Abstract:4RESUMO -Caesalpinia leiostachya (Benth.) Ducke (pau-ferro) é uma leguminosa arbórea nativa do Brasil, cujas sementes são de diferentes tamanhos e formas, apresentando dormência imposta pela impermeabilidade do tegumento à água. Objetivando melhorar a qualidade do lote, as sementes foram classificadas pela largura em peneiras de crivos circulares (números 13, 14, 15, 16 e 17) e a seguir separadas manualmente pela forma em alongadas, arredondadas e angulares. Foi determinada a massa de 1.000 sementes, medida a … Show more
“…Studies with larger seed species showed positive results in overcoming coat dormancy with the use of sulfuric acid, as in Leucena diversifolia (Souza et al, 2007), Caesalpinia leiostachya (Biruel et al, 2010), and Colubrina glandulosa (Brancalion et al, 2011). These researchers observed that a successful treatment is related to the species and acid exposure time.…”
-The objective of this study was to identify the most efficient method for overcoming coat-imposed dormancy and determine the optimal germination temperature for Ornithopus pinnatus seeds. Treatments to overcome dormancy were: intact seeds; immersion in hot water at 60 ºC, followed by soaking in the same water (unheated)/24 h; immersion in hot water at 90 ºC, followed by soaking in the same water (unheated)/24 h; mechanical scarification; chemical scarification, H 2 SO 4 /5 min; and chemical scarification, H 2 SO 4 /10 min. Percentages were calculated for germinated, abnormal, dormant, and dead seeds. Optimal germination temperatures were calculated using eight constant temperatures (0, 5, 10, 15, 20, 25, 30, and 35 °C), with 8 h of light and 16 h of darkness. Germination rate, frequency, and synchronization index of germination were used as parameters to establish optimum temperature for germination. A completely randomized experimental design was used, with twelve repetitions of 100 seeds per treatment. Data obtained were subjected to analysis of variance and Tukey's test at a 5% significance level. O. pinnatus seeds exhibit dormancy caused by the seed coat's impermeability to water. Mechanical scarification was efficient in promoting seed germination. The species is stenothermal, meaning it cannot tolerate significant temperature variations. The germination rate of seeds was linearly dependent on temperature. Synchronization of the germination process is greater in the optimum temperature range, established between 15 and 20 °C.
“…Studies with larger seed species showed positive results in overcoming coat dormancy with the use of sulfuric acid, as in Leucena diversifolia (Souza et al, 2007), Caesalpinia leiostachya (Biruel et al, 2010), and Colubrina glandulosa (Brancalion et al, 2011). These researchers observed that a successful treatment is related to the species and acid exposure time.…”
-The objective of this study was to identify the most efficient method for overcoming coat-imposed dormancy and determine the optimal germination temperature for Ornithopus pinnatus seeds. Treatments to overcome dormancy were: intact seeds; immersion in hot water at 60 ºC, followed by soaking in the same water (unheated)/24 h; immersion in hot water at 90 ºC, followed by soaking in the same water (unheated)/24 h; mechanical scarification; chemical scarification, H 2 SO 4 /5 min; and chemical scarification, H 2 SO 4 /10 min. Percentages were calculated for germinated, abnormal, dormant, and dead seeds. Optimal germination temperatures were calculated using eight constant temperatures (0, 5, 10, 15, 20, 25, 30, and 35 °C), with 8 h of light and 16 h of darkness. Germination rate, frequency, and synchronization index of germination were used as parameters to establish optimum temperature for germination. A completely randomized experimental design was used, with twelve repetitions of 100 seeds per treatment. Data obtained were subjected to analysis of variance and Tukey's test at a 5% significance level. O. pinnatus seeds exhibit dormancy caused by the seed coat's impermeability to water. Mechanical scarification was efficient in promoting seed germination. The species is stenothermal, meaning it cannot tolerate significant temperature variations. The germination rate of seeds was linearly dependent on temperature. Synchronization of the germination process is greater in the optimum temperature range, established between 15 and 20 °C.
“…That result may have occurred due to the greater amount of the reserves present in the medium and large-sized seeds. The seeds with greater reserve germinate more uniformly and at a higher percentage and seedling vigor is directly related to seed size, which justifies the adoption of size classes for the production of seedlings (Biruel, Paula, & Aguiar, 2010). Such results are of great relevance, since the production of seedlings in a short period of time is desirable as far as agronomic issues and those related to cost reduction are concerned.…”
The fruit plant ‘Longan’ is considered as being native to Asia and is at present commercially explored in some regions. The objective of this work was to study the influence of seed size on seed emergence and initial seedling growth. The experiment was carried out using a randomized block design (DBC), with three treatments, namely, the seed sizes at seedling emergence according to their longitudinal diameter: small, medium and large. Each plot was composed of six seeds and five replications per treatment. The following characteristics were evaluated: emergence speed index, average time, percentage and relative frequency of emergence, leaf number, stem diameter, plant height, shoot dry mass and root dry mass. Seeds of medium and large size are those that presented satisfactory results for the characteristics related to seed emergence. The same ones stood out in relation to the small seeds for the variables percentage, average time, average speed and emergence speed index. Small seeds are not recommended for the production of ‘Longan’ seedlings, given the long period of time to emerge and the low probability of the seedlings establishing satisfactorily in the field. The medium and large seeds were the most promising for the variables number of leaves, stem diameter, plant height, dry shoot mass and dry root mass.Therefore, according to the conditions in which the present work was conducted, the use of medium and large seeds for the production of ‘Longan’ seedlings is suggested.
“…Autores como Malcolm et al (2003), Biruel et al (2010); Alves et al (2005) verificaram que as sementes mais pesadas germinaram de forma mais uniforme e em maior percentual e que o vigor das plântulas encontra-se diretamente relacionado com o tamanho das sementes o que para estes autores justifica a adoção de classes de tamanho para a produção de mudas. Para os tempos de embebição verificou-se que as sementes pequenas a partir de 24 horas de embebição apresentaram um desenvolvimento mais pronunciado do sistema radicular.…”
Neste trabalho, objetivou-se determinar o efeito do tempo de embebição e do tamanho das sementes na germinação e no crescimento inicial de plântulas de Anacardium microcarpum Ducke (cajuí). Para tal, um ensaio foi conduzido em arranjo fatorial 2 x 5, utilizando-se dois tamanhos de sementes (grandes e pequenas) e cinco tempos de embebição (0, 12, 24, 48, 96 h) dispostos num delineamento inteiramente casualizado com quatro repetições de 50 sementes cada. O ensaio foi conduzido no Laboratório de Análise de Sementes do Departamento de Fitotecnia do CCA/UFC. A semeadura foi realizada em canteiro de alvenaria tendo como substrato areia. As avaliações foram realizadas aos 60 dias após a semeadura. As variáveis analisadas foram: percentagem de germinação (%G), altura da planta (AP), número de folhas (NF), diâmetro do caule (DC), comprimento da raiz (CR), massa seca da parte aérea (MSPA) e do sistema radicular (MSSR). Os dados das variáveis estudadas foram submetidos à análise de variância e os resultados expressos em gráficos. Houve diferença significativa dos efeitos principais e da interação para todas as variáveis estudadas. Percebeu-se que as plantas provenientes de sementes grandes mostraram-se com maior vigor, sendo este fato comprovado pelos resultados expressos pelas variáveis estudadas. Conclui-se que sementes grandes e os maiores tempos de embebição influenciaram positivamente a germinação e o desenvolvimento inicial de cajuí.
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