Allelopathy of extracts of Cyperus rotundus and Oxalis latifolia on snapdragon seeds germination

Snapdragon (Anthirrhinum majus L.) is an ornamental plant propagated by seeds and usually cultivated in beds. In production fields occur many weeds, such as Cyperus rotundus and Oxalis latifolia, which can decrease flower production by competition or releasing allelopathic components. However, there is few knowledge about the effect of these allelopathic components on snapdragon seed germination. Therefore, this study aimed to determine the allelopathic potential of aqueous extracts of C. rotundus and O. latifolia on the germination of snapdragon. For this, 10 g of material vegetal from whole plants of C. rotundus or O. latifolia were ground in 100 mL of water (10% w v-1). The dilutions of aqueous extracts in 75%, 50%, 25% and 0 were prepared using distilled water. The seeds were kept in paper moistened with extracts, in box gerbox-type, and conditioned in a germination chamber for 11 days. After 11 days the percentage of germination, vigor, germination speed index (GSI), percentage of abnormal seedlings and dead seeds, root length and shoot seedlings were evaluated. Extracts of C. rotundus and O. latifolia reduced the percentage of seed germination by up to 17.6% and 43.7%, respectively. The vigor was reduced from 55.0% to 28.5% and IVG reduced from 27 to 12 in extracts of O. latifolia. The maximum of 49.5% and 35.5% of dead seeds was obtained in extracts of O. latifolia and C. rotundusrespectively. The highest concentrations of extracts of both species altered the morphology of snapdragons seedlings reducing the length of radicle and shoot

Morfologia de sementes de gergelim

O gergelim tem sido considerado uma espécie de importante cultivo em função das perspectivas econômicas, contudo, para viabilizar o seu efetivo emprego é de fundamental importância dotar-se de sementes de boa qualidade. Desta forma, objetou-se descrever morfologicamente, bem como promover os estudos de análise de imagem das sementes de gergelim através do equipamento SAS® (Sistema de Análise de Sementes). Foram utilizadas sementes de gergelim das cultivares CNPA G2 (safra 2010), CNPA G3 (safra 2010), CNPA G4 (safra 2014) e BRS Seda (safra 2015). Foram realizadas a caracterização do perfil dos lotes, caraterização morfológica das sementes e plântulas, composição centesimal, análise de imagem e a caracterização anatômica das sementes. Conclui-se, quanto à caracterização morfológica das plantas, que a morfologia das sementes de gergelim em germinação é do tipo epígea, com emergência vertical ereta e plântula fanerocotiledonar, com folhas carnosas, hipocótilo verde esbranquiçado e uma radícula esbranquiçada. A composição centesimal das sementes se caracteriza pela presença de 34% a 48% de extrato etéreo. Com relação à caracterização morfoanatômicas verificou-se pouca variabilidade na forma entre as sementes, com hilo e a micrópila visível. A análise de imagem de sementes permitiu diferenciar os lotes, principalmente avaliando a área convexa e o perímetro

