925 resultados para Plants and civilization


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An in vitro protocol for Ficus carica cv. 'Roxo de Valinhos' was optimized. Nodal explants containing two buds were excised from field-grown mature plants, and transferred to different proliferation media consisting of combinations of distinct concentrations of activated charcoal with benzyladenine (BA), kinetin with gibberellic acid (GA(3)), and WPM (woody plant medium) with kinetin. The regular strength of WPM in combination with 0.5 mg l(-1) kinetin was the best condition for shoot proliferation of Ficus carica 'Roxo de Valinhos' plants. The addition of activated charcoal in the medium completely inhibited shoot proliferation. The inclusion of BA in the medium induced excessive callus formation as well as small and vitrified shoots, while GA(3) induced excessive elongation associated with vitrification, chlorosis, and tip-burned shoots.

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

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

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O pepino (Cucumis sativus L.) é, dentre os produtos hortícolas, um dos mais visados para o cultivo em estufas no Brasil devido ao ciclo vegetativo curto e ao elevado valor econômico no período da entressafra. Estudou-se, em condições de ambiente protegido, a influência de diferentes cores de cobertura plástica de solo no florescimento e na produção de pepino híbrido 'Yoshinari' enxertado ou não sobre abóbora híbrida 'Ikky'. Os tratamentos de cobertura foram: preto, preto pintado de branco, verde, e sem cobertura. Os tratamentos cobertos com plástico e sem enxertia apresentaram florescimento com distribuição mais uniforme na planta. O número de flores foi superior no tratamento preto/branco enxertado. Para as plantas não enxertadas, todas as coberturas favoreceram o florescimento. A enxertia favoreceu o florescimento somente para os tratamentos com plástico preto ou verde. A fixação dos frutos aumentou pelo uso de cobertura plástica, mas a enxertia não teve influência. A distribuição uniforme do florescimento manteve-se na frutificação apenas para os tratamentos com plantas enxertadas e cobertura do solo com plástico preto ou verde. Tanto o uso de cobertura plástica quanto a enxertia favoreceram a colheita precoce. Os frutos de melhor qualidade e as maiores produções, em número de frutos, foram obtidos nos tratamentos preto e preto/branco, não enxertados. A enxertia 'Yoshinari'/'Ikky' provocou o aparecimento de frutos mais grossos e menores, fora do padrão de comercialização.

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Lettuce mottle virus (LeMoV) and dandelion yellow mosaic virus (DaYMV) infect lettuce in South America and Europe, respectively. LeMoV and DaYMV possess isometric particles, occur at low concentrations in plants and have narrow host ranges. Partial genome sequences of both viruses were obtained using purified viral preparations and universal primers for members of the family Sequiviridae. DaYMV and LeMoV sequences were analyzed and showed identity with other members of the family. Universal primers that detect both viruses and specific primers for LeMoV and DaYMV were designed and used in RT-PCR-based diagnostic assays. These results provide the first molecular data on the LeMoV and DaYMV genomes and suggest that LeMoV is a member of the genus Sequivirus, probably distinct from DaYMV.

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Fungi isolated in Brazil, from lettuce, broccoli, spinach, melon and tomato, were identified as Rhizoctonia solani. All lettuce isolates anastomosed with both AG 1-IA and IB subgroups and all isolates from broccoli, spinach, melon and tomato anastomosed with AG 4 subgroup HG-I, as well as with subgroups HG-II and HG-III. DNA sequence analyses of ribosomal internal transcribed spacers showed that isolates from lettuce were AG 1-IB, isolates from tomato and melon were AG 4 HG-I, and isolates from broccoli and spinach were AG 4 HG-III. The tomato isolates caused stem rot symptoms, the spinach, broccoli and melon isolates caused hypocotyl and root rot symptoms on the respective host plants and the lettuce isolates caused bottom rot. This is the first report on the occurrence in Brazil of R. solani AG 4 HG-I in tomato and melon, of AG 4 HG-III in broccoli and spinach and of AG 1-IB in lettuce.

