Maria Ângela André Tillmann

Pré-hidratação em sementes de soja e eficiência do teste de condutividade elétrica

O presente trabalho objetivou avaliar a influencia da pre-hidratacao na eficiencia do teste de condutividade eletrica para avaliacao do potencial fisiologico de sementes de soja. Sementes de seis lotes da cultivar BRS- 231, de tamanho uniforme por sua retencao na peneira 6,5mm, foram submetidas aos tratamentos de pre-hidratacao em atmosfera saturada e em substrato umedecido, por 3, 6, 9 e 12 horas, antes da imersao em agua e posterior leitura da condutividade eletrica com 18 e 24 horas. A qualidade dos lotes foi avaliada pela determinacao do teor de agua e pelos testes de germinacao, frio sem solo, envelhecimento acelerado, condutividade eletrica sem pre-hidratacao apos 18 e 24 horas e emergencia das plântulas em campo. Os metodos de pre-hidratacao em atmosfera saturada e substrato umedecido contribuem para melhorar a eficiencia do teste de condutividade eletrica, quando comparados com a imersao das sementes diretamente em agua.Tempos de pre-hidratacao, a partir das seis horas ate doze horas podem ser utilizados para identificacao de diferencas menos acentuadas na qualidade fisiologica, de sementes de soja para leituras de condutividade eletrica apos 18 e 24 horas de embebicao.

Comparação de métodos na detecção de sementes de soja geneticamente modificada resistente ao glifosato

Due to the great importance of the trade business, there are significant world efforts in establishing GMO detection methods. Currently, bioassays that analyse seedling phenotype, the ELISA test and kits that enable specific transgene protein identification, and PCR to detect specific DNA sequences are frequently used. The aim of this study was to compare the efficiency of different methods to detect RR soybean. Genetically modified seed samples, tolerant to glyphosate and susceptible parental seeds were submitted to bioassays (pre-imbibed, imbibed and immersion in herbicide solutions and seedling spraying), the Kit trait test and PCR detection. Bioassays were shown to be more efficient, comparing the ratio cost/benefit. The seedling visual analysis is a very important parameter to be considered in GM soybean seeds detection.

Detecção de sementes de soja geneticamente modificada tolerante ao herbicida glifosato

The objective of this study was to adjust methodology to detect soybean seeds tolerant to glyphosate, to characterize the symptoms, to establish the necessary minimum time capable to allow safe and possible evaluation of being reproduced. Three independent assays were done, based on the germination test. In study 1, seeds were pre-imbibed in a substrate containing herbicide solution for 16 hours. In study 2 the substratum was imbibed with the herbicide. In the study 3, seeds were immersed in solution of the herbicide. The standard germination test, speed of germination, length of seedling root and shoot and percentage of seedling secondary roots were used as evaluation parameters. Evaluations were made in the fourth day, until the final count, on the eighth day. All three methods allowed detection of soybean seeds tolerant to the herbicide glyphosate, in the period of five days. The most recommended methodlogies for routine use in seed analysis laboratory were sowing in substratum moistened with solution of the herbicide, at the concentration of 0,03% (480 g/l active ingredient) and pre-imbibing of the seeds for 16 hours, with solution containing 0,4% and 0,6% of glyphosate (480 g/l active ingredient) because they allow germination and the normal development of the aerial parts and root system of genetically modified seedlings. The following symptoms were observed in non GM seedlings : thickened points, longitudinal grooves and with yellowing of the hypocotyl, inhibition of the development of the primary root and of the emission of secondary roots, and the hypocotyl was proportionally larger than the primary root.

Maturação fisiológica de sementes de calêndula (Calendula officinalis L.)

The experiment was carried out using vigorous plants placed in individual vases to study the maturation process of calendula seeds. When 50% of the florets in were anthesis, the flowers were selected. The seeds were harvested at six times after the anthesis: 20, 24, 28, 32, 36 and 40 days after the anthesis (DAA). At each harvest, the seeds, due to their disuniformity, were separated in larger (equal or longer or wider than 9,0 mm and 2,5 mm) and smaller, as well as for coloring: green, pale green, cream, paler brown and dark brown. The determinations were: moisture content, seed dry matter weight, germination test, first account of the germination and primary root emission. It was observed that the largest accumulation of dry matter occurred in the period between 28 and 32 DAA when there were still seeds with pale green coloration, but the germination and vigor (first account of the germination and emission of primary root) were superior to 36 DAA, and there was no difference between larger and smaller seeds and they presented cream, pale brown and dark brown colorings. Although there was no coincidence in time among dry matter accumulation, germination and vigor, it is possible to consider that the point of physiological maturity happened between 28 and 32 DAA with moisture content of 36%. Harvesting is suggested at 36 DAA with moisture content aT 20%, before fruit dehiscence of the fruits.The objective of this research was to evaluate the effects of soybean seed vigor on field plant performance. Nine seed lots of the cv. M-Soy 109 were used. This study utilized commercially acceptable soybean seed lots (germination greater than 75%) and was conducted in the agricultural year 1998/1999, in Jaboticabal, Sao Paulo State, Brazil. In the characterization of the lots in laboratory, the following tests were used: moisture content, germination in sand, speed of emergence index, seedling length, seedling dry weight, electrical conductivity and accelerated ageing. These tests allowed the classification of the nine seed lots in high, medium, and low vigor lots. With the germination data, the number of seeds sown was calculated for a population of 400,000 plants per hectare, in a spacing of 0.50m between lines. Measurements of some parameters made during the vegetative and reproductive growth (speed of emergence index, total emergence, initial and final stand, plant height, amount of plants with flowers in R1, first pod insertion height, plants survival, yield components and yield) showed that the effects of seed vigor were observed in early soybean plant establishment (total emergence, emergence speed and stand). There was a delay in the beginning of the flowering period. The yield (kg.ha-1) was not affected by soybean seed vigor.

