A espécie Cassia fistula L. (Fabaceae-Caesalpinioidea) propaga-se por sementes, e para promover a produção das mudas faz-se necessário superar a dormência natural das sementes que é causada pela impermeabilidade do tegumento à água. Assim, objetivou-se avaliar diferentes tratamentos pré-germinativos para superar a dormência de sementes de C. fistula. As sementes foram submetidas aos seguintes tratamentos: testemunha-sementes intactas (T 1); escarificação mecânica com lixa d'água n o 80 na região lateral da semente (T 2); escarificação mecânica com lixa d'água nº 80, seguida de embebição em água à temperatura ambiente por 12 e 24 h (T 3 e T 4 , respectivamente); imersão em ácido sulfúrico por 1, 5, 10, 15 e 20 min (T 5 , T 6 , T 7 , T 8 , T 9 , respectivamente) e imersão em água na temperatura de 100°C até esfriamento (T 10). As características avaliadas foram: porcentagem de emergência, primeira contagem de emergência, índice de velocidade de emergência, comprimento e massa seca de plântulas. Os resultados dos tratamentos que envolveram a imersão em água na temperatura de 100°C não superaram a dormência de sementes de C. fistula. A maior porcentagem de emergência das plântulas de C. fistula foi observada para sementes escarificadas com lixa d'água nº 80 na região lateral da semente.

Substrates and temperatures in the germination of

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-Tabebuia caraiba (Mart.) Bureau, commonly known as Silver Trumpet Tree is a forestal species, belonging to Bignoniaceae family, which can be utilized as medicinal plant or in landscaping of urban and rural areas; besides producing large mechanical resistance wood. Despite its wide use and ecological importance, basic studies on storages of their seeds are scarce. This way, the objective of this study was to determine the most adequate packaging and the best temperatures, for storing seeds of T. caraiba. For this, seeds were stored in two types of packaging: Kraft paper bags and transparent polyethylene bags; which were then stored during 150 days under three different environments: laboratory normal environment (25±2 °C); cold chamber (8±2 °C); and refrigerator (6±2 °C). After periods of 0, 30, 60, 90, 120, and 150 days, seed moisture content, percentage of emergence, emergence speed index, and seedling length were evaluated. Seeds of T. caraiba kept in packaging of paper and polyethylene bags and stored at laboratory environmental condition, have lost more quickly their vigor along the storage period. For storage, it is recommended the maintenance of T. caraiba seeds in polyethylene bags into cold chamber; and/or polyethylene bags or Kraft paper bags into refrigerator.Index terms: emergence, vigor, seed preservation. Armazenamento de sementes de Tabebuia caraiba (Mart.)Bureau em diferentes embalagens e temperaturas RESUMO -Tabebuia caraiba (Mart.) Bureau, conhecida popularmente por craibeira, pertencente à família Bignoniaceae é uma espécie florestal utilizada na medicina popular e na arborização urbana e rural; além de produzir madeira de alta resistência mecânica. Apesar de seu uso e importância ecológica, os estudos básicos sobre o armazenamento de suas sementes são escassos. Desta forma, o objetivo neste estudo foi determinar as embalagens mais adequadas e as melhores temperaturas, para o armazenamento de sementes de T. caraiba. Para tanto, as sementes foram acondicionadas em dois tipos de embalagens: sacos de papel Kraft; e sacos de polietileno transparente; e armazenadas por 150 dias, em três ambientes: natural de laboratório (25±2 °C), câmara fria (8±2 °C) e geladeira (6±2 °C). Após períodos de 0, 30, 60, 90, 120 e 150 dias foram determinados: grau de umidade; porcentagem de emergência; índice de velocidade de emergência e comprimento de plântulas. As sementes de T. caraiba acondicionadas nas embalagens de papel e polietileno e armazenadas no ambiente de laboratório perderam mais rapidamente o vigor ao longo do armazenamento. Para o armazenamento recomenda-se a manutenção das sementes em sacos de polietileno em câmara fria; e/ou em saco de polietileno ou de papel Kraft em geladeira.Termos para indexação: emergência, vigor, conservação de sementes.1

