Abstract The introgression of M. enterolobii resistance-related genes in guava breeding programs can be compromised by incompatibility among Psidium species. This study aimed to evaluate the female parent preference and genetic diversity of Psidium interspecific hybrids using morphoagronomic traits and resistance to M. enterolobii. There were evaluated cross successes and germination from crosses between accesses of P. cattleyanum, P. guineense and P. guajava and the genetic diversity by Ward-MLM method of hybrids according to descriptors developed for the genus. Crosses were more successful when P. cattleyanum was the female parent. Germination was more successful in crosses involving P. cattleyanum and P. guajava. Four groups were formed. The group IV clustered the most resistant genotypes, composed by genotypes of P. cattleyanum x P. guineense, while the group II was the most susceptible. The groups I and III grouped some genotypes of P. cattleyanum x P. guajava with low levels of susceptibility. There are preferences of female parent species among crosses. Some individuals of groups I and III can be used as source of resistance genes for the breeding program, due the presence of favorable alleles inherited from guava parent. The high susceptibility leads to reduction in root development. M resistancerelated related P WardMLM Ward MLM genus formed susceptible program development

Abstract There are no guava cultivars resistant to the Meloidogyne enterolobii; for this reason, genetic breeding has been performed by introgressing genes into the current cultivars through interspecific hybridization. We used 33 microsatellite markers for the genetic-molecular characterization of segregating populations of Psidium resistant to M. enterolobii, aiming at selection within and between populations for generation advancement in the guava breeding program. The average number of alleles per locus ranged from 1.60 to 2.09. Populations 1 (P. guineense × P. cattleyanum) and 5 (P. guajava × P. cattleyanum) obtained the greatest genetic diversity, which can be confirmed by the higher observed-heterozygosity values (0.422 and 0.312, respectively). Bayesian analysis showed that the populations were subdivided into three groups, agreeing with the number of groups observed by Nei’s genetic distance. The population obtained from the P. guineense × P. cattleyanum cross differed from the others with a clear structuring, whereas the P. guajava × P. cattleyanum and P. cattleyanum × P. guineense populations were the most similar between each other. The SSR markers were efficient in discriminating the populations, and individual 80 may be employed in future crosses with guava, allowing generation advancement in the guava breeding program aimed at resistance to M. enterolobii.

ABSTRACT: Genetically diverse interspecific hybrids of Vitis were selected for resistance to Pratylenchus brachyurus. Three segregating populations with 57 hybrid crosses were evaluated. The parents included Vitis romanetiiC166-043 × 07355-075, 06354-047 × Cereza and 06354-047 × Nocera, selected from the germplasm bank at the University of California, Davis, the United States. The experiment was arranged in a randomized block design, with three replications and three plants per plot. Root mass, nematodes per gram of root and reproduction factor were determined and used as quantitative variables; 16 multi categoric descriptors were also evaluated. The traits were analyzed using the Ward-Modified Location Model procedure (Ward-MLM) for the composition of genotype groups. Genetic parameters and prediction of genetic values by Restricted Maximum Likelihood / Best Linear Unbiased Prediction (REML / BLUP) were assessed. The Ward-MLM classification strategy supported the formation of three homogeneous groups. Group I comprised 13 hybrids; Group II, 26 hybrids; and Group III, 18 hybrids. Groups II and III contained hybrids resistant to P. brachyurus. High broad sense heritability values were found for root mass, reproduction factor and nematodes per gram of root, which provided genetic gain and allowed selection of resistant genotypes available for cloning, since the total genetic variance occurred due to the dominance effects. Of the 57 genotypes assessed, those with the lowest genotypic values for reproduction factor were selected as resistant, including: CH3.2, CH3.23, CH3.8, CH3.37, CH3.38, CH3.41, CH3.36, CH2.1, CH2.7, CH1.1, CH1.3 and CH1.2.

