Thermogravimetric studies of the decomposition kinetics of four different Hevea rubber clones using Ozawa's approach

Thermal degradation of natural rubber extracted from four different rubber clones of the Hevea brasiliensis species was investigated by thermogravimetry using Ozawa's approach to assess the kinetic parameters of the decomposition process. The results are discussed in terms of the order of reaction, kinetic parameters such as activation energy as a function of conversion degree, and thermal stability for each of the clones.

Resistência da seringueira ao mal das folhas e modelagem no patossistema Hevea sp. – Microcyclus ulei através dos parâmetros monocíclicos

Pós-graduação em Ciência Florestal - FCA

Phytoseiidae mites associated with Hevea spp. from the Amazon region: a hidden diversity under the canopy of native trees

Despite the Amazon Forest being the largest tropical forest in the world, and cradle of rubber trees (Hevea brasiliensis), no studies have aimed to report the occurrence of mites associated with native trees from this ecosystem. Our survey investigates the phytoseiid mites associated with five species of native rubber trees from nine sites of the Amazon Forest, and also presents a major review of phytoseiid species from natural vegetation in Brazil. We found a total of 1305 mites, belonging to 30 species, of which seven were new to science, Amblydromalus akiri sp. nov., Amblyseius chicomendesi sp. nov., Amblyseius duckei sp. nov., Amblyseius manauara sp. nov., Iphiseiodes katukina sp. nov., Iphiseiodes raucuara sp. nov. and Typhlodromips igapo sp. nov.; beyond two new records for Brazil, Iphiseiodes kamahorae and Amblyseius martus. Our results emphasize the importance of Amazon native trees as an unexplored source of predator mites, which in turn may be further studied as biological control agents of pest mites on rubber trees. The impressive diversity, endemism and rate of new species found highlight the importance of studies on arthropod communities associated with the Amazon vegetation.

Padrões de distribuição espacial e temporal em comunidades de ácaros em seringueira (Hevea SPP.) no Brasil

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

Yield and chemical properties of rubber of Hevea clones according to phenological stages

The objective of this work was to evaluate the yield performance and macronutrient content of rubber extracted from four Hevea brasiliensis clones, under different tapping systems and plant phenological stages. The experiment was carried out in the 2010 and 2011 crop seasons, in a split-plot randomized complete block design, with four replicates. The main treatments - GT 1, PB 235, IAN 873, and RRIM 600 clones - were allocated in the plots, and the secondary treatments, which were the tapping systems 1/2S d/2, 1/2S d/4 ET 2.5%, and 1/2S d/7 ET 2.5%, were allocated in the subplots. The analyzed variables were natural rubber yield and macronutrient contents. Samples of natural rubber were obtained in the leaf development, mature leaf, and leaf senescence phenological stages. Rubber yield and its macronutrient contents are more influenced by tapping practice than by genetic material in the restrictive phenological stages of foliage.

Evaluation of the profitability of fast-growing tropical trees.

The profitability of fast-growing trees was investigated in the northeastern and eastern provinces of Thailand. The financial, economic, and tentative environmental-economic profitability was determined separately for three fast-growing plantation tree species and for three categories of plantation managers: the private industry, the state (the Royal Forest Department) and the farmers. Fast-growing tree crops were also compared with teak (Tectona grandis), a traditional medium or long rotation species, and Para rubber (Hevea brasiliensis) which presently is the most common cultivated tree in Thailand. The optimal rotation for Eucalyptus camaldulensis pulpwood production was eight years. This was the most profitable species in pulpwood production. In sawlog production Acacia mangium and Melia azedarach showed a better financial profitability. Para rubber was more profitable and teak less profitable than the three fast-growing species. The economic profitability was higher than the financial one, and the tentative environmental-economic profitability was slightly higher than the economic profitability. The profitability of tree growing is sensitive to plantation yields and labour cost changes and especially to wood prices. Management options which aim at pulpwood production are more sensitive to input or output changes than those options which include sawlog production. There is an urgent need to improve the growth and yield data and to study the environmental impacts of tree plantations for all species and plantation types.

Controle biologico do percevejo-de-renda (Leptopharsa heveae Drake & Poor) em seringais de cultivo.

