Influência da luz e giberelina na velocidade de germinação das sementes de cafeeiro (Coffea arabica L.)

There are various factors that interfere with seed germination. In this research the effect of light, gibberellins and paclobutrazol in coffee seed germination were evaluated. Seeds of coffee (Coffea arabica L.) from cultivar Rubi harvested at the developmental stage known as cherry were dried until 12% of water content. The first trial was performed in factorial design (2x2), the condtions being two (light and dark), presence and absence of gibberellins. The substrate was imbibed with 20ml of GA3 (100mM) and the control treatment with distillated water. The second trial was performed in factorial design (4x2x3), with four concentrations of paclobutrazol (0; 0,1;1,0; and 10 mM), two conditions (light and dark) and three storage conditions (0, 4 and 8 months). The substrate was imbibed with 20mL of paclobutrazol and the control treatment with distillated water. Both trials were performed in four replications of fifty seeds. Seed sowing was performed in gerbox tray with two blotting papers and one germitest paper. The dark condition was created by wrapping the gerbox with an aluminum foil. The germiantion velocity rate, germination at thirty days and the time to 50% root protrusion were evaluated. The gibberellin treatment in seed coffee decreases the germination velocity rate and percentage of germination. The gibberellin inhibitor decreases the gemination velocity rate but it did not reduce the effect of light. High values of germination velocity rate were observed in dark.Vários são os fatores que interferem no processo de germinação de sementes de cafeeiro (Coffea arabica L.). Nesta pesquisa, foi avaliado o efeito da luz, da giberelina e do bloqueador de giberelina paclobutrazol na germinação das sementes. Foram utilizadas sementes da cultivar Rubi, colhidas no estádio cereja e secas até 12% de umidade. O ensaio I foi realizado em esquema fatorial (2x2), dois ambientes (claro e escuro), na presença e ausência de giberelina. O substrato foi umedecido com 20 mL de GA3 (100mM) ou com água destilada no caso da testemunha. O ensaio II foi realizado em esquema fatorial (4x2x3): quatro concentrações de paclobutrazol (0; 0,1; 1,0 e 10,0 mM), dois ambientes (claro e escuro) e três épocas de armazenamento (0, 4 e 8 meses). O substrato foi umedecido com 20 mL do bloqueador e o substrato da testemunha, com água destilada. Ambos os ensaios foram realizados com quatro repetições de 50 sementes e a semeadura foi feita em caixas tipo gerbox sobre dois papéis mata-borrão e sob uma folha de papel germiteste. Para simular o ambiente escuro, os gerbox foram envolvidos em papel alumínio, e a avaliação, feita no escuro com luz verde. Avaliou-se o índice de velocidade de germinação (IVG), germinação aos 30 dias e o tempo para que ocorresse 50% de protrusão radicular (T50). A adição de giberelina na embebição de sementes de cafeeiro reduziu a velocidade e a porcentagem de germinação. Independentemente da luz, o paclobutrazol reduziu a velocidade de germinação a partir da concentração de 1,0 mM. A maior velocidade de germinação após 4 meses de armazenamento ocorreu na ausência de luz