ABSTRACT. Since 2001, the disease known as 'guava decline', resulting from the interaction between the phytonematode Meloidogyne enterolobii and the fungus Fusarium solanie, has caused direct and indirect economic losses to the entire guava production chain. Given the lack of sources of resistance in guava genotypes, interspecific hybrids of Psidium spp. were obtained for resistance to the nematode M. enterolobii. To classify the level of resistance of the interspecific hybrids, we evaluated the plant classification methodologies proposed by Oostenbrink (1966) and Moura and Régis (1987). Estimates of genetic parameters were obtained using the REML/BLUP approach. Interspecific hybrids resistant to M. enterolobii were selected that can be used as rootstocks or in new crosses for the development of the guava breeding program.

Abstract Energy budgets for juvenile Pacific whiteleg shrimp, Litopenaeus vannamei (1.7-4.0 g ) fed with different diets were assessed. The energy partitioning between growth, respiration, ammonia excretion, feces and exuvia was calculated to estimate for total food energy intake. Shrimp oxygen consumption and ammonia excretion were quantified in sealed chambers (25°C, 34 ppt). Energy allocated for growth and feces were obtained from the wet combustion of whole body and feces samples, exuvia was estimated as 10% growth energy. Three diets were tested: 100% chopped fish (Fish), 100% commercial feed (Feed), and 50-50% chopped fish and commercial feed (Mix). Most of the energy from the diets was channeled into respiration (49.7-70.5%). Shrimp fed the Feed diet used more energy in growth (24.4%) than those fed Mix (13.4%) or Fish diets (13.2%), either in absolute (joule) or relative (% of ingested energy) terms. Conversely, energy loss as ammonia excretion was lower in shrimp fed Feed (1.0%) compared to shrimp fed Mix (4.2%) or Fish diets (7.8%). Less energy was lost in feces by shrimp fed Fish diet (7.3%) compared to Mix (20.2%) and Feed diets (22.2%). The calculated energy intake by shrimp fed Fish, Mix and Feed were 0.995, 1.100, and 1.255 kJ ind-1day-1, respectively. According to the O:N atomic ratios (oxygen consumed to nitrogen excreted), protein tented to be the predominant substrate catabolized by shrimp fed Fish (O:N=16±5.2), and Mix (O:N=25±11.6), with increasing use of carbohydrates and/or lipids in the Feed (O:N=74±37.3). Results suggest diet composition may affect energy budget and partitioning differently between metabolism and growth either in absolute or relative terms, as shrimp fed Fish and Mix diets used protein as main substrate for metabolism, whereas shrimp fed Feed diet channeled protein for growth, and lipids and carbohydrates for other metabolic functions.

Resumo A produção da aquicultura vem crescendo em todo o mundo e o cultivo de peixes marinhos no Brasil é ainda muito recente. Condições intensivas de aquicultura podem causar estresse fisiológico ao organismo do cultivo, o que pode ser avaliado por biomarcadores citogenotóxicos. O objetivo desse estudo foi avaliar o efeito genotóxico das condições de cultivo nos eritrócitos de juvenis de beijupirás Rachycentron canadum usando o ensaio cometa e o ensaio de micronúcleo e outras anormalidades nucleares. Juvenis de beijupirá foram cultivados por 13 semanas em um tanque indoor com circulação aberta de água e em um tanque-rede. O ensaio comera e o ensaio de anormalidades nucleares detectaram um maior dano ao DNA e uma maior frequência de anormalidades nucleares em eritrócitos de peixes cultivados no tanque indoor. Results showed that two methods are complementary. Além disso, beijupirás foram injetados com β-naftoflavona (BNF) nas concentrações de 2mgkg-1 e 10mgkg-1 em condições controladas de laboratório e mantidos por 7 dias em tanques separados para um melhor entendimento dos mecanismos de resposta dessa espécie a uma substância tóxica. O ensaio cometa não detectou nenhuma diferença significativa entre os peixes injetados com BNF e os da condição controle, enquanto que o ensaio das anormalidades nucleares apresentaram diferenças significativas entre peixes injetados com BNF e os do controle. Os danos identificados pelo ensaio cometa são quebras reparáveis na fita do DNA, enquanto que as anormalidades nucleares são permanentes. Possivelmente, o período de de manutenção dos peixes nos tanques após a injeção foi suficiente para limpar a BNF dos organismos e reparar as quebras na fita do DNA. Como os beijupirás parecem responder muito bem a compostos genotóxicos, o ensaio cometa e o ensaio de anormalidades nucleares podem ser ferramentas úteis para monitorar as condições de cultivo.

