41 research outputs found

    Teste de tetrazólio para Pinus taeda: preparo, coloração e classes de viabilidade das sementes

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    The objective of this work was to evaluate preparation and staining methods used in the tetrazolium test for Pinus taeda seeds, with the definition of viability classes. The procedures carried out were those described in the rules for seed testing in Brazil and Association of Official Seed Analysts, as well as an alternative method for the tetrazolium test. For each procedure, different combinations of types of seed cuts, concentrations of tetrazolium salt, and exposure periods were used. The test conducted with the alternative procedure (longitudinal cut adjacent to the embryo and staining of only the half with the embryo) is the most practical. The obtained results allowed classifying seeds into two different viability classes (viable and nonviable), and 0.2% tetrazolium salt for 4 hours is the most effective combination.O objetivo deste trabalho foi avaliar métodos de preparo e coloração usados no teste de tetrazólio para sementes de Pinus taeda, com definição de classes de viabilidade. Foram realizados os procedimentos descritos nas regras para análise de sementes no Brasil e na Association of Official Seed Analysts, além de um método alternativo para o teste de tetrazólio. Para cada procedimento, foram utilizadas diferentes combinações de cortes da semente, concentrações do sal de tetrazólio e tempo de exposição. O teste conduzido com o procedimento alternativo (corte longitudinal adjacente ao embrião e coloração somente da metade que contém o embrião) apresenta a maior praticidade. Os resultados obtidos permitiram classificar as sementes em duas classes de viabilidade (viável e não viável), e 0,2% de sal de tetrazólio por 4 horas é a combinação mais eficiente

    DETERMINATION OF MOISTURE CONTENT AND STORAGE POTENTIAL OF GUANANDI SEEDS

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    Guanandi is a native forest species with particularities that make it difficult to store of seeds, because of its recalcitrant behavior and since a specific and practical protocol to determine the moisture content of its seeds is not available yet. This work had the purpose to test procedures to determine the moisture content and to study different environmental conditions of the storage of the guanandi seeds. In order to determine the moisture content, the low-temperature oven method at 101 – 105°C was used, testing seed preparation methods (intact, cut in half and fragments smaller than 7.0 mm) and different drying periods. Four environments (wet chamber, dry chamber, cooler and laboratory environment) were tested for the storage of the seeds, with two packaging types, during four periods (0, 1, 2, 3 and 4 months). For the statistical analysis, a completely randomized design, with a factorial arrangement, was used for moisture content; a split-split plot design was used for storage. A regression analysis was performed to evaluate the physiological potential and moisture content during the storage, adjusting the significant equation by Tukey's test. From the obtained results, it was observed that the low-temperature oven method 101 - 105°C / 17 h, using intact seeds, should be used to determine the moisture content of guanandi seeds. The best combination of environment and packaging to store seeds was the laboratory environment condition (average between 19.6 - 23.1 °C and RH 53-62%) in polyethylene packaging

