Perception of Sunflecks by the UV-B Photoreceptor UV RESISTANCE LOCUS8

Sunflecks, transient patches of light that penetrate through gaps in the canopy and transiently interrupt shade, are eco-physiologically and agriculturally important sources of energy for carbon gain, but our molecular understanding of how plant organs perceive and respond to sunflecks through photoreceptors remains limited. The UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) is a recent addition to the list of plant photosensory receptors, and we have made considerable advances in our understanding of the physiology and molecular mechanisms of action of UVR8 and its signaling pathway. However, the function of UVR8 in the natural environment is poorly understood. Here, we show that the UVR8 dimer/monomer ratio responds quantitatively and reversibly to the intensity of sunflecks that interrupt shade in the field. Sunflecks reduced hypocotyl growth and increased CHALCONE SYNTHASE (CHS) and ELONGATED HYPOCOTYL5 gene expression and CHS protein abundance in wild-type Arabidopsis (Arabidopsis thaliana) seedlings, but the uvr8 mutant was impaired in these responses. UVR8 was also required for normal nuclear dynamics of CONSTITUTIVELY PHOTOMORPHOGENIC1. We propose that UVR8 plays an important role in the plant perception of and response to sunflecks.Fil: Moriconi, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Binkert, Melanie. Universidad de Ginebra; SuizaFil: Costigliolo Rojas, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Sellaro, Romina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Ulm, Roman. Universidad de Ginebra. Facultad de Ciencias; SuizaFil: Casal, Jorge José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Family farming in the agricultural census of 2006: the legal mark and the options for their identification.

(Agricultura familiar no censo agropecuário 2006: o marco legal e as opções para sua identificação). Visando delimitar a agricultura familiar no Censo Agropecuário 2006, o Ministério do Desenvolvimento Agrário (MDA) e o Instituto Brasileiro de Geografia e Estatística (IBGE) elaboraram metodologia para construção de uma variável identificando os estabelecimentos agropecuários recenseados e que se ajustam ao conceito previsto na Lei n.11.326, de 24 de julho de 2006. O texto apresenta os passos metodológicos utilizados e alguns resultados

Environmental context of endophyte symbioses: Interacting effects of water stress and insect herbivory

Symbiotic associations between grasses and fungal endophytes are generally regarded as mutualistic, yet benefits to host plants may vary with environmental context. Previous studies have emphasized how endophytes influence plant responses to single stressors. In contrast, the outcome of endophyte-grass interactions under simultaneous biotic and abiotic stresses remains poorly explored. We hypothesized that benefits from endophyte symbiosis become most apparent in "complex" environments where hosts experience multiple stresses. We evaluated the performance of endophyte-infected (E+) vs. endophyte-uninfected (E-) Lolium multiflorum plants in a factorial experiment with water supply (control vs. drought) and insect herbivory (with aphids vs. without aphids). Endophyte infection delayed tiller production in well-watered plants, while water stress reduced tillering in E- plants. Endophyte mediation of herbivory tolerance was contingent on water supply. Whereas aphid herbivory was detrimental to E+ plants in well-watered soils, aphids interacted with drought stress in decreasing the reproductive output of E- but not E+ plants. Moreover, endophyte presence decreased aphid densities on drought-stressed plants only. Thus, endophyte symbiosis enhanced host tolerance to overlapping biotic and abiotic stresses, although infected plants failed to outgrow their uninfected counterparts. These results support the view that mutualistic endophyte effects may not arise in low-stress environments. © 2011 by The University of Chicago. All rights reserved.Fil: Miranda, M. Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Omacini, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Chaneton, Enrique Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Historical forest biomass dynamics modelled with Landsat spectral trajectories

Acknowledgements National Forest Inventory data are available online, provided by Ministerio de Agricultura, Alimentación y Medio Ambiente (España). Landsat images are available online, provided by the USGS.Peer reviewedPostprin

Peasantry and Society in France since 1789 [book review].