A mosca-de-renda ou percevejo-de-renda (Leptopharsa heveae - Hemiptera: Tingidae) e o mais importante inseto-praga da seringueira no Brasil. Essa praga de origem amazonica invadiu os seringais do Estado de Mato Grosso por volta de 1985 e, de 1992 a 1998, chegou aos seringais do Estado Sao Paulo e de Goias. Acredita-se que breve chegara aos Estados da Bahia, Espirito Santo e Minas Gerais. O principal agente disseminador desse inseto-praga entre estados e seringais tem sido os veiculos transportadores de coagulos e latex semiprocessado (GEB). O controle quimico dessa praga, alem de muito caro, coloca em risco os aplicadores e o meio ambiente. Em 1986, no Amazonas, o fungo Sporothrix insectorum foi constatado parasitando individuos do percevejo-de-renda. Com base nessa constatacao foram feitos alguns estudos em campo e laboratorio onde se determinaram a eficiencia biologica (capacidade do inimigo natural para infectar e destruir a praga) e a eficiencia tecnica (capacidade do inimigo natural para reduzir os danos causados na planta pela acao da praga). Os resultados desses testes evidenciaram o elevado potencial do S. insectorum para o controle do percevejode-renda. Imediatamente apos os testes, esse fungo foi enviado para os Estados de Mato Grosso, Acre, Rondonia, e mais recentemente para Sao Paulo e Goias onde vem sendo utilizado com o fungo Hirsutella verticillioides por diversos produtores e empresas. O fungo H. verticillioides, outro inimigo natural do percevejo-de-renda, isolado em 1990, na Guiana Francesa, vem sendo bem mais agressivo nos seringais da regiao Centro-Oeste e de Sao Paulo que o S. insectorum. Os resultados obtidos de avaliacoes efetuadas em alguns seringais de Goias, Mato Grosso e Sao Paulo indicam eficiencia biologica (porcentagem de insetos colonizados e fixados na folha por ambos os fungos em fevereiro), variando de 53% a 100%. Por outro lado, a eficiencia tecnica, medida pelo nivel de descoloracao da folha ou % de danos causados pela praga em fevereiro, tendo como referencia folhas nao atacadas, variou de 16% a 63%.

Sistemas agroflorestais de seringueira com cafeeiro.

Esta publicacao tem por objetivo reunir as informacoes disponiveis na literatura sobre os sistemas agroflorestais de seringueira com cafeeiro, de modo a auxiliar os agricultores e extensionistas nas tomadas de decisoes e servir como referencial para pesquisas futuras nessa area. Sao discutidos os aspectos economicos e tecnicos das culturas, tais como: exigencias de clima e solo, compatibilidade vegetativa e fitossanitaria, materiais geneticos, tipos de sistemas, indice de equivalencia de area e praticas de manejo, visando a viabilidade tecnica e economica das culturas e dos sistemas como um todo.

Abertura de painel de sangria de seringueira com raspador de casca.

2001

Desempenho de clones de seringueira sob diferentes sistemas de sangria.