PRIMING EM MATRIZ SÓLIDA DE SEMENTES DE CAFÉ ARMAZENADAS COM ALTA UMIDADE

The water content of seeds and temperature affect the biological processes, determining different results when seeds areexposed to different levels of these factors. When seeds are subjected to priming, we expect improvement in the physiological qualityof seeds, but while promising, this procedure is still in the experimental phase in coffee seeds. In order to evaluate the effects of solidmatrix priming at three different temperatures to evaluate the performance of coffee seeds (Coffea arabica L.) stored for up to twelvemonths, we carried out this research at the Central Laboratory of Seed Analysis in the Agriculture Department, Universidade Federalde Lavras, Lavras - MG. Seeds with 36.0% moisture content were sorted, processed, packed in polyethylene bags and kept in coldstorage for up to 12 months. At quarterly intervals, the seed samples were subjected to solid matrix priming, at temperatures of 20 °C,30 °C and 40 °C for 6 days. One control, without priming, was also evaluated. The physiological conditioning of solid matrix primingof C. Arabica seeds, held for 6 days at 20 °C and 30 °C favors the emergence of seedlings in seeds stored for 9 months and under 40°C, is harmful to the C. arabica seeds.O conteúdo de água das sementes e a temperatura afetam os processos biológicos, determinando variados resultadosquando as sementes são submetidas a diferentes níveis desses fatores. Quando as sementes são submetidas ao priming, esperam-serespostas em razão da melhoria na qualidade fisiológica dessas sementes, mas, embora promissor, esse procedimento ainda seencontra em fase experimental em sementes de café. Com objetivo de avaliar os efeitos do priming em matriz sólida em três diferentestemperaturas sobre o desempenho de sementes de café (Coffea arabica L.) armazenadas por até doze meses, realizou-se a presentepesquisa no Laboratório Central de Análise de Sementes do Departamento de Agricultura da Universidade Federal de Lavras, Lavras –MG. Sementes com 36,0% de umidade foram classificadas, tratadas, acondicionadas em embalagens de polietileno e armazenadas emcâmara fria por até 12 meses. Em intervalos trimestrais, as amostras de sementes foram submetidas ao priming em matriz sólida, emtemperaturas de 20 oC, 30 oC e 40 oC, por 6 dias. Uma testemunha, sem priming, foi também avaliada. O condicionamento fisiológicoem matriz sólida de sementes de C. arabica. realizado por 6 dias nas temperaturas de 20 °C e 30 °C favorece a emergência de plântulasem sementes armazenadas por 9 meses e, sob temperatura de 40 °C, é prejudicial às sementes de C. arabic

Temperatura e regime de luz na germinação de sementes de Tabebuia impetiginosa (Martius ex A. P. de Candolle) Standley e T. serratifolia Vahl Nich. - Bignoniaceae Temperature and light in germination of Tabebuia impetiginosa (Martius ex A. P. de Candolle) Standley and T. serratifolia Vahl Nich. seeds - Bignoniaceae

O teste mais tradicionalmente utilizado para a avaliação da qualidade de lotes de sementes é o teste de germinação. A metodologia do teste de germinação ainda não está bem definida para sementes de Tabebuia impetiginosa (ipê-roxo) e T. serratifolia (ipê-amarelo), uma vez que são encontrados na literatura poucos trabalhos referentes especificamente à definição das condições ideais para a realização do teste nessas espécies. Objetivou-se com este trabalho verificar o efeito de temperatura e luz na germinação de sementes de diferentes lotes de ipê-roxo e ipê-amarelo. Para o ipê-roxo, a seleção das temperaturas foi realizada inicialmente em mesa de termogradiente, com temperaturas variando de 20,9ºC a 34,4ºC e, posteriormente, em BODs, com temperaturas de 25ºC, 30ºC e 35ºC. Para o estudo do efeito da luz na germinação das sementes de ambas as espécies, os tratamentos foram instalados em BODs sob três regimes de luz: luz branca contínua/temperatura de 30ºC, branca alternada com fotoperíodo de 8 horas/temperatura de 20/30ºC e escuro/temperatura de 30ºC. A temperatura de 30ºC foi adequada para a germinação de sementes de ipê-roxo, independente do ano de colheita ou da qualidade fisiológica dos lotes, enquanto a resposta da germinação em relação ao regime de luz variou conforme o ano de colheita. A condição ideal para realização do teste de germinação em sementes de ipê-amarelo, independente da procedência e do ano de colheita, foi sob luz constante a 30ºC.The most traditionally used test in order to evaluation seed lots quality is the germination test. However, the germination test methodology is not well defined for Tabebuia impetiginosa (ipê-roxo) and T. serratifolia (ipê-amarelo) seeds. This is probably due to the little attention that the species received, specifically, about the definition of the ideals conditions for germination of these species. Thus, the objective of this research was to verify the effect of temperature and light on germination of T. impetiginosa and T. serratifolia seeds. The research was performed in a thermo-gradient table with temperature varying from 20,9ºC to 34,4ºC and in BODs with temperatures adjusted at 25ºC, 30ºC and 35ºC. To study the effect of light on germination for both species the seeds were incubated in BODs at white light/temperature 30ºC, alternate white with photoperiod 8 hours/temperature 20/30ºC and in the darkness/temperature 30ºC. The temperature of 30ºC was suitable for the germination of T. impetiginosa seeds, irrespective of the year of collection or physiological quality of the batches, while the effect of light on germination varied according to the year of collection. The ideal condition for accomplishment of the germination test in T. serratifolia seeds, irrespective of the provenance and year of collection, was under constant light at 30ºC