Identification of geneticaly modified soybean seeds resistant to glyphosate

Avancos na engenharia genetica tem resultado na obtencao de plantas tolerantes a certos herbicidas que usualmente nao sao seletivos. Para fins praticos e comerciais e importante ser capaz de detectar a presenca ou ausencia dessas caracteristicas nos genotipos. O objetivo desta pesquisa foi desenvolver um procedimento para identificacao de soja (Glycine max L. Merr.) geneticamente modificada com resistencia ao herbicida glifosato. Dois estudos foram conduzidos baseados no teste de germinacao. No primeiro estudo, sementes de soja foram pre-embebidas em papel toalha com solucao do herbicida e apos transferidas para papel toalha umedecido para o teste de germinacao. No segundo estudo, as sementes foram colocadas diretamente nas solucoes do herbicida em copos plasticos e avaliada a germinacao pelo metodo do papel toalha. Oito genotipos de soja foram comparados: quatro Roundup Ready, que contem o gen de resistencia ao herbicida (G99-G725, Prichard RR, G99-G6682 e H7242 RR) e quatro cultivares parentais nao transgenicas (Boggs, Haskell, Benning e Prichard). No primeiro estudo, as sementes foram embebidas por 16 horas a 25°C nas concentracoes do herbicida entre 0,0 e 1,5% do ingrediente ativo glifosato. No segundo, sementes foram submetidas a concentracoes entre 0,0 e 0,48%, por uma hora, a 30°C. Os parâmetros de avaliacao foram: germinacao, comprimento do hipocotilo, comprimento da raiz e comprimento total das plântulas. Ambos os metodos sao eficientes na identificacao de genotipos de soja que sao resistentes ao glifosato. E possivel identificar genotipos de soja geneticamente modificada apos tres dias, pela embebicao das sementes em 0,12% da solucao do herbicida e apos 6 dias se o substrato for pre embebido em 0,6% da solucao do herbicida. As caracteristicas de resistencia foram identificadas em todas as cultivares, independente da qualidade fisiologica inicial das sementes.

Detecção de soja geneticamente modificada tolerante ao glifosato por métodos baseados na atividade de enzimas

Progress in genetic engineering allow the production of genetically modified plants tolerant to the use of certain herbicides. The use of seeds of genetically modified plants is increasing quickly, and fast, practical and low cost detection methods need to be developed. The objective of this research was to establish a method for detection of soybean tolerant to glyphosate. Two soy cultivars were compared, one tolerant to glyphosate and its genetically unmodified parent. The seeds were submitted to treatments of pre-imbibition for 16 hours, in water and herbicide solution containing 0,6% of the active ingredient at the temperature of 25°C for seven days. Afterwards, the extraction and the determination of the activity of the enzyme peroxidase were carried out through the evaluation of the eletroforesis and of color reaction. The obtained results allowed the conclusion that it is possible to differentiate soy tolerance to herbicide glyphosate through color reaction. Differences were observed in the enzyme peroxidase activity tolerant and susceptible to glyphosate cultivars.

Métodos para avaliação da qualidade fisiológica de sementes de feijão vigna

The aim of this research was to compare vigor tests for seed quality evaluation. Four seed lots of vigna bean (Vigna unguiculata W.) of two cultivares (EPACE-10 and IPA-206), were stored for six months (november/94 to may/95) at natural environmen conditions of Pelotas, RS, Brazil and evaluated at two month intervals, throught the following tests: germination, accelerated aging, cold test without soil, electrical condutivity, seedling dry weight and field emergence tests. The analysis and interpretation of the results showed that the evaluation of the physiological quality of vigna bean seeds needs to be based on different vigor tests. Among the tests, the cold test without soil was the best related with seedling field emergence. The seedling dry weight was not effective to separate vigna bean seed lots in different vigor levels.