Interaction between soil microorganisms, weeds and cultures of corn and soybean

A habilidade competitiva das culturas e plantas daninhas depende da utilização eficiente dos recursos do meio. Acredita-se haver relação entre as associações das espécies vegetais com a microbiota do solo e consequentemente sobre o grau de interferência. Nesta pesquisa avaliou-se a interferência de três espécies de plantas daninhas (Bidens pilosa L., Brachiaria decumbens Stapf. (Syn. Urochloa decumbens) e Eleusine indica (L.) Gaertn.) sobre a cultura do milho e da soja em duas condições: a) plantas daninhas competindo sem contato com as raízes da cultura; b) com contato entre raízes. Para isso foram montados dois experimentos referentes a cultura do milho e soja. As espécies B. pilosa e E. indica quando em competição com o milho apresentaram maior colonização micorrízica e foram as que mais interferiram negativamente no crescimento e no acúmulo de nutrientes. O potencial de solubilização do fósforo inorgânico do solo rizosférico de plantas milho submetido à competição com contato das raízes entre espécies aumentou em 2,58 μg por grama de solo. Este contato entre as raízes das espécies em competição contribuiu para redução da colonização micorrízica arbuscular das raízes do milho e aumento da colonização nas raízes de plantas daninhas. Com relação à cultura da soja em competição com plantas daninhas houve menor oxidação da matéria orgânica por unidade de biomassa microbiana, resultando em menor quociente metabólico, em comparação com a rizosfera da soja em monocultivo. Ocorreu interação positiva para a colonização micorrízica da soja e das plantas competidoras independente da espécie e do contato entre as raízes. Esse aumento da colonização micorrízica foi de 53, 40 e 33 % quando a soja estava em competição com as espécies B. decumbens, E. indica e B. pilosa, respectivamente. As plantas daninhas apresentaram diferentes estratégias competitivas e mostram-se boas competidoras e em muitos casos não tiveram suas variáveis de crescimento e nutricionais reduzidas quando em competição com as culturas. As combinações entre culturas e espécies de plantas daninhas alteram de modo variado o comportamento da microbiota do solo e o contato entre raízes mostrou-se de grande importância na interferência entre as espécies.The competitive ability of agriculture and weeds depends on the efficacy use of the resources from the environment. It is believed that could have relation between associations with plants species and soil microbiota and its capacity to change it, affecting the level of interference. This research evaluated causes and consequences of the interference in three species of weeds (Bidens pilosa L., Brachiaria decumbens Stapf. (Syn. Urochloa decumbens) and Eleusine indica (L.) Gaertn.) under culture of corn and soybean in two different conditions: a) weeds competing without any contact with other culture roots b) same conditions as the first but now with contact among the roots. It was set it up two experiments with soybean s and corns culture. Each culture composes an isolated experiment, so there wasn t any comparable variant in corn and soybean cultures. The species B. pilosa and E. indica when exposed in a competition with soybean culture showed higher mycorrhizal colonization and it did interfere negatively in growing aspects and accumulation of nutrients. The Inorganic phosphorus solubilization potential of the corn s rhizosphere soil submitted to a competition in contact with roots between other species raised a value of 2.58 μg by gram of soil. This contact among the roots in competition was able to contribute to a reduction of the arbuscular mycorrhizal colonization of corn s roots and increased the weeds roots colonization. In relation with soybean culture in competition with weeds, and occurred less oxidation of the organic material by unit of microbiological biomass and resulted lower metabolic quotient compared to the monoculture of soybean rhizosphere. It happened a positive interaction in soybean mycorrhizal colonization and competitive weeds independently of the species of weed and its contacts among roots. The raise of mycorrhizal colonization was 53, 40 e 33% during the competitive stage with soybean and species of Brachiaria decumbens, Eleusine indica and Bidens pilosa, respectively. The weeds showed different competitive strategies and acted as good challengers and in many cases they kept the variant stable avoiding being reduced when in competition with the cultures. It was able to conclude that the combinations among cultures and species of weeds alters in many ways the behavior of the soil microbiota the contact between the roots showed great importance during interference among the species.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Weed effect on the growth and nutrition of young Coffea arabica L. plants

