Microscopic evidence supports the hypothesis of high cellulose degradation capacity by the symbiotic fungus of leaf-cutting ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características morfológicas de gramas em resposta à aplicação de trinexapac-ethyl

O presente trabalho teve como objetivo avaliar os efeitos da aplicação de duas doses de trinexapac-ethyl sobre a morfologia das espécies de gramas São Carlos (Axonopus compressus), Batatais (Paspalum notatum), Santo Agostinho (Stenotaphrum secundatum) e Esmeralda (Zoysia japonica). Os gramados foram cortados à altura de 3 cm no início do experimento e 20 dias depois. Após cada corte, foram realizadas duas aplicações sequenciais de trinexapac-ethyl nas doses de 56,5 + 56,5 e 113,0 + 113,0 g ha-1 , além de uma testemunha sem aplicação, para cada espécie avaliada. O delineamento experimental utilizado foi o de blocos ao acaso com quatro repetições. A redução do crescimento foi avaliada por meio da altura das plantas. Semanalmente, o número e altura de inflorescências foram avaliados por amostragem, realizada em 0,25 m² no centro das parcelas; no final do experimento, avaliou-se a massa seca total. A aplicação do trinexapac-ethyl retardou o crescimento vegetativo e a emissão das inflorescências, assim como não provocou danos aparentes nos gramados. O uso do trinexapac-ethyl nos gramados avaliados pode reduzir a necessidade de cortes em até 55 dias após a segunda aplicação.

Differentiation in Selection of Dicots and Grasses by the Leaf-Cutter Ants Atta capiguara, Atta laevigata and Atta sexdens rubropilosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Isolation and growth of the symbiotic fungus of Atta capiguara (Hymenoptera: Formicidae)

This work's objectives were to isolate and evaluate the growth of the symbiotic fungus of Atta capiguara Gonçalves on artificial medium, under different pH and temperature conditions. Isolation was accomplished using the following media: Sabouraud, oat-agar, PDA, and PDA with the addition of extracts from the grasses Paspalum sp. Flügge and Hyparrhenia rufa (Nees) Stapf.. The medium used in the growth study was PDA with the addition of a Paspalum sp. (0.22%, w/v) extract at initial pH values of 4.5, 6.0, and 7.5. Mycelium disks were transferred to plates containing the culture medium. The plates were maintained at temperatures of 20, 23, and 26 ± 1°C. Mycelial radial growth evaluations were performed at 7, 14, 21, 28, and 35 days of incubation. Fungus isolation was obtained in all media studied. The highest radial means were obtained at initial pH values of 6.0 and 7.5 and temperatures of 23 and 26± 1°C. Greater plot losses occurred at the initial pH condition of 7.5. In general, A. capiguara fungi can be grown in the medium studied, at an initial pH of 6.0 and temperatures of 23 or 26± 1°C. Radial growth evaluations at 14 and 28 days of incubation can be recommended for substrate studies involving the symbiotic fungus.

Seletividade de herbicidas aplicados sobre espécies de gramas em relação às características morfo-anatômicas foliares

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características anatômicas foliares e morfológicas de quatro espécies de gramas sob aplicação de trinexapac-ethyl

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fungos nematófagos em diferentes solos e caracterização filosófica de Arthrobotrys oligospora

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de dez gramíneas forrrageiras na região noroeste do Estado de São Paulo

Pós-graduação em Zootecnia - FCAV

Soil compressibility and least limiting water range of a constructed soil under cover crops after coal mining in Southern Brazil