Abstract Aquaculture production is continuously growing worldwide, and marine fish farming in Brazil is still in its infancy. Intensive farming conditions may cause physiological stress to the cultured organism, which can be evaluated by citogenotoxic biomarkers. The aim of this study was to assess the genotoxic effect of the rearing conditions in red blood cells of juvenile cobia Rachycentron canadum by using comet assay and micronucleus and other nuclear abnormalities assay. Juvenile cobia were reared for 13 weeks in indoor tank with open water circulation and in near shore cage. The comet assay and the nuclear abnormalities assay detected higher DNA damage and higher nuclear abnormalities frequency in erythrocytes of fish reared in the indoor tank. Results showed that two methods are complementary. Additionally, cobia were injected with ß-naphthoflavone (BNF) at concentrations of 2mgkg-1 and 10mgkg-1 in laboratory controlled conditions, and maintained for 7 days in separate tanks to better understand the response mechanisms of this species to a toxic substance. The comet assay did not detect any significant differences between BNF injected and control fish, whereas nuclear abnormalities assay showed significant differences between BNF injected and the control groups. The damages identified by the comet assay are repairable breaks in the DNA strands, whereas nuclear abnormalities may be permanent. Possibly the period of maintenance after injection was enough to clean BNF from the organisms and to repair the breaks in the DNA strands. As cobia seems to respond very well to genotoxic elements, comet assay and nuclear abnormalities assay would be useful tools to monitor farming conditions.

RESUMO: Este trabalho teve por objetivo avaliar a resistência de genótipos de P. cattleyanum a M. enterolobii. O experimento foi conduzido em DIC, com seis tratamentos, constituídospor cinco genótipos de P. cattleyanum, pela goiabeira 'Paluma' (testemunha) e oito repetições constituídas por clones desses genótipos. A classificação quanto à resistência foi determinada de acordo com o fator de reprodução (FR), avaliado aos 135 dias após inoculação com o nematoide. Os genótipos de P. cattleyanum avaliados foram resistentes a M. enterolobii com FR iguais ou inferiores a 0,2.

ABSTRACT: This research aimed to evaluate genotypes of P. cattleyanum by resistance to M. enterolobii. The experiment was conducted in a completely randomized design with six treatments, consisting of five genotypes of P. cattleyanum and guava 'Paluma' (control) and eight replicates. Genotypes classification for resistance was determined by the reproduction factor (RF), evaluated at 135 days after inoculation with the nematode. Genotypes of P. cattleyanum were considered as resistant once reproduction factors evaluated had less than or equal to 0.2.

Séries de biomonitoramentos foram executadas semanalmente, durante o mês de fevereiro de 2012, para se investigar a genotoxicidade de ambientes costeiros rasos no entorno da Estação Antártica "Comandante Ferraz (EACF). O ensaio cometa foi aplicado para se avaliar os danos ao DNA hemocitário de crustáceos anfípodes Gondogeneia antarctica coletados em áreas rasas próximas aos tanques de armazenamento de combustível (FT) e saída de efluentes da estação de tratamento de esgoto (STO), em comparação aos danos ao DNA de animais provenientes de Punta Plaza (PPL) e Yellow Point (YP), locais naturais distantes da EACF, definidos como controles experimentais. O dano ao DNA hemocitário de G. antarctica não foi significativamente diferente entre locais, nos biomonitoramentos I e II. No biomonitoramento III, o dano ao DNA de animais coletados em águas rasas próximas aos tanques de combustível e saída de efluentes de esgoto foi significativamente maior do que aquele do controle de Punta Plaza. No biomonitoramento IV, a diferença foi significativa somente entre os locais dos tanques de combustível e de Punta Plaza. Estes resultados demonstram que a contaminação das águas em frente à EACF pode ser genotóxica e que, tanto o ensaio cometa quanto os hemócitos de G. antarcticasão ferramentas úteis na avaliação da genotoxicidade em estudos de biomonitoramento de habitats marinhos costeiros da Antártica.

