Abstract: Given the lack of information on the use of controlled-release fertilizers in yerba mate seedlings production, this study aimed to evaluate growth and morphological characteristics of seedlings produced with two controlled-release fertilizers applied at different doses. We used seeds from a clonal seed orchard, which were sown in a commercial substrate based on peat and vermiculite, with Osmocote® MiniPrill 3M (CRF 3M) and Basacote® Plus 9M (CRF 9M) fertilizers, both in doses of 0, 2, 4, 6, 8, 10, and 12 kg m-3. Seedling height and stem diameter were measured at 60, 90, 120, and 180 days after sowing and, at 180 days, shoot, root, and total biomass, tube withdrawal ease, and root aggregation. From these data, we calculated Dickson's quality index, technical efficiency, Height/Stem diameter ratio, and maximum technical efficiency dose. We verified values statistically superior to control treatment (0 kg m-3) in all variables in response to controlled-release fertilizer 3M and 9M, demonstrating the viability of yerba mate seedling production using controlled-release fertilizers. This is also evidenced through results obtained for growth in height and stem diameter. Although CRF 3M favored seedling growth, CRF 9M showed similar efficiency. The Osmocote® MiniPrill 3M is more efficient than Basacote® Plus 9M in most of the variables analyzed and has a lower input required to obtain quality seedlings. For these reasons, Osmocote® MiniPrill 3M is indicated to produce yerba mate seedlings in the dose 8.50 kg m-3.

Abstract The success of seedlings establishment for commercial planting and forest restoration depends on the availability of nutrients during seedlings production. The objective was to evaluate the efficiency in controlled-release fertilizer use in Cordyline spectabilis seedlings production and what is the additional cost per seedling produced. Seedling production was performed with doses of 0.0 (control); 2.5; 5.0; 7.5; 10.0 and 12.5 kg m-³ of Basacote® Plus 9M (16-08-12) controlled-release fertilizer added to the substrate. The experiment was placed in a greenhouse and we evaluated morphological parameters to determine seedlings growth. The dose of 10.7 kg m-3 provided a greater number of leaves (11.4) and leaf length (24.9 cm), higher values of shoot (4.64 g), root (2.32 g) and shoot root ratio (1.99) were obtained above 10.7 kg m-3 fertilizer. We recommend the use of 10.7 kg m-3 controlled-release fertilizer for seedlings production with an increase of R$ 0.05 per seedling produced.

Abstract This study aimed to verify the influence of accelerated aging test in the vigor of seeds of Mimosa tenuiflora (Willd.) Poiret. After the measurement of the biometric characteristics of seeds, the treatment to overcome dormancy was applied, which consisted in the use of water at 100ºC for 4 minutes. The accelerated aging test was conducted in a completely randomized design, with four replications of 50 seeds in each treatment. The seeds were artificially aged at 40, 43 and 46 ºC during 24, 48, 72 and 96 hours. The degree of humidity (8.51 %) is characteristic of orthodox seeds, this value increased as the time of permanence of the seeds in aging treatments. The germination percentage and the germination speed index showed significant reduction in seeds subjected to higher temperatures and times, although there is no significant increase in average time of germination. The frequency of germination was homogeneous in seeds that were subjected to 40 °C, the homogeneity decreases with increasing temperature and the period of artificial aging. The results suggest that Mimosa tenuiflora seed deterioration during accelerated ageing is closely related to a decrease in germination.

Resumo Objetivou-se verificar a influência do envelhecimento acelerado no vigor de sementes de Mimosa tenuiflora (Willd.) Poiret. Após avaliação da biometria das sementes, estas foram submetidas a tratamento para superação de dormência, que consistiu na aplicação de água a 100 ºC durante 4 minutos. O envelhecimento acelerado foi conduzido em delineamento inteiramente casualizado, com quatro repetições de 50 sementes em cada tratamento. Os tratamentos aplicados foram de 40 ºC, 43 ºC e 46ºC em 24, 48, 72 e 96 horas de permanência na câmara de envelhecimento. O grau de umidade inicial (8,51 %) é característico de sementes ortodoxas, este valor aumentou conforme o tempo de permanência das sementes na câmara de envelhecimento. A porcentagem e o índice de velocidade de germinação apresentaram redução significativa nos tratamentos com maiores temperaturas e tempos, apesar de não haver aumento significativo do tempo médio de germinação. A frequência de germinação foi mais homogênea nos tratamentos em que as sementes foram submetidas a 40 ºC, a homogeneidade diminui com o aumento da temperatura e do tempo de permanência na câmara. Isto evidencia a redução do vigor das sementes de Mimosa tenuiflora, possivelmente devido a degradação das mesmas pelas altas temperaturas e incidência de fungos.

SUMMARY: Jatropha mollissima is a species of the semiarid region of northeastern Brazil. It is known that individuals of the same species may present differences in seeds viability, thus it is necessary to define methodologies to evaluate the physiological potential of seeds. This study aimed at determining the best pre-moistening time and the concentration of the tetrazolium solution to evaluate the viability of J. mollissima seeds. Three pre-moistening times were tested (12, 14 and 16 hours) and two tetrazolium solution concentrations (0.25 and 0.5 %). As a comparative study, a germination test was performed, which consisted of two treatments: seeds between paper and on vermiculite. The values obtained in the tetrazolium test were similar, with average viable seeds of 21.3% for concentration 0.25 % and 27.3 % for the concentration of 0.5 %. It was observed, in the germination test, that the percentage of germination had averages equal to 22.5 % for the treatment between paper and 13.5 % for the treatment with vermiculite. The best procedure for performing the tetrazolium test in J. mollissima seeds is using the concentration of 0.25 % of tetrazolium solution, pre-moistening time of 16 hours, between paper at 25 ºC and staining for 4 hours at 40 °C in the dark.

RESUMEN: Jatropha mollissima es una especie que se encuentra en Caatinga, región semiárida del Nordeste Brasileño. Se sabe que los individuos de la misma especie pueden presentar diferencias en la viabilidad, por lo que es necesario definir metodologías para evaluar el potencial fisiológico de las semillas, especialmente para ajustar estándar de calidad. El objetivo de esta investigación fue determinar el mejor tiempo de humectación previa y la concentración de la solución de tetrazólio más adecuada para evaluar la viabilidad de las semillas de J. mollissima. Se probaron tres tiempos de humectación previa: 12, 14 y 16 h y dos concentraciones de solución de tetrazolio (0,25 y 0,5 %). A modo de comparación, se realizó una prueba de germinación con dos tratamientos: entre papel y vermiculita. Los valores obtenidos en los tres tiempos y en las dos concentraciones fueran similares, con semillas viables con un promedio de 21,3 % para 0,25 % y 27,3 % para 0,5 %. Se observó en la prueba de germinación que el porcentaje de germinación tenía promedios iguales a 22,5% para el tratamiento con papel y 13,5 % para el tratamiento con vermiculita. Se sugiere que el mejor procedimiento para realizar la prueba de tetrazolio en las semillas de Jatropha mollissima es usar una concentración de 0,25 % de sal de tetrazolio, 16 horas de tiempo de humectación previa, entre papel a 25 ºC y coloración por 4 horas a 40 ºC en la obscuridad.