Toxicidade de algumas crotolárias

This paper deals with some testes of Crotalaria as forage, using rabbits as laboratory animals to detect toxicity, at Piracicaba, São Paulo, Brazil. 1. C. intermedia and C. juncea were palatable, non toxic, the last more productive. Tests on cattle are recommended and selection to improve characteristics as forage too. 2. C. incana and C. verrucosa were little palatable, probably non toxic, poor productive. 3. C. paulina, C. lanceolata (four strains), C. mysorensis, C. gratiana, C. spectabilis, C. breviflora and C. campista were toxic. This results are not according those of others AA. Others species are beeing tested since Crotalaria is a drought resistent legume on this area.

Efeitos alelopáticos de algumas leguminosas e gramíneas sobre a flora invasora

Foram estudados os efeitos alelopáticos produzidos por cinco espécies vegetais: as gramíneas Avena sativa L., e Lolium multiflorum Lamb.; e as leguminosas Vicia sp., Mediaago sativa L. e Trifolium repens L. Canteiros isolados foram preparados, adubados e semeados de acordo com as recomendações técnicas usuais. Nos resultados obtidos observou-se alta incidência de invasoras nos canteiros de Trifolium repens L. e Medicago sativa L., contrastando com os canteiros de Avena sativa L. e Lolium multiflorum Lamb., onde poucas foram as espécies encontradas; enquanto o canteiro de Vicia sp. manteve posição intermediária. Com base nos dados obtidos, pode-se recomendar as duas gramíneas como cultura de cobertura com propriedades alelopáticas, assim como a Vicia sp. quando desejar-se além da redução das plantas invasoras, matéria orgânica para incorporação.

Distribution of Lymnaeidae (Mollusca: Pulmonata), intermediate snail hosts of Fasciola hepatica in Venezuela

An extensive malacological survey was carried out between 2005-2009 in order to clarify the exact number of lymnaeid species which may be intermediate hosts of Fasciola hepatica in Venezuela. Four species were discovered during this survey, including two local species: Lymnaea cubensis and Lymnaea cousini and two exotic species: Lymnaea truncatula and Lymnaea columella. The most common local species was L. cubensis which was found at 16 out of the 298 sampling sites. This species has a large distribution area throughout the Northern part of Venezuela and was encountered from sea level to an altitude of 1,802 m in state of Trujillo. The second local species L. cousini was collected at only two sites of the Andean Region at altitudes of 3,550 m and 4,040 m, respectively. The European L. truncatula was found at 24 sites all located in the states of Mérida and Táchira at an altitude varying between 1,540-4,000 m. The respective distribution areas of L. cubensis and L. truncatula do not appear to overlap, but more detailed malacological surveys are needed. The fourth lymnaeid species, L. columella was collected in a canal from Mérida at an altitude of 1,929 m and in an irrigation canal from the state of Guárico, at an altitude of 63 m. The role of these four lymnaeid species in the transmission of fascioliasis in Venezuela is discussed.

