentabilidad de los agroecosistemas, aun cuando las especies nativas puedan convertirse en raras o localmente extintas.Fil: Falco, Liliana. Universidad Nacional de LujánFil: Coviella, Carlos. Universidad Nacional de Lujá

Estudi de viabilitat de vivendes de renda lliure en bloc aïllat a Can Amat (San Esteve de Sesrovires)

El objecte del present document és el desenvolupament d’un estudi de viabilitat de Tres blocs plurifamiliars a la població de Sant Esteve Sesrovires per a l’Escola Politècnica Superior d’Edificació de Barcelona, per part de l’alumne Ivan Alexandre Coviella Carreras.L’objectiu del present treball és obtenir una sèrie de dades que permetin decidir el producte immobiliari proposat és econòmicament viable, mitjançant l’aplicació dels coneixements adquirits.L’estudi de viabilitat es basa principalment en el desenvolupament de quatre estudis previs: Estudi jurídic, on es realitza una mostra de dades referents al solar, al Cadastre i al Registre de la Propietat. Estudi legal-urbanístic, consistent en normativa urbanística de Sant Esteve Sesrovires i dels articles d’aplicació al nostre solar. Estudi de mercat, on es realitza un treball de camp, recollint dades de promocions immobiliàries similars al nostre producte immobiliari proposat i realitzant un estudi de la competència. Estudi econòmic-financer on, mitjançant les dades recollides a l’estudi de mercat, i fixant una rendibilitat mínima esperada de la promoció, establir les previsions de la tresoreria i la inversió necessària. Amb el desenvolupament d’aquests quatre apartats i la posterior definició del nostre producte immobiliari i les necessitats de recursos per a la seva realització, s’arribarà a unes conclusions necessàries per a arribar a la decisió final sobre la viabilitat de la promoció

A novel source of cytoplasmic male sterility in Calibrachoa pubescens

Calibrachoa pubescens is a species native from the south of Brazil, Uruguay and northeast Argentina. An accession identified as 7.3.1.1 was collected at San Martín Department in Corrientes Province, Argentina and is included in the calibrachoa breeding program at the Institute of Floriculture, INTA. This accession is male sterile and produces male-sterile progeny, characterized by the lack of pollen production. Male sterility may be controlled by nuclear or cytoplasmic genes with each type presenting a different mode of inheritance. The objective of this research was to present a novel source of cytoplasmic male sterility in Calibrachoa pubescens. Crosses were made in the greenhouse between the male-sterile line 7.3.1.1 as the female parent and seven male-fertile lines of diverse origin. F1s were backcrossed and self-pollinated. Individual plants of the progenies were classified as male-fertile or male-sterile according to pollen viability. Analyses of observed segregations showed that male sterility observed in 7.3.1.1 results from the interaction of a male sterile cytoplasm and nuclear restorer genes. A novel male sterile cytoplasm is now available for breeders. Main advantages of cytoplasmic male sterility in ornamentals breeding are: efficient hybrid production, increased flower longevity, avoidance of pollen allergens and control of plant invasiveness.Inst. de Genética "Ewald A. Favret"- IGEAFFil: Colombo, Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Coviella, Maria Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Intistuto de Floricultura; ArgentinaFil: Hagiwara, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; Argentin

Reproductive biology and functional response of Dineulophus phtorimaeae, a natural enemy of the tomato moth, Tuta absoluta

The tomato moth, Tuta absoluta (Lepidoptera: Gelechiidae), is a major pest in South America and is at present an important invasive species in the Mediterranean Basin. The larval stadium mines leaves, stems, and fruits, and chemical control is the most used control method in both its original range and the invaded distribution regions. Since current T. absoluta control strategies seem limited, biological control is a prominent tool to be applied abroad. The naturally occurring larval ectoparasitoid in Argentina and Chile Dineulophus phtorimaeae (Hymenoptera: Eulophidae) has been reported to have potential biocontrol efficiency. In this study, the ovigeny strategy of D. phtorimaeae was analyzed throughout the adult female lifetime, and the functional response of females offered a range of 2-15 T. absoluta larvae was measured over a 48-hour period. Mean D. phtorimaeae egg load was 4.15 eggs, and egg production resulted in extremely synovigenic behavior. Meanwhile, a decreasing number of eggs, due to resorption, was found. Proportions of attacked (host-fed and/or parasitized) and only host-fed hosts by the ectoparasitoid were density independent for the tested host range, exhibiting a type I functional response to T. absoluta, with an attack rate of 0.20 host larvae. Meanings of this reproductive strategy in evolutionary time as well as the consequences for augmentative biological control programs are discussed.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

Reproductive biology and functional response of Dineulophus phtorimaeae, a natural enemy of the tomato moth, Tuta absoluta

