Abstract Temperature may affect the mobilization and hydrolysis of storage reserves for energy production during seed germination. This study investigated germination performance and reserve mobilization in Dalbergia spruceana Benth. seeds incubation at 20, 25, 30, 35, and 40°C. The germination process was favored by incubation at 25 to 35°C and negatively affected at 20 and 40°C. At 35°C there reduction in germination speed, however, without significantly compromising the final germination percentage. The results showed that lipids and proteins are the predominant metabolites in D. spruceana seeds. Mobilization of soluble sugars was highest at 25 and 30°C. At 20 and 40°C, mobilization occurred more slowly, negatively affecting germination. This finding, combined with changes in lipid and protein reserves, suggests that lipid and protein hydrolysis products were used for starch synthesis. Reserve mobilization patterns in D. spruceana embryos were influenced by germination temperature, with the highest utilization efficiency occurring between 25 and 35°C.

Abstract Temperature may affect the mobilization and hydrolysis of storage reserves for energy production during seed germination. This study investigated germination performance and reserve mobilization in Dalbergia spruceana Benth. seeds incubation at 20, 25, 30, 35, and 40°C. The germination process was favored by incubation at 25 to 35°C and negatively affected at 20 and 40°C. At 35°C there reduction in germination speed, however, without significantly compromising the final germination percentage. The results showed that lipids and proteins are the predominant metabolites in D. spruceana seeds. Mobilization of soluble sugars was highest at 25 and 30°C. At 20 and 40°C, mobilization occurred more slowly, negatively affecting germination. This finding, combined with changes in lipid and protein reserves, suggests that lipid and protein hydrolysis products were used for starch synthesis. Reserve mobilization patterns in D. spruceana embryos were influenced by germination temperature, with the highest utilization efficiency occurring between 25 and 35°C.

Resumo: O estresse causado por temperatura pode ser mensurado pela atividade de enzimas antioxidantes e predizer a tolerância das espécies ao estresse térmico. Este trabalho investigou os efeitos da temperatura na germinação e atividade de enzimas antioxidantes em sementes de Dalbergia spruceana Benth. As sementes foram incubadas a temperaturas constantes de 20, 25, 30, 35 e 40 °C durante dez dias e avaliada a porcentagem de germinação, índice de velocidade de germinação, atividade de enzimas antioxidantes e condutividade elétrica. A temperatura afetou o processo germinativo das sementes, mas não a atividade das enzimas antioxidantes. Temperaturas entre 25 e 35 °C proporcionam o máximo percentual e velocidade de germinação, enquanto 20 e 40 °C geram os menores valores. A atividade da SOD se mostra indiferente às variações da temperatura e os níveis de atividades da CAT e da POX não permitem estabelecê-las como indicadoras de estresse térmico. O padrão crescente de vazamento de eletrólitos revelou tendência na perda da semipermeabilidade das membranas celulares, em temperaturas mais altas.

Abstract: Antioxidant enzyme activity can be used to measure heat stress and predict the tolerance of a species to heat stress. This study investigated the effects of temperature on germination and antioxidant enzyme activity in Dalbergia spruceana Benth. seeds. Seeds were incubated at constant temperatures of 20, 25, 30, 35, and 40 °C for ten days; and germination percentage, germination speed index, antioxidant enzyme activity, and electrical conductivity were evaluated. Temperature affected the seed germination process but not antioxidant enzyme activity. Germination percentage and germination speed index were higher at 25 and 35 °C and lower at 20 and 40 °C. Superoxide dismutase activity was not affected by temperature. Catalase and peroxidase activities were too low to be used as indicators of temperature stress. The pattern of increasing electrolyte leakage manifested a trend toward loss of cell membrane semipermeability at higher temperatures.

RESUMO O objetivo deste trabalho foi determinar a influência da procedência e da concentração do ácido indol-3-butírico (AIB) no enraizamento de estacas provenientes de mudas de paricá. As procedências testadas foram: Belém-PA, Tucuruí-PA e Sinop-MT das quais foram obtidas sementes e produzidas mudas para obtenção de estacas. As estacas foram imersas em solução de AIB nas concentrações de 0, 2.000 e 3.000 ppm durante 10 segundos e plantadas em bandejas plásticas contendo vermiculita e fibra de coco como substrato (1:1 v/v). O delineamento foi inteiramente ao acaso, em esquema fatorial 3 x 3 (procedências x concentração de AIB) com quatro repetições e dez estacas por parcela. Após 45 dias foram obtidos dados de percentagem de estacas enraizadas, número médio de raízes, comprimento da maior raiz, percentagem de estacas vivas sem formação de raiz, percentagem de estacas mortas e percentagem de estacas que emitiram brotos. A análise de variância indicou que não houve diferenças estatísticas significativas entre as procedências, porém, para a concentração verificou-se que as soluções a 2.000 e 3.000 ppm foram mais eficientes para enraizamento e desenvolvimento de raiz. A interação indicou comportamento diferencial entre procedências devido à procedência Sinop-MT ter apresentado comportamento inferior na ausência do AIB, contudo, com uma resposta superior às demais procedências quando da aplicação da solução de AIB. Nesse sentido, faz-se necessário definir concentrações mais adequadas para o enraizamento de estacas obtidas de diferentes procedências geográficas.

ABSTRACT This work aimed at determining the influence of the origin and of the concentration of Indole-3-butyric acid (IBA) over the rooting of paricá cuttings. The origins tested were: Belém (PA), Tucuruí (PA) and Sinop (MT). We obtained seeds from those locations and produced seedlings from which cuttings. The cutting were immersed in IBA solution in the concentrations of 0, 2000 and 3000 ppm (parts per million) for 10 seconds and planted in plastic trays containing vermiculite and coconut fiber as substrate (1:1 v/v). We employed a fully randomized delineation, in a factorial scheme of 3x3 (origins x IBA concentrations) with four repetitions and ten cuttings per part. After 45 days we measured the percentage of rooted cuttings, average number of roots, length of the longer root, percentage of rootless living cuttings, percentage of dead cuttings and percentage of cuttings that produced sprouts. The variance analysis suggested that there were no significant statistical difference between the origins. On the other hand, we verified that the solutions with concentrations of 2000 and 3000 ppm were more efficient for both rooting and root development. The interaction indicated a difference in behavior between the origins, since specimens from Sinop (MT) had lower performance without the IBA, but having a superior response, compared to the other origins, when immersed in the IBA solution. Therefore, it becomes necessary to define the proper concentrations for the rooting of cuttings coming from different geographical locations.