Sociedad rural; Agricultura; Francia;

Age and habitat quality matters: isotopic variation of two sympatric species of rodents in Neotropical Forest

Dietary studies allow us to understand important ecological patterns such as intra- and interpopulation variation and interspecific differences regarding the use of food sources. Stable isotopes have been successfully employed to detect dietary differences between species and feeding shifts within a species, as a response to age, habitat use, and resource availability. Here we investigated the stable isotope compositions of carbon and nitrogen of young and adult specimens of Euryoryzomys russatus and Sooretamys angouya and their stomach contents, in a complex mosaic of vegetation in the Brazilian Atlantic Forest. Isotopes indicated a pronounced inter- and intraspecific plasticity in resource use for E. russatus and S. angouya. Plant sources were the prevalent feeding items for E. russatus, with low to intermediate consumption of arthropods. For S. angouya, plants were dominant in the stomach content, but arthropod arose as an important source. E. russatus showed more variation in isotopic signature between grids than S. angouya, suggesting that the former was more affected by habitat changes. These results allow us to better understand the ontogeny, diet and the behavioral responses to environmental variations of both species. Finally, our study contributes to reduce the lack of knowledge about sympatric species ecology and aggregates information for their conservation.Fil: Bovendorp, Ricardo Siqueira. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Universidade Estadual Paulista “Júlio de Mesquita Filho”; BrasilFil: Simoes Libardi, Gustavo. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Sarmento, Mariana Montagner de Moraes. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Camargo, Plínio Barbosa. Universidade de Sao Paulo; BrasilFil: Reis Percequillo, Alexandre. Universidade Do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasi

Augmentative releases of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) for Ceratitis capitata (Diptera: Tephritidae) control in a fruit-growing region of Argentina

Field-open augmentative releases were conducted to assess the efficacy of Diachasmimorpha longicaudata (Ashmead) for the regulation of Ceratitis capitata (Weidemann) infesting Ficus carica (L.) in a commercial area located in a fruit-producing irrigated-valley of San Juan, central-western Argentina. Parasitoids were reared on Sensitive Lethal Temperature Vienna-8 strain of C. capitata at the BioPlanta San Juan facilities, and were weekly released throughout 9 weeks over two experimental plots of ca. 2.3 ha each with a density of 5200 wasps/plot. Host mortality and medfly emergence at the release plots were significantly 1.9-times higher and 1.5-times lower, respectively, than those recorded in the control plots. D. longicaudata females increase their effectiveness on medfly at both higher temperature (22–23 °C) and relative humidity (54–62%) values. Parasitoid females used in the study showed a good ability to spread once released in open-field. Between 16 and 75% of host mortality during the parasitoid release period was due to D. longicaudata, which appears to be promising for the control of medfly in San Juan as well as in other similar Argentinean fruit-growing semi-arid regions.Fil: Sánchez, Guillermo. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Murúa, Fernando. Universidad Nacional de San Juan; Argentina. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Suárez, Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Van Nieuwenhove, Guido Alejandro. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Taret, Gustavo Abelardo Ariel. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Pantano, Valeria. Provincia de San Juan. Dirección de Sanidad Vegetal, Animal y Alimentos; ArgentinaFil: Bilbao, Mariana. Provincia de San Juan. Ministerio de Producción y Desarrollo Económico. Secretaria de Agricultura, Ganadería y Agroindustria. Programa de Control y Erradicación de Mosca de los Frutos; ArgentinaFil: Schliserman, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentin

A 2020 vision for food, agriculture, and the environment in Latin America.:

This is a thoughtful statement representing a genuine Latin American perspective of the goals and strategies relating to food, agriculture, and the environment as we head toward the year 2020. This document represents a synthesis of documents prepared by three working groups participating in a workshop on Latin America, jointly sponsored by IFPRI, the Centro Internacional de Agricultura Tropical (CIAT) and the Instituto Interamericano de Cooperación para la Agricultura (IICA), in Cali, Colombia, March 20–22, 1995.Food security Latin America., Agricultural development Latin America., Agriculture Environmental aspects Latin America.,