Series of biomonitoring surveys were undertaken weekly in February 2012 to investigate the genotoxicity of the shallow waters around the Brazilian Antarctic Station "Comandante Ferraz" (EACF). The comet assay was applied to assess the damage to the DNA of hemocytes of the crustacean amphipods Gondogeneia antarctica collected from shallow waters near the Fuel Tanks (FT) and Sewage Treatment Outflow (STO) of the research station, and compare it to the DNA damage of animals from Punta Plaza (PPL) and Yellow Point (YP), natural sites far from the EACF defined as experimental controls. The damage to the DNA of hemocytes of G. antarctica was not significantly different between sites in the biomonitoring surveys I and II. In survey III, the damage to the DNA of animals captured in shallow waters near the Fuel Tanks (FT) and Sewage Treatment Outflow (STO) was significantly higher than that of the control site of Punta Plaza (PPL). In biomonitoring survey IV, a significant difference was detected only between the FT and PPL sites. Results demonstrated that the shallow waters in front of the station may be genotoxic and that the comet assay and hemocytes of G. antarctica are useful tools for assessing genotoxicity in biomonitoring studies of Antarctic marine coastal habitats.

O orçamento energético de animais ectotérmicos antárticos estenotérmicos e/ou estenohalinos é fortemente modulado pelas variações da temperatura e da salinidade. O efeito conjunto desses fatores em animais polares é pouco estudado. Dados sobre esse assunto são necessários para avaliar a demanda energética de organismos antárticos, como os anfípodes, principalmente devido a sua importância ecológica e aos possíveis impactos ocasionados por mudanças globais. Os experimentos foram realizados na Estação Antártica Brasileira "Comandante Ferraz", em condições controladas. Indivíduos de Bovallia gigantea coletados na Baía do Almirantado foram aclimatados às temperaturas de 0ºC, 2,5ºC e 5ºC e às salinidades de 35, 30 e 25. Foram realizadas 30 medições para cada uma das nove combinações possíveis entre os fatores. Foram mensurados o consumo de oxigênio e a excreção de produtos nitrogenados, em câmaras respirométricas seladas. A 0ºC e 2,5ºC, as taxas metabólicas de indivíduos aclimatados às salinidades 30 ou 35 foram muito semelhantes, indicando um possível mecanismo de independência metabólica à temperatura. A 5,0ºC, as taxas metabólicas foram sempre mais elevadas. Os efeitos da temperatura sobre as taxas de consumo de oxigênio e de excreção de produtos nitrogenados foram intensificados pela diminuição da salinidade. Indivíduos de B. gigantea apresentam independência térmica das taxas metabólicas em uma pequena janela de variação, que pode ainda ser modificada pela salinidade.

The energy budget of Antarctic stenothermic and/or stenohaline ectotherms is modulated by variations of temperature and salinity. The joint effects of these latter on polar organisms have been but little studied. Data on this subject are of great importance for an understanding of the energy demand of Antarctic animals such as amphipods, especially when considering their ecological importance and the possible impacts of global changes. Experiments were carried out at the Brazilian Antarctic Station "Comandante Ferraz" under controlled conditions. Specimens of Bovallia gigantea were collected in Admiralty Bay and acclimated to temperatures of 0ºC; 2.5ºC and 5ºC and to salinities of 35, 30 and 25. Thirty measurements were taken for each of the nine possible combinations of the three temperatures and the three salinities. Metabolic rates were assessed based on oxygen consumption and total ammonia nitrogenous excretion in sealed respirometers. At 0ºC and 2.5ºC, the metabolic rates of the animals that were acclimated to salinities of 30 or 35 were similar, indicating a possible mechanism of metabolic independence of temperature. However, the metabolic rates were always higher at 5.0ºC. The effects of temperature on oxygen consumption and on ammonia excretion rates were intensified by lower salinities. Individuals of B gigantea have a temperature-independent metabolic rate within a narrow temperature window that can be modified in accordance with salinity.