    QUALIDADE SANITÁRIA E FISIOLÓGICA DE SEMENTES DE ARAUCÁRIA DURANTE ARMAZENAMENTO

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    Araucaria angustifolia is a species of ecological and social-economic importance in the southern Brazil region, but it is at risk of extinction. Its seeds are classified as recalcitrant, requiring storage under controlled temperature and humidity to obtain greater longevity. Another aspect is the seed health quality, which is impaired by high seed moisture content that causes fungus proliferation and may reduce germination and seedling quality. The objective of this study was to evaluate the physiological and sanitary quality of araucaria seeds treated with 0.5, 1 and 3 % of sodium hypochlorite (NaClO) and stored at different periods (2, 4, 6, 8 and 12 months). The seed quality was evaluated by germination, vigor and seed health tests. The disinfection of seeds, regardless of the concentration used, temporarily delayed the seed germinations, but did not negatively affect seedling emergence. After 12 months of storage, the seeds showed infection by Schizophyllum commune, which caused the reduction of the germination. The seeds treated with NaClO showed lower fungal incidence, especially Schizophyllum commune, ensuring the seed health quality during storage for 12 months. The treatment with NaClO positively favors the physiological quality of Araucaria seeds that will be stored for a period exceeding four months.Araucaria angustifolia é uma espécie de importância ecológica e socioeconômica na região Sul do Brasil, porém, em risco de extinção. Sua semente é classificada como recalcitrante, necessitando armazenamento sob temperatura e umidade relativa controladas para maior longevidade. Outro aspecto refere-se à qualidade sanitária das sementes, a qual é prejudicada pelo elevado teor de água que causa a proliferação de fungos, os quais podem reduzir a germinação. Este trabalho teve como objetivo avaliar a qualidade sanitária e fisiológica de sementes de araucária desinfestadas com solução de hipoclorito de sódio (NaClO) a 0,5; 1 e 3 % e submetidas a diferentes períodos de armazenamento (2, 4, 6, 8 e 12 meses). A qualidade das sementes foi avaliada pelos testes de germinação, vigor e sanidade. A desinfestação das sementes, independentemente da concentração utilizada, retardou temporariamente a germinação das mesmas, porém, não afetou negativamente a emergência das plântulas. Após 12 meses de armazenamento, verificou-se a infecção das sementes por Schizophyllum commune, o que causou a redução da germinação. As sementes tratadas com NaClO apresentaram menor incidência de fungos, especialmente Schizophyllum commune, garantindo a qualidade sanitária das mesmas durante o armazenamento por 12 meses. O tratamento com NaClO favorece positivamente a qualidade fisiológica das sementes de araucária que serão armazenadas por período superior a 4 meses

    QUALIDADE SANITÁRIA E FISIOLÓGICA DE SEMENTES DE ARAUCÁRIA DURANTE ARMAZENAMENTO

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    Araucaria angustifolia is a species of ecological and social-economic importance in the southern Brazil region, but it is at risk of extinction. Its seeds are classified as recalcitrant, requiring storage under controlled temperature and humidity to obtain greater longevity. Another aspect is the seed health quality, which is impaired by high seed moisture content that causes fungus proliferation and may reduce germination and seedling quality. The objective of this study was to evaluate the physiological and sanitary quality of araucaria seeds treated with 0.5, 1 and 3 % of sodium hypochlorite (NaClO) and stored at different periods (2, 4, 6, 8 and 12 months). The seed quality was evaluated by germination, vigor and seed health tests. The disinfection of seeds, regardless of the concentration used, temporarily delayed the seed germinations, but did not negatively affect seedling emergence. After 12 months of storage, the seeds showed infection by Schizophyllum commune , which caused the reduction of the germination. The seeds treated with NaClO showed lower fungal incidence, especially Schizophyllum commune , ensuring the seed health quality during storage for 12 months. The treatment with NaClO positively favors the physiological quality of Araucaria seeds that will be stored for a period exceeding four months

    Genetic variability of soybean cultivars obtained through microsatellite markers in agarose gel

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    O objetivo deste trabalho foi avaliar a variabilidade genética de cultivares de soja com marcadores microssatélites selecionados e caracterizados quanto à informatividade para uso em gel de agarose. O DNA de 23 cultivares de soja foi amplificado com 283 marcadores microssatélites em gel de agarose a 3%. Posteriormente, 53 marcadores que apresentaram polimorfismo facilmente detectável nos géis de agarose foram utilizados na caracterização de 53 cultivares. Nessas cultivares foram detectados 124 alelos, com média de 2,34 alelos por loco, e os valores de conteúdo de informação polimórfica variaram entre 0,16 e 0,66, com média de 0,47. As frequências alélicas variaram de 0,02 a 0,91, com média de 0,43. A distância genética calculada variou de 0,02 a 0,73, com média de 0,47. A menor distância observada foi entre as cultivares CD201 e CD208, e a maior distância entre CD210 e BRSMT Uirapuru. Os marcadores utilizados possibilitaram a identificação das 53 cultivares avaliadas. Os locos microssatélites de soja, avaliados em gel de agarose, apresentam elevada informatividade. É possível detectar variabilidade significativa no germoplasma brasileiro de soja avaliado, mesmo entre cultivares elite, quando se usa marcadores moleculares microssatélites selecionados por sua informatividade.The objective of this work was to evaluate the genetic variability of soybean cultivars with microsatellite markers selected and characterized for their informativity to be used in agarose gel system. The DNA of 23 soybean cultivars was amplified with 283 microsatellite markers, using a 3% agarose gel systems. The 53 markers with clearly detectable polymorphism in the agarose gels were used to characterize 53 cultivars. In these 53 cultivars, 124 alleles were detected, with an average of 2.34 alleles per locus. Polymorphism information content values varied between 0.16 and 0.66, with an average of 0.47. Allele frequencies were of 0.02 to 0.91, with an average of 0.43. Genetic distance was of 0.02 to 0.73, with an average value of 0.47. The shortest distance was between cultivars CD201 and CD208, and the largest between CD210 and BRSMT Uirapuru. The markers used permitted the identification of all bean 53 cultivars. The soybean microssatellite loci evaluated in agarose gel presented high informativity. It is possible to detect significant variability in the Brazilian soybean germplasm evaluated, even among elite cultivars, when microssatellite molecular markers, selected for their informativity, are used