Relatório - Detecção de Tuta Absoluta (Myerick, 1917) em Cabo Verde

Tuta absoluta é praga minadora de folhas desenvolve-se principalmente no tomate (Lycopersicon esculentum) e não só mas também em outras espécies de Solanáceas tais como batata comum (Solanum tuberosum), beringela (Solanum melongina), Pimentos (Capsicum sp.) e no tomate silvestre (Lycopersicon hirsutum), (Solanum dulcamara), (Solanum nigrum), (Solanum elaeagnifolium), (Datura stramonium), (Datura ferox) e (Nicotiana glauca). No entretanto, esta praga ataca espécies de tomate em grande escala a nível dos trópicos, Sub-trópicos e regiões temperadas causando prejuízos económicos consideráveis (USDA, 2011). Esta praga encontra-se presente na América do Sul, (Chili, Bolívia, Brasil, Colômbia, Equador, Uruguai, Perú, Venezuela, Argentina). No continente Africano ela encontra-se na Africa Ocidental e Central designadamente no Benim, Camarões Cabo-Verde, Costa do Marfim, Congo Brazzaville, Gambia, Gabão, Ghana, Guiné-Conakry, Guiné- Bissau, Mali, Mauritânia, Niger, Nigéria, República Democrático do Congo, Serra Leoa, Senegal, Tchad e Togo. Pela primeira vez T. absoluta foi assinalada na Europa em 2006, e em Espanha na comunidade Valenciana em 2007 (Vieira, 2008). O cultivo de tomate em Cabo Verde tem aumentado nos últimos anos. Atualmente tomate é o legume mais cultivado em Cabo Verde. A sua quota parte na produção hortícola que não ultrapassavam os 1.000 t há uns anos, atinge atualmente 4200 t, o que representa 23% da produção total dos legumes. Apesar de alguns constrangimentos, nomeadamente problemas de ordem fitossanitária e escassez de água de rega a disponibilidade e a utilização generalizada das variedades locais, permitiram um escalonamento da produção durante o na, compreendendo o período quente e húmido. Um outro fator que contribui para o aumento substancial da produção, é a salinização de água de rega, em várias zonas do regadio. Os agricultores destas zonas viram nesta cultura a única saída para obterem algum rendimento (MAP/ CPDA/INIDA/ FAO GCP/CV/036/NET s/data). Em Cabo Verde a área média de um campo de produção de tomate é de 750 m2 sendo máxima de 1.400 m2. Este trabalho teve como objetivo estabelecimento instantâneo de presença ou ausência da nova praga Tuta absoluta no país que foi recentemente encontrada na Sub-região Saariana na Costa Ocidental e Central de África.

Relatório Detecção de Tuta Absoluta (Myerick,1917) em Cabo Verde

Tuta absoluta é praga minadora de folhas desenvolve-se principalmente no tomate (Lycopersicon esculentum) e não só mas também em outras espécies de Solanáceas tais como batata comum (Solanum tuberosum), beringela (Solanum melongina), Pimentos (Capsicum sp.) e no tomate silvestre (Lycopersicon hirsutum), (Solanum dulcamara), (Solanum nigrum), (Solanum elaeagnifolium), (Datura stramonium), (Datura ferox) e (Nicotiana glauca). No entretanto, esta praga ataca espécies de tomate em grande escala a nível dos trópicos, Sub-trópicos e regiões temperadas causando prejuízos económicos consideráveis (USDA, 2011). Esta praga encontra-se presente na América do Sul, (Chili, Bolívia, Brasil, Colômbia, Equador, Uruguai, Perú, Venezuela, Argentina). No continente Africano ela encontra-se na Africa Ocidental e Central designadamente no Benim, Camarões Cabo-Verde, Costa do Marfim, Congo Brazzaville, Gambia, Gabão, Ghana, Guiné-Conakry, Guiné- Bissau, Mali, Mauritânia, Niger, Nigéria, República Democrático do Congo, Serra Leoa, Senegal, Tchad e Togo. Pela primeira vez T. absoluta foi assinalada na Europa em 2006, e em Espanha na comunidade Valenciana em 2007 (Vieira, 2008). O cultivo de tomate em Cabo Verde tem aumentado nos últimos anos. Atualmente tomate é o legume mais cultivado em Cabo Verde. A sua quota parte na produção hortícola que não ultrapassavam os 1.000 t há uns anos, atinge atualmente 4200 t, o que representa 23% da produção total dos legumes. Apesar de alguns constrangimentos, nomeadamente problemas de ordem fitossanitária e escassez de água de rega a disponibilidade e a utilização generalizada das variedades locais, permitiram um escalonamento da produção durante o na, compreendendo o período quente e húmido. Um outro fator que contribui para o aumento substancial da produção, é a salinização de água de rega, em várias zonas do regadio. Os agricultores destas zonas viram nesta cultura a única saída para obterem algum rendimento (MAP/ CPDA/INIDA/ FAO GCP/CV/036/NET s/data). Em Cabo Verde a área média de um campo de produção de tomate é de 750 m2 sendo máxima de 1.400 m2. Este trabalho teve como objetivo estabelecimento instantâneo de presença ou ausência da nova praga Tuta absoluta no país que foi recentemente encontrada na Sub-região Saariana na Costa Ocidental e Central de África.