Alterações ambientais podem modificar a alocação de energia dos organismos, principalmente dos ectotermos estenotérmicos e/ou estenohalinos. Nesse contexto, este trabalho contribui com o conhecimento da demanda de energia do anfípode antártico Gondogeneia antarctica em função da temperatura e da salinidade. Experimentos foram realizados na Estação Antártica Brasileira "Comandante Ferraz", em condições laboratoriais controladas. Animais coletados na Baía do Almirantado foram aclimatados a temperaturas de 0ºC; 2.5ºC e 5ºC e salinidades de 35, 30 and 25. Foram realizadas trinta medições para cada uma das nove combinações das três temperaturas com as três salinidades, totalizando 270 medições. As taxas metabólicas foram estimadas por meio do consumo de oxigênio e excreção de amônia, em câmaras respirométricas seladas. Quando aclimatados a salinidades 30 ou 35, as taxas metabólicas a 0ºC e 2.5ºC foram semelhantes indicando possível mecanismo de compensação térmica, nessa faixa de variação dos fatores. A 5.0ºC, no entanto, as taxas metabólicas foram sempre mais elevadas. Baixas salinidades potencializaram os efeitos da temperatura no consumo de oxigênio e na excreção de produtos nitrogenados. Os resultados estão relacionados a mecanismos adaptativos para economia de energia em indivíduos G. antarctica, ajustados a um ambiente que tem condições estáveis de temperatura e de salinidade. Pouco se sabe sobre os efeitos conjugados da salinidade e temperatura nos organismos e este trabalho é uma importante contribuição para esse conhecimento.

Changes in environmental factors may deeply affect the energy budget of Antarctic organisms as many of them are stenothermal and/or stenohaline ectotherms. In this context, the aim of this study is to contribute to knowledge on variations in the energy demand of the Antarctic amphipod, Gondogeneia antarctica as a function of temperature and salinity. Experiments were held at the Brazilian Antarctic Station "Comandante Ferraz", under controlled conditions. Animals collected at Admiralty Bay were acclimated to temperatures of 0ºC; 2.5ºC and 5ºC and to salinities of 35, 30 and 25. Thirty measurements were made for each of the nine combinations of the three temperatures and three salinities, totalling 270 measurements. Metabolic rates were assessed by oxygen consumption and total nitrogenous ammonia excretion, in sealed respirometers. When acclimated to salinities 30 or 35, metabolic rates at 0ºC and 2.5ºC were very similar indicating a possible mechanism of metabolic compensation for temperature. At 5.0ºC, however, metabolic rates were always higher. Lower salinities enhanced the effects of temperature on metabolism and ammonia excretion rates. The physiological adaptations of individuals of G. antarctica suggest adaptive mechanisms for energy saving, adjusted to an environment with stable conditions of temperature and salinity. Little is known about the joint effects of salinity and temperature and this study is an important contribution to the understanding of the mechanism of polar organisms in their adaptation to both factors.

Ambientalmente, o antraceno é considerado persistente, bioacumulativo e tóxico para organismos aquáticos. A biotransformação de substâncias xenobióticas, como o antraceno, produz espécies reativas de oxigênio que podem agir sobre o DNA. O objetivo deste trabalho foi avaliar o dano ao DNA em T. carolinus expostos a diferentes concentrações de antraceno (8, 16 e 32 µg.L-1) por 24 h no escuro e subsequentemente mantidos em água limpa para depuração por três diferentes períodos de tempo (48, 96 e 144 h) através de ensaio cometa. Os resultados obtidos demonstram que o antraceno é genotóxico para T. carolinus e o dano ao DNA foi dose- e tempo de depuração- dependente. A genotoxicidade do antraceno foi detectada nas três concentrações utilizadas. A depuração pareceu ser mais eficiente nos peixes expostos a menor concentração de antraceno e mantidos por 96 h em água limpa.