    POLYPHENOLS IN YERBA MATE SEEDS: POTENTIAL INHIBITORS OF GERMINATION

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    Due to its economic, social, and ecological potentials, yerba mate can be a source of employment and income in the southern region of Brazil. The objectives of the present study was to (1) quantify the total polyphenols in fresh yerba mate seeds (FS), seeds dehydrated for 70 d (SD), and seeds stratified in sand for 180 d (SS); (2) evaluate the potential germination and growth inhibitory effects of water, ethanol + water (1:1), and ethanol (99%) extracts of yerba seeds (FS, SD, and SS) using lettuce seedlings; and (3) verify the presence of polyphenols in fresh seeds of yerba mate through histochemical methods. In the bioassay, extracts of yerba mate seeds were used in the germination of lettuce seeds. For the histochemical analysis, sections of yerba mate seeds were stained with specific dyes. The results revealed that yerba mate fresh seeds contain higher concentration of phenolic compounds, which decreased in dehydrated seeds, and almost no phenolic compound was observed in stratified seeds. The bioassay results showed that the polyphenols present in the extracts of yerba mate seeds resulted in phytotoxic effect on the roots of lettuce seedlings. The histochemical observations revealed the presence of “lignified rough barrier” and phenolic compounds between the endocarp and endosperm of the yerba mate seeds.Due to its economic, social, and ecological potentials, yerba mate can be a source of employment and income in the southern region of Brazil. The objectives of the present study was to (1) quantify the total polyphenols in fresh yerba mate seeds (FS), seeds dehydrated for 70 d (SD), and seeds stratified in sand for 180 d (SS); (2) evaluate the potential germination and growth inhibitory effects of water, ethanol + water (1:1), and ethanol (99%) extracts of yerba seeds (FS, SD, and SS) using lettuce seedlings; and (3) verify the presence of polyphenols in fresh seeds of yerba mate through histochemical methods. In the bioassay, extracts of yerba mate seeds were used in the germination of lettuce seeds. For the histochemical analysis, sections of yerba mate seeds were stained with specific dyes. The results revealed that yerba mate fresh seeds contain higher concentration of phenolic compounds, which decreased in dehydrated seeds, and almost no phenolic compound was observed in stratified seeds. The bioassay results showed that the polyphenols present in the extracts of yerba mate seeds resulted in phytotoxic effect on the roots of lettuce seedlings. The histochemical observations revealed the presence of “lignified rough barrier” and phenolic compounds between the endocarp and endosperm of the yerba mate seed

    QUANTIFICAÇÃO DO TEOR DE ÁGUA DE SEMENTES DE Araucaria angustifólia (Bertol.) Kuntze

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    Sementes de Araucaria angustifolia são consideradas de comportamento recalcitrante, não tolerando a desidratação. Assim, a determinação do teor de água é importante para o monitoramento da perda de água durante o armazenamento e, consequentemente, para a manutenção da sua viabilidade. O objetivo do presente trabalho foi estabelecer critérios para avaliação do teor de água de sementes de araucária. Para tanto foram testadas duas quantidades de sementes por amostra, quatro formas de preparo da semente (sementes íntegras, cortadas em três partes, cortadas em quatro partes e cortadas em fragmentos menores que 7,0 mm); e dois métodos de secagem (estufa a 105°C e estufa a 101-105°C), por diferentes períodos. Com base nos resultados obtidos pode-se concluir que o procedimento mais indicado para a determinação do teor de água de araucária é a utilização do preparo das sementes cortando-as em três partes, pelo método de estufa a 101-105 °C, durante 17 h
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