Deterioration of sunflower seeds during storage

The speed on deterioration of oil-seeds depends on conditions of the storage environment and on particularities of the species, which include the seed chemical composition. Within this study, the changes on quality of sunflower seeds, stored in different packaging types and environmental conditions, were investigated. The packaging used were multiwall Kraft paper and plastic packaging (with and without vacuum), under cold chamber and conventional storage conditions. Seed quality was evaluated by tests of: germination and accelerated aging; besides alterations on oil content, fatty acids profile, and isoenzymatic systems. The storage under cold chamber conditions was more efficient in maintaining physiological quality of sunflower seeds; and under such environment, the Kraft paper packaging was the most adequate. Under conventional storage facility, however, the plastic packaging, sealed with vacuum, has provided better maintenance of physiological quality. Changes in the sunflower seed quality were detected by the enzymatic systems: alcohol dehydrogenase and superoxide dismutase. The oil content in seeds decreases over time, regardless of storage condition. The linoleic and oleic acids constituted 80% of the total amount of fatty acids scanned. There have been no significant differences on the fatty acid profiles of the sunflower oil under the different storage conditions studied

TEOR DE ÁGUA NA COLHEITA E TEMPERATURA DE SECAGEM NA QUALIDADE DE SEMENTES DE SORGO, DURANTE O ARMAZENAMENTO

Harvest is a procedure which must happen as fast as possible when the physiological maturity of seedis reached. In sorghum, this maturity can occur with the water content around 25 to 35%. Nevertheless, seeds withhigh water content can be damaged at drying time, so requiring the adoption of drying methods which ensure seedquality during storage. Thus, the objective of this work was to evaluate the quality of sorghum seeds, cultivar BR 310,harvested with different moisture contents (19 and 27%), submitted to drying under three temperatures (35, 45 and35/45 °C). For alternating temperature, the drying started with 35 ºC until seed reached 15% and then temperature wasraised to 45 ºC. Seeds were later stored in a conventional environment and in a cold and dry chamber, for 9 months. Thequality of the seeds was determined by testing moisture content, germination and seedling emergence, emergence rateindex (IVE), cold test, tetrazolium, mass electrical conductivity and isoenzyme analysis. The gemination of sorghumseeds increased with storage when they were dried at 35/45 °C. Alternating drying maintained quality of the seedsharvested with 19% moisture content. A reduction in the percent of dormant seeds at three months was observed whenstored in cold and dry chamber, regardless the initial water content

Physical, physiological and biochemical changes during the development of sorghum seeds with different concentrations of tannin

With the interest of verifying the relationship among tannin concentration and seed dormancy, it was intended, in this research, to evaluate the biochemical, physical and physiological alterations occurred during the development of sorghum seeds with different concentrations of tannin. Seeds of cultivars BR 305 and BR 310, collected in seven development stages (100, 103, 107, 113, 119, 121, 127 days after sowing) according to water content. The seeds collected in each stage were divided into two lots, one submitted to drying at 35C to the moisture of 12% and the other lot without drying. The quality of seeds was evaluated by germination and enzyme profile tests. In addition, the tannin concentration in the seed in each development stage was measured. Beneficial effects of drying on germination of higher water seeds are found. In the seeds evaluated without drying, the percentage of dormancy is greater when compared to that of seeds submitted to artificial drying. For cultivar BR 305, drying favored tannin concentration in seeds collected in different development stages. The same occurred for cultivar BR 310 in seeds collected at 100, 103 and 119 days after sowing. For the enzyme profiles, increased activities of the enzyme alcohol dehydrogenase, malato dehydrogenase, catalase, a-amilase and catalase and esterase were observed in the seeds of the low tannin cultivar BR 310 and after drying