In the environment, anthracene is characterized as being persistent, bioaccumulative and toxic to aquatic organisms. Biotransformation of xenobiotic substances, such as anthracene, produces reactive oxygen species that may induce DNA strand breaks. The aim of the present study was to evaluate the DNA damage in juvenile T. carolinus exposed to different concentrations (8, 16 and 32 µg.L-1) of anthracene for 24 h in the dark then subsequently allowed to depurate in clean water for different periods of time (48, 96 or 144 h) using the comet assay. Our results show that anthracene is genotoxic to T. carolinus and that DNA damage was dose- and depuration/time- dependent. Anthracenegenotoxicity was observed in all experimental concentrations. Depuration seemed to be more efficient in fish exposed to thelowest anthracene concentration and maintained in clean water for 96 h.

O declínio da goiabeira, uma doença complexa envolvendo Meloidogyne enterolobii e Fusarium solani, tem causado grandes prejuízos diretos para os produtores brasileiros. Apesar de várias estratégias terem sido discutidas para o controle do nematoide, a utilização de matéria orgânica adicionada ao solo é atualmente a melhor abordagem para conviver com essa doença. Para avaliar a dose adequada de farinha de carne e ossos (FCO) a ser incorporada ao solo, mudas de goiabeira inoculadas com M. enterolobii foram tratadas com 1-5% v/v da FCO. Noventa dias após foram avaliadas variáveis relacionadas à reprodução do nematoide e ao desenvolvimento das plantas, indicando um possível efeito nematicida da FCO a 3%. Outro experimento avaliou variáveis relacionadas ao nematoide e à planta 90 dias após o tratamento das mudas com FCO, quitosana, casca de camarão e torta de nem a 3%, 0,05%, 2% e 0,1% v/v, respectivamente. A FCO reduziu a reprodução do nematoide, destacando-se em relação aos demais tratamentos. Esta dosagem de FCO foi convertida para 25 kg planta-1 e avaliada em três regimes de aplicação (mensal, bimestral ou trimestral), por seis meses, em pomar de goiaba acometido pelo declínio. As variáveis avaliadas foram densidade no solo de unidades formadoras de colônia (UFC) de bactérias e fungos, e a densidade no solo e/ou raiz de M. enterolobii, Helicotylenchus sp., e de diferentes grupos tróficos de nematoides. Em todos os três regimes de aplicação a FCO reduziu todos os nematoides parasitas de plantas no solo e o número de UFC de fungos, e promoveu aumento no número de UFC de bactérias e nematoides bacteriofagos.

Guava decline is a complex disease involving Meloidogyne enterolobii and Fusarium solani and it has caused major direct losses to Brazilian growers. Although several strategies have been sought to control the nematode, the use of organic soil amendments is currently the best approach to manage this disease. To assess the best amount of meat and bone meal (MBM) to be incorporated into the soil, guava seedlings inoculated with M. enterolobii were treated with 1-5% v/v of the MBM. Ninety days later variables related to nematode reproduction and plant development were evaluated, which indicated a potential nematicidal effect of the MBM at 3%. Another experiment assessed nematode- and plant-related variables 90 days after treatment of the seedlings with MBM, chitosan, shrimp shell or neem cake at 3%, 0.05%, 2% and 0.1% v/v, respectively. The MBM ranked first, reducing nematode reproduction. This MBM rate was converted to 25 kg/tree and assessed in three application regimes (monthly, bimonthly or trimonthly), for six months, in an orchard affected by guava decline. The variables assessed were soil density of colony forming units (CFU) of bacteria and fungus, and soil and/or root density of M. enterolobii, Helicotylenchus sp., and of different nematode trophic groups. In all three application regimes the MBM reduced all plant-parasitic nematodes in the soil and the fungus CFUs. It also promoted an increase in bacterial CFU and bacterivorous nematodes.

