Perdas de solo e água em plantio de Acacia mangium wild e savana em Roraima, norte da Amazônia

Plantios florestais de Acacia mangium constituem uma alternativa cada vez mais adotada em áreas de savanas do norte da Amazônia (Roraima) e podem causar alterações significativas de características do solo. Neste sentido, o objetivo deste estudo foi determinar perdas de solo e de água por erosão, que ocorrem em escoamento superficial (run off) em savana nativa e plantios de acácia na região Amazônica. Para isso, foram instaladas em duas fazendas, Santa Rita e Araçá, localizadas no município de Bonfim, na região da Serra da Lua, calhas coletoras de sedimentos, acopladas a caixas d'água, em Argissolo Vermelho-Amarelo. Foram determinadas a granulometria, a densidade aparente (Dap), a resistência à penetração (RP) e a velocidade de infiltração (VIB), bem como parâmetros físicos relacionados a perdas de solo. O delineamento experimental utilizado foi o de blocos ao acaso, com três tratamentos: cobertura natural de savana (SV), plantio de Acacia mangium com um ano de idade (P1) e plantio de Acacia mangium com quatro anos de idade (P4), em três repetições. O experimento teve a duração de 12 meses (setembro de 2006 a agosto de 2007). Os resultados indicaram maiores perdas de solo e de água no plantio mais recente de acácia (P1), de savana nativa e do plantio com 4 anos (P4). Os resultados foram atribuídos à exposição do solo no período inicial de desenvolvimento da planta, ao selamento superficial e à coesão do solo. O pico de perdas de solo ocorreu nos meses de abril a agosto, sendo o tipo de cobertura vegetal o fator determinante para redução das perdas de solo e de água por erosão, sendo que as práticas de plantio no sentido do declive provavelmente agravaram as perdas de solo nos plantios de Acácia. Neste trabalho, a densidade do solo e o teor de matéria orgânica não representaram bons indicadores do tipo de manejo adotado na área.

Isoenzymatic variability in wild potatoes

Two species of wild potato Solanum commersonii, subspecies commersonii and malmeanum, and S. chacoense, subspecies muelleri occur in southern Brazil. Their rusticity and easy adaptation to extreme climatic conditions make them valuable for breeding programs. The objective of this work was to analyze the isoenzymatic variability of 113 clones of wild potato subspecies. They were collected and maintained at Embrapa-Centro de Pesquisa Agropecuária de Clima Temperado, at Pelotas, RS, Brazil. Enzymes involved in energetic (group I) or in peripherical (group II) metabolism constituted the material used. Polyacrylamide horizontal gel electrophoresis was used to analyze peroxidase, aspartate transaminase, phosphoglucomutase and isocitrate dehydrogenase isoenzymes. Solanum spp. has considerable genetic variability for isoenzymatic patterns. Cluster analysis classified the clones into 51 subgroups, based on electrophoretic variants of group I enzymes, and into 89, when group II enzyme variants were added. Genotypic differentiation of S. chacoense muelleri in relation to S. commersonii commersonii and S. commersonii malmeanum is evident when expressed through similarity and cluster analysis.

Chemical similarity among domesticated and wild genotypes of peanut based on n-alkanes profiles

The objective of this work was to analyze the epicuticular n-alkane profile of domesticated and wild peanut genotypes. Foliar epicuticular n-alkanes of four Arachis hypogaea genotypes and two wild species - A. monticola and A. stenosperma - were analyzed by gas chromatography. Chemical relationships between them were evaluated using the Dice coefficient and UPGMA method. Two clusters were formed: one with four A. hypogaea genotypes and the other with the two wild species. There is more similarity between the BR1 and LIGO-PE06 genotypes and between the BRS 151 L-7 and BRS Havana genotypes.