Pré-hidratação de sementes de ervilha e sua interferência na avaliação do potencial fisiológico

O presente trabalho teve o objetivo de estudar alteracoes bioquimicas e fisiologicas decorrentes da pre-hidratacao de sementes de ervilha, com enfase a lixiviacao de eletrolitos. Foram utilizados lotes de sementes de ervilha, cultivares Axe e Maria, caracterizados quanto ao teor de agua, geminacao, primeira contagem de germinacao, envelhecimento acelerado, condutividade eletrica e emergencia de plântulas em campo. As sementes de cada lote foram pre-hidratadas empregando atmosfera saturada e substrato umedecido, ate atingirem teores de agua de 10, 12 e 14%. Apos a pre-hidratacao, as sementes foram avaliadas pelos testes de condutividade eletrica e lixiviacao de calcio, potassio e magnesio. A pre-hidratacao de sementes de ervilha empregando atmosfera saturada ou substrato umedecido afeta diferentemente o processo de reestruturacao do sistema de membranas celulares das sementes, refletindo-se em alteracoes no padrao de lixiviacao de eletrolitos. Discrepâncias sao observadas entre resultados obtidos pelo teste de condutividade eletrica para avaliacao do potencial fisiologico de sementes de ervilha, dependendo do procedimento adotado para a pre-hidratacao das sementes.

Bioensaio em casa-de-vegetação na detecção e quantificação de sementes de soja geneticamente modificada

Concerns with the intrinsic and extrinsic quality attributes in foods have been growing in the last decades and the controversy was incited with the entrance of genetically modified foods on the global consumer market. Research institutes, inspection agencies and companies in several countries have developed strategies and methods to detect GM seeds. In this context, the objective of this experiment was to verify the efficacy of greenhouse bioassays to detect and quantify GM soybean seeds mixtures in conventional seeds samples. Conventional seeds samples were prepared with 0, 1, 3 and 5% of GM soybean seeds and sown in plastic trays containing sifted sand. The trays were maintained in an acclimatized greenhouse and, after fifteen days, the herbicide glyphosate was applied to the seedlings. Fourteen days after the herbicide application, the number of surviving seedlings was recorded. The greenhouse bioassay was efficient in detecting and estimating the quantity of GM soybean seeds in conventional soybean samples.

Comparação de métodos para avaliação da qualidade fisiológica em sementes de calêndula

Calendula (Calendula officinalis L.) is a plant with medicinal properties used in phytotherapic production and in the cosmetic industry. Seed is the basic input, so requirements of physiological quality to guarantee the establishment of cultivations with high productivity is essencial. Four lots were used with different origins and storage times of storage to evaluate the efficiency of methods that allow separation of lots of calendula seeds in vigor levels. The lots were evaluated using germination test, seed moisture content, seed dry matter weight, weight of 1000 seeds, first count of the germination test, emission of primary root, electrical conductivity, seedling emergence, speed of seedling emergence, seedling length, seedling green matter and dry matter weight. The tests of first count of the germination, emission of the primary root, and speed of seedling emergence index allowed the separation of the lots in vigor levels. The combination of the information supplied by the comparison of averages and for the correlation analysis between different vigor test and seedling emergency facilitates better evaluation of the seed quality.The performance of IAC-Carioca SH bean seeds, after they have been submitted to the classification processes by sieves and separation by density in the gravitational table, were evaluated in relation to the physiologic and sanitary quality of the seeds, contained in three fractions of discharge of the gravitational table. The vigor test was not influenced by the size of the seed and its acting is related to the degree of humidity. Higher density seeds could be stored for twelve months with small loss of their germination percentage without compromising the stand. Seeds of medium density retained in the sieves 10, 12 and 13 and stored until the tenth month can be used as seed. Seeds with lower density, are not recommended for planting and they present larger index of contamination by field fungi. Seed contamination by storage fungi Aspergillus spp. and Penicillium spp., was directly related to the relative humidity of the storage facility.Calendula (Calendula officinalis L.) is a plant with medicinal properties used in phytotherapic production and in the cosmetic industry. Seed is the basic input, so requirements of physiological quality to guarantee the establishment of cultivations with high productivity is essencial. Four lots were used with different origins and storage times of storage to evaluate the efficiency of methods that allow separation of lots of calendula seeds in vigor levels. The lots were evaluated using germination test, seed moisture content, seed dry matter weight, weight of 1000 seeds, first count of the germination test, emission of primary root, electrical conductivity, seedling emergence, speed of seedling emergence, seedling length, seedling green matter and dry matter weight. The tests of first count of the germination, emission of the primary root, and speed of seedling emergence index allowed the separation of the lots in vigor levels. The combination of the information supplied by the comparison of averages and for the correlation analysis between different vigor test and seedling emergency facilitates better evaluation of the seed quality.