The tomato moth, Tuta absoluta (Lepidoptera: Gelechiidae), is a major pest in South America and is at present an important invasive species in the Mediterranean Basin. The larval stadium mines leaves, stems, and fruits, and chemical control is the most used control method in both its original range and the invaded distribution regions. Since current T. absoluta control strategies seem limited, biological control is a prominent tool to be applied abroad. The naturally occurring larval ectoparasitoid in Argentina and Chile Dineulophus phtorimaeae (Hymenoptera: Eulophidae) has been reported to have potential biocontrol efficiency. In this study, the ovigeny strategy of D. phtorimaeae was analyzed throughout the adult female lifetime, and the functional response of females offered a range of 2-15 T. absoluta larvae was measured over a 48-hour period. Mean D. phtorimaeae egg load was 4.15 eggs, and egg production resulted in extremely synovigenic behavior. Meanwhile, a decreasing number of eggs, due to resorption, was found. Proportions of attacked (host-fed and/or parasitized) and only host-fed hosts by the ectoparasitoid were density independent for the tested host range, exhibiting a type I functional response to T. absoluta, with an attack rate of 0.20 host larvae. Meanings of this reproductive strategy in evolutionary time as well as the consequences for augmentative biological control programs are discussed.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

Tomo 48 • N° 1 •

Abstract The contribution of the introduced species Amynthas gracilis (Kinberg, 1867) and Octolasion cyaneum (Savigny, 1826) to the physical stability of the soil was evaluated in a mesocosm experiment. Pore formation and stable aggregates were measured; as well as changes in bulk density, porosity, and soil moisture. Mesocosm pots were organized into three treatments: 1-soil + Amynthas gracilis, 2-soil + Octolasion cyaneum and 3-soil (control containers). The experiment ran for 13 weeks and it was conducted in controlled conditions in a greenhouse. At the end of the experiment both treatments with earthworms had higher number of pores and stable aggregates at the two considered depths (0 -5 cm and 5 -10 cm). The presence of both earthworm species favors the formation of a significantly higher proportion of stable aggregates larger than 5 mm (60%), when compared to the control without worms. These structures helped maintaining bulk density and porosity and improved water circulation. The results show that when compared to the control, both treatments had a lower loss of pore space, lower bulk density, and higher soil moisture, all attributable to earthworm presence. It is concluded that, despite both being introduced species, in intensive agricultural systems, A. gracilis and O. cyaneum can contribute to the maintenance of soil physical stability thus helping to preserve the sustainability of agro-ecosystems, even if native species became rare or locally extinct. Revista de la Facultad de Ciencias Agrarias Resumen En un experimento de mesocosmos se evaluó la contribución a la estabilidad física del suelo de las especies introducidas Amynthas gracilis (Kinberg, 1867) y Octolasion cyaneum (Savigni, 1826). Se midió la formación de poros y de agregados estables, así como cambios en la densidad aparente, porosidad y humedad del suelo. Los contenedores de los mesocosmos fueron organizados en tres tratamientos: 1-suelo + A. gracilis, 2. Soil + O. cyaneum, and 3. Soil (contenedores control). El experimento se realizó a lo largo de 13 semanas en condiciones controladas en invernáculo. Al final del experimento los tratamientos con ambas especies generaron poros y mostraron mayor proporción de agregados estables a las dos profundidades consideradas (0 -5 cm y 5 -10 cm). Ambas especies de lombrices facilitaron la generación de una proporción significativamente mayor de agregados mayores a 5 mm (60%), en comparación con los controles sin lombrices. Estas estructuras ayudaron a mantener la densidad aparente y la porosidad y mejoraron la circulación de agua. Los resultados muestran que, comparados con el control, ambos tratamientos tuvieron una menor pérdida de espacio de poros, menor densidad aparente y mayor humedad de suelo, todos atribuibles a la presencia de las lombrices. Se concluyó que, a pesar de ser ambas especies introducidas, en sistemas agrícolas intensivos A. gracilis y O. cyaneum pueden contribuir al mantenimiento de la estabilidad del suelo, ayudando así a preservar la sustentabilidad de los agroecosistemas, aun cuando las especies nativas puedan convertirse en raras o localmente extintas. Palabras clave poros • estabilidad física del suelo • estabilidad de agregados • especies introducidas • lombrice

Modificaciones fisarias en la rata tras enclavijamiento: estudio comparativo entre implantes plásticos y metálicos