Field capture of Thyanta perditor with pheromone-baited traps

The objective of this work was to evaluate the field attractiveness of Thyanta perditor synthetic sex pheromone-baited traps, its attractivity to other stink bug species, and the response of T. perditor to a geometric isomer of the sex pheromone. Two-liter transparent plastic bottles traps were baited with rubber septa impregnated with the treatments: 1 mg of methyl-(2E,4Z,6Z)-decatrienoate [(2E,4Z,6Z)-10:COOMe], the male sex pheromone of T. perditor; 1 mg of (2E,4Z,6Z)-10:COOMe protected from sunlight in standard PVC plumbing pipe; 1 mg of its geometric isomer [(2E,4E,6Z)-10:COOMe]; and traps with rubber septa impregnated with hexane (control). The experiment was carried out in field during the soybean reproductive stages. Traps were monitored weekly, and the captures were compared to the population density estimated by the sampling cloth and visual inspection monitoring techniques. Traps baited with the sex pheromone, protected or not, were more effective in capturing T. perditor than traps baited with the isomer or the hexane. Thyanta perditor sex pheromone showed cross-attraction to other stink bug species, such as Euschistus heros, Edessa meditabunda, Piezodorus guildinii and Nezara viridula. Pheromone-baited traps can be used in population monitoring and to identify the relative composition of stink bug guilds.

Genetic diversity of cultivated accessions and wild species of rubber tree using EST‑SSR markers

The objective of this work was to evaluate the efficiency of EST‑SSR markers in the assessment of the genetic diversity of rubber tree genotypes (Hevea brasiliensis) and to verify the transferability of these markers for wild species of Hevea. Forty‑five rubber tree accessions from the Instituto Agronômico (Campinas, SP, Brazil) and six wild species were used. Information provided by modified Roger's genetic distance were used to analyze EST‑SSR data. UPGMA clustering divided the samples into two major groups with high genetic differentiation, while the software Structure distributed the 51 clones into eight groups. A parallel could be established between both clustering analyses. The 30 polymorphic EST‑SSRs showed from two to ten alleles and were efficient in amplifying the six wild species. Functional EST‑SSR microsatellites are efficient in evaluating the genetic diversity among rubber tree clones and can be used to translate the genetic differences among cultivars and to fingerprint closely related materials. The accessions from the Instituto Agronômico show high genetic diversity. The EST‑SSR markers, developed from Hevea brasiliensis, show transferability and are able to amplify other species of Hevea.

Storage protein profile and amino acid content in wild rice Oryza glumaepatula

- The objective of this work was to determine the total protein profile and the contents of the four major protein fractions (albumin, globulin, prolamin and glutelin) and of the amino acids in the endosperm of the rice wild species Oryza glumaepatula. The experiment was performed with 29 accessions of this species, collected from 13 Brazilian locations, and two commercial cultivars. Protein samples were prepared using dried, polished, and ground grains to obtain homogeneous, dry flour used in the preparation of extracts. Oryza glumaepatula accessions were identified with the highest levels of total protein, albumin and glutelin protein fractions, and amino acids (with the exception of tryptophan) in comparison to the two analized rice cultivars. The albumin and glutelin profiles in SDS-Page were distinct between rice cultivars and O. glumaepatula. This wild species has the potential to increase the nutritional quality of rice storage protein through interspecific crosses.

Morphometric comparison between hatchery-reared and wild-caught megalopae of the mangrove crab

The objective of this work was to compare the morphometry of hatchery-reared and wild-caught mangrove crab (Ucides cordatus) megalopae. Ten U. cordatus megalopae of each group (hatchery-reared and wild-caught) were individually analyzed using a stereoscopic microscope equipped with an ocular micrometer. Length, width, and height of all megalopae were measured, and the size of body appendices was determined. The results indicate that the hatchery-reared megalopae are more robust than the wild ones. Furthermore, some significant differences in the size of certain appendices can be cues of the kind of alterations that hatchery-reared individuals experience.

CHEMICAL COMPOSITION VARIABILITY IN THE Uncaria tomentosa (cat’s claw) WILD POPULATION

Uncaria tomentosa (cat's claw) is a vine widely distributed throughout the South-American rainforest. Many studies investigating the chemical composition of cat's claw have focused on the pentacyclic (POA) and tetracyclic oxindole alkaloids (TOA), quinovic acid glycosides (QAG), and polyphenols (PPH). Nevertheless, it is still uncertain how environmental factors affect chemical groups. The aim of this work was to better understand the influence of environmental factors (geographic origin, altitude, and season) on cat's claw chemical composition. Stem bark, branches and leaf samples were extracted and analyzed by HPLC-PDA. The data obtained were explored by multivariate analysis (HCA and PCA). Higher amounts of oxindole alkaloids and PPH were found in leaves, followed by stem bark and branches. No clear relationship was verified among geographic origin or altitude and chemical composition, which remained unchanged regardless of season (dry or rainy). However, three oxindole alkaloid chemotypes were clearly recognized: chemotype I (POA with cis D/E ring junction); chemotype II (POA with trans D/E ring junction); and chemotype III (TOA). Thus, environmental factors appear to have only a minor influence on the chemical heterogeneity of the cat's claw wild population. Nevertheless, the occurrence of different chemotypes based on alkaloid profiles seems to be clear.