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In studies on the evaluation of methodologies for the analysis of soil, phosphorus (P) has been the single most studied aspect, due to the complexity of this dynamic element in soil. However, these studies have been limited regarding soil conditions in Paranaa. The present study aimed to evaluate the efficiency of the Mehlich-1, Mehlich-3 and ion exchange resin methods in the evaluation of available P for soybean (Glycine max) in the soils of Paranaa State. Twelve soil samples collected from the upper 0-20 cm were planted with soybean for a period of 42 days in the greenhouse. The ability to extract soil P followed the order of decreasing average amount of extracted P: Mehlich-3 > resin > Mehlich-1. The correlation coefficients between the content of P extracted by Mehlich-1, Mehlich-3 and resin and the amount of P accumulated in the plants were 0.86, 0.90 and 0.93, respectively. Mehlich-1, Mehlich-3 and resin showed similar efficiency in the evaluation of P availability to plants and, under conditions of natural fertility and in soils that had received no application of poorly natural reactive phosphates, can be used to quantify the concentrations of P in the soils of Parana State.

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Plant nutrition can positively influence quality of seeds by improving plant tolerance to adverse climate. In this context, silicon is currently considered a micronutrient and it is beneficial to plant growth, especially Poaceaes such as white oat and wheat, thereby improving physiological quality of seeds. This study had the objective of evaluating the effects of silicon leaf application on plant tillering, silicon levels and physiological quality of white oat and wheat seeds besides establishing correlations between them. Two experiments were carried out in winter with white oat and wheat. The experimental design was the completely randomized block with eight replications. Treatments consisted of foliar application of silicon (0.8% of soluble silicon, as stabilized orthosilicic acid) and a control (with no application). Silicon levels in leaves were determined at flowering whereas the number of plants and panicles/spikes per area was counted right before harvest. Seed quality was evaluated right after harvest through mass, germination and vigor tests. Data was submitted to variance analysis and means were compared by the Tukey test at a probability level of 5%. Person's linear correlation test was performed among silicon level in plants, tillering and seed quality data. Silicon leaf application increases root and total length of white oat seedlings as an effect of higher Si level in leaves. Silicon leaf application increases mass of wheat seeds without affecting germination or vigor.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Crude extract (CE) and aqueous (AqF) and ethyl acetate (EtOAcF) fractions of Guazuma ulmifolia LAM., Sterculiaceae and the corresponding AqF, EtOAcF of Stryphnodendron adstringens (MART.) COVILLE, Leguminosae were tested for their antiviral activity against poliovirus 1 (P-1) and bovine herpesvirus 1 (BHV-1) in HEp2 cultured cells. The antiviral activity was monitored by plaque assay and immunolluorescence assay (IFA) under virucidal and therapeutic protocols. The therapeutic protocol demonstrated statistically significant positive results with both plants and for both virus strains. The highest percentages of viral inhibition were found for G. ulmifolia EtOAcF which inhibited BHV-1 and P-1 replication by 100% and 99%, respectively (p < 0.05, Student's t-test). For S. adstringens, AqF was the most efficient, inhibiting BHV-1 and P-1 by 97% and 93%, respectively (p < 0.05). In the virucidal protocol, G. ulmifolia CE inhibited the replication of BHV-1 and P-1 by 60% and 26%, respectively (p < 0.05), while, for S. adstringens, inhibition of 62% (p < 0.05) was demonstrated only with EtOAcF for P-1. IFA demonstrated that the greatest reduction in fluorescent cell number occurred with G. ulmifolia, under the therapeutic protocol for both virus strains. However, AqF and EtOAcF of S. adstringens were most efficient with the virucidal protocol for P-1 In conclusion, we demonstrated that G. ulmifolia and S. adstringens inhibited BHV-1 and P-1 replication, as well as, blocked the synthesis of viral antigens in infected cell cultures.

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The accurate identification of the nitrogen content in plants is extremely important since it involves economic aspects and environmental impacts, Several experimental tests have been carried out to obtain characteristics and parameters associated with the health of plants and its growing. The nitrogen content identification in plants involves a lot of non-linear parameters and complexes mathematical models. This paper describes a novel approach for identification of nitrogen content thought SPAD index using artificial neural networks (ANN). The network acts as identifier of relationships among, crop varieties, fertilizer treatments, type of leaf and nitrogen content in the plants (target). So, nitrogen content can be generalized and estimated and from an input parameter set. This approach can form the basis for development of an accurate real time system to predict nitrogen content in plants.

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

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