Francisco Amaral Villela

Alterações fisiológicas e bioquímicas em sementes de feijão envelhecidas artificialmente

O presente trabalho teve o objetivo de avaliar as alteracoes fisiologicas e bioquimicas em sementes de feijao submetidas ao envelhecimento artificial. Utilizaram-se dois lotes de sementes de feijao, cultivar Iapar 44, com diferentes qualidades fisiologicas, submetidos ao envelhecimento artificial (41oC e 100% UR do ar), por periodos de zero, 24, 48, 72 e 96 horas. As analises fisiologicas constaram de teste de germinacao, primeira contagem de germinacao, condutividade eletrica, comprimento de hipocotilo e de raizes das plântulas; as analises bioquimicas foram realizadas pela tecnica de eletroforese de sistemas enzimaticos, avaliando-se a fosfatase acida, malato e glutamato desidrogenase e esterase. Os resultados obtidos permitem concluir que: a) lotes com alta germinacao apresentam acentuada diferenca na resposta ao processo de envelhecimento, verificados pela reducao na capacidade seletiva das membranas das sementes e pelo crescimento e desenvolvimento das plântulas de feijoeiro; b) a partir de 72 horas de envelhecimento artificial, ha reducao na atividade das enzimas fosfatase acida e esterase; c) a atividade das enzimas fosfatase acida, malato desidrogenase, glutamato desidrogenase e esterase e influenciada pelo periodo de envelhecimento e pela qualidade inicial dos lotes

Modificações fisiológicas e bioquímicas em sementes de feijão no armazenamento

RESUMO – Para avaliar alteracoes fisiologicas e bioquimicas em sementes de feijoeiro durante oarmazenamento em condicoes ambientais nao controladas de temperatura e umidade relativa do ar,foi realizado o presente trabalho. Foram utilizadas as cultivares Iapar 44, Macotaco, TPS Bonito,TPS Bionobre e TPS Nobre. As sementes foram avaliadas durante o armazenamento, em condicoesambientais nao controladas, no municipio de Santa Maria-RS, pelo periodo de oito meses. Asavaliacoes fisiologicas constaram do teste de germinacao, primeira contagem de germinacao,comprimento de hipocotilo e de raizes, condutividade eletrica e emergencia em campo. As avaliacoesbioquimicas das sementes foram obtidas pela tecnica de eletroforese de sistemas enzimaticos,avaliando-se a atividade das enzimas fosfatase acida, malato desidrogenase, glutamatodesidrogenase e esterase. Todas as avaliacoes foram realizadas antes e a cada dois meses duranteo armazenamento. Os resultados permitem concluir que a atividade das enzimas malato e glutamatodesidrogenase e estavel durante o armazenamento em condicoes ambientais nao controladas noscultivares vigorosos (TPS Bionobre, TPS Nobre e Iapar 44); a enzima esterase tem sua atividadeincrementada durante o armazenamento nao controlado, independentemente da qualidadefisiologica das sementes de feijao; potenciais de armazenamento sob condicoes ambientais naocontroladas sao diferentes nos cultivares TPS Bionobre, TPS Nobre, TPS Bonito, Macotaco eIapar 44.Termos para indexacao:

Teste de envelhecimento acelerado para avaliação do potencial fisiológico de sementes de rabanete

The objective of this study was to compare different procedures to conduct the accelerated aging test for radish seeds. Six lots of radish seeds, cultivar Vip Crimson were used. The initial quality of the seeds was evaluated through the following tests: moisture content, germination, germination first count, germination at low temperature, and seedling emergence at different temperatures. In the first stage, the seeds were tested by traditional and saturated salt accelerated aging and in the second stage non-saturated NaCl solution for 48, 72 and 96 hours at 41oC. The experimental design for the first stage was six treatments (lots) and in the second stage four treatments (lots) with four replicates. In the procedures used in the accelerated aging test, the exposure periods of 72 hours at 41oC with saturated NaCl solution and of 48h at 41oC with non- saturated NaCl solution were adequate for the physiological potential of radish seeds.

Teste de deterioração controlada para avaliação do vigor de sementes de feijão

The controlled deterioration test has frequently been used to evaluate the vigour of several species and could be an alternative for evaluation of the vigour in bean seeds. However, the conditions for the accomplishment of this test are not still completely defined. Due to this the objective of the present study was to determine the conditions more adapted for the conduction of the controlled deterioration test in bean seeds compare its efficiency with the accelerated ageing test. Five lots of bean seeds were used with different physiological qualities. The initial quality of each seed lot was evaluated by: germination test, first germination count, ageing accelerated test, electric conductivity and field emergence. The initial moisture of the seeds was established to be 15, 20 and 25% and for each initial moisture content, there were four combinations of deterioration period of 24 and 48 hours and deterioration temperature of 40 and 45°C. The results allowed the conclusion that seeds with 20% initial moisture, for 48 hours under temperature of 45oC presented high correlation with the accelerated ageing test.