Buscando o controle biológico do declínio da goiabeira, foram obtidos 120 isolados de rizobactérias de goiabeiras assintomáticas, localizadas em pomares infestados por M. enterolobii. Dos 120 isolados, 44 foram avaliados em seu potencial para reduzir o nível populacional do nematoide. Para cada isolado, seis estacas vegetativas de goiabeira foram embebidas com suspensão bacteriana por 8 horas e transplantadas para sacolas de 5 L. Após o desenvolvimento das raízes, as mudas foram submetidas à inoculação com 2.000 ovos de M. enterolobii e mantidas por quatro meses em casa de vegetação. Mudas submetidas à inoculação com água, com ou sem M. enterolobii, serviram como controles. Os 46 tratamentos foram equivalentes nas cinco variáveis que avaliaram o desenvolvimento das plantas. Várias rizobactérias reduziram (p<0,05) a população final do nematoide (PF), PF/g de raiz e fator de reprodução, embora em níveis insatisfatórios. Posteriormente, um experimento bianual foi estabelecido em um pomar afetado pelo declínio da goiabeira, no qual três rizobactérias foram comparadas com os produtos biológicos Nemat® e Nemaplus® em sua capacidade de reduzir o parasitismo pelo nematoide e aumentar a produtividade da goiabeira. Sete aplicações bimensais desses tratamentos não reduziram o parasitismo pelo nematoide e não houve aumento de produtividade. A morte de algumas plantas levou à finalização antecipada do experimento após a primeira colheita. Em conclusão, aplicações de rizobactérias parecem incapazes de diminuir o parasitismo por M. enterolobii, e menos ainda reduzir a extensa necrose radicular e o estresse fisiológico ocorrido nas árvores afetadas pelo declínio de goiabeira.

In an effort to devise a biological strategy to control guava decline, 120 rhizobacteria isolates were obtained from symptomless guava trees located in Meloidogyne enterolobii-infested orchards. Of those isolates, 44 were assessed for their potential to reduce nematode's reproduction: for each isolate, six guava stem cuttings were embedded for eight hours with bacterial suspension and transplanted. Upon development of the roots, the plants were inoculated with 2000 nematode eggs and allowed to grow for four months under greenhouse. Seedlings embedded with water, inoculated or not with the nematode, served as controls. All treatments were equivalent in the five variables that assessed plant development. Several rhizobacteria reduced (p<0.05) the final nematode population (Fp), Fp/gram of root and reproduction factor, although not to satisfactory levels. Subsequently, a two-year experiment was set up in a guava orchard affected by guava decline, in which three of the most effective rhizobacterial isolates were compared with the biological products Nemat® and Nemaplus® for their ability to reduce variables related to nematode parasitism and increase guava productivity. Seven bimonthly applications of these treatments under the tree canopy were unable to reduce nematode parasitism and increase productivity. The decline and death of some plants forced the experiment to be stopped after the first harvest. In conclusion, rhizobacteria applications seem unable to reduce the parasitism of M. enterolobii on guava plants, and even less to reduce the extensive root decay or alleviate the physiological stress suffered by trees affected by guava decline.

Foi avaliado o efeito de três concentrações de auxina (0, 2.000 e 6.000 ppm) (ácido indol-bultírico - AIB) para induzir a formação de raízes adventícias em três tipos de estacas caulinares (herbáceas, semilenhosas e lenhosas) de malvavisco (Malvaviscus arboreus Cav.). As estacas foram cortadas em bisel, com aproximadamente 12 cm cada, tratadas com o fungicida benomyl e, posteriormente, com AIB. As avaliações foram feitas 30 dias após o plantio, sendo avaliado o aparecimento ou não de calos, raízes e brotações. Entre as estacas, as lenhosas apresentaram melhor capacidade regenerativa, atingindo o máximo de tecido caloso, enraizamento e brotação, independentemente da concentração de AIB utilizada. No tratamento com AIB na concentração de 2.000 ppm, em estacas herbáceas e lenhosas, obtiveram-se melhores resultados para enraizamento.