Apesar da grande área ocupada pelo café no território brasileiro a produtividade média desta cultura no Brasil é baixa. Dentre os vários fatores que contribuem para isto destaca-se a interferência das plantas daninhas, que competem pelos recursos água, luz e nutrientes. Na fase inicial de crescimento do cafeeiro é considerado uma das fases mais sensíveis à interferência das plantas daninhas, sobretudo, na linha de cultivo da cultura. Porém, a manutenção da lavoura durante todo o ciclo, livre de qualquer planta daninha deixa o solo desprotegido contra a erosão. Nos últimos anos, visando maior sustentabilidade da atividade cafeeira, tem-se procurado desenvolver sistemas integrados de manejo de plantas daninhas. Neste sistema cultiva-se entre as linhas do café espécies de plantas daninhas que têm como finalidade a promover a cobertura do solo e a reciclagem de nutrientes. Neste trabalho objetivou-se avaliar os efeitos da Interferência de plantas daninhas no crescimento e nutrição de plantas jovens de Coffea arabica L. Para isso, foram realizados três experimentos em casa de vegetação. No primeiro experimento avaliou-se quatro espécies de plantas daninhas: Brachiaria decumbens, Digitaria horizontalis, Brachairia plantaginea, Mucuna aterrima, em quatro densidades (zero, duas, quatro e seis plantas por vaso) em competição com plantas de café. O plantio das espécies de plantas daninhas foi realizado 60 dias após o transplantio do café e estas conviveram em mesmo vaso por 90 dias. A M. aterrima e B. plantaginea foram às espécies que mais influenciaram negativamente o crescimento do café. Ocorreu relação negativa entre aumento da densidade de plantas daninhas, com as variáveis de crescimento de plantas de café e razões de massa radicular e sistema radicular/parte aérea. No segundo experimento avaliaram-se os teores foliares de nutrientes nas plantas de café e nas espécies daninhas cultivadas em competição. Todas as espécies de plantas daninhas, quando em convivência com o café, proporcionaram menor teor de nutrientes nas folhas da planta cultura, principalmente, com o incremento da densidade de plantas. Exceção foi observada para as concentrações de N nas folhas do cafeeiro que conviveram com M. aterrima. Os teores de nutrientes nas folhas das plantas daninhas diferiram por espécie indicando capacidade diferenciada de reciclagens de nutrientes. No terceiro experimento avaliaram-se os efeitos de interferência da Brachiaria decumbens e Brachiaria plantaginea sobre o crescimento de plantas de café aos 60 dias após transplantio (60 DAT) e aos 180 dias após o transplantio (180 DAT). A interferência das gramíneas no crescimento das plantas de café mais jovem (60 DAT) foi maior em relação às plantas de café aos 180 DAT. Os efeitos da competição das espécies de plantas daninhas nas plantas mais jovens de café (60 DAT) foram similares não diferindo para a maioria das variáveis relacionadas ao crescimento das plantas de café. Todavia, quando a competição se instalou mais tarde aos 180 DAT, a B. plantaginea foi à espécie mais competitiva. O aumento da densidade de plantas daninhas promoveu maior alocação de fotoassimilados para parte área em detrimento ao sistema radicular do café.The average national yield of coffee is low, in spite of the large area occupied by this culture in Brazil. Among several other reasons for that, the effect of weeds deserves especial attention. They compete for water, light and food resources. The initial growth stage of coffee plants is considered one of the most sensitive stages to weed effects, mainly in the culture line. However, when crops are maintained free from any weeds during the whole cycle, the soil becomes unprotected. In recent years, aiming at a higher sustainability of the coffee sector, integrated systems of weed management have been developed. In these systems, some species of weeds have been cultivated between the lines of coffee with the purpose of promoting soil coverage and nutrient recycling. The present work aimed at evaluating the effects of weeds on the growth and nutrition of young plants of Coffea arabica L. For such, three experiments were carried out in a greenhouse. In the first experiment, four species of weeds were evaluated: Brachiaria decumbens, Digitaria horizontalis, Brachairia plantginea and Mucuna aterrima, in four densities (zero, two, four and six plants per vase), in competition with coffee plants. The planting of weed species was performed 60 days after the transplanting of the coffee plants and they remained in the same vase for 90 days. M. aterrima and B. plantginea were the species that most affected the coffee growth. A negative relation was observed between the density of weeds and the growth variables of coffee plants and between root mass and root system/aerial part ratios. In the second experiment, the nutrient leaf contents in the coffee plants and in the competing weed species were evaluated. All the weed species provided a lower content of macro and micronutrients on the leaves of the coffee plants, mainly with the increase in the density of the plants. An exception was observed for the N concentrations in theleaves of the coffee plant which was together with M. aterrima. The nutrient contents in the leaves of the weeds varied according to the species, indicating the different capacity of competition and nutrients. In the third experiment, the effects of Brachiaria decumbens and Brachiaria plantginea on the growth of coffee plants was evaluated at 60 and 180 days after transplanting (DAT). The effects of the grasses on the growth of the coffee plants was higher at 60 DAT, in comparison to the coffee plants at 180 DAT. The effects of the competition on the growth variables were similar among the weeds, when cultivated at 60 DAT. However, when the competition was installed later (180 DAT), B. plantginea was the most competitive species. The increase in the density of weeds promoted higher allocation of photoassimilates for theaerial part of the coffee plant, to the detriment of the root system.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Provas proibidas no processo penal

