Growth of Stuckenia pectinata under greenhouse and irrigation canal conditions in the lower valley of the Colorado River (Argentina)

Stuckenia pectinata is an invasive submerged weed in the irrigation district in the lower valley of the Colorado River, Argentina. The objective of this study was to analyze the initial growth of S. pectinata from tubers, and its annual growth cycle in irrigation canals, in order to be efficient in adapting future control techniques. Tubers were planted in aquaria in order to evaluate the effect of their size, depth of burial and below zero temperatures on the initial growth. Under field conditions, samples of plants were collected from two irrigation canals, from October to March, in two complete growth cycles. Plant height and biomass of the leaves, stems and spikes were measured. The largest tubers were able to emerge from deep burial and generated larger plants than the smallest tubers. Frozen tubers did not germinate at any burial depths. Maximum biomass in the irrigation canal reached 1660 g DM m-2 with a peak at the beginning of summer. The elimination of biomass at the end of the irrigation season would result in small tubers that would die in the winter time. The information generated could lead to more appropriate and sustainable control.Stuckenia pectinata is an invasive submerged weed in the irrigation district in the lower valley of the Colorado River, Argentina. The objective of this study was to analyze the initial growth of S. pectinata from tubers, and its annual growth cycle in irrigation canals, in order to be efficient in adapting future control techniques. Tubers were planted in aquaria in order to evaluate the effect of their size, depth of burial and below zero temperatures on the initial growth. Under field conditions, samples of plants were collected from two irrigation canals, from October to March, in two complete growth cycles. Plant height and biomass of the leaves, stems and spikes were measured. The largest tubers were able to emerge from deep burial and generated larger plants than the smallest tubers. Frozen tubers did not germinate at any burial depths. Maximum biomass in the irrigation canal reached 1660 g DM m-2 with a peak at the beginning of summer. The elimination of biomass at the end of the irrigation season would result in small tubers that would die in the winter time. The information generated could lead to more appropriate and sustainable control

Seed production of common teasel (Dipsacus fullonum) and response to intraspecific competition in Buenos Aires province, Argentina

Dipsacus fullonum L. (common teasel) is a short-lived perennial plant that has become an invasive weed in Argentina and many other countries. It reduces native species diversity and forage production in natural protected areas and grasslands. Reproduction is only through seeds. Field surveys were carried out to determine reproductive potential under natural populations growing in four different locations of Buenos Aires province, Argentina (Bahía Blanca, Saldungaray, Necochea and Energía). At the onset of flowering, 30 plants were randomly tagged at each location. Selected plants included those considered growing in a group and those growing alone (when no other plant was adjacent for at least 60 cm). Once plant senescence was identified, all heads were counted and harvested individually. A linear regression model that described the relationship between the weight of seeds from a single head and the number of seeds was used to estimate the total seed production of each plant. The number of heads per plant varied from 3 (Energía) to 62 (Bahía Blanca). No differences were detected in the number of seeds in the principal head at the different growth situations. Across growth situations, principal heads from plants growing in Bahía Blanca showed 16%, 12%, and 22% more seeds than Energía, Necochea and Saldungaray, respectively. Total seed production per plant ranged from 1,485 (Energía) to 15,551 (Bahía Blanca). Plants growing in Bahía Blanca produced a number of heads and seeds higher than the other evaluated locations. Plants growing alone showed 46% and 48% greater head production and seed production across locations than plants in groups, respectively. This high production potential of common teasel plants growing alone would encourage the invasion of new areas, when compared with plants growing in dense patches.Dipsacus fullonum L. (carda silvestre) es una especie perenne de vida corta considerada una maleza invasora en Argentina y en varios otros países. La carda silvestre compite con especies nativas en los sitios que invade reduciendo la diversidad florística en áreas protegidas y la disponibilidad de forraje en pastizales naturales. Su modo de reproducción es únicamente a través de semillas. El objetivo de este trabajo fue determinar el potencial reproductivo y el efecto de la competencia intraespecífica sobre este mismo parámetro, en poblaciones naturales de carda creciendo en cuatro localidades diferentes de la provincia de Buenos Aires, Argentina (Bahía Blanca, Saldungaray, Necochea y Energía). Al inicio de la floración, se marcaron 30 plantas al azar en cada población. Las plantas se seleccionaron incluyendo aquellas creciendo en grupos y creciendo aisladas (cuando ninguna otra planta de carda se encontraba creciendo dentro de un radio de al menos 60 cm). Una vez identificada la senescencia de la planta, todas las inflorescencias (capítulos) fueron cosechadas individualmente. Se utilizó un modelo de regresión lineal para describir la relación entre el peso de semillas de un solo capítulo y el número de semillas, con el objetivo de estimar la producción total de semillas de cada planta. El número de capítulos por planta varió entre 3 (Energía) y 62 (Bahía Blanca). No se detectaron diferencias en el número de semillas del capítulo principal en las diferentes condiciones de crecimiento. El capítulo principal de las plantas que se encontraban creciendo en Bahía Blanca mostró un número de semillas 16%, 12% y 22% más alto que Energía, Necochea y Saldungaray, respectivamente. La producción total de semillas registrada por planta osciló entre 1.485 (Energía) y 15.551 (Bahía Blanca). Las plantas que se encontraban creciendo en Bahía Blanca produjeron un mayor número de capítulos y semillas que el resto de las localidades. Las plantas que crecieron aisladas mostraron un 46% y un 48% más de producción de capítulos y semillas en todas las localidades censadas que las plantas en grupos, respectivamente. Este alto potencial de producción de semillas, en plantas de carda silvestre creciendo aisladas, fomentaría la invasión de nuevas áreas, en comparación con plantas que se encuentran creciendo en parches densos.Gerencia de Contenidos Periodísticos y Editoriales, DNACI, INTAFil: Daddario, Juan Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Daddario, Juan Facundo. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Daddario, Juan Facundo. Universidad Nacional del Sur. Departamento de Agronomía; Argentina.Fil: Tucat, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Tucat, Guillermo. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Fernández, Osvaldo A. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Bentivegna, Diego Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiarida; ArgentinaFil: Bentivegna, Diego Javier. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiarida; Argentin