El presente trabajo se efectuó para estudiar las modificaciones locales inducidas por implantes que atraviesan el cartílago de crecimiento. Se utilizaron 20 ratas macho de 5 semanas de edad. A través de una incisión parapatelar externa se insertó una aguja de Kirschner en el fémur derecho y una de plástico en el izquierdo, ambas de 1 mm de diámetro, atravesando la placa fisaria distal. Cinco animales por grupo fueron sacrificados al cabo de 1,2,8 y 16 semanas. Tras denudar los fémures de partes blandas, su extremidad distal fue procesada para estudio histológico, histomorfométrico e histoquímico. Los resultados demuestran que desde la segunda semana la fisis tuvo mayor altura en los fémures con implante metálico, aunque las diferencias no fueron estadísticamente significativas. No se apreciaron diferencias histológicas remarcables entre las placas fisarias con uno u otro implante a lo largo del estudio. La captación de azul alcián fue asimismo similar, salvo en la decimosexta semana en que fue marcadamente menor alrededor de los implantes metálicos. Se concluye que la naturaleza del implante condiciona las modificaciones fisarias inducida por éste.A study is made of the local changes induced by implants transversing growth cartilage. Twenty 5-week-old rats were used. A Kirschner needl e 1 mm. of diameter was introduced through an external parapatellar incision into the right femur, while a plastic needle of the same dimensions was passed into the left femur. Both needles wer e advanced until the distal physeal plates wer e pierced. The rats wer e sacrificed in groups of 5 after 1,2,8 and 16 weeks. After soft tissue removal, the distal femoral ends were processed for histological, histomorphometric and histochemical study. After the second week the physeal portions wer e taller in the femurs that received metal implants, although the differences were not statistically significant. No important histological differences wer e noted between the physeal plates corresponding to either implant during the study; alcian blue uptake was likewise similar, with the sole exception of the 16th week, during which uptake was markedly less intense around the metal implants. To conclude, implant type is seen to condition the physeal change s induced

Microbiological activity of a soil under different uses and its relation with physico-chemical variables

Gran parte de los procesos microbianos que contribuyen a la fertilidad de los agroecosistemas y el ciclado de nutrientes ocurren en el suelo. Este ciclado de nutrientes depende críticamente de la actividad microbiológica de los suelos, la cual a su vez está mediada por la estructura y funcionamiento de la microbiota edáfica. En este contexto, el objetivo de este trabajo, fue determinar si la actividad microbiana puede ser buena indicadora de la intensidad de uso del suelo, analizando: 1- si las diferencias en la intensidad de uso del suelo se relacionan con diferencias en la actividad microbiológica estimada a través de la respiración edáfica y la actividad enzimática; y 2- las posibles relaciones entre estas variables microbiológicas y las variables físico-químicas. Entre 2008 y 2010 se realizaron muestreos trimestrales en campos de la provincia de Buenos Aires en suelos Argiudoles bajo diferentes usos: 1- Agricultura intensiva continua, 2- Agricultura reciente, y 3- Pastizales naturalizados. Tres sitios de muestreo se seleccionaron como réplicas para cada uso de suelo, con 5 muestras por fecha y réplica. La actividad microbiana se evaluó midiendo la respiración edáfica y la actividad de las enzimas nitrogenasas y se analizaron variables físico- químicas. Tanto las variables microbiológicas como las físico-químicas se analizaron mediante Kruskall-Wallis (P < 0,05). Se exploró la asociación entre las variables físico-químicas y microbiológicas aplicando el coeficiente de correlación no paramétrico (Spearman). Los distintos usos de un mismo suelo presentaron diferencias en la actividad microbiológica. La respiración edáfica fue significativamente mayor en los pastizales naturalizados que en los sistemas con agricultura. La actividad nitrogenasa resultó significativamente mayor en los pastizales naturalizados respecto de la agricultura continua y no se diferenció significativamente de la agricultura reciente. Las variables físico- químicas resultaron menos consistentes en detectar diferencias entre usos. Se detectaron correlaciones significativas entre la actividad microbiológica y algunas de las variables físico-químicas. Los resultados muestran que la actividad microbiológica puede resultar útil para diferenciar intensidades de usos de suelo.Much of the microbial processes that contribute to agroecosystems fertility and nutrient cycling take place in the soil. This nutrient cycling depends critically on the soils' microbiological activity, which is, in turn, mediated by the structure and functioning of the edaphic biota. In this context, the objective of this work was to determine if the microbial activity can be a good indicator of soil use intensity, by analyzing: 1- if differences in soil use intensity are related to differences in microbiological activity estimated through soil respiration and enzymatic activity, and 2- the possible relationships between these variables and physico-chemical variables. Samplings were conducted every three months between 2008 and 2010 in fields in the Buenos Aires province on argiudoll soils under different land uses: 1- Intensive continuous agriculture, 2- Recent agriculture and 3- Naturalized grasslands. Three sampling sites (replicates) were selected for soil use and five samples were collected per replicate and date. Microbial activity was then assessed by measuring soil respiration and nitrogenase enzyme activity, and physico-chemical variables were measured as well. Data were analyzed by means of a Kruskal-Wallis test (P < 0.05). A non- parametric analysis was performed (Spearman multiple correlation) between the physicochemical and microbiological variables. The different uses of the same soil showed significant differences in microbiological activity. Soil respiration was higher in the naturalized grasslands and lower in the continuous agricultural system. Nitrogenase activity was higher in the naturalized grasslands, intermediate in the recent agricultural system and lower in the continuous agriculture fields. The physico-chemical variables measured were less consistent in detecting differences among soil uses. Significant correlations were detected between microbiological activity and some of the physico-chemical variables measured. The results show that microbiological activity can be useful to detect differences in soil use intensity.Fil: Di Ciocco, Cesar Augusto. Universidad Nacional de LujánFil: Sandler, Rosana Veronica. Universidad Nacional de LujánFil: Falco, Liliana Beatriz. Universidad Nacional de LujánFil: Coviella, Carlos Eduardo. Universidad Nacional de Lujá