Grafia correta do título: Provas proibidas no processo penal = Evidence in criminal cases probesDiscorre sobre as provas no processo penal brasileiro, tendo como enfoque principal a utilização das provas obtidas por meio ilícito. Apresenta conceitos gerais de provas, bem como sua utilização na instrução processual. Aborda questões relacionadas às provas ilícitas, sua admissibilidade e inadmissibilidad

Image analysis of coffee seeds submitted to the LERCAFE test

ABSTRACT. The aim of this experiment was to quantify the stained areas of coffee seeds submitted to the LERCAFE test using image analysis. The seeds used were of the Catuaí Vermelho IAC 99 and Paradise cultivars. The physiological quality of the lots was assessed using germination tests, moisture content and a germination speed index. The LERCAFE test was conducted using seeds without parchment immersed in a solution of 3% sodium hypochlorite for 3 hours. Color photographs (RGB) with a resolution of 5 MPx were taken of each seed. The seeds were visually evaluated, and the functions generated from the analyses of the stained and non-stained regions were quantified by the Matlab R2009b program. Classification models were developed based on the Fisher Linear Discriminant Function and the evaluation of the adequacy of the models confusion matrix between the visual references and the classification generated by the linear functions. The image analysis for the creation of Fisher's linear discriminant function in the development of classifiers for the coffee seeds submitted to the LERCAFE test is potentially efficient; however, it remains necessary to test other discriminant functions and quantification methodologies

Mycorrhizal association in soybean and weeds in competition

The purpose of this study was to evaluate the effects of mycorrhizal association on the interference of Bidens pilosa, Urochloa decumbens and Eleusine indica on soybean culture in two conditions: a) plants competing without contact with roots of another species; b) with contact between roots. At 60 days after planting, growth, nutrient accumulation and mycorrhizal colonization of soybean and weeds were evaluated. The contact between roots of soybean plant and weed species increased the negative interference effects for both species, with less growth and nutrient accumulation. With the individualization of roots, higher competition occurred for soil resources up to 60 days of coexistence between species. In competition with soybean, Bidens pilosa and Urochloa decumbens stood out in accumulation of most nutrients without differing from when cultivated in monocultivation. The increase of the soybean mycorrhizal colonization was 53, 40 and 33% when in competition with Urochloa decumbens, Eleusine indica and Bidens pilosa species, respectively. A positive interaction occurred for soybean mycorrhizal colonization and competing plants irrespective of weed species or root contact.

Impact of sulfentrazone, isoxaflutole and oxyfluorfen on the microorganisms of two forest soils

