Obesity is becoming a global epidemic. Around 1

RESUMO -Procurou-se relacionar alguns aspectos importantes da biologia e do manejo das plantas daninhas infestantes em áreas cultivadas sob sistema de plantio direto, com o objetivo de mostrar que a viabilidade deste plantio depende do controle eficiente das plantas daninhas. Nesse sistema de cultivo ocorrem algumas espécies de plantas daninhas comumente não observadas no sistema convencional, sendo essas constatações relacionadas ao não-revolvimento do solo, favorecendo o desenvolvimento de espécies de plantas daninhas perenes, e às alterações nas condições de temperatura e incidência de luz no interior do solo, influenciando os mecanismos de dormência das sementes de algumas espécies. A estratégia adequada para o controle das plantas daninhas em plantio direto exige conhecimento da dinâmica populacional do banco de sementes do solo e deve reunir métodos integrados de controle para reduzir o uso de herbicidas. A liberação de substâncias alelopáticas de algumas culturas de cobertura e o efeito supressor da camada de palha são medidas importantes para integrar ao controle químico das plantas daninhas. Entretanto, deve-se atentar para os efeitos negativos sobre algumas espécies de plantas cultivadas. As pesquisas na área de biologia das plantas daninhas e alelopatia das culturas de cobertura, associadas com a tecnologia de aplicação de herbicidas e a agricultura de precisão, poderão contribuir para a otimização do controle das plantas daninhas em áreas de plantio direto.Palavras-chave: semeadura direta, banco de sementes, palhada, glyphosate.ABSTRACT -Some important aspects of weed biology and control under no tillage are described to show that the viability of this system depends on weed control efficiently performed. Some of the weeds infesting this cropping system are present in much greater density under the conventional system, this being probably due to the little soil disturbance under no tillage systems, where the occurrence of perennial weeds is more feasible, and changes in the temperature and light incidence on the soil surface influence dormancy of some weed species. Adequate strategy for weed control under the no tillage system requires knowledge on weed seed bank dynamics and must integrate methods of weed control in order to reduce the use of herbicides. The release of alellopathic compounds by some of the cover crops and the suppressive effects of crop residue cover are important measures in order to integrate the chemical control of weeds. However, it is important to be aware of the negative impacts over certain cultivated species of plants. Studies on weed biology and alellopathy of cover crops, associated to herbicide application technology and precision agriculture may contribute to weed control optimization in areas under no tillage system.

Image analysis using X-rays is an efficient technique for assessing the seed quality of several species, presenting itself as a rapid response method that is simple to execute, reproducible and non-destructive. Thus, this research adjusted a methodology that aims to relate the internal morphology of broccoli seeds to their physiological potential through radiographic analysis of seeds and computerized images of seedlings. The broccoli cultivars used were Piracicaba Precoce and Ramoso Santana represented by ten lots of each one. The study was conducted using X-ray imaging for seed analysis, in which the area, density and circularity measures were obtained as internal morphology characteristics of seeds. After a germination test, the seedling length was obtained 5 days after sowing. Multivariate analysis was carried out using principal components analysis. It was concluded that the X-ray test is efficient for evaluating the internal morphology of broccoli seeds and associating it with seedling length, thereby classifying seed lots at different levels of vigor.

RESUMO -O pinhão manso (Jatropha curcas L.) apresenta elevado potencial para produção de biocombustível; porém, existem poucos estudos relacionados à avaliação da qualidade de suas sementes. Assim, a pesquisa objetivou estudar os procedimentos para a condução do teste de tetrazólio e verificar a eficiência dos testes de tetrazólio e de raios X para a avaliação da viabilidade de sementes desta espécie. Para o teste de tetrazólio, foi comparado o pré-condicionamento entre papel e imersão em água, até que as sementes atingissem os teores de água de 30% e 40%. Após esta etapa, o tegumento das sementes foi retirado manualmente e os embriões foram imersos em solução de 2,3,5 trifenil cloreto de tetrazólio nas concentrações de 0,075% e 0,5%, por 120 minutos, a 40°C. Os resultados do teste de germinação foram confrontados com os resultados do teste de tetrazólio. A hidratação entre papel, até as sementes atingirem 30% de água e a coloração do embrião em solução 0,5% de tetrazólio, durante 120 minutos, no escuro, a 40ºC, produzem informações consistentes. As sementes de pinhão manso foram submetidas ao teste de raios X, na intensidade de 25 Kv durante 60s; posteriormente, foi realizado o teste de germinação, relacionando-se os resultados obtidos nesses dois testes. Concluiu-se que é possível utilizar o teste de tetrazólio e de raios X para avaliar a viabilidade das sementes de pinhão manso.Termos para indexação: análise de imagens, potencial fisiológico, oleaginosas. EVALUATION OF THE Jatropha curcas L. SEED VIABILITY BY TETRAZOLIUM AND X-RAY TESTSABSTRACT-The Jatropha curcas L. presents a great potential for fuel, but there are few studies to assess seed quality of this species. Therefore, this research aimed to study the performance of the tetrazolium salt test procedures and to verify the efficiency of the X-ray test to evaluate the seed viability of this species. Seeds were hydrated between paper towel and immersed in water to reach 30 and 40% m.c.. Following, seed coat was removed manually and seeds were immersed in 0,075 and 0,5% tetrazolium solutions for 120 min., respectively, at 40°C. Best results of tetrazolium test comprised the hydration between paper, until the seeds reach 30% m.c. and coloration in contact with a solution of 0,5%. The Jatropha curcas L. seeds were also submitted to X-ray test, in intensity of the 25Kv for 60s. Results of tetrazolium and X-ray tests were compared to germination and it was shown that both are efficient to assess Jatropha curcas L. seeds viability.

