Francisco Carlos Barboza Nogueira

Caracterização da germinação e morfologia de frutos, sementes e plântulas de Dalbergia cearensis Ducke (pau-violeta) - Fabaceae

This study describes and illustrates the morphological characteristics of fruits, seeds, early stages of germination and seedlings of Dalbergia cearensis for the first 28 days after sowing. The fruit, which is supported by a 3-5 mm stipe, is a dry, indehiscent samara, oblong with acute base and apex, 1-seeded, flat, with a central seminiferous nucleus, thin pericarp, aliform, slightly reticulate. The seed is exalbuminous, oblong, flat, reniform, with a smooth seed coat; it is a brownish color when ripe. Germination is epigeous, with the tegument adhering to the cotyledons in the initial seedling growth phase; it begins on the third day after sowing in laboratory conditions. Mean germination of 70% was observed at 14 days. On day 28 after sowing, seedlings had an axial root system, a pivotal main root, 231.54 mm long, cylindrical, flexible, yellowish-white. The seedlings are classified as phanero-epigeal-reserve (PER) type.

Fenologia de Dalbergia cearensis Ducke (Fabaceae) em um fragmento de floresta estacional, no semiárido do Nordeste, Brasil

In general, tree species that occur in the Caatinga vegetation in the Brazilian semiarid of the northeastern region, have their phenophases (flowering, fruiting and foliage change) conditioned by the duration and intensity of seasonal drought. This study records the phenology of leaf-fall, leaf incision, flowering and fruit production of 32 Dalbergia cearensis Ducke individuals. Samples were collected every 15 days from 2009 to 2011 at the Unidade de Conservacao de Uso Sustentavel Fazenda Nao me Deixes, a conservation area in the Brazilian semiarid. The frequency of occurrence of the phenophases was related to the elements of climate (average monthly rainfall, monthly average temperature, monthly average insolation and soil water availability). The vegetative phenology, leaf fall and sprouting of new leaves, followed the seasonality of rainfall during the dry and rainy seasons. The flowering and fruiting occurred at the beginning of the rains, and the diaspores of D. cearensis were scattered throughout the year after they broke off slowly from the compact axillary panicles.

Efeito da temperatura e luz na germinação de sementes de Luetzelburgia auriculata (Alemão) Ducke - Fabaceae

Luetzelburgia auriculata (Alemao) Ducke e uma especie arborea nativa do Brasil, pertencente a familia das Fabaceae, importante pela utilidade economica de sua madeira na construcao civil, marcenaria e producao de lenha e carvao. O experimento foi conduzido em laboratorio para avaliar o processo germinativo de suas sementes, na ausencia e presenca de luz, submetido as temperaturas constantes de 20, 25, 30, 35, 40 °C e alternada de 20-40 °C, sob fotoperiodo de 12 horas e escuro continuo. As variaveis avaliadas foram porcentagem, velocidade e tempo medio de germinacao. As sementes germinaram na presenca e na ausencia de luz, com as maiores medias alcancadas em 20-40 °C, 20 °C, 25 °C, 30 °C e 35 °C e as menores em 40 °C. Suas sementes sao indiferentes a luz. A faixa otima de temperatura entre 25 a 30 °C possibilitou alta germinabilidade e menor tempo medio de germinacao.

The effect of the temperature and light on the seed germination of Dalbergia cearensis Ducke

The knowledge about the germination behavior of a plant species is major important to the adoption of the techniques that aim its spreading. The work analyzed the seed germination process of Dalbergia cearensis Ducke in the presence and absence of light, that was subjected to constant temperatures of 20, 25, 30, 35, 40 oC and alternating temperatures of 20 - 45 oC, all under a photoperiod of 12 hours and continuous darkness. The variables evaluated were: the percentage, the speed and the medium time of the germination. The seeds germinated in the presence and absence of light and the higher percentages of germination were 25, 30 and 35 oC. Thus, to trigger the germination process of this species, there is no need of exposure or absence of light. So they can be characterized as neutral photoblastic seeds. No germination was observed at alternating temperatures of 20 oC to 45 oC. The optimum temperature range between 25 to 35 oC increases speed and reduces the average time of germination of Dalbergia cearensis for both the dark and for light.

EFEITO DA TEMPERATURA E LUZ NA GERMINAÇÃO DE SEMENTES DE Dalbergia cearensis Ducke

The knowledge about the germination behavior of a plant species is major important to the adoption of the techniques that aim its spreading. The work analyzed the seed germination process of Dalbergia cearensis Ducke in the presence and absence of light, that was subjected to constant temperatures of 20, 25, 30, 35, 40 oC and alternating temperatures of 20 - 45 oC, all under a photoperiod of 12 hours and continuous darkness. The variables evaluated were: the percentage, the speed and the medium time of the germination. The seeds germinated in the presence and absence of light and the higher percentages of germination were 25, 30 and 35 oC. Thus, to trigger the germination process of this species, there is no need of exposure or absence of light. So they can be characterized as neutral photoblastic seeds. No germination was observed at alternating temperatures of 20 oC to 45 oC. The optimum temperature range between 25 to 35 oC increases speed and reduces the average time of germination of Dalbergia cearensis for both the dark and for light.