PYROLIGNEOUS LIQUOR PRODUCED FROM ACACIA MEARNSII DE WILD WOOD UNDER CONTROLLED CONDITIONS AS A RENEWABLE SOURCE OF CHEMICALS

Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS). Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 ºC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.

Print-capture PCR for detection of tomato begomoviruses from plants and whiteflies

Print-capture (PC) Polymerase chain reaction (PCR) was evaluated as a novel detection method of plant viruses. Tomato (Lycopersicon esculentum) plants infected with begomovirus (fam. Geminiviridae, gen. Begomovirus) and viruliferous whiteflies were used to study the efficiency of the method. Print-capturing steps were carried out using non-charged nylon membrane or filter paper as the solid support for DNA printings. Amplified DNA fragments of expected size were consistently obtained by PCR from infected plants grown in a greenhouse, after direct application of printed materials to the PCR mix. However, virus detection from a single whitefly and from field-grown tomato samples required a high temperature treatment of printed material prior to PCR amplification. Comparison of nylon membrane and filter paper as the solid support revealed the higher efficiency of the nylon membrane. The application of print-capture PCR reduces the chances of false-positive amplification by reducing manipulation steps during preparation of the target DNA. This method maintains all the advantages of PCR diagnosis, such as the high sensitivity and no requirement of radioactive reagents.

Avaliação da eficiência nutricional de três procedências australianas de acácia-negra (Acacia mearnsii De Wild.)

O objetivo do presente trabalho foi avaliar a eficiência nutricional de macronutrientes N, P, K, Ca, Mg e S nos diferentes componentes das árvores de três procedências de acácia-negra (Acacia mearnsii De Wild.), com 2,4 anos de idade, plantadas em Butiá-RS (Brasil). As procedências selecionadas foram Lake George, Bodalla e Batemans Bay. Foi constatada variação na eficiência nutricional entre as procedências. Em ordem decrescente de eficiência de utilização dos nutrientes para produção de casca e madeira, cujos produtos são explorados dos povoamentos, obteve-se: Bodalla > Batemans Bay > Lake George. Embora a Lake George seja a procedência menos eficiente no uso dos nutrientes para formação de copa, casca e madeira, ela possui grande capacidade produtiva.

Conteúdo e exportação de micronutrientes em acácia-negra (Acacia Mearnsii De Wild.) procedência batemans bay (Austrália)

O objetivo do presente trabalho foi estimar o conteúdo e a exportação de micronutrientes (Mn, B, Cu, Zn e Fe) e o Na nos diferentes componentes de árvores de um povoamento de acácia-negra (Acacia mearnsii De Wild.), procedência australiana Batemans Bay, com 2,4 anos de idade, em Butiá-RS (Brasil). A biomassa total estimada foi de 36.155 kg/ha, apresentando distribuição de 46,0, 20,0, 19,5, 12,0 e 3,0%, na madeira do lenho, nas folhas, nos galhos vivos, na casca e nos galhos mortos, respectivamente. A proporção de micronutrientes acumulados na biomassa dos componentes da árvore foram 43,76% nas folhas, 26,94% na madeira do tronco, 19,56% nos galhos vivos, 7,21% na casca e 2,54% nos galhos mortos. A quantidade estimada de micronutrientes contidos na biomassa acima do solo foi 10,4 kg/ha, acumulados da seguinte forma: Na (58,84%), Fe (21,79%), Zn (9,16%), B (4,09%), Mn (4,59%) e Cu (1,54%). A casca e a madeira do lenho acumulou Na (21,47%), Fe (6,71%), Mn (2,11%), Zn (1,66%), B (1,58%) e Cu (0,63%). A copa (folhas e galhos vivos e mortos) acumularam Na (37,36%), Fe (15,07%), Zn (7,49%), B (2,53%), Mn (2,48%) e Cu (0,91%). A exploração intensiva de áreas com a procedência Batemans Bay gera suspeitas de possíveis ocorrências de deficiências nutricionais de Na nas rotações futuras, tornando necessário o emprego de fertilizantes para manter a produtividade do sítio.