Detecção e Monitorização de Tuta Absoluta (Meyrick, 1917) em Cabo Verde

Tuta absoluta (Meyrick, 1917) (Microlepidoptera:Gelechiidae) é praga minadora de folhas desenvolve-se principal-mente no tomate (Lycopersicon esculentum) e não só mas também em outras espécies de Solanáceas tais como batata comum (Solanum tuberosum), beringela (Solanum melongina), Pimentos (Capsicum sp.) e no tomate silvestre (Lycopersicon hirsutum), (Solanum dulcamara), (Solanum nigrum), (Solanum elaeagnifolium), (Datura stramonium), (Datura ferox) e (Nicotiana glauca). Esta praga ataca espécies de tomate em grande escala a nível dos trópicos, Sub-trópicos e regiões temperadas causando prejuízos económicos consideráveis (USDA, 2011). Esta praga encontra-se presente na América do Sul, (Chili, Bolívia, Brasil, Colômbia, Equador, Uruguai, Perú, Venezuela, Argentina). No continente Africano ela encontra-se na Africa Ocidental e Central designadamente no Benim, Camarões, Cabo-Verde, Costa do Marfim, Congo Brazzaville, Gambia, Gabão, Ghana, Guiné-Conakry, Guiné- Bissau, Mali, Mauritâ-nia, Niger, Nigéria, República Democrático do Congo, Serra Leoa, Senegal, Tchad e Togo. Pela primeira vez T. abso-luta foi assinalada na Europa em 2006, e em Espanha na comunidade Valenciana em 2007 (Vieira, 2008). O cultivo de tomate em Cabo Verde tem aumentado nos últimos anos. Actualmente tomate é o legume mais cultivado em Cabo Verde. A sua quota parte na produção hortícola que não ultrapassavam os 1.000 t há uns anos, atinge actualmente 4200 t, o que representa 23% da produção total dos legumes. Apesar de alguns constrangimentos, nomeadamente problemas de ordem fitossanitária e escassez de água de rega a disponibi-lidade e a utilização generalizada das variedades locais, permitiram um escalonamento da produção durante o ano, compreendendo o período quente e húmido. Um outro fator que contri-bui para o aumento substancial da produção, é a salinização de água de rega, em várias zonas do regadio. Os agricultores destas zonas viram nesta cultura a única saída para obterem algum rendimento (MAP/ CPDA/INIDA/ FAO GCP/CV/036/NET s/data). Em Cabo Verde a área média de um campo de produção de tomate é de 750 m2 sendo máxima de 1.400 m2. Este trabalho teve como objetivo estabelecimento instantâneo de presença ou ausência da nova praga Tuta absoluta no país que foi recentemente encontrada na Sub-região Saariana na Costa Ocidental e Central de África.

Arbuscular mycorrhiza-specific signaling in rice transcends the common symbiosis signaling pathway.

Knowledge about signaling in arbuscular mycorrhizal (AM) symbioses is currently restricted to the common symbiosis (SYM) signaling pathway discovered in legumes. This pathway includes calcium as a second messenger and regulates both AM and rhizobial symbioses. Both monocotyledons and dicotyledons form symbiotic associations with AM fungi, and although they differ markedly in the organization of their root systems, the morphology of colonization is similar. To identify and dissect AM-specific signaling in rice (Oryza sativa), we developed molecular phenotyping tools based on gene expression patterns that monitor various steps of AM colonization. These tools were used to distinguish common SYM-dependent and -independent signaling by examining rice mutants of selected putative legume signaling orthologs predicted to be perturbed both upstream (CASTOR and POLLUX) and downstream (CCAMK and CYCLOPS) of the central, calcium-spiking signal. All four mutants displayed impaired AM interactions and altered AM-specific gene expression patterns, therefore demonstrating functional conservation of SYM signaling between distant plant species. In addition, differential gene expression patterns in the mutants provided evidence for AM-specific but SYM-independent signaling in rice and furthermore for unexpected deviations from the SYM pathway downstream of calcium spiking.

