Germinação de sementes de Citharexylum pernambucense Moldenke e de Vachellia farnesiana (L.) Wight & Arn.

Abstract

This study aimed to define procedures for analysis of seed germination of species from the Atlantic Forest biome, Citharexylum pernambucense Moldenke (willow) and Vachellia farnesiana (L.) Wight & Arn. (butt). With seeds collected in Lagoa dos Gatos / PE and the Archipelago of Fernando de Noronha / PE, experiments were carried out in two stages, the first being an initial test and the second a definitive experiment. In the first step were tested treatments pre-germination and vermiculite paper towel type germitest at room temperature of 20 ° C overnight to 25 ° C during the day. The statistical design was completely randomized in a factorial 3 x 3 (3 pre-germination treatments and 3 substrates) for the species and willow, 4 x 3 (4 pre-germination treatments and 3 substrates) for the species stock. Using four replicates of 25 seeds was evaluated the germination capacity through the formation of the number of normal seedlings and germination speed index (GSI). In the second step, using the preferred method of breaking the dormancy and the best substrate, we tested the effect of temperature and light, using the incubators greenhouses BOD (Biochemical Oxygen Demand) and Mangelsdorf, with constant temperatures (20, 25, 30 and 35 º C) and presence and absence of light. Count was conducted daily directly observed the radicle emission and the formation of normal seedling. For the species C. pernambucense, the seeds were placed in vermiculite, and the best results of germination, root length and shoot, weight of fresh and dry mass occurred at a temperature of 25 ° C in the presence of light, showing that light is a factor essential for germination and early seedling development. For species V. farnesiana, the substrate was sand, resulting in a high percentage of germination in the presence of light, at temperatures of 20, 25 and 30 ° C. Seeds subjected to an environment with no light showed no germination. At temperatures of 20, 25 and 30 ° C, the higher root growth in seedlings were in an environment without light, but does so with the shoot length, whose best results occurred in an environment with light. On the weight of fresh and dry weight of seedlings with and without cotyledons, temperatures of 25 to 30 ° C provided the best results with more vigorous seedlings under laboratory conditions. As V. farnesiana has germination epigeal-foliaceous, their cotyledons are photosynthetic function, light is essential to the formation and initial development of these seedlings.