Retorno de nutrientes via deposição de serapilheira em um povoamento de acácia-negra (Acacia mearnsii De Wild.) no Estado do Rio Grande do Sul

Com este estudo, objetivou-se avaliar os aspectos envolvidos na transferência de serapilheira e nutrientes ao solo em um povoamento de acácia-negra (Acacia mearnsii De Wild.) com 3 anos de idade, em Butiá-RS. Para tanto, foram alocadas, sistematicamente, cinco parcelas de 18 x 24 m, onde foram distribuídos 20 coletores de serapilheira de 1 m² (quatro em cada). Para coleta de galhos, foram demarcadas na superfície do solo 15 subparcelas de 3 x 3 m. O material interceptado foi coletado mensalmente entre maio/1999 e dezembro/2001. Após a coleta, o material foi separado em frações (folhas, galhos, flores, frutos e fezes), seco em estufa, pesado, moído e analisado quanto aos teores de N, P, K, Ca e Mg. A deposição média anual de serapilheira alcançou 5,85 Mg/ha, sendo composta por 77% de folhas, 3,7% de galhos, 2,5% de flores, 2,4% de frutos e 14,3% de fezes de lagarta. A baixa deposição de galhos foi atribuída à pequena intensidade do processo de desrama natural da espécie, principalmente nessa idade do povoamento. A deposição de serapilheira foi mais concentrada no verão. O maior fornecimento de nutrientes ao solo ocorreu através da fração folhas. As frações com maiores teores de N, P e Mg foram flores e frutos, somente perdendo para as folhas e fezes quanto à concentração de Ca e não diferindo em relação ao K. A magnitude de transferência de nutrientes ao solo, em kg/ha, foi igual a 106,2 de N > 62,8 de Ca > 41,8 de K > 9,4 de Mg > 3,4 de P.

Eficiência do uso de micronutrientes e sódio em três procedências de acácia-negra (Acacia mearnsii De Wild.)

Objetivou-se avaliar a eficiência nutricional de micronutrientes (Mn, B, Cu, Zn e Fe) e Na nos diferentes componentes das árvores de três procedências de acácia-negra (Acacia mearnsii), com 2,4 anos de idade, plantadas em Butiá-RS (Brasil). As procedências selecionadas foram Lake George, Bodalla e Batemans Bay. Constatou-se grande variação na eficiência nutricional entre as procedências. A Lake George, além de acumular maior biomassa total, foi também a mais eficiente na utilização dos nutrientes na produção de biomassa total das árvores. No entanto, a Bodalla mostrou ser a procedência mais eficiente no uso dos nutrientes para produção de biomassa da casca e da madeira.

Multiplicação in vitro de gemas axilares de acácia-negra (Acacia mearnsii De Wild.)

A acácia-negra (Acacia mearnsii De Wild.) é uma espécie de difícil micropropagação devido à pequena capacidade de multiplicação e desenvolvimento de gemas. O presente estudo visou determinar a influência de diferentes citocininas na proliferação de gemas axilares em segmentos nodais de A. mearnsii. Plântulas germinadas in vitro forneceram explantes que foram inoculadas em meio básico B5 (GAMBORG et al., 1968). Testaram-se as citocininas: BAP (6-benzilaminopurina), BA (6-benziladenosina), 2iP (gama,gama-isopenteniladenina) e cinetina (6-furfuralamino-purina). Diferentes concentrações desses reguladores de crescimento foram empregadas: 1 mgL-1, 2 mgL-1 e 3 mgL-1. Utilizou-se o delineamento de blocos casualizados, em arranjo fatorial, com seis repetições e cinco plantas por parcela. As avaliações foram feitas aos 30 dias, através da contagem de gemas alongadas e da presença de calos. A utilização de BAP a 2 mgL-1 promoveu a maior taxa de multiplicação de gemas (3,5 brotos/explante).