A BDI architecture for high level robot deliberation

In this work we present a BDI agent architecture used for high level reasoning agents that control mobile robots that play soccer. This architecture is build on top of layered system, where each of these layers is associated with a di®erent level of abstraction. The proposed approach allows the speci¯cation of declarative goal driven robot behavior, that uses sophisticated high level reasoning and reactivity when needed. The elements of mental components are studied with their interaction and their syntaxis and semantics are de¯ned.Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

A layered architecture using schematic plans for controlling mobile robots

Robotic soccer is a way of putting different developments in intelligent agents into practice, including not only problems such as multi-agent planning and coordination, but also physical problems related to vision and communication subsystems. In this work, we present the design used as the basis for a multi-agent system, implemented for controlling a team of robots, having as main goal to facilitate the testing of new theories developed on reasoning, knowledge representation, planning, agent communication, among others Artificial Intelligence techniques. The implementation of the system was carried out following a three-layer architecture which consists of a reactive layer, an executive layer and a deliberative layer, each of which is associated with a different level of abstraction. This layered design allows to construct a functional system with basic services that can be tested and refined progressively. We will focus our explanation on the executive layer, responsible for sensorial processing and the execution of schematic plans.Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Desarrollo de agentes inteligentes basados en argumentación para Robótica Móvil

El objetivo principal de esta línea de investigación es el estudio de métodos de representación de conocimiento para agentes de software inteligentes deliberativos. En particular, este trabajo se enfocará en la implementación de una arquitectura de agentes BDI basada en mecanismos argumentativos. Por lo tanto, los componentes mentales de estos agentes se especificarán mediante Programación en Lógica Rebatible. El propósito de esta arquitectura es el desarrollo de agentes con capacidades de razonamiento de alto nivel, para controlar robots móviles que juegan al fútbol.Eje: Agentes y Sistemas inteligentesRed de Universidades con Carreras en Informática (RedUNCI

A layered architecture using schematic plans for controlling mobile robots

Robotic soccer is a way of putting different developments in intelligent agents into practice, including not only problems such as multi-agent planning and coordination, but also physical problems related to vision and communication subsystems. In this work, we present the design used as the basis for a multi-agent system, implemented for controlling a team of robots, having as main goal to facilitate the testing of new theories developed on reasoning, knowledge representation, planning, agent communication, among others Artificial Intelligence techniques. The implementation of the system was carried out following a three-layer architecture which consists of a reactive layer, an executive layer and a deliberative layer, each of which is associated with a different level of abstraction. This layered design allows to construct a functional system with basic services that can be tested and refined progressively. We will focus our explanation on the executive layer, responsible for sensorial processing and the execution of schematic plans.Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

A BDI architecture for high level robot deliberation

In this work we present a BDI agent architecture used for high level reasoning agents that control mobile robots that play soccer. This architecture is build on top of layered system, where each of these layers is associated with a di®erent level of abstraction. The proposed approach allows the speci¯cation of declarative goal driven robot behavior, that uses sophisticated high level reasoning and reactivity when needed. The elements of mental components are studied with their interaction and their syntaxis and semantics are de¯ned.Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Desarrollo de agentes inteligentes basados en argumentación para Robótica Móvil

El objetivo principal de esta línea de investigación es el estudio de métodos de representación de conocimiento para agentes de software inteligentes deliberativos. En particular, este trabajo se enfocará en la implementación de una arquitectura de agentes BDI basada en mecanismos argumentativos. Por lo tanto, los componentes mentales de estos agentes se especificarán mediante Programación en Lógica Rebatible. El propósito de esta arquitectura es el desarrollo de agentes con capacidades de razonamiento de alto nivel, para controlar robots móviles que juegan al fútbol.Eje: Agentes y Sistemas inteligentesRed de Universidades con Carreras en Informática (RedUNCI