Rendimento de matéria seca de quatro cultivares de alfafa em um latossolo vermelho-amarelo submetido à calagem e adubação potássica

Em casa de vegetação da Escola Superior de Agricultura "Luiz de Queiroz", em Piracicaba (SP), no período de janeiro a agosto de 1992, foi desenvolvido um experimento com amostra superficial de um latossolo vermelho-amarelo textura argilosa. Utilizou-se um esquema fatorial 4 x 3 x 4, com doses de calcário (0; 380; 760 e 1.140 mg kg-1 de terra), doses de potássio (0; 40 e 120 mg kg-1 de terra) e quatro cultivares de alfafa (Crioula, Moapa, Florida 77 e CUF 101). O delineamento experimental foi o de blocos ao acaso, com quatro repetições. Efetuou-se o primeiro corte 70 dias após a semeadura, enquanto o segundo corte foi realizado entre 34 e 41 dias após o primeiro. Os cultivares de maior rendimento de matéria seca no primeiro corte foram Florida 77 e CUF 101, que se igualaram aos cultivares Crioula e Moapa no segundo corte. As máximas produções de matéria seca e quantidades totais de nitrogênio estimadas corresponderam às doses de calcário dolomítico entre 886 e 1.095 mg kg-1, que elevaram a saturação por bases do solo para 64,8 a 68,6%, enquanto, para o potássio, esses pontos de máximo foram estimados para doses entre 44,7 e 74,2 mg kg-1. Sintomas visuais de deficiência de potássio foram observados na alfafa, nos tratamentos sem adubação potássica.

Soybean response to starter nitrogen and Bradyrhizobium inoculation on a Cerrado oxisol under no-tillage and conventional tillage systems

In Brazil, Bradyrhizobium inoculation has successfully replaced the use of N fertilizer on soybean [Glycine max (L) Merr.] crops. However, with the expansion of no-tillage cropping systems in the Cerrados region, the idea that it is necessary to use small N rates at the sowing to overcome problems related with N immobilization has become widespread, mainly when soybean is cultivated after a non-legume crop. In this study we examined soybean response to small rates of N fertilizer under no-tillage (NT) and conventional tillage (CT) systems. Four experiments (a completely randomized block with five replicates) were carried out in a red yellow oxisol, during the periods of 1998/1999 and 1999/ 2000, under NT and CT. The treatments consisted of four urea rates (0, 20, 30 and 40 kg ha-1 N). All treatments were inoculated with Bradyrhizobium japonicum strains SEMIA 5080 and SEMIA 5079, in the proportion 1 kg of peat inoculant (1,5 x 10(9) cells g-1) per 50 kg of seeds. In both experiments, soybean was cultivated after corn and the N fertilizer was band applied at sowing. In all experiments, N rates promoted reductions of up to 50 % in the nodule number at 15 days after the emergence. Regardless of the management system, these reductions disappeared at the flowering stage and there was no effect of N rates on either the number and dry weight of nodules or on soybean yields. Therefore, in the Brazilian Cerrados, when an efficient symbiosis is established, it is not necessary to apply starter N rates on soybean, even when cultivated under notillage systems.

Relationships between grain yield and accumulation of biomass, nitrogen and phosphorus in common bean cultivars

Shoot biomass is considered a relevant component for crop yield, but relationships between biological productivity and grain yield in legume crops are usually difficult to establish. Two field experiments were carried out to investigate the relationships between grain yield, biomass production and N and P accumulation at reproductive stages of common bean (Phaseolus vulgaris) cultivars. Nine and 18 cultivars were grown on 16 m² plots in 1998 and 1999, respectively, with four replications. Crop biomass was sampled at four growth stages (flowering R6, pod setting R7, beginning of pod filling R8, and mid-pod filling R8.5), grain yield was measured at maturity, and N and P concentrations were determined in plant tissues. In both years, bean cultivars differed in grain yield, in root mass at R6 and R7 stages, and in shoot mass at R6 and R8.5, whereas at R7 and R8 differences in shoot mass were significant in 1998 only. In both years, grain yield did not correlate with shoot mass at R6 and R7 and with root mass at R6. Grain yield correlated with shoot mass at R8 in 1999 but not in 1998, with shoot mass at R8.5 and with root mass at R7 in both years. Path coefficient analysis indicated that shoot mass at R8.5 had a direct effect on grain yield in both years, that root mass at R7 had a direct effect on grain yield in 1998, and that in 1999 the amounts of N and P in shoots at R8.5 had indirect effects on grain yield via shoot mass at R8.5. A combined analysis of both experiments revealed that biomass accumulation, N and P in shoots at R6 and R7 as well as root mass at R6 were similar in both years. In 1998 however bean accumulated more root mass at R7 and more biomass and N and P in shoots at R8 and R8.5, resulting in a 57 % higher grain yield in 1998. This indicates that grain yield of different common bean cultivars is not intrinsically associated with vegetative vigor at flowering and that mechanisms during pod filling can strongly influence the final crop yield. The establishment of a profuse root system during pod setting, associated with the continuous N and P acquisition during early pod filling, seems to be relevant for higher grain yields of common bean.

