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Orrutea A.G.,Centro Universitario Luterano Of Ji Parana | Melo V.F.,Federal University of Parana | Motta A.C.V.,Federal University of Parana | Lima V.C.,Federal University of Parana
Acta Amazonica | Year: 2012

The high soil temperatures that take place during the burning of the Amazon rainforest may induce soil mineralogical transformations. This study aimed to evaluate mineralogical changes in sand, silt and clay fractions and to assess K reserve of soils submitted to different managements (11 years of secondary forest, pasture and coffee plantation) after slashing and burning of a native forest in the Southern Amazon, Cacoal, Rondonia State, Brazil. An area of ombrophilous dense native forest with homogeneous pedologic features was divided into four parts, being three of them submitted to slash and burn and then cropped. In each area, soil profile was described and the A, AB, B1, 2B2 and 2BC horizons were sampled. Mineralogical analyses of clay, silt and sand fractions were performed by X ray diffraction. Clay fraction was also submitted to selective solvent with citrate-bicarbonate-dithionite (CBD) and ammonium oxalate (AO). The soil contents of non-exchangeable K was extracted by boiling with 1 mol L-1 HNO3. Soil mineralogical analysis indicated that kaolinite was the predominant mineral in the clay fraction. There was also evidence of a large reserve K, associated to the occurrence of mica in clay, silt and sand fractions. Chemical analysis indicated that land use did not change the concentration of Fe2O3CBD and Fe2O3AO. However, the highest goethite/hematite ratio [Gt(Gt+Hm)] calculated for the A horizon of the forest soil suggests that the burning favored the partial transformation of goethite in hematite into those areas where it was carried out. Source

Rocha R.B.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Vieira D.S.,Centro Universitario Luterano Of Ji Parana | Ramalho A.R.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Teixeira A.L.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria
Coffee Science | Year: 2013

Efficient strategies to manipulate the genetic variability are crucial to the success of breeding programs Coffea canephora. Combinations between divergent parents express greater heterosis effect, and the selection of matrices consider both genetic divergence and superior agronomic performance. The objective of this study was to quantify the genetic diversity of C. canephora accesses Active Germplasm Bank of Embrapa Rondônia, in order to identify plants of greater genetic diversity and higher yield potential for hybridization. For this, between 1100 accessions were pre-selected 89 plants for evaluation of major components in the production of processed coffee. For quantification of genetic diversity technique for principal components associated landmarks to gather the information of genetic divergence and agricultural performance in a single analysis was used. The selected accessions showed significant genetic variability for the major components of production, highlighting the values of average blend above 17, which indicates a favorable condition for performing controlled crosses for selection of plants for increased productivity and grain size. Source

Hymenaea courbaril L. var. stilbocarpa (Hayne) Lee et Lang. is a clímax shadow tolerant specie and Enterolobium contortisiliquum (Vell.) Morong., by the other hand, is considered as a pioneer specie. The development of these species may reflect its adaptation ability to different environmental elements (light, water and temperature) at its growth site. An inadequate supply of some of these elements may reduce plant vigor and limit its development. This work aimed to evaluate the effects of shade intensity on the growth and photosynthetic pigment concentration of two arboreal legumes that are typical to northern Brazil, namely, the Hymenaea courbaril L. var. stilbocarpa (Hayne) Lee et Lang. and the Enterolobium contortisiliquum (Vell.) Morong. The experiment was carried out at the Centro Universitário Luterano de Ji-Paraná (CEULJ/ULBRA)/Rondônia. During the formation of the seedlings, both species were exposed to four treatments of shade: 0% (control - without shade); 30%; 50% e 80%. Each treatment was carried out with three replications for each species; the experimental design was completely randomized. Four month after sowing, the following analyses were carried out: number of leaves, plant height, roots length, dry mass and photosynthetic pigment concentration. The treatment under 0% shade impaired the seedling growth of both species. The most favorable treatments were 50% and 80% shade. According to the shade intensity, the chlorophyll a/b ratio decreased and the chlorophyll and carotenoids increased. Source

Barbieri A.M.,University of Sao Paulo | Venzal J.M.,University of the Republic of Uruguay | Marcili A.,University of Sao Paulo | Almeida A.P.,University of Sao Paulo | And 3 more authors.
Vector-Borne and Zoonotic Diseases | Year: 2013

The Borrelia burgdorferi sensu lato (s.l.) group comprises genetically related spirochetes, mostly associated with tick species belonging to the Ixodes ricinus complex in the Northern Hemisphere. The present study evaluated borrelial infection in the tick Ixodes pararicinus, which is the only representative species of the I. ricinus complex in Uruguay. A total of 137 I. pararicinus ticks were collected from deer, cattle, or vegetation in 2 Uruguayan Departments. A part of these ticks was tested directly by PCR targeting the borrelial gene flagellin (fla), whereas another part of the ticks was inoculated into Barbour-Stoenner-Kelly (BSK)-H medium in an attempt to isolate Borrelia. Overall, Borrelia infection was detected in 9 males and 1 nymphal tick pool. These ticks were found to be infected by unique fla haplotypes, which were shown through phylogenetic analysis to represent possibly 2 new B. burgdorferi s.l. genospecies, 1 associated with B. bissettii, the other phylogenetically closest to B. americana. These results were reinforced by PCR and DNA sequencing analyses of portions of 2 additional borrelial genes, rrfA-rrlB intergenic spacer region (IGS) and 16S rDNA (rrs). Weekly examinations of BSK cultures by dark-field microscopy failed to demonstrate live Borrelia through a 100-day incubation period. However, Borrelia DNA was detected by fla-PCR in culture media from 2 vials up to 90 days after inoculation. To the best of our knowledge, this is the first report of B. burgdorferi s.l. infecting ticks in South America. © Mary Ann Liebert, Inc. Source

Da Silva J.,Centro Universitario Luterano Of Ji Parana | Saccini V.A.V.,Paulista University | Dos Santos D.M.M.,Sao Paulo State University
Semina:Ciencias Agrarias | Year: 2015

It was studied the effects of seed treatment with polyamines of pigeonpea for proline content of seedling in order to verify that the application of these polyamines attenuates temperature stress on germination and early seedling growth, and see if exogenous putrescine and spermidine induce the accumulation of proline, this amino acid may be biochemical and physiological indicator in seedlings that are under suboptimal temperatures and supraoptmail. The seeds of pigeonpea cv. BRS Mandarin and cv. Caqui, treated with a solution of 0.5 mM of putrescine and spermidine, were subjected to suboptimal temperature (20°C, 18°C, 16°C and 14°C) and supraoptimal (36°C, 38°C, 40°C and 44°C) for 24 hours and 48 hours. After these periods, were subjected to 25°C until day 10, when the percentage of seed germination were observed, the proline content of vegetative parts and the dry mass of the seedlings. A completely randomized design in a factorial arrangement was used 3×4×2+3 (solutions with polyamines, temperature stress by cooling/heating, time of exposure to stress, plus additional factors em25°C with 0.0 mM and 0.5mM of Put and Spd), with four replicates of 25 seeds. The results were submitted to analysis of variance and means were compared by Tukey test at 5% probability, separately for each cultivar. Both exogenous polyamines attenuate the effects of cooling and heating, contributing to the growth of germinated seeds. Also, putrescine and spermidine exogenous mitigated the adverse effects by inducing proline accumulation, which leads to osmotic adjustment temperatures, although this physiological response has not minimized the negative effects of temperature stress on seedling growth of pigeonpea. Proline can be considered biochemical and physiological indicator in seedlings of both cultivars of pigeonpea treated with polyamines under temperature stress. Source

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