The correct assessment of the physiological quality of seed lots is necessary for the quality control program of companies. For such purpose, tests that detect differences in the physiological potential of seed lots and that meet the minimum market requirements. Thus, the study was conducted towards assessing the efficiency of laboratory tests in differentiating the quality of Brachiaria brizantha cv. Xaraés seed lots. Seeds from nine lots were assessed regarding water content, germination, first germination count, electrical conductivity and seedling emergence in sand in the laboratory (normal seedlings, first count and germination rate index), and the results were compared with those from the seedling emergence test conducted in the field. The experimental design used was completely randomized, with four replicates, and the Pearson correlation coefficient between the values from the germination, vigor and field seedling emergence tests was determined. The germination and seedling emergence in sand tests and the seedling emergence rate index efficiently assess the physiological quality of Brachiaria brizantha cv. Xaraés seed lots, providing data similar to those from seedling emergence in the field. Key words: Brachiaria brizantha. Germination. Forrage grass. Vigor tests. ResumoA avaliação correta da qualidade fisiológica dos lotes de sementes é necessária para o programa de controle de qualidade das empresas, para isso se utiliza testes que detectam diferenças no potencial fisiológico de lotes e que atendam às exigências mínimas para a comercialização. Assim, o trabalho foi conduzido com o objetivo de verificar a eficiência de testes de laboratório na diferenciação da qualidade dos lotes de sementes de Brachiaria brizantha cv. Xaraés. As sementes de nove lotes foram avaliadas quanto ao teor de água, germinação, primeira contagem de germinação, condutividade elétrica, emergência de plântulas em areia no laboratório (plântulas normais, primeira contagem e índice de velocidade de emergência) e os resultados comparados aos obtidos no teste de emergência de plântulas em campo. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro repetições e determinado o coeficiente de correlação de Pearson entre os valores obtidos nos testes de germinação e de vigor e o teste de emergência em campo. O teste de germinação, emergência de plântulas em areia e índice de velocidade de emergência de plântulas em areia são eficientes na avaliação da qualidade fisiológica de lotes de sementes de Brachiaria brizantha cv. Xaraés, fornecendo informações equivalentes à emergência de plântulas em campo. Palavras-chave: Brachiaria brizantha. Germinação. Gramíneas forrageiras. Testes de vigor.

Recent research reports the importance of preserving plants in Brazilian semiarid regions, in this context, the scientific literature has reported different pharmacological studies from plant extracts with an antifungal potential, coming from forest species that can contribute as a control and management strategy in the transmission of phytopathogens. This study aimed to evaluate the effect of biotech treatments in controlling the transmission of Colletotrichum sp. in seeds of S. obtusifolium. In this study, 100 seeds were subjected to the following preventive treatments: fungicide Captan ® , extract of Caesalpinia ferrea Mart. Ex. Tul., and biological control with Trichoderma spp. The biological control with Trichoderma spp. and the alternative control using C. ferrea extract provided a greater protection to seeds and seedlings of S. obtusifolium facing the transmissibility of Colletotrichum sp.The treatment based on plant extract is more efficient for this purpose only in large seeds and does not interfere on the germination percentage and speed. Therefore it is necessary to perform other studies with Trichoderma spp. and C. ferrea extract to test different doses of these products.

In Brazil the Caatinga biome is formed by endemic species with numerous applications in medicine, cosmetics and agrochemicals. However, only 8% of the country’s plant species are chemically evaluated annually. Thus, the work aimed to determine the free amino acid composition and phenolic substances of Caatinga plant species extracts, their antioxidant activity and the potential use of these compounds in the control of A. alternata in citrus. Leaf extracts from fourteen native plant species were evaluated for free amino acid contents; total and individual polyphenols; total flavonoids and antifungal susceptibility test. The relationship between the contents of the compounds detected in each plant extract with its antioxidant capacity and antifungal activity, has not yet been fully clarified. However, it is a fact that the extract of Cleome hassleriana constitutes a source rich in free amino acids. It is also verified that the extracts of Mimosa tenuiflora and Caesalpinia ferrea are efficient alternatives in the control of Alternaria alternata in citrus, because they present similar results for this purpose, and in the evaluation of their compositions in free amino acids, phenolic substances and antioxidant activity.

This study searches for efficient and low environmental impact alternatives to control Spodoptera frugiperda. Application of elicitors capable of inducing resistance in plants has already been highlighted. The elicitors trigger the plant's defense capacity against attack of herbivores and phytopathogenic organisms. Thus, the present study aimed to evaluate the effect of resistance elicitors on some biological aspects and food preference of Spodoptera frugiperda (J. E. Smith) in corn in laboratory conditions. The treatments consisted of: Control (distilled water); Biofertilizer (25 mL L-1); Acibenzolar-S-methyl-ASM (2 mg mL-1); Potassium silicate (10 mL L-1) and T5: Potassium silicate (10 mL L-1) + ASM (2 mg mL-1). The treatments were foliar application of elicitors with adjustable jet pressure sprayer to the whole plant with an amount of 20 mL of the solution per plant. The larval phase (weight at 7 and 14 days, duration and viability); pupal phase (weight after 24 h, duration and viability) and adult phase (number of eggs / female, number of eggs/posture/female and longevity of adults) were evaluated. Free-choice and no-choice food preference test experiments were also carried out on 1st and 3rd instar caterpillars, after which the leaves collected at 5 and 10 days after spraying. The results showed that Acibenzolar-S-methyl induces resistance in corn plants when applied either alone or together with potassium silicate. Therefore, it adversely affects development of S. frugiperda. The leaves treated with Potassium Silicate + ASM were less preferred and consumed by 1st and 3rd instar caterpillars in free-choice food preference test.