-The software Seed Vigor Imaging System (SVIS ® ), has been successfully used to evaluate seed physiological potential by automated analyses of scanned seedlings. In this research, the efficiency of this system was compared to other tests accepted for assessing cucumber (Cucumis sativus L.) seed vigor of distinct seed lots of Supremo and Safira cultivars. Seeds were subjected to germination, traditional and saturated salt accelerated aging, seedling emergence, seedling length and SVIS analyses (determination of vigor indices and seedling growth uniformity, lengths of primary root, hypocotyl and whole seedlings). It was also determined whether the definition of seedling growth/uniformity ratios affects the sensitivity of the SVIS ® . Results showed that analyses SVIS have provided consistent identification of seed lots performance, and have produced information comparable to those from recommended seed vigor tests, thus demonstrating a suitable sensitivity for a rapid and objective evaluation of physiological potential of cucumber seeds. Analyses of four-days-old cucumber seedlings using the SVIS ® are more accurate and growth/uniformity does not affect the precision of results.

No abstract

COQ10 deletion in Saccharomyces cerevisiae elicits a defect in mitochondrial respiration correctable by addition of coenzyme Q2. Rescue of respiration by Q2 is a characteristic of mutants blocked in coenzyme Q6 synthesis. Unlike Q6 deficient mutants, mitochondria of the coq10 null mutant have wild-type concentrations of Q6. The physiological significance of earlier observations that purified Coq10p contains bound Q6 was examined in the present study by testing the in vivo effect of over-expression of Coq10p on respiration. Mitochondria with elevated levels of Coq10p display reduced respiration in the bc1 span of the electron transport chain, which can be restored with exogenous Q2. This suggests that in vivo binding of Q6 by excess Coq10p reduces the pool of this redox carrier available for its normal function in providing electrons to the bc1 complex. This is confirmed by observing that extra Coq8p relieves the inhibitory effect of excess Coq10p. Coq8p is a putative kinase, and a high copy suppressor of the coq10 null mutant. As shown here, when over-produced in coq mutants, Coq8p counteracts turnover of Coq3p and Coq4p subunits of the Q-biosynthetic complex. This can account for the observed rescue by COQ8 of the respiratory defect in strains over-producing Coq10p.

RESUMO -O presente trabalho foi conduzido com o objetivo de verificar a eficiência do sistema computadorizado de avaliação do vigor de sementes (SVIS ® ), em comparação com outros procedimentos disponíveis, em sementes de milho superdoce. Foram utilizadas sementes dos híbridos SWB 551 e SWB 585, cada uma representada por cinco lotes, conduzindo-se testes de germinação, envelhecimento acelerado (tradicional e com solução saturada de NaCl) e emergência de plântulas em campo. Para a determinação do vigor das sementes por meio do SVIS ® , as plântulas foram avaliadas aos três dias após a semeadura do teste de germinação, sendo obtidos dados referentes ao índice de vigor, à uniformidade de desenvolvimento e ao comprimento de plântulas. Para ambos os híbridos avaliados, os resultados fornecidos pelo SVIS ® foram coerentes com os do teste de envelhecimento acelerado tradicional. Concluiu-se que o SVIS ® é eficiente para avaliação do vigor de sementes de milho superdoce, constituindo alternativa viável para a determinação do potencial fisiológico.Termos para indexação: Zea mays L., potencial fisiológico, análise de sementes.Evaluation of supersweet corn seed vigor using an automated computer imaging system ABSTRACT -The objective of this study was to verify the efficiency of an automated system for seedling evaluation (SVIS ® ) to assess supersweet corn seed vigor compared to information from accepted vigor tests. Five seed lots, each of the SWB 551 and SWB 585 hybrids, were subjected to germination, accelerated aging (traditional and saturated salt) and field seedling emergence tests. The Seed Vigor Imaging System (SVIS ® ) parameters comprised mean seedling growth, uniformity and a vigor index, computed in scanned images of three-day old seedlings from the germination test. The results for both hybrids provided by SVIS ® were comparable to those from the traditional accelerated aging test, thus demonstrating an efficient vigor evaluation of supersweet corn seeds.