Aurélio Rubio Neto
Abstract:
The several uses of palm trees, and especially the oleaginous potential of Arecaceas, has aroused great economic interest. Among these plants stands out macaúba, with high oil content in seeds and great productive capacity. However, the main form of propagation of this plant, that is, the sexual propagation needs studies, since the seed germination is slow, uneven and occurs in low percentages. For this purpose, the effect of different water contents of seeds and fruits obtained through drying or soaking, the effect of different types of scarification and the effect of different application forms and concentrations of gibberellic acid were evaluated. It was evidenced that in fruits the loss of water is drastic until the fifteenth day of drying, being more intense at the beginning of the drying period. In seeds, dehydration was slow in all drying periods evaluated. Seed extraction is facilitated by drying the fruits for up to nine days, without loss of viability of the embryos. Using simple linear regression it was possible to estimate seed water content based on fruit water content. Soaking seeds in distilled water favored the increase of dead seeds contaminated by microorganisms. Mortality of scarified seeds kept in germination occurred in low percentages, but in greenhouse this number was above 50% when thermal scarification was used in hot water for 2 minutes and sulfuric acid for 4 minutes. Physical scarification, removing the seed coat in the hilum region, substantially favored germination of seeds kept in germination and seedling emergence in a greenhouse, constituting the most suitable scarification type for overcoming dormancy in this species. The use of gibberellic acid for up to 200mg.L-1 is not recommended, regardless of its application.