Questions regarding the application of pre-emergence herbicides for control weeds in eucalyptus are noteworthy due to the impact of this practice on the environment, particularly on soil microbial activity and beneficial microorganisms such as mycorrhizal fungi and phosphate solubilizing microorganisms. The aim of this study was to evaluate the impact of applying herbicides sulfentrazone, isoxaflutole and oxyfluorfen on mycorrhizal colonization, microbial biomass and microbial activity of two forest soils cultivated with eucalyptus. The experiment was conducted in a greenhouse using two soils (clayey and sandy loam) distributed in 12 dm3 pots. The 4x3 factorial design was used, with three herbicides (sulfentrazone, oxyfluorfen, isoxaflutole) over the untreated control and three assessments (5, 20 and 70 days after application (DAA)), in a completely randomized design with four replications. After herbicide application, seedlings of the hybrid Eucalyptus grandis x Eucalyptus urophylla were transplanted. We evaluated the microbial biomass, respiration rate, metabolic quotient and the potential of solubilization of inorganic phosphate at 5, 20 and 70 DAA. At 70 DAA verified the percentage of roots colonized by mycorrhizal fungi and spore viability in the soil. The sulfentrazone, isoxaflutole and oxyfluorfen as well as the time of application affected the microbiological indicators differently. In the sandy loam soil sulfentrazone was more harmful to microbial biomass, mycorrhizal colonization and microorganisms solubilizing inorganic phosphate. However, in clayey soil, the application of the three herbicides did not affect microbial biomass, but the root colonization of eucalyptus by mycorrhizal fungi and the potential solubilization of inorganic phosphate were reduced. The sulfentrazone caused an increase in the number of non-viable spores of mycorrhizal fungi in the soil.Questões referentes à aplicação de herbicidas em pré-emergência das plantas daninhas na cultura do eucalipto merecem destaque devido ao impacto dessa prática no ambiente, principalmente sobre a atividade microbiana do solo e micro-organismos benéficos, como os fungos micorrízicos e os solubilizadores de fosfatos. Objetivou-se estudar o impacto da aplicação dos herbicidas sulfentrazona, isoxaflutol e oxyfluorfem sobre a colonização micorrízica, biomassa e atividade microbiana de dois solos florestais cultivados com eucalipto. O ensaio foi conduzido em casa de vegetação utilizando um solo argiloso e um solo franco- arenoso distribuídos em vasos de 12 dm3. O esquema fatorial utilizado foi 4 x 3, sendo três herbicidas (sulfentrazona, isoxaflutol e oxyfluorfem) mais a testemunha e três avaliações (5, 20 e 70 dias após a aplicação – DAA), no delineamento inteiramente casualizado com quatro repetições. Após a aplicação dos herbicidas na dose recomendada para a cultura transplantaram-se as mudas do híbrido de Eucalyptus grandis x E. urophylla. Avaliaram-se a biomassa microbiana, a taxa respiratória do solo, o quociente metabólico e o potencial de solubilização de fosfato inorgânico aos 5, 20 e 70 DAA. Aos 70 DAA verificou-se a colonização micorrízica e a viabilidade de esporos. Os herbicidas sulfentrazona, isoxaflutol e oxyfluorfem, bem como o tempo decorrido da aplicação afetaram os indicadores microbiológicos de maneira diferenciada. No solo franco-arenoso, o sulfentrazona foi mais prejudicial à biomassa microbiana, à colonização micorrízica e aos micro-organismos solubilizadores de fosfato inorgânico. No solo argiloso, no entanto, a aplicação dos três herbicidas não afetou a biomassa microbiana, mas reduziu a colonização radicular do eucalipto por fungos micorrízicos arbusculares e o potencial de solubilização de fosfato inorgânico. O herbicida sulfentrazona se destacou por provocar aumento do número de esporos não viáveis de fungos micorrízicos arbusculares nesse solo

Fitossociologia da comunidade de plantas daninhas na cultura da soja transgênica sob dois sistemas de preparo do solo