Este trabalho teve como objetivo avaliar o crescimento e a producao da borracha de clones seringueira [Havea brasiliensis ( Wild. Ex Adr. De Juss.) Muell. Arg.] sob diferentes sistemas de sangria, em condição de Cerrado dos Municipios de Barro Alto Goianesia no Estado de Goais. O plantio foi feito em fevereiro de 1992, no espacamento de 8,0 x 2,5 m (500 plantas/ha), em talhoes de 8 a 10 hectares para cada um dos clones RRIM 600, GT 1, PB 217, PB 235, PR 107 e PR 255 os quais receberam as mesmas praticas de manejo. Aos oito anos de idade, foram feitas as seguintes avaliacoes: estande final; circunferencia do caule a 1,20 m do solo; porcentagens de plantas aptas a sangria; producao de borracha acumulada na caneca pesada mensalmente; incidencia de seca de painel. A producao foi avaliada em nove sistemas de sangria em meia espiral (1/2 S), praticados cinco dias por semana (5d/7) e 10 meses ao ano (10m/12), variando na frequência de sangria (d/4 e d/7 = a cada 4 e 7 dias), a concentracao de Ethephon (ET 0,25%, 2,5%,3,3% e 5,0%) e sua frequencia de aplicacao durante o periodo chuvoso ( a cada 22, 28 e 35 dias), como segue: 1) 1/2S, d/7, ET 2,5% a cada 22 dias; 2)1/2S, d/7, ET 2,5% a cada 30 dias (referncia); 3) 1/2S. d/4, ET 2,5% a cada 30 dias; 4) 1/2S, d/7, ET 3,3% a cada 22 dias; 5)1/2S, d/7, ET 3,3% a cada 30 dias; 6) 1/2S. d/7, ET 5,0% a cada 22 dias 7) 1/2S, d/7, ET 5,0% a cada 30 dias; 8) 1/2S, d/7, ET 5,0% a cada 35 dias; 9) 1/2S, d/7, ET 0,25% (pulverizando 10 ml por painel) a cada 22 dias. Nos sistemas 1 a 8, o Ethephon foi pincelado ( 1mL) na canaleta de corte e ate 2 cm acima dela (Pa e La). O delineamento experimental foi de blocos ao acaso, com quatro repeticoes de 10 plantas poe parcela. Cada clone constitui um experimento separado, sendo os resultados de producao acumulada anual submetidos a analise de variancia e, nos caso de significancia, as medias dos sistemas foram comparadas pelo teste Tukey, ao nível de 5% de probabilidade. Nao foi constatada qualquer incidencia de seca de painel e os resultados possibilitaram as seguintes conclusoes para as condicoes da regiao: 1) o sistema 1/2S, d/7, ET 2,5% a cada 30 dias e o mais indicado par a sangria dos clones PR 255, PR 107, PB 235, PB 217 e GT 1; 2) o sistema 1/2S, d/7, ET 3,3% a cada 30 dias e o mais indicado para a sangria do clone RRIM 600; 3) a producao individual de borracha em kg/planta/ano e maior nos clones RRIM 600, PB 217 e PR 255, enquanto a producao total em kg/ha/ano e superior nos clones RRIM 600 e PB 235; 4)os clones PB 217 e PR 255 sao menos adaptados a regiao, apresentando menores valores de estande final, circunferencia do caule, porcentagem de plantas em sangria e de producao total de borracha por hectare.

Ataque de Lonomia sp. (Lepidoptera: Saturniidae) em seringueira no município de Bujari, AC.

Os estudos dos insetos associados às culturas agrícolas e florestais são dinâmicos, em função da evolução dos sistemas de cultivo, do avanço da fronteira agrícola, da introdução de novas pragas e da resistência aos produtos químicos historicamente aplicados. Nesse contexto, os avanços nos estudos dos insetos-praga periodicamente precisam ser integrados em publicações de referência, que permitam fácil acesso a esses conhecimentos. Assim, o objetivo desta publicação é documentar o ataque de lagartas do gênero Lonomia, popularmente conhecidas como lagartas-de-fogo, causando intensa desfolha em cultivos de seringueira (Hevea brasiliensis) no Acre. Há um grande número de trabalhos publicados sobre esse gênero, no que tange aos problemas acarretados pelo contato direto de pessoas com as lagartas, provocando acidentes hemorrágicos graves, dependendo da área lesionada e da extensão do contato. No entanto, não havia relatos dessas lagartas causando intenso desfolhamento em seringais de cultivo, ocasionando prejuízos econômicos. A partir da intensificação do cultivo, surtos populacionais de insetos, considerados pragas secundárias em muitas culturas, podem acontecer com mais frequência, necessitando de conhecimento e estratégias de manejo que visem ao monitoramento, distribuição e controle de populações de insetos no Estado do Acre, a fim de prevenir surtos populacionais de pragas e, consequentemente, prejuízos elevados aos produtores acrianos.

Análisis de las estrategias de cooperación sur-sur para el desarrollo económico y social binacional. Estudio de caso: proyectos en materia agropecuaria en el marco del convenio de cooperación técnica y científica entre Brasil y Colombia, periodo 2007-2011

Las desigualdades económicas y sociales entre los Estados del Norte y del Sur son evidentes, ante esta premisa surge la Cooperación Sur-Sur como una herramienta eficaz para potencializar el desarrollo económico y social de las naciones del Sur bajos los principios de horizontalidad, consenso y equidad. En este sentido, se analizan las estrategias de Cooperación Sur-Sur entre Brasil y Colombia y su aplicación en uno de los sectores prioritarios de los Estados del Sur como es el sector agropecuario.

