Superação da dormência em sementes de mutamba (guazuma ulmifolia lam. - sterculiaceae)

Sobrinho, Severino de Paiva; Siqueira, Aline Gonçalves; Morais, Petrina de Bessa; Silva, Sérgio José da

doi:10.1590/s0100-67622012000500001

Cited by 7 publications

(4 citation statements)

References 17 publications

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“…As this species has primary dormancy (Araújo-Neto and Aguiar, 2000; Paiva Sobrinho et al, 2012), the seeds were scarified with hot water at 100 o C for 5 min in order to overcome seeds dormancy (Carvalho, 2007). For the germination bioassays, 5.0 mL of each solution, at concentrations of 0, 250, 500 and 1,000 mg L -1 , were poured onto autoclaved Whatman no.…”

Section: Germination Bioassaysmentioning

confidence: 99%

Can Allelopathic Grasses Limit Seed Germination and Seedling Growth of Mutambo? A Test with Two Species of Brachiaria Grasses

et al. 2016

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-Tree establishment in pasture areas can be inhibited, at least in part, by exotic grasses allelopathy and this can represent an important limitation by changing the patterns of both germination and seedling growth of tree species. This study aims to evaluate the allelopathic potential of Urochloa brizantha and U. decumbens on germination, growth and metabolism of Guazuma ulmifolia seedlings. We performed bioassays evaluating the effect of the crude ethanol extract and semipurified fractions (hexane fraction, ethyl acetate fraction and ethanol-water fraction) of U. brizantha and U. decumbens using completely randomized design, with four concentrations (0, 250, 500, 1,000 mg L -1) and four replications. The variables analyzed were germination percentage, mean germination time, shoot and root growth, catalase and peroxidase activity, chlorophyll content and root respiration. The results showed that both grasses have an inhibitory effect on G. ulmifolia metabolism, affecting both germination and seedlings growth and inducting metabolic defense. Thus, these results show that the grass species evaluated have the potential to restrict the re-introduction of G. ulmifolia in pasture areas due to interference competition.Keywords: Guazuma ulmifolia, interference competition, exotic grasses, direct sowing, restoration, Urochloa. RESUMO -O estabelecimento

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Section: Germination Bioassaysmentioning

confidence: 99%

Can Allelopathic Grasses Limit Seed Germination and Seedling Growth of Mutambo? A Test with Two Species of Brachiaria Grasses

et al. 2016

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“…Guazuma ulmifolia has more orthodox seeds that possess physical dormancy ( Araújo Neto and Aguiar 2000 ; Sobrinho et al 2012 ). This explains the low germination of Amazonian and Cerrado seeds of this species in the present experiments.…”

Section: Discussionmentioning

confidence: 99%

Flood tolerance in two tree species that inhabit both the Amazonian floodplain and the dry Cerrado savanna of Brazil

et al. 2018

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Comparing plants of the same species thriving in flooded and non-flooded ecosystems helps to clarify the interplay between natural selection, phenotypic plasticity and stress adaptation. We focussed on responses of seeds and seedlings of Genipa americana and Guazuma ulmifolia to substrate waterlogging or total submergence. Both species are commonly found in floodplain forests of Central Amazonia and in seasonally dry savannas of Central Brazil (Cerrado). Although seeds of Amazonian and Cerrado G. americana were similar in size, the germination percentage of Cerrado seeds was decreased by submergence (3 cm water) and increased in Amazonian seeds. The seeds of Amazonian G. ulmifolia were heavier than Cerrado seeds, but germination of both types was unaffected by submergence. Three-month-old Amazonian and Cerrado seedlings of both species survived 30 days of waterlogging or submersion despite suffering significant inhibition in biomass especially if submerged. Shoot elongation was also arrested. Submersion triggered chlorosis and leaf abscission in Amazonian and Cerrado G. ulmifolia while waterlogging did so only in Cerrado seedlings. During 30 days of re-exposure to non-flooded conditions, G. ulmifolia plants that lost their leaves produced a replacement flush. However, they attained only half the plant dry mass of non-flooded plants. Both submerged and waterlogged G. americana retained their leaves. Consequently, plant dry mass after 30 days recovery was less depressed by these stresses than in G. ulmifolia. Small amounts of cortical aerenchyma were found in roots 2 cm from the tip of well-drained plants. The amount was increased by flooding. Waterlogging but not submergence promoted hypertrophy of lenticels at the stem base of both species and adventitious rooting in G. ulmifolia. Despite some loss of performance in dryland plants, flood tolerance traits were present in wetland and dryland populations of both species. They are part of an overall stress-response potential that permits flexible acclimation to locally flooded conditions.

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“…(LOPES et al, 1998), tratamento térmico para sementes de Guazuma ulmifolia Lam. (SOBRINHO et al, 2012), entre outras. A escarificação mecânica é uma técnica simples, eficaz e de baixo custo, assim como a imersão em água em diferentes temperaturas, com ou sem escarificação das sementes (BRASIL, 2009).…”

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SUPERAÇÃO DA DORMÊNCIA DE SEMENTES DE <i>Sapindus saponaria</i> L.

et al. 2018

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Sapindus saponaria L. (Sapindaceae) é uma espécie nativa do Brasil utilizada na recuperação de áreas degradadas e detém propriedades medicinais, mas a dormência das suas sementes dificulta a germinação e a obtenção de plântulas de forma rápida. O presente estudo teve por objetivo avaliar a eficiência de diferentes métodos na superação da dormência de sementes de Sapindus saponaria. Os tratamentos para a superação da dormência das sementes foram: testemunha - sementes intactas; imersão em ácido sulfúrico concentrado (H2SO4 96% P.A) por 60, 70, 80 e 90 minutos; imersão em ácido sulfúrico concentrado por 60, 70, 80 e 90 minutos seguido de embebição em água destilada à temperatura ambiente por 12, 24 e 36 horas; imersão em água a 70°C por 10 e 15 minutos seguida de exposição em geladeira (6°C) por 30 minutos; imersão em água a 70°C por 10 e 15 minutos seguida de exposição em freezer (-18°C) por 30 minutos; choque térmico mediante a exposição das sementes em estufa de circulação forçada de ar regulada a 70°C por 5, 10 e 15 minutos seguida de transferência para geladeira e freezer durante 30 minutos. Para fins de comparação entre os tratamentos foram avaliados a porcentagem de emergência, velocidade e primeira contagem de emergência, comprimento de parte aérea e raiz primária, massa seca de parte aérea e raízes. A imersão das sementes em ácido sulfúrico por 80 minutos seguida de embebição em água por 24 horas é eficiente para superar a dormência, acelerar e promover a emergência e crescimento das plântulas de Sapindus saponaria.

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Superação da dormência em sementes de mutamba (guazuma ulmifolia lam. - sterculiaceae)

Cited by 7 publications

References 17 publications

Can Allelopathic Grasses Limit Seed Germination and Seedling Growth of Mutambo? A Test with Two Species of Brachiaria Grasses

Can Allelopathic Grasses Limit Seed Germination and Seedling Growth of Mutambo? A Test with Two Species of Brachiaria Grasses

Flood tolerance in two tree species that inhabit both the Amazonian floodplain and the dry Cerrado savanna of Brazil

SUPERAÇÃO DA DORMÊNCIA DE SEMENTES DE <i>Sapindus saponaria</i> L.

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