The use of cover crops affects the support capacity of soil and least limiting water range to crop growth. The objective of this study was to quantify preconsolidation pressure (sigma(p)), compression index (CI) and least limiting water range (LLWR) of a reclaimed coal mining soil under different cover crops, in Candiota, RS, Brazil. In the experiment, with randomized blocks design and four replicates, the following cover crops (treatments) were evaluated: Hemarthria altissima (Poir.) Stapf & C.E. Hubbard, treatment 1 (T1), Paspalum notatum Flugge, treatment 4 (T4), Cynodon dactilon (L) Pers., treatment 5 (T5), control Brachiaria brizantha (Hochst.) Stapf, treatment 7 (T7) and without cover crop treatment 8 (reference treatment, T8). Soil compression and least limiting water range were evaluated with undisturbed samples at a depth of 0.00-0.05 m. In order to evaluate parameters of soil compressibility, the soil samples were saturated with water and subjected to -10 kPa matric potential and then submitted to a uniaxial compression test under the following pressures: 25, 50, 100, 200, 400, 800 and 1600 kPa. Cover crops decreased the preconsolidation pressure of constructed soils after coal mining and the greatest soil reclamation was obtained with the H. altissima cover crop, where the lowest degree of soil compactness and soil load capacity were observed. Soils cultivated under H. altissima or B. brizantha presented the highest least limiting water range and these two cover crops generated similar soil critical bulk density obtained by least limiting water range and soil load support capacity. (C) 2012 Elsevier B.V. All rights reserved.

Padrão de n-alcanos de algumas gramíneas nativas do bioma Pampa.

O objetivo do presente trabalho foi estudar o perfil de n-alcanos em lâminas foliares de algumas espécies de gramíneas nativas do Bioma Pampa a fim de avaliar o potencial destes indicadores para estimar composição da dieta de animais em pastejo.

Paspalum vaginatum Swartz, Seashore Paspalum 'SDX-1'

‘SDX-1’ originated as an open-pollinated chance seeding in an old green of ‘Adalayd’ seashore paspalum (US Plant Patent 3939) surrounded by an undefined local ecotype of the same species. ‘SDX-1’ was finer textured and had a denser, more prostrate growth habit than its putative parents which are ‘Adalayd’ (maternal) and an undefined parental genotype growing among the surrounding local ecotype. ‘SDX-1’ was compared with other promising seedlings discovered similarly at the same time, and was selected on the basis of its dwarf growth habit, tolerance of low cutting height, turf density, fine-textured growth, and apparent salt tolerance under field conditions. Breeder: Stewart T Bennett, Paul H Tillman, Michael DePew, Enviro Turf LC, Terkonsha, MI, USA. PBR Certificate Number 3660, Application Number 2006/160, granted 16 December 2008.

Paspalum vaginatum Swartz, Seashore Paspalum 'SI98'

‘SI98’ was selected from a worldwide collection of 300 accessions of seashore paspalum collected by Dr Ronny R. Duncan, primarily from seashore paspalum plantings on golf courses as variants in growth habit, leaf texture, and level of salt tolerance, having potential for improved turf type selections. ‘SI98’ was selected as a finer textured genotype with a denser, more prostrate growth habit than the surrounding wild ecotype. The original samples were vegetatively propagated and evaluated first in the greenhouse at Griffin, GA, USA, and later expanded to field evaluations at Griffith under mowing heights ranging from 4.8 mm to 50 mm. Extensive further evaluations were undertaken between 2002 and 2007. Breeder: Dr Ronny R. Duncan, University of Georgia, Griffin, GA, USA. PBR Certificate Number 3648, Application Number 2008/073, granted 16 December 2008.

Determinación de dosis y época de aplicación de glifosato, en control de Paspalum fasciculatum Willd

El presente trabajo se realizo en la colonia agrícola El Guayabo ubicada en la jurisdicción de Turrialba, Costa Rica; durante los meses de Febrero y Marzo del año 1978. Consistió en usar un terreno cubierto de Gramalote (Paspalum fasciculatum Willd.) donde se evaluaron nueve tratamientos que resultaron de la combinación de tres dosis de aplicación (0.5, 1.0 y 1.5 kg e.a/ha) del herbicida glifosato en tres fechas (7, 14 y 21 días) posteriores a la limpia mecánica (chapia) de la graminea, mas tres tratamientos donde dichas dosis fueron aplicadas sin haber efectuado la chapia. El diseño usado fue bloques completos al azar. Los datos de campo se tomaron en base a peso verde 28 días después de la aplicación; fueron transformados a porcentaje de control y posteriormente a grados angulares para proceder a realizar el análisis de varianza. Los resultados obtenidos indicaron que las dosis y tiempos de aplicación considerados fueron igualmente efectivos sobre el rebrote de la graminea y que las dosis consideradas ejercieron excelente control cuando fueron aplicadas directamente sobre el gramalote sin podar.