Combinatorial peptide ligand libraries and plant proteomics: a winning strategy at a price

The mechanism of action and properties of a solid-phase ligand library made of hexapeptides (combinatorial peptide ligand libraries or CPLL), for capturing the "hidden proteome", i.e. the low- and very low-abundance proteins constituting the vast majority of species in any proteome, as applied to plant tissues, are reviewed here. Plant tissues are notoriously recalcitrant to protein extraction and to proteome analysis. Firstly, rigid plant cell walls need to be mechanically disrupted to release the cell content and, in addition to their poor protein yield, plant tissues are rich in proteases and oxidative enzymes, contain phenolic compounds, starches, oils, pigments and secondary metabolites that massively contaminate protein extracts. In addition, complex matrices of polysaccharides, including large amount of anionic pectins, are present. All these species compete with the binding of proteins to the CPLL beads, impeding proper capture and identification / detection of low-abundance species. When properly pre-treated, plant tissue extracts are amenable to capture by the CPLL beads revealing thus many new species among them low-abundance proteins. Examples are given on the treatment of leaf proteins, of corn seed extracts and of exudate proteins (latex from Hevea brasiliensis). In all cases, the detection of unique gene products via CPLL capture is at least twice that of control, untreated sample.

Combinatorial peptide ligand libraries and plant proteomics: a winning strategy at a price

The mechanism of action and properties of a solid-phase ligand library made of hexapeptides (combinatorial peptide ligand libraries or CPLL, for capturing the "hidden proteome", i.e. the low- and very low-abundance proteins Constituting the vast majority of species in any proteome. as applied to plant tissues, are reviewed here. Plant tissues are notoriously recalcitrant to protein extraction and to proteome analysis, Firstly, rigid plant cell walls need to be mechanically disrupted to release the cell content and, in addition to their poor protein yield, plant tissues are rich in proteases and oxidative enzymes, contain phenolic Compounds, starches, oils, pigments and secondary metabolites that massively contaminate protein extracts. In addition, complex matrices of polysaccharides, including large amount of anionic pectins, are present. All these species compete with the binding of proteins to the CPLL beads, impeding proper capture and identification I detection of low-abundance species. When properly pre-treated, plant tissue extracts are amenable to capture by the CPLL beads revealing thus many new species among them low-abundance proteins. Examples are given on the treatment of leaf proteins, of corn seed extracts and of exudate proteins (latex from Hevea brasiliensis). In all cases, the detection of unique gene products via CPLL Capture is at least twice that of control, untreated sample. (c) 2008 Elsevier B.V. All rights reserved.

Dynamics of biochemical and morphophysiological changes during zygotic embryogenesis in Acca sellowiana (Berg.) Burr.

Acca sellowiana (Berg.) Burr. is a native Myrtaceae from southern Brazil and Uruguay, now the subject of a domestication and breeding program. Biotechnological tools have been used to assist in this program. The establishment of a reliable protocol of somatic embryogenesis has been pursued, with a view to capturing and fixing genetic gains. The rationale behind this work relies on the fact that deepening comprehension of the general metabolism of zygotic embryogenesis may certainly improve the protocol for somatic embryogenesis. Thus, in the present work we studied the accumulation of protein, total sugars, starch, amino acids, polyamines (PAs), IAA and ABA, in different stages of A. sellowiana zygotic embryogenesis. Starch is the predominant storage compound during zygotic embryo development. Increased synthesis of amino acids in the cotyledonary stage, mainly of asparagine, was observed throughout development. Total free PAs showed increased synthesis, whereas total conjugated PAs were mainly observed in the early developmental stages. IAA decreased and ABA increased with the progression from early to late embryogenesis. Besides providing basic information on the morphophysiological and biochemical changes of zygotic embryogenesis, the results here obtained may provide adequate strategies towards the modulation of somatic embryogenesis in this species as well as in other woody angiosperms.