This objective of this work was to carry out a phytosociological assessment of the weed communiy before and after post-emergents herbicides application on transgenic soy crop. The treatments were arranged in random blocks by using:lactofen + chlorimuron-ethyl (150 + 50 g ha-1), imazethapyr + fomesafen (100 + 250 g ha-1) and glyphosate (1000 g ha-1) underno-tillage and conventional systems. The weed community sampling occurred in four seasons: before herbicide application (V2 stage); seven days after herbicide application (V4 stage); at the beginning of flowerage (R1) and at soy pre-harvest (R8 stage), using the inventory square method applied through a square of 0.25 m², randomly placed twice. The species found were identified, counted and weighed to obtain phytosociological parameters. The families that showed higher density, abundance and importance value index in the area were: Brachiaria plantaginea, Euphorbia heterophylla, Ipomoea sp., Cyperus rotundus and Digitaria horizontalis, meanwhile B. plantaginea and C. rotundus showed higher importance value index under conventional system and B. plantaginea and D. horizontalis showed importance value index under no-tillage systems. Comparing the systems, at the end of the crop cycle, the management using only glyphosate under conventional system allowed a significative C. rotundus infestation. Under no-tillage system, at the same season, B. plantaginea predominated followed by D. horizontalis wasn’t present in parcels treated with imazethapyr + fomesafenObjetivou-se com este trabalho realizar o levantamento fitossociológico de plantas daninhas antes e após aplicação de herbicidas pós-emergentes na cultura da soja transgênica. Os tratamentos foram distribuídos em blocos casualizados com os herbicidas: lactofen + chlorimuron-ethyl (150 + 50 g ha-1), imazethapyr + fomesafen (100 + 250 g ha-1) e glyphosate (1000g ha-1) nos sistemas de plantio direto e convencional. As amostragens de plantas daninhas ocorreram em quatro épocas: antes da aplicação dos herbicidas (estádio V2); aos sete dias após aplicação dos herbicidas (estádio V4); no início do florescimento da cultura (R1) e em pré-colheita da soja (estádio R8), utilizando quadrado inventário (0,25 m²) jogado ao acaso nas parcelas por duas vezes. As espécies vegetais amostradas foram identificadas, contadas e pesadas para obtenção dos parâmetros fitossociológicos. As plantas daninhas de maior densidade, abundância e índice de valor de importância no local foram: Brachiaria plantaginea, Euphorbia heterophylla, Ipomoea sp., Cyperus rotundus e Digitaria horizontalis. No sistema de plantio convencional B. plantaginea e C. rotundus apresentaram os maiores índices de valor de importância, e no sistema de plantio direto B. plantaginea e D. horizontalis. Ao final do ciclo da cultura, no sistema de plantio convencional, o controle feito com somente glyphosate permitiu reinfestação por C. rotundus. No sistema de plantio direto, nessa mesma época, observouse predomínio de B. plantaginea seguida por D. horizontalis, sendo que a última não esteve presente nas parcelas tratadas com imazethapyr + fomesafen.  Abstract This objective of this work was to carry out a phytosociological assessment of the weed communiy before and after post-emergents herbicides application on transgenic soy crop. The treatments were arranged in random blocks by using:lactofen + chlorimuron-ethyl (150 + 50 g ha-1), imazethapyr + fomesafen (100 + 250 g ha-1) and glyphosate(1000 g ha-1) underno-tillage and conventional systems. The weed community sampling occurred in four seasons: before herbicide application (V2 stage); seven days after herbicide application (V4 stage); at the beginning of flowerage (R1) and at soy pre-harvest (R8 stage), using the inventory square method applied through a square of 0.25 m², randomly placed twice. The species found were identified, counted and weighed to obtain phytosociological parameters. The families that showed higher density, abundance and importance value index in the area were: Brachiaria plantaginea, Euphorbia heterophylla, Ipomoea sp., Cyperus rotundus and Digitaria horizontalis, meanwhile B. plantaginea and C. rotundus showed higher importance value index under conventional system and B. plantaginea and D. horizontalis showed importance value index under no-tillage systems. Comparing the systems, at the end of the crop cycle, the management using only glyphosate under conventional system allowed a significative C. rotundus infestation. Under no-tillage system, at the same season, B. plantaginea predominated followed by D. horizontalis wasn’t present in parcels treated with imazethapyr + fomesafen