Physiological performance of cotton seeds treated with thiametoxam.

The introduction of new seed treatment products is increasing and bioactivators, such as the insecticide thiametoxam, are used to increase plant yield potential by modifying metabolism. The objective of this study was to evaluate the effects of thiametoxam on the physiological quality of cotton seeds, particularly on seedling root growth, and establish product concentrations for seed pre-treatment. Three seed lots of the cultivar CD 408 were evaluated which had been treated with six dosages of Cruiser® 350 FS containing 35 g/L A.I. of thiametoxam, at 0, 2, 4, 6, 8 and 10 mL per kg of seeds. Parameters measured included: standard germination test, germination first count, accelerated ageing, root dry matter and length, emergence velocity rate and final seedling emergence. Cotton seeds treated with thiametoxam demonstrated improved physiological quality of the seeds and the dosages of 5.0 to 7.0 mL of the Cruiser® 350 FS/kg of seeds were more efficient in improving the physiological performance of cotton seeds.

Condicionamento osmótico de sementes de beterraba

Rapid and uniform establishment of seedlings in the field are two important prerequisites to achieve a good stand and to ensure the productivity and quality of harvest especially in the case of the vegetable crops. Several techniques have been developed with the objective of increasing the speed and uniformity of the germination and emergence of the seedlings, and osmotic conditioning of the seeds is one of the most promising. The purpose of this study was to evaluate the response of beet seeds to osmotic conditioning in order to achieve more rapid germination and emergence of the seedlings. Three beet seed lots were submitted to seven conditioning treatments: prehydration in distilled water for zero (control), 16 and 24h; prehydration in PEG solution for 24, 48 and 72h and prehydration in MgSO4 solution for 24h. Germination was evaluated at eight and fourteen day at 15oC and 20oC along with index of germination speed and emergence, mean times to germination and seedling emergence. Although the osmotic conditioning of beet seeds of average and high physiologic quality has provided benefits to the speed of germination and seedling emergence, the technique needs to be adjusted for the species, given the adaptation need of the conditioning methodology to the different lots produced by the seed industry.

Potencial fisiológico de sementes de brássicas com ênfase no teste de envelhecimento acelerado

O presente trabalho comparou diferentes testes para a avaliacao do potencial fisiologico de sementes de brassicas, com enfase no teste de envelhecimento acelerado (TEA). Foram utilizados quatro lotes de sementes de repolho, cultivar Coracao de Boi, quatro de sementes de couve-brocolis, cultivar Piracicaba Precoce, e cinco de sementes de couve, cultivar Georgia. Foram realizados os testes de germinacao, primeira contagem de germinacao, emergencia de plântulas, condutividade eletrica e envelhecimento acelerado. Neste, foram empregados tres procedimentos: tradicional (agua), solucao saturada (40 g 100 mL-1) e solucao diluida (11 g 100 mL-1) de NaCl, a 42°C, por periodos de 48, 72 e 96 horas. Foi utilizado o delineamento inteiramente casualizado, com quatro repeticoes e analises isoladas para cada teste. Os testes de primeira contagem de germinacao e velocidade de emergencia de plântulas apresentaram potencial para avaliacao do potencial fisiologico de sementes de repolho e couve-brocolis. Ja para sementes de couve, os testes de emergencia de plântulas e condutividade eletrica foram os mais eficientes. TEA tambem foi eficiente na avaliacao do potencial fisiologico de sementes de brassicas. Para repolho, a melhor distincao entre o potencial fisiologico das sementes atraves do TEA aconteceu seguindo o procedimento tradicional e empregando solucao diluida de NaCl, ambos por 48 e 72 horas, e solucao saturada de NaCl por 72 e 96 horas. Para couve-brocolis, todas as variacoes do TEA testadas foram eficientes na identificacao dos lotes de semente de qualidade superior. Ja para couve, os melhores resultados foram obtidos aplicando TEA na metodologia tradicional por 96 horas e solucao diluida por 72 horas. Observou-se ainda que, em comparacao com o uso de agua, a utilizacao de solucao salina no TEA inibiu sensivelmente o crescimento e desenvolvimento de fungos.

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.