Allelopathic effect of Baccharis ulicina on germination and initial growth of Avena sativa, Lolium perenne and Raphanus sativus

Baccharis ulicina es una maleza ampliamente distribuida en los pastizales de la zona semiárida argentina. A fin de evaluar sus posibles efectos alelopáticos, se utilizaron extractos acuosos de B. ulicina (hoja, tallo, raíz y planta entera) a dos concentraciones (50 y 150 g tejido/L agua) sobre la germinación y crecimiento inicial de Avena sativa, Lolium perenne y Raphanus sativus. Para cada especie se regaron 100 semillas y se mantuvieron a 25°C y oscuridad. Se registraron la germinación de las semillas y la longitud de coleóptilo / hipocótile (C/H) y radícula (R). Con los datos obtenidos se determinó: porcentaje de germinación, coeficiente de velocidad de germinación, vigor de la germinación, inhibición de la germinación, inhibición de la longitud de la radícula y del coleóptilo / hipocótile e índice de vigor de radícula y de coleóptilo / hipocótile. Los extractos con alta concentración redujeron la germinación en promedio 65% mientras que inhibieron la longitud en 58,8% (C/H) y 93,3% (R) para A. sativa; 71,5% (C/H) y 87,9% (R) para L. perenne, y 93,8% (C/H) y 94,5% (R) para R. sativus. Se registró un evidente efecto fitotóxico de B. ulicina sobre las especies evaluadas, indicando que la alelopatía sería una estrategia ecológica de la especie.Baccharis ulicina is a weed widely distributed in pastures of the semiarid zone of Argentina. With the aim of evaluate potential allelopathic effects, aqueous extracts of B. ulicina (leaf, stem, root and whole plant) at two concentrations (50 and 150 g tissue/L water) were used on germination and initial growth of Avena sativa, Lolium perenne and Raphanus sativus. For each species, 100 seeds were watered and maintained at 25°C at darkness. Seed germination and length of coleoptile / hypocotyl (C/H) and radicle (R) was measured. Then, germination percentage, germination rate coefficient, germination vigor, inhibition of germination, inhibition of radicle length and coleoptile / hypocotyl length, radicle vigor index and the coleoptile / hypocotyl vigor index were calculated. High concentration extracts reduced germination an average of 65%, in addition, they produced a length inhibition of 58.8% (C/H) and 93.3% (R) to A. sativa; 71.5% (C/H) and 87.9% (R) to L. perenne, and 93.8% (C/H) and 94.5% (R) to R. sativus. There was an evident phytotoxic effect of B. ulicina on evaluated species, indicating that allelopathy would be an ecological strategy of the species.Fil: Tucat, Guillermo. Centro de Recursos Naturales Renovables de la Zona Semiárida (Buenos Aires, Argentina).Fil: Bentivegna, Diego. Centro de Recursos Naturales Renovables de la Zona Semiárida (Buenos Aires, Argentina).Fil: Fernández, Osvaldo. Universidad Nacional del Sur. Departamento de AgronomíaFil: Busso, Carlos. Universidad Nacional del Sur. Departamento de AgronomíaFil: Brevedan, Roberto. Universidad Nacional del Sur. Departamento de AgronomíaFil: Mujica, María de la Merced.Fil: Torres, Yanina. Universidad Nacional del Sur. Departamento de AgronomíaFil: Daddario, Juan. Centro de Recursos Naturales Renovables de la Zona Semiárida (Buenos Aires, Argentina).Fil: Ithurrart, Leticia. Universidad Nacional del Sur. Departamento de AgronomíaFil: Giorgetti, Hugo. Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental Patagones.Fil: Rodríguez, Gustavo. Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental Patagones.Fil: Montenegro, Oscar. Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental Patagones.Fil: Baioni, Sandra. Universidad Nacional del Sur. Departamento de AgronomíaFil: Entío, José.Fil: Fioretti, María Nélida. Universidad Nacional del Sur. Departamento de Agronomí

Plant growth and survival of five introduced and two native/naturalized perennial grass genotypes exposed to two defoliation managements in arid Argentina

The field performance of the native Pappophorum vaginatum, the naturalized Eragrostis curvula and various cultivars of the introduced Achnatherum hymenoides and Leymus cinereus was evaluated as potential forage resources in rangelands of arid Argentina during the warm seasons of 2007/2008 and 2008/2009. Plants of these grass species, obtained from seeds, were transplanted to the field in 2006, when they were 1 year old. During the study years, there were two defoliation managements: plants of all study genotypes either remained undefoliated (controls) or were defoliated twice a year during spring at 5 cm stubble height. Despite tiller number being lower (P 0·05) between defoliation managements by mid-spring, there were no differences (P > 0·05) in dry weight production between defoliated and undefoliated plants in all genotypes at the end of the second growing season. Plants of one or more of the introduced genotypes showed a similar (P > 0·05) or greater (P 0·05) or greater (P 70%) or naturalized (>39%) genotypes at the end of the first or second growing seasons.Facultad de Ciencias Agrarias y Forestale