Germinación in vitro de Calibrachoa thymifolia y Calibrachoa missionica nativas de la Argentina = In vitro germination of Calibrachoa thymifolia and Calibrachoa missionica native to Argentina

Calibrachoa es un género originario de América del Sur que pertenece a la familia Solanaceae. La utilización de semillas de especies de calibrachoa nativas de la Argentina sirve como fuente de variabilidad natural y con fines de investigación, por lo que su germinación in vitro representa una herramienta rápida y confiable frente a otras técnicas de germinación tradicionales. Por ello, en este trabajo se evaluó la germinación in vitro de C. thymifolia y C. missionica bajo los medios de cultivos Murashige y Skoog y Woody plant medium, y se vio que ambos son eficientes para la germinación de estas especies. A su vez, se determinó que, bajo las condiciones de este experimento, C. thymifolia logra germinar una mayor cantidad de semillas en un menor tiempo con respecto a C. missionica.Calibrachoa is a genus native to South America wich belongs to the Solanaceae family. The use of seeds of calibrachoa species native to Argentina serves as a source of natural variability and for research purposes, so their in vitro germination represents a fast and reliable tool compared to other traditional germination techniques. Therefore, in this work the in vitro germination of C. thymifolia and C. missionica was evaluated under Murashige and Skoog and Woody plant medium, and it was found that both are efficient for the germination of these species. In turn, it was determined that, under these conditions, C. thymifolia germinates more seeds in a shorter time than C. missionica.Instituto de FloriculturaFil: Tombion, Leticia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; ArgentinaFil: Coviella, María Andrea. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; ArgentinaFil: Pannunzio, María Julia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; ArgentinaFil: Soto, María Silvina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; ArgentinaFil: Bologna, Paula. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; Argentin

Development of an Environmentally Friendly Larvicidal Formulation Based on Essential Oil Compound Blend to Control Aedes aegypti Larvae: Correlations between Physicochemical Properties and Insecticidal Activity

Oil in water (o/w) emulsions stabilized by an amphiphilic copolymer have been studied in relation to their potential insecticidal activity against Aedes aegypti mosquito larvae. These emulsions contain as oil phase different blends of two isomeric essential oil compounds, thymol and carvacrol. The results show that the addition of carvacrol facilitates the dispersion of the oil within the aqueous phase, with the stabilization and polydispersity of the emulsions being controlled by the change of the ratio between the copolymer concentration and that of the oil phase (Rcop/EOC). Emulsions containing pure essential oil compounds as oil phase do not present any significant difference on their larvicidal activity against mosquito larvae, with emulsions containing only thymol being slightly more effective than those containing only carvacrol as oil phase. Furthermore, the use of blendscontaining different weight fractions of thymol and carvacrol as oil phase results in formulations with an additive larvicidal activity in relation to those with the pure compounds. Despite the larvicidal activity of the emulsions, they do not provoke inhibition to the emergence of adult individuals in Aedes aegypti populations. The spreading and evaporation of the emulsions onto solid surface, which may be an important parameter for the performance of larvicidal formulations, was found to be dependent on the same parameters that govern the stability of the emulsions. This study helps on seeking new alternatives for the preparation of new eco-sustainable formulations against insect pest.Fil: Lucia, Alejandro. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ecología y Desarrollo Sustentable; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales. Centro de Investigación de Sanidad Vegetal; ArgentinaFil: Girard, Clemence. École Nationale Supérieure de Chimie de Lille; FranciaFil: Fanucce, Micaela. Ministerio de Salud de la Nación; ArgentinaFil: Coviella, Carlos Eduardo. Universidad Nacional de Luján. Instituto de Ecología y Desarrollo Sustentable. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ecología y Desarrollo Sustentable; ArgentinaFil: Rubio, Ramón G.. Universidad Complutense de Madrid. Facultad de Ciencias Químicas; EspañaFil: Ortega, Francisco. Universidad Complutense de Madrid. Facultad de Ciencias Químicas; EspañaFil: Guzmán, Eduardo. Universidad Complutense de Madrid. Facultad de Ciencias Químicas; Españ