The study evaluated the effect of three concentrations of auxin (0; 2,000 and 6,000 ppm) (indolbutiric acid - IBA) in inducing the formation of adventitious roots in three types of stem stakes (herbaceous, woody and semi-woody) of wax mallow (Malvaviscus arboreus Cav.). The stakes were cut into a bezel angle, with approximately 12 cm each, treated with the fungicide Benlate and later with IBA. The assessments were made 30 days after planting, evaluating the appearance or absence of calluses, roots and shoots. Among the stakes, the woody ones showed the best regenerative capacity, reaching the maximum corpus callosum, rooting and shooting, regardless of IBA concentration. In the treatment with 2000 ppm IBA concentration, herbaceous and woody stakes showed the best results for rooting.

Avaliaram-se aspectos da bioenergética de H. steindachneri, em função do peso e da temperatura (15°C, 20°C e 26°C), através do consumo de oxigênio e da excreção de amônia de exemplares jovens coletados na região costeira de Ubatuba (23°30'S), SP, Brasil. Os valores de Q10 e das elevações a das regressões entre o consumo de oxigênio e o peso úmido não revelaram diferenças significativas entre os dados obtidos nas temperaturas de 15°C e 20°C. Por outro lado, os valores de Q10 e das elevações a entre 20°C e 26°C foram significativamente diferentes. A excreção de amônia aumentou significativamente entre as três temperaturas testadas, conforme demonstram as análises do Q10 e das elevações a. Sugere-se que o intervalo de temperatura de 15°C a 20°C seja uma faixa de independência térmica do metabolismo de H. steindachneri, o que, provavelmente, está relacionado a adaptação fisiológica às condições ambientais. A partir dos dados de consumo de oxigênio, calcularam-se os gastos energéticos diários com o metabolismo de rotina e estimaram-se, também, os demais parâmetros da equação bioenergética segundo modelo proposto na literatura. Para peixes de 20 g e 70 g de peso (mínimo e máximo comuns às 3 temperaturas testadas) estimou-se que as necessidades energéticas diárias a 15°C foram 868,83 cal/dia e 3168,65 cal/dia; a 20°C 893,22 cal/dia e 2654,04 cal/dia e a 26°C foram 1390,30 cal/dia e 5046,61 cal/dia. Os resultados obtidos contribuem para o conhecimento do papel ecológico da espécie e de seus mecanismos de adaptação aos fatores ambientais.

Bioenergetic aspects of juvenile Haemulon steindachneri collected at Ubatuba (23°30'S), SP, Brazil, were evaluated as function of body weight and temperature (15°C, 20°C e 26°C) through the oxygen consumption and ammonia excretion analyses. Q10 values and elevations a of the regression of oxygen consumption on wet weight at 15°C and 20°C were not significantly different. On the other hand, Q10 and elevations a were significantly different between 20°C and 26°C. It is suggested that 15-20°C is a temperature range of thermal metabolic independence for H. steindachneri, and this might be related to physiological adaptation to the environmental constraints. Daily energetic costs of routine metabolism were calculated from oxygen consumption data and other parameters of the bioenergetic equation were estimated following a model proposed in the literature. For a fish of 20g and 70g body weight (the minimum and maximum common weights at the 3 tested temperatures), it was estimated that their daily energetic demand at 15°C were 868.83 cal/day and 3168.65 cal/day; at 20°C are 893.22 cal/day and 2654.04 cal/day and at 26°C were 1390.30 cal/day and 5046.61 cal/day. Results contribute to the understanding of the ecological role of the species and its adaptation to the environment.