Tracing the metabolic rift in Colombia's greengrocer: an environmental history of the Anaime Valley

This paper stems from research to reconstruct an environmental history of agriculture in the Anaime Canyon Valley and better understand the environmental consequences of having transformed the area into “Colombia's greengrocer”. We trace the origins and development of agro-food production and explore how commercial agriculture and dairy operations have transformed the landscape and local ecosystems in the Anaime valley, in light of Marx's concept of metabolic rift. Research is based on archival sources and a participatory reconstruction of the Anaime landscape from the historical memory of the campesinos, or rural inhabitants. The data shows how internal migration, rapid urban growth and improved transportation infrastructure in the valley during the mid-twentieth century hastened the turn toward intensive commercial agriculture. Increasing links to Colombia's urban markets have led to agricultural intensification and specialization in arracacha (Arracacia xanthorrhiza) production in the Anaime Canyon. As a result, soils and ecosystems have been depleted and agriculture depends increasingly on chemical inputs including fertilizers, indicating a growing metabolic rift.Este artículo nace de una investigación que busca reconstruir la historia ambiental de la agricultura en el cañón de Anaime, para entender las consecuencias ambientales de su conversión en la despensa agrícola de Colombia. Rastrea la producción agroalimentaria en el cañón hasta sus inicios y explora cómo la agricultura comercial y la producción de lácteos han transformado el paisaje y los ecosistemas locales. Las transformaciones en el paisaje de Anaime se analizan a la luz del concepto de brecha metabólica de Marx. La investigación se nutre de datos procedentes de fuentes de archivo y de una reconstrucción participativa del paisaje anaimuno, a partir de la memoria histórica de sus habitantes campesinos. Los datos muestran que la migración interna, la rápida urbanización y las mejoras en la infraestructura de transporte a mediados del siglo xx aceleraron la intensificación de la agricultura en el cañón. La creciente integración de Anaime a los mercados urbanos de Colombia condujo a la intensificación agrícola y a la especialización en la producción de arracacha (Arracacia xanthorrhiza). Como resultado, los suelos y los ecosistemas se han deteriorado, y la agricultura depende cada vez más de insumos químicos, incluidos fertilizantes, lo que evidencia una creciente brecha metabólica

The heterotrimeric G-protein complex modulates light sensitivity in arabidopsis thaliana seed germination

Release of dormancy and induction of seed germination are complex traits finely regulated by hormonal signals and environmental cues such as temperature and light. The Red (R):Far-Red (FR) phytochrome photoreceptors mediate light regulation of seed germination. We investigated the possible involvement of heterotrimeric G-protein complex in the phytochrome signaling pathways of Arabidopsis thaliana seed germination. Germination rates of null mutants of the alpha (Gα) and beta (Gβ) subunits of the G-protein (Atgpa1-4 and agb1-2, respectively) and the double mutant (agb1-2/gpa1-4) are lower than the wildtype (WT) under continuous or pulsed light. The Gα and Gβ subunits play a role in seed germination under hourly pulses of R lower than 0.1 μmol m -2 s -1 whereas the Gβ subunit plays a role in higher R fluences. The germination of double mutants of G-protein subunits with phyA-211 and phyB-9 suggests that AtGPA1 seems to act as a positive regulator of phyA and probably phyB signaling pathways, while the role of AGB1 is ambiguous. The imbibition of seeds at 4°C and 35°C alters the R and FR light responsiveness of WT and G-protein mutants to a similar magnitude. Thus, Gα and Gβ subunits of the heterotrimeric G-protein complex modulate light induction of seed germination by phytochromes and are dispensable for the control of dormancy by low and high temperatures prior to irradiation. We discuss the possible indirect role of the G-protein complex on the phytochrome-regulated germination through hormonal signaling pathways.Fil: Botto, Javier Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Ibarra, Silvia Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Jones, Alan M.. University of North Carolina; Estados Unido