Occurrence of plant growth-promoting traits in clover-nodulating rhizobia strains isolated from different soils in Rio Grande do Sul state

In the last decades, the use of plant growth-promoting rhizobacteria has become an alternative to improve crop production. Rhizobium leguminosarum biovar trifolii is one of the most promising rhizobacteria and is even used with non-legume plants. This study investigated in vitro the occurrence of plant growth-promoting characteristics in several indigenous R. leguminosarum biovar trifolii isolated from soils in the State of Rio Grande do Sul, Brazil. Isolates were obtained at 11 locations and evaluated for indoleacetic acid and siderophore production and inorganic phosphate solubilization. Ten isolates were also molecularly characterized and tested for antagonism against a phytopathogenic fungus and for plant growth promotion of rice seedlings. Of a total of 252 isolates, 59 produced indoleacetic acid, 20 produced siderophores and 107 solubilized phosphate. Some degree of antagonism against Verticillium sp. was observed in all tested isolates, reducing mycelial growth in culture broth. Isolate AGR-3 stood out for increasing root length of rice seedlings, while isolate ELD-18, besides increasing root length in comparison to the uninoculated control, also increased the germination speed index, shoot length, and seedling dry weight. These results confirm the potential of some strains of R. leguminosarum biovar trifolii as plant growth-promoting rhizobacteria.

Liming influence on soil chemical properties, nutritional status and yield of alfalfa grown in acid soil

Alfalfa is an important forage crop with high nutritive value, although highly susceptible to soil acidity. Liming is one of the most efficient and prevailing practices to correct soil acidity and improve alfalfa yield. The objective of this study was to evaluate response to liming of alfalfa grown in a greenhouse on a Typic Quartzipsamment soil. The treatments consisted of four lime rates (0, 3.8, 6.6 and 10.3 Mg ha-1) and two cuts. Alfalfa dry matter increased quadratically with increasing lime rates. In general, dry matter yield was maximized by a lime rate of 8.0 Mg ha-1. Except for the control, the dry matter nutrient contents in the treatments were adequate. The positive linear correlation between root and nodule dry matter with lime rates indicated improvement of these plant traits with decreasing soil acidity. The soil acidity indices pH, base saturation, Ca2+ concentration, Mg2+ concentration, and H + Al were relevant factors in the assessment of alfalfa yield. The magnitude of influence of these soil acidity indices on yield as determined by the coefficient of determination (R²) varied and decreased in the order: base saturation, H + Al, pH, Ca and Mg concentrations. Optimum values of selected soil chemical properties were defined for maximum shoot dry matter; these values can serve as a guideline for alfalfa liming to improve the yield of this forage on acid soils.

Persistence of a biocontrol Pseudomonas inoculant as high populations of culturable and non-culturable cells in 200-cm-deep soil profiles

Little is known about the ecology of soil inoculants used for pathogen biocontrol, biofertilization and bioremediation under field conditions. We investigated the persistence and the physiological states of soil-inoculated Pseudomonas protegens (previously Pseudomonas fluorescens) CHA0 (108 CFU g−1 surface soil) in different soil microbial habitats in a planted ley (Medicago sativa L.) and an uncovered field plot. At 72 days, colony counts of the inoculant were low in surface soil (uncovered plot) and earthworm guts (ley plot), whereas soil above the plow pan (uncovered plot), and the rhizosphere and worm burrows present until 1.2 m depth (ley plot) were survival hot spots (105-106 CFU g−1 soil). Interestingly, strain CHA0 was also detected in the subsoil of both plots, at 102-105 CFU g−1 soil between 1.8 and 2 m depth. However, non-cultured CHA0 cells were also evidenced based on immunofluorescence microscopy. Kogure's direct viable counts of nutrient-responsive cells showed that many more CHA0 cells were in a viable but non-culturable (VBNC) or a non-responsive (dormant) state than in a culturable state, and the proportion of cells in those non-cultured states depended on soil microbial habitat. At the most, cells in a VBNC state amounted to 34% (above the plow pan) and those in a dormant state to 89% (in bulk soil between 0.6 and 2 m) of all CHA0 cells. The results indicate that field-released Pseudomonas inoculants may persist at high cell numbers, even in deeper soil layers, and display a combination of different physiological states whose prevalence fluctuates according to soil microbial habitats.

Enzymatic activity and mineralization of carbon and nitrogen in soil cultivated with coffee and green manures

There are great concerns about degradation of agricultural soils. It has been suggested that cultivating different plant species intercropped with coffee plants can increase microbial diversity and enhance soil sustainability. The objective of this study was to evaluate enzyme activity (urease, arylsulfatase and phosphatase) and alterations in C and N mineralization rates as related to different legume cover crops planted between rows of coffee plants. Soil samples were collected in a field experiment conducted for 10 years in a sandy soil in the North of Paraná State, Brazil. Samples were collected from the 0-10 cm layer, both from under the tree canopy and in-between rows in the following treatments: control, Leucaena leucocephala, Crotalaria spectabilis, Crotalaria breviflora, Mucuna pruriens, Mucuna deeringiana, Arachis hypogaea and Vigna unguiculata. The soil was sampled in four stages of legume cover crops: pre-planting (September), after planting (November), flowering stage (February) and after plant residue incorporation (April), from 1997 to 1999. The green manure species influenced soil enzyme activity (urease, arylsulfatase and phosphatase) and C and N mineralization rates, both under the tree canopy and in-between rows. Cultivation of Leucaena leucocephala increased acid phosphatase and arilsulfatase activity and C and N mineralization both under the tree canopy and in-between rows. Intercropped L. leucocephala increased urease activity under the tree canopy while C. breviflora increased urease activity in-between rows.

Exopolysaccharides produced by the symbiotic nitrogen-fixing bacteria of leguminosae

The process of biological nitrogen fixation (BNF), performed by symbiotic nitrogen fixing bacteria with legume species, commonly known as α and β rhizobia, provides high sustainability for the ecosystems. Its management as a biotechnology is well succeeded for improving crop yields. A remarkable example of this success is the inoculation of Brazilian soybeans with Bradyrhizobium strains. Rhizobia produce a wide diversity of chemical structures of exopolysaccharides (EPS). Although the role of EPS is relatively well studied in the process of BNF, their economic and environmental potential is not yet explored. These EPS are mostly species-specific heteropolysaccharides, which can vary according to the composition of sugars, their linkages in a single subunit, the repeating unit size and the degree of polymerization. Studies have showed that the EPS produced by rhizobia play an important role in the invasion process, infection threads formation, bacteroid and nodule development and plant defense response. These EPS also confer protection to these bacteria when exposed to environmental stresses. In general, strains of rhizobia that produce greater amounts of EPS are more tolerant to adverse conditions when compared with strains that produce less. Moreover, it is known that the EPS produced by microorganisms are widely used in various industrial activities. These compounds, also called biopolymers, provide a valid alternative for the commonly used in food industry through the development of products with identical properties or with better rheological characteristics, which can be used for new applications. The microbial EPS are also able to increase the adhesion of soil particles favoring the mechanical stability of aggregates, increasing levels of water retention and air flows in this environment. Due to the importance of EPS, in this review we discuss the role of these compounds in the process of BNF, in the adaptation of rhizobia to environmental stresses and in the process of soil aggregation. The possible applications of these biopolymers in industry are also discussed.