Germinação de sementes de Passiflora setacea e dormência induzida pelo armazenamento

Abstract

RESUMO -Objetivou-se nesse trabalho avaliar a germinação inicial de sementes de Passiflora setacea DC com diferentes níveis de umidade e após a conservação sob diferentes temperaturas. Foram utilizados tratamentos pré-germinativos com nitrato de potássio (KNO 3 ) e ácido giberélico (GA 3 ). A germinação foi conduzida em papel germitest embebido em água. O teste de tetrazólio foi empregado para verificar a viabilidade das sementes após os períodos de armazenamento. Foi possível verificar que: (i) as sementes de P. setacea podem ser desidratadas até atingir, aproximadamente 4,7% de água (base úmida) sem perda da capacidade de germinação; (ii) o armazenamento de sementes com baixo teor de água, a baixas temperaturas pode induzir a dormência de sementes de P. setacea; (iii) a dormência é superada pelo tratamento das sementes com ácido giberélico, até o quinto mês de armazenamento; (iv) as sementes conservadas sob temperaturas subzero apresentaram maior porcentagem de viabilidade em relação às armazenadas a 4 °C. Diante destes resultados, pode-se concluir que sementes de P. setacea podem ser conservadas por até 8 meses, sob baixas temperaturas, a -20 ou -196 °C, pois mantêm os padrões mínimos de viabilidade estabelecidos internacionalmente.Termos para indexação: maracujá do mato, viabilidade, conservação, ácido giberélico. GERMINATION OF Passiflora setacea SEEDS AND STORAGE INDUCED DORMANCYABSTRACT -The objective in this study was establish long-term conservation conditions for Passiflora setacea seeds by testing different seed moisture contents and storage temperatures. Seeds were treated with potassium nitrate (KNO 3 ) and gibberellic acid (GA 3 ) before germination in moistened paper towels. Seed viability was verified by the tetrazolium test after the seeds had been treated. It was observed that: (i) P. setacea seeds can be dried to approximately 4.7% of water content (fresh weight basis) without a significant reduction in germination, (ii) low temperatures and low water content induced dormancy in P. setacea seeds; (iii) dormancy could be overcome by seed treatment with gibberellic acid until the fifth month of storage; (iv) seeds maintained at subzero temperatures showed a higher viability compared to those stored at 4 °C. It was concluded that P. setacea seeds can be stored for up to eight months, at -20 or -196 °C, since they maintain the minimum international standards for viability.

Anti-oxidant activity of seedlings from rice seeds stored in different temperatures over 10 years

“…Researches with sunflower seeds have shown that storage at low temperatures (10 °C) occasioned the maintenance of seed quality compared with those stored at 25 °C, but the reduction in germination occurred independent of temperature after three months of storage (Abreu et al, 2011). Passiflora setacea seed maintains viability when stored at subzero temperatures for three months, but after the eighth month of storage the seeds not treated with gibberellic acid do not germinate and those treated with GA3 showed very low germination (3-15%) (Pádua et al, 2011).…”

Morphometry, in vitro-ex vitro germination and tetrazolium testing of stinking passionflower [Passiflora foetida var. glaziovii Killip] (Passifloraceae) seeds

“…Moreover, the lack of reference of TZ staining patterns for Passiflora makes it difficult to evaluate the results. In some studies in which the TZ test was performed to evaluate the viability of Passifloraceae seeds, such as in P. alata (Zucareli et al, 2003;Ferreira et al, 2005) and P. setacea (Pádua et al, 2011), no images were provided that could be used for comparison with other species, such as in the present study (P. foetida var. glaziovii).…”

“…When the hard seeds of P. alata were evaluated by the TZ test to determine the percentage of dormant and damaged seeds, viable seeds showed red or pink staining, whereas unviable seeds were milky-white or red (Zucareli et al, 2003). Pádua et al (2011) evaluated the seeds of P. setacea and observed that viable seeds showed pinkish colouration in at least half of the cotyledons and throughout the embryonic axis. These examples highlight the importance of standardisation and comparison between staining results.…”

Advances in passion fruit (Passiflora spp.) propagation

“…Besides the differences within species, there are differences between distinct accessions or cultivars in the same species (ALEXANDRE et al, 2004). Several other factors also influence seed germination and storage, including quality and physiological maturity (NEGREIROS et al, 2006), presence or absence of dormancy (PÁDUA et al, 2011;SANTOS et al, 2012a;REGO et al, 2014) and different methods of seed extraction, processing and storage (PEREIRA e DIAS, 2000;OSIPI et al, 2011;MELETTI et al, 